1
|
Aleman J, Ravikumar K, Wiegand C, Schurdak ME, Vernetti L, Gavlock D, Reese C, DeBiasio R, LaRocca G, Angarita YD, Gough A, Soto-Gutierrez A, Behari J, Yechoor V, Miedel MT, Stern AM, Banerjee I, Taylor DL. A metabolic-dysfunction associated steatotic liver acinus biomimetic induces pancreatic islet dysfunction in a coupled microphysiology system. bioRxiv 2024:2024.04.22.590598. [PMID: 38712135 PMCID: PMC11071380 DOI: 10.1101/2024.04.22.590598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Preclinical and clinical studies suggest that lipid-induced hepatic insulin resistance is a primary defect that predisposes to dysfunction in pancreatic islets, implicating a perturbed liver-pancreas axis underlying the comorbidity of T2DM and MASLD. To investigate this hypothesis, we developed a human biomimetic microphysiological system (MPS) coupling our vascularized liver acinus MPS (vLAMPS) with primary islets on a chip (PANIS) enabling MASLD progression and islet dysfunction to be quantitatively assessed. The modular design of this system (vLAMPS-PANIS) allows intra-organ and inter-organ dysregulation to be deconvoluted. When compared to normal fasting (NF) conditions, under early metabolic syndrome (EMS) conditions, the standalone vLAMPS exhibited characteristics of early stage MASLD, while no significant differences were observed in the standalone PANIS. In contrast, with EMS, the coupled vLAMPS-PANIS exhibited a perturbed islet-specific secretome and a significantly dysregulated glucose stimulated insulin secretion (GSIS) response implicating direct signaling from the dysregulated liver acinus to the islets. Correlations between several pairs of a vLAMPS-derived and a PANIS-derived secreted factors were significantly altered under EMS, as compared to NF conditions, mechanistically connecting MASLD and T2DM associated hepatic factors with islet-derived GLP-1 synthesis and regulation. Since vLAMPS-PANIS is compatible with patient-specific iPSCs, this platform represents an important step towards addressing patient heterogeneity, identifying complex disease mechanisms, and advancing precision medicine.
Collapse
|
2
|
Mohamed Ghouse MA, Ravikumar K, Maruthamuthu G, Murugan B. A rare case of colonic diverticulum in a Bitch. Iran J Vet Res 2023; 24:157-161. [PMID: 37790114 PMCID: PMC10542875 DOI: 10.22099/ijvr.2023.46410.6663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 06/04/2023] [Accepted: 06/17/2023] [Indexed: 10/05/2023]
Abstract
Abstract. Background Colonic diverticulum is one of the rare findings in dogs characterized by an out-pouching of mucosal and submucosal layers through the defect in muscularis layer of the colon. Case description A five years old intact female Labrador was presented with an anamnesis of dyschezia and tenesmus. Findings/treatment and outcome Rectal examination was normal, and the survey radiograph showed an almost crescent shaped abnormal dilatation (10.52 cm × 6.21 cm) with gas and increased radiopaque material, dorsal to the urinary bladder and ventral to the descending colon suggesting fecal stasis. Ultrasonographic examination revealed gas-filled out-pouching with hyperechoic colon wall and acoustic shadowing. Exploratory celiotomy confirmed the diagnosis of colonic diverticulum, and diverticulectomy was performed. All four layers of the colonic wall were detected histopathologically in the biopsy sample and excluded neoplasia. The dog recovered uneventfully with no post-operative complications. Conclusion This surgery produced an excellent resolution of clinical signs. To our knowledge, this is one of the few cases of colonic diverticulum reported in dogs.
Collapse
Affiliation(s)
- M. A. Mohamed Ghouse
- Department of Clinics, Madras Veterinary College, Tamil Nadu Veterinary and Animal Sciences University (TANUVAS), Chennai, Tamil Nadu, India
| | - K. Ravikumar
- Veterinary Dispensary, Devakottai, Sivagangai-630 302, Tamil Nadu, India
| | - G. Maruthamuthu
- Department of Clinics, Madras Veterinary College, Tamil Nadu Veterinary and Animal Sciences University (TANUVAS), Chennai, Tamil Nadu, India
| | - B. Murugan
- Department of Clinics, Madras Veterinary College, Tamil Nadu Veterinary and Animal Sciences University (TANUVAS), Chennai, Tamil Nadu, India
| |
Collapse
|
3
|
Vinod M, Malashree G, Goud ES, Ravikumar K. Dexmedetomidine as an adjuvant to 0.25% bupivacaine in ultrasound guided femoral nerve block for preoperative positioning and postoperative analgesia in patients undergoing elective surgery for fracture shaft of femur. Anesth Essays Res 2022; 16:98-103. [PMID: 36249150 PMCID: PMC9558656 DOI: 10.4103/aer.aer_152_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/12/2022] [Accepted: 02/09/2022] [Indexed: 11/04/2022] Open
Abstract
Background: Femur fracture causes excruciating pain and surgical repair is recommended. To obtain satisfactory patient co-operation in the perioperative period, various analgesics have been used. Femoral nerve block (FNB) provides an excellent alternative for analgesia in the perioperative period. Dexmedetomidine of up to 2 μg.kg−1 has been used in FNB as adjuvants in lower limb surgeries. Aims: The aim was to study the effect of addition of Dexmedetomidine to Bupivacaine in FNB on the comfort of positioning for subarachnoid block (SAB) and postoperative analgesia. Materials and Methods: Prospective, randomized, double-blind design was followed. Seventy American Society of Anesthesiologist I and II patients aged 18–70 years of either gender were randomly allocated into Group B (20 mL 0.25% Bupivacaine + 2 mL Normal Saline) and Group BD (received 20 mL 0.25% Bupivacaine + Dexmedetomidine 2 μg.kg−1 diluted to 2 mL) for FNB. Numerical rating scale (NRS) was recorded before and after FNB and comfort of positioning graded. After 10 min, subarachnoid block (SAB) was administered. NRS was recorded postoperatively until 24 h. Results: The comfort of positioning improved in both the groups after FNB but was statistically not significant when compared among the groups (P = 0.7). Duration of postoperative analgesia was significantly higher in the Group BD (741 min ± 97 min) compared to the Group B (440 min ± 45 min) (P = 0.001) and was statistically significant. Conclusion: FNB improved the comfort of positioning for SAB, but the addition of Dexmedetomidine did not have any added advantages with respect to comfort of positioning. However, the addition of Dexmedetomidine significantly increased the duration of postoperative analgesia with minimal hemodynamic changes.
Collapse
|
4
|
Krishnan VG, Elango P, Ravikumar K, Marnadu R, Aldossary OM, Ubaidullah M. Noticeable improvement in the toxic gas-sensing activity of the Zn-doped TiO 2 films for sensing devices. NEW J CHEM 2021. [DOI: 10.1039/d1nj01079d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sensing element view, sening mechanism, stability, response and recovery time of the Zn-doped TiO2 films.
Collapse
Affiliation(s)
- V. Gopala Krishnan
- Department of Physics
- Dr N.G.P. Arts and Science College
- Coimbatore - 641048
- India
| | - P. Elango
- Department of Physics
- Government Arts College
- Coimbatore - 641018
- India
| | - K. Ravikumar
- Department of Physics
- Vivekanandha College of Arts and Science for Women
- Tiruchengode-673205
- India
| | - R. Marnadu
- Department of Physics
- Sri Ramakrishna Mission Vidyalaya College of Arts and Science
- Coimbatore-641 020
- India
| | - Omar M. Aldossary
- Department of Physics and Astronomy, College of Science
- King Saud University
- Riyadh 11451
- Saudi Arabia
| | - Mohd Ubaidullah
- Department of Chemistry
- College of Science
- King Saud University
- Riyadh 11451
- Saudi Arabia
| |
Collapse
|
5
|
Richardson T, Wiegand C, Adisa F, Ravikumar K, Candiello J, Kumta P, Banerjee I. Engineered peptide modified hydrogel platform for propagation of human pluripotent stem cells. Acta Biomater 2020; 113:228-239. [PMID: 32603868 DOI: 10.1016/j.actbio.2020.06.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 06/19/2020] [Accepted: 06/23/2020] [Indexed: 12/24/2022]
Abstract
Human pluripotent stem cells (hPSCs) have enormous potential to alleviate cell needs for regenerative medicine, however these cells require expansion in cell colonies to maintain cell-cell contact, thus limiting the scalability needed to meet the demands of cell therapy. While the use of a Rho-associated protein kinase (ROCK) inhibitor will allow for culture of single cell hPSCs, typically only 50% of cells are recovered after dissociation. When hPSCs lose cell-cell contact through E-cadherin, dissociation induced apoptosis occurs. In this study, we hypothesized that the extracellular E-cadherin domain of hPSCs will bind to synthetic E-cadherin peptides presented on a hydrogel substrate, mimicking the required cell-cell contact and thereby retaining single-cell viability and clonogenicity. Hence, the objective of this study was to functionalize alginate hydrogels with synthetic peptides mimicking E-cadherin and evaluate peptide performance in promoting cell attachment, viability, maintaining pluripotency, and differentiation potential. We observed that alginate conjugated with synthetic E-cadherin peptides not only supported initial cell attachment with high viability, but also supported hPSC propagation and high fold expansion. hPSCs propagated on the peptide modified substrates maintained the hPSC characteristic pluripotency and differentiation potential, characterized by both spontaneous and directed differentiation. STATEMENT OF SIGNIFICANCE: Human pluripotent stem cells (hPSCs) have enormous potential to alleviate cell needs for regenerative medicine and cell therapy. However, scalable culture of hPSCs is challenged by its need for maintenance of cell-cell contact, dissociation of which triggers the apoptotic pathway. Hence hPSCs are commonly maintained as colonies over Matrigel coated culture plates. Furthermore, use of xenogenic and undefined Matrigel compromises the translational potential of hPSCs. In this work we have developed a completely defined substrate to enable adherent culture of hPSCs as single cells. This substrate prevents apoptosis of the single cells and allows significant fold expansion of hPSCs while maintaining pluripotency and differentiation potential. The developed substrate is expected to be a cost-effective and translatable alternative to Matrigel.
Collapse
Affiliation(s)
- Thomas Richardson
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, United States
| | - Connor Wiegand
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, United States
| | - Fatimah Adisa
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, United States
| | - K Ravikumar
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, United States
| | - Joe Candiello
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, United States
| | - Prashant Kumta
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, United States; Department of Bioengineering, University of Pittsburgh, United States; McGowan Institute for Regenerative Medicine, United States
| | - Ipsita Banerjee
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, United States; Department of Bioengineering, University of Pittsburgh, United States; McGowan Institute for Regenerative Medicine, United States.
| |
Collapse
|
6
|
Ramakrishnan KM, Ramachandran B, Ravikumar KG, Ravikumar K, Putli S, Jayaraman V, Mathivanan T, Ravi R, Gnanamani S, Babu M. Electrical injury in pediatric patients – A case series. Indian J Burns 2020. [DOI: 10.4103/ijb.ijb_27_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
7
|
Ansar EB, Ravikumar K, Suresh Babu S, Fernandez FB, Komath M, Basu B, Harikrishna Varma PR. Inducing apatite pre-layer on titanium surface through hydrothermal processing for osseointegration. Mater Sci Eng C Mater Biol Appl 2019; 105:110019. [PMID: 31546429 DOI: 10.1016/j.msec.2019.110019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 03/21/2019] [Accepted: 07/25/2019] [Indexed: 12/29/2022]
Abstract
Commercially available titanium (Ti) having high mechanical strength and a low area of cross-section can be adequately exploited for minimally invasive dental implantation. Current directions in clinical dental implant therapy focus on endosseous dental implant surfaces with nanoscale topographies using easy and economical processing approaches. The present study describes the generation of a novel nanolayer nucleating agent on the surface of Ti implant for early endosseous after implantation. The strategy is to modify the surface of Ti implant using Ca(OH)2 via hydrothermal technique (Ti-HT). The X-ray photoelectron spectroscopy analysis confirmed the presence of chemically bonded Ca ions on the Ti surface in the form of CaTiO3. In vitro studies are carried out to confirm the bone bonding ability of calcium enriched Ti surface. The apatite deposition on the surface after exposure to SBF for 7 days is confirmed via scanning electron microscopy, X-ray powder diffraction, Fourier-transform infrared spectroscopy and energy-dispersive X-ray spectroscopy techniques. The cell viability of Ti-HT was evaluated using direct contact method and MTT assay. The potential of Ca2+ ion on Ti surface via hydrothermal pre-treatment to enhance osseointegration of Ti has been proposed for achieving early stability for dental implants.
Collapse
Affiliation(s)
- E B Ansar
- Division of Bioceramics, Sree Chitra Tirunal Institute for Medical Sciences & Technology, 695012, India; Department of Chemistry, M.E.S Asmabi College, P. Vemballur, Kodungallur 680671, India
| | - K Ravikumar
- Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - S Suresh Babu
- Division of Bioceramics, Sree Chitra Tirunal Institute for Medical Sciences & Technology, 695012, India
| | - F B Fernandez
- Division of Bioceramics, Sree Chitra Tirunal Institute for Medical Sciences & Technology, 695012, India
| | - Manoj Komath
- Division of Bioceramics, Sree Chitra Tirunal Institute for Medical Sciences & Technology, 695012, India
| | - Bikramjit Basu
- Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - P R Harikrishna Varma
- Division of Bioceramics, Sree Chitra Tirunal Institute for Medical Sciences & Technology, 695012, India.
| |
Collapse
|
8
|
Ramakrishnan KM, Ramachandran B, Ravikumar KG, Ravikumar K, Putli S, Jayaraman V, Mathivanan, Ravi, Ganamani A, Babu M. Management of Acinetobacter baumannii infection of burn wound with the evidence of sepsis. Indian J Burns 2019. [DOI: 10.4103/ijb.ijb_12_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
9
|
Sangeetha K, Ravikumar K. Defense Against Protocol Level Attack in Tor Network using Deficit Round Robin Queuing Process. Egyptian Informatics Journal 2018. [DOI: 10.1016/j.eij.2018.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
10
|
Ravikumar K, Muthukumar S, Sadacharan D, Suresh U, Sundarram T, Periyasamy S. The Impact of Thyroiditis on Morbidity and Safety in Patients Undergoing Total Thyroidectomy. Indian J Endocrinol Metab 2018; 22:494-498. [PMID: 30148096 PMCID: PMC6085970 DOI: 10.4103/ijem.ijem_209_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND The indications for surgery in thyroiditis vary from compressive symptoms to cosmesis. We analyzed the complications in patients who underwent total thyroidectomy (TT) in goiters associated with thyroiditis. MATERIALS AND METHODS This retrospective study was done in an endocrine surgical center over 4 years. A total of 724 patients, who underwent TT for benign thyroid disorders, were included in the study. Patients were divided into two groups based on histopathology into Group A (nonthyroiditis cases) and Group B (thyroiditis cases); Group B is subdivided into Group B1 (nodular goiter with associated thyroiditis) and Group B2 (Hashimoto's thyroiditis). The preoperative parameters analyzed were serum calcium, serum Vitamin D, serum parathyroid hormone (PTH), and vocal cord status. The intraoperative parameters observed were operating time, parathyroid preservation, and autotransplantation and course of recurrent laryngeal nerve (RLN). Postoperative parameters monitored were serum calcium, serum PTH, serum magnesium, signs and symptoms of hypocalcemia, and vocal cord status. Follow-up was done at 6 months with serum calcium, serum PTH, and video laryngoscopy. RESULTS Both groups were age and sex matched. All preoperative and intraoperative parameters were comparable among groups. Both transient complications (<6 months) were higher in Group B than A. Transient hypocalcemia was higher in Group B (39.70%) than Group A (24.77%) (P = 0.001). Transient hypocalcemia was higher in Group B1 (36.58%) than Group B2 (44.44%) (P = 0.014). Transient RLN palsy was higher in Group B (9.55%) than Group A (7.52%) (P = 0.040). Transient RLN palsy was higher in Group B1 (8.53%) than Group B2 (11.11%) (P = 0.039). Permanent hypoparathyroidism and permanent RLN palsy were comparable between the Groups A and B and between Groups B1 and B2. CONCLUSION The incidences of transient complications are higher in patients with thyroiditis. Careful analysis of surgical indications will avoid unnecessary surgery in thyroiditis cases.
Collapse
Affiliation(s)
- Krishnan Ravikumar
- Department of Endocrine Surgery, Christian Medical College, Vellore, Tamil Nadu, India
| | - Sankaran Muthukumar
- Department of Endocrine Surgery, Madurai Medical College, Madurai, Tamil Nadu, India
| | | | - Umadevi Suresh
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
| | - Thalavai Sundarram
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
| | | |
Collapse
|
11
|
Muthukumar S, Ravikumar K, Dhalapathy S, Gomathy T, Umadevi S, Maruthupandian D. A Prospective Comparative Study on Improvement of Hyperthyroid Cardiovascular Dysfunction in Patients Undergoing Total Thyroidectomy Versus Medical Management. World J Surg 2018. [DOI: 10.1007/s00268-018-4571-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
12
|
Ramakrishnan KM, Ramachandran B, Ravikumar KG, Ravikumar K, Ramkumar R, Jayaraman V, Mathivanan T. Exfoliative diseases of the integument and mucous membrane that mimic deep 2 nd-degree burns with or without sepsis. Indian J Burns 2018. [DOI: 10.4103/ijb.ijb_28_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
13
|
Affiliation(s)
- K Ravikumar
- Materials Research Centre, Indian Institute of Science, Bangalore, India
| | - Debasish Sarkar
- Department of Ceramic Engineering, National Institute of Technology, Rourkela, India
| | - Bikramjit Basu
- Materials Research Centre, Indian Institute of Science, Bangalore, India
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore, India
| |
Collapse
|
14
|
Sridhar B, Ravikumar K. Role of halogen-halogen contacts in the crystal structures of three new solvates of the drug oxyclozanide. Acta Crystallogr C Struct Chem 2017; 73:1056-1063. [PMID: 29206115 DOI: 10.1107/s2053229617015923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/01/2017] [Indexed: 11/11/2022]
Abstract
Halogen-halogen contacts are electrostatic in nature and exhibit directionality similar to hydrogen bonds. Oxyclozanide [systematic name: 2,3,5-trichloro-N-(3,5-dichloro-2-hydroxyphenyl)-6-hydroxybenzamide] is a drug used for the treatment of fascioliasis in domestic animals. The molecule carries five chlorine substituents and represents an ideal candidate for the study of halogen bonds in the crystal. Three new crystalline solvates of oxyclozanide, namely, oxyclozanide benzene hemisolvate, C13H6Cl5NO3·0.5C6H6, (I), oxyclozanide xylene hemisolvate, C13H6Cl5NO3·0.5C8H10, (II), and oxyclozanide toluene hemisolvate, C13H6Cl5NO3·0.5C7H8, (III), were structurally characterized. In this context, the crystal structure of oxyclozanide chlorobenzene hemisolvate, C13H6Cl5NO3·0.5C6H5Cl, (IV), was redetermined based on intensity data collected at 100 K. In all four solvates, the cocrystallized solvent molecules are located on crystallographic inversion centres. Solvates (I)-(IV) exhibit similar one-dimensional hydrogen-bonded chains generated by O-H...O, O-H...Cl and Cl...Cl interactions. The extension of these one-dimensional chains into two-dimensional layers is promoted by Cl...Cl and C-H...π contacts. Solvates (III) and (IV) are isostructural and differ from (I) and (II) with respect to subtle details concerning the intermolecular contacts.
Collapse
Affiliation(s)
- Balasubramanian Sridhar
- Center for X-ray Crystallography, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Krishnan Ravikumar
- Center for X-ray Crystallography, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| |
Collapse
|
15
|
Ravikumar K, Sadacharan D, Muthukumar S, Sundarram T, Periyasamy S, Suresh RV. A Prospective Study on Role of Supplemental Oral Calcium and Vitamin D in Prevention of Postthyroidectomy Hypocalcemia. Indian J Endocrinol Metab 2017; 21:498-503. [PMID: 28670529 PMCID: PMC5477433 DOI: 10.4103/ijem.ijem_402_16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Postoperative transient hypocalcemia is sequelae of total thyroidectomy (TT), which is observed in up to 50% of patients. Routine oral calcium and Vitamin D supplementation have been proposed to prevent symptomatic hypocalcemia preventing morbidity and facilitating early discharge. PATIENTS AND METHODS A total of 208 patients with nontoxic benign thyroid disorders, undergoing TT, were serially randomized into four groups: Group A (no supplements were given), Group B (oral calcium - 2 g/day given), Group C (calcium and calcitriol - 1 mcg/day are given), and Group D (calcium, calcitriol, and cholecalciferol - 60,000 IU/day are given). Patients were monitored for clinical and biochemical hypocalcemia (serum calcium, [Sr. Ca] <8 mg/dl), along with serum intact parathormone (Sr. PTH) and magnesium 6 h after surgery and Sr. Ca every 24 h. Intravenous (IV) calcium infusion was started, if any of the above four groups exhibit frank hypocalcemia. Patients are followed up with Sr. Ca and Sr. PTH at 3 and 6 months. RESULTS All groups were age and sex matched. Hypocalcemia was observed in 72/208 (34.61%) cases. Incidence of hypocalcemia was higher in Group A (57.69%) and Group B (50%) compared to Group C (15.38%) and Group D (15.38%). Hypocalcemia necessitating IV calcium occurred in 31/208 (14.90%) patients. IV calcium requirement exceeded in Group A (26.92%) and Group B (23.07%) compared to Group C (5.76%) and Group D (3.84%). There was no statistical difference in basal levels of serum Vitamin D, calcium, magnesium, intact PTH, and 6 h after surgery. Permanent hypoparathyroidism developed in five patients on follow-up. CONCLUSION Routine postoperative supplementation of oral calcium and Vitamin D will help in the prevention of postthyroidectomy transient hypocalcemia significantly. Preoperative Vitamin D levels do not predict postoperative hypocalcemia.
Collapse
Affiliation(s)
- Krishnan Ravikumar
- Department of Endocrine Surgery, Christian Medical College, Vellore, Chennai, Tamil Nadu, India
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
| | | | - Sankaran Muthukumar
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
- Department of Endocrine Surgery, Madurai Medical College, Madurai, Tamil Nadu, India
| | - Thalavai Sundarram
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
| | | | - R. V. Suresh
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
| |
Collapse
|
16
|
Sridhar B, Nanubolu JB, Ravikumar K, Karthik G, Reddy BVS. Three isostructural solvates of a tetrahydrofurochromenone derivative. Acta Crystallogr C Struct Chem 2017; 73:407-413. [PMID: 28469067 DOI: 10.1107/s2053229617005940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 04/19/2017] [Indexed: 11/10/2022]
Abstract
Isostructurality is more likely to occur in multicomponent systems. In this context, three closely related solvates were crystallized, namely, benzene (C27H21BrO6·C6H6), toluene (C27H21BrO6·C7H8) and xylene (C27H21BrO6·C8H10) with methyl 3a-acetyl-3-(4-bromophenyl)-4-oxo-1-phenyl-3,3a,4,9b-tetrahydro-1H-furo[3,4-c]chromene-1-carboxylate, and their crystal structures determined. All three structures belong to the same space group (P-1) and display similar unit-cell dimensions and conformations, as well as isostructural crystal packings. The isostructurality is confirmed by unit-cell and isostructural similarity indices. In each solvate, weak C-H...O and C-H...π interactions extend the molecules into two-dimensional networks, which are further linked by C-H...Br and Br...Br interactions into three-dimensional networks. The conformation of the core molecule is predominantly responsible for governing the isostructurality.
Collapse
Affiliation(s)
- Balasubramanian Sridhar
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Jagadeesh Babu Nanubolu
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Krishnan Ravikumar
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Govindaraju Karthik
- Natural Product Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Basi Venkata Subba Reddy
- Centre for Semiochemicals, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| |
Collapse
|
17
|
Affiliation(s)
- N. Balachandran
- Ecology Department, French Institute of Pondicherry, Puducherry, India
| | - K. Ravikumar
- School of Conservation of Natural Resources, Foundation for Revitalization of Local Health Traditions (FRLHT), Bangalore, India
| | - K. Rajendiran
- Department of Botany, Kanchi Mamuniver Centre for Post Graduate Studies, Puducherry, India
| | | |
Collapse
|
18
|
Gaurav A, Kumar R, Gupta H, Ravikumar K, Sridhar B, Tewari AK. Unprecedented folding in linker based flexible tripodal molecule and their conformational analysis. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.01.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
19
|
Girish K, Mandava J, Chandra RR, Ravikumar K, Anwarullah A, Athaluri M. Effect of obturating materials on fracture resistance of simulated immature teeth. J Conserv Dent 2017; 20:115-119. [PMID: 28855759 PMCID: PMC5564237 DOI: 10.4103/0972-0707.212238] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Aim: The aim of this study was to evaluate the fracture resistance of simulated immature teeth, when the root canals were completely filled either with mineral trioxide aggregate (MTA) or Biodentine, comparing with that of roots filled with apexification procedure. Materials and Methods: Sixty mandibular premolar teeth with single, straight canals decoronated at cementoenamel junction were divided into five groups (n = 12 each). Group 1 samples served as negative control and remaining four groups root samples were shaped and cleaned using ProTaper rotary files. To simulate immature roots, a #5 Peeso reamer was passed beyond the apex so that apices were enlarged to a diameter of 1.5 mm. Group 2 and 4 samples were filled with 5 mm of MTA or Biodentine apical plug and backfilling with gutta-percha using AH Plus sealer. Group 3 and 5 root samples were completely obturated with MTA and Biodentine, respectively. All the teeth were loaded vertically until fracture, using the universal testing machine. Statistical Analysis: Forces at which fracture of the roots occurred were subjected to statistical analysis using SPSS/PC version 2 software, and the results were analyzed with the one-way analysis of variance and Newman–Keuls multiple post hoc test. Results: Complete root canal obturation with MTA or Biodentine has shown significantly higher fracture resistance (P < 0.05) when compared to apexification with MTA or Biodentine. Conclusion: Obturation of the root canals with bioactive materials has shown highest fracture resistance when compared to apexification groups.
Collapse
Affiliation(s)
- Karri Girish
- Department of Conservative Dentistry and Endodontics, GITAM Dental College, Visakhapatnam, Andhra Pradesh, India
| | - Jyothi Mandava
- Department of Conservative Dentistry and Endodontics, GITAM Dental College, Visakhapatnam, Andhra Pradesh, India
| | - R Ravi Chandra
- Department of Conservative Dentistry and Endodontics, GITAM Dental College, Visakhapatnam, Andhra Pradesh, India
| | - K Ravikumar
- Department of Conservative Dentistry and Endodontics, GITAM Dental College, Visakhapatnam, Andhra Pradesh, India
| | - Anupreeta Anwarullah
- Department of Conservative Dentistry and Endodontics, GITAM Dental College, Visakhapatnam, Andhra Pradesh, India
| | - Mounika Athaluri
- Department of Conservative Dentistry and Endodontics, GITAM Dental College, Visakhapatnam, Andhra Pradesh, India
| |
Collapse
|
20
|
Nanubolu JB, Ravikumar K. Designing a new cocrystal of olanzapine drug and observation of concomitant polymorphism in a ternary cocrystal system. CrystEngComm 2017. [DOI: 10.1039/c6ce02227h] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
21
|
Govindan V, Nagraj G, Ravikumar K, Ganaie F. Serotype Distribution and Antimicrobial Resistance of Invasive S. pneumoniae among Indian Children before the Introduction of Pneumococcal Conjugate Vaccine. J PEDIAT INF DIS-GER 2016. [DOI: 10.1055/s-0036-1597650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Vandana Govindan
- Central Research Laboratory, Department of Microbiology, Kempegowda Institute of Medical Sciences, Hospital and Research Center, Bangalore, India
| | - Geetha Nagraj
- Central Research Laboratory, Department of Microbiology, Kempegowda Institute of Medical Sciences, Hospital and Research Center, Bangalore, India
| | - K. Ravikumar
- Central Research Laboratory, Department of Microbiology, Kempegowda Institute of Medical Sciences, Hospital and Research Center, Bangalore, India
| | - Feroze Ganaie
- Central Research Laboratory, Department of Microbiology, Kempegowda Institute of Medical Sciences, Hospital and Research Center, Bangalore, India
| |
Collapse
|
22
|
Gali S, Ravikumar K, Sreenivasamurthy B, Basu B. Mica glass ceramics with yttria stabilized zirconia for dental restorations. Dent Mater 2016. [DOI: 10.1016/j.dental.2016.08.211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
23
|
Abstract
Structural reasons for the melting point variations in isostructural cocrystals of the aripiprazole drug are investigated through combined spectroscopic and diffraction studies.
Collapse
Affiliation(s)
- Jagadeesh Babu Nanubolu
- Centre for X-ray Crystallography
- CSIR-Indian Institute of Chemical Technology
- Hyderabad 500607, India
| | - Krishnan Ravikumar
- Centre for X-ray Crystallography
- CSIR-Indian Institute of Chemical Technology
- Hyderabad 500607, India
| |
Collapse
|
24
|
Ravikumar K, Sridhar B, Nanubolu JB, Karthik G, Reddy BVS. Structural consequences of weak interactions in dispirooxindole derivatives. Acta Crystallogr C Struct Chem 2015; 71:1001-9. [PMID: 26524175 DOI: 10.1107/s2053229615019610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/16/2015] [Indexed: 11/10/2022]
Abstract
Spiro scaffolds are being increasingly utilized in drug discovery due to their inherent three-dimensionality and structural variations, resulting in new synthetic routes to introduce spiro building blocks into more pharmaceutically active molecules. Multicomponent cascade reactions, involving the in situ generation of carbonyl ylides from α-diazocarbonyl compounds and aldehydes, and 1,3-dipolar cycloadditon with 3-arylideneoxindoles gave a novel class of dispirooxindole derivatives, namely 1,1''-dibenzyl-5'-(4-chlorophenyl)-4'-phenyl-4',5'-dihydrodispiro[indoline-3,2'-furan-3',3''-indoline]-2,2''-dione, C44H33ClN2O3, (I), 1''-acetyl-1-benzyl-5'-(4-chlorophenyl)-4'-phenyl-4',5'-dihydrodispiro[indoline-3,2'-furan-3',3''-indoline]-2,2''-dione, C39H29ClN2O4, (II), 1''-acetyl-1-benzyl-4',5'-diphenyl-4',5'-dihydrodispiro[indoline-3,2'-furan-3',3''-indoline]-2,2''-dione, C39H30N2O4, (III), and 1''-acetyl-1-benzyl-4',5'-diphenyl-4',5'-dihydrodispiro[indoline-3,2'-furan-3',3''-indoline]-2,2''-dione acetonitrile hemisolvate, C39H30N2O4·0.5C2H3N, (IV). All four compounds exist as racemic mixtures of the SSSR and RRRS stereoisomers. In these structures, the two H atoms of the dihydrofuran ring and the two substituted oxindole rings are in a trans orientation, facilitating intramolecular C-H···O and π-π interactions. These weak interactions play a prominent role in the structural stability and aid the highly regio- and diastereoselective synthesis. In each of the four structures, the molecular assembly in the crystal is also governed by weak noncovalent interactions. Compound (IV) is the solvated analogue of (III) and the two compounds show similar structural features.
Collapse
Affiliation(s)
- Krishnan Ravikumar
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Balasubramanian Sridhar
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Jagadeesh Babu Nanubolu
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Govindaraju Karthik
- Natural Product Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Basi Venkata Subba Reddy
- Natural Product Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| |
Collapse
|
25
|
Ravikumar K, Sridhar B, Nanubolu JB, Karthik G, Reddy BVS. Three structures of dispirooxindole derivatives generatedin situthrough a three-component one-pot strategy with complete regio- and stereoselectivity. Acta Crystallogr C Struct Chem 2015; 71:721-7. [DOI: 10.1107/s2053229615013273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 07/10/2015] [Indexed: 11/10/2022]
Abstract
The challenging molecular architecture of spirooxindoles is appealing to chemists because it evokes novel synthetic strategies that address configurational demands and provides platforms for further reaction development. The [3+2] cycloaddition of the carbonyl ylide with arylideneoxindoleviaa five-membered cyclic transition state gave a novel class of dispirooxindole derivatives, namelytert-butyl 4′-(4-bromophenyl)-1′′-methyl-2,2′′-dioxo-5′-phenyl-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-1-carboxylate, C36H31BrN2O, (Ia), 5′-(4-bromophenyl)-1,1′′-dimethyl-4′-phenyl-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-2,2′′-dione, C32H25BrN2O3, (Ib), andtert-butyl 1′′-methyl-2,2′′-dioxo-4′-phenyl-5′-(p-tolyl)-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-1-carboxylate, C37H34N2O5, (Ic). Crystal structure analyses of these dispirooxindoles revealed the formation of two diastereoisomers selectively and confirmed their relative stereochemistry (SSSRandRRRS). In all three structures, intramolecular C—H...O and π–π interactions between oxindole and dihydrofuran rings are the key factors governing the regio- and stereoselectivity, and in the absence of conventional hydrogen bonds, their crystal packings are strengthened by intermolecular C—H...π interactions.
Collapse
|
26
|
Sadacharan D, Mahadevan S, Muthukumar S, Ravikumar K. A rare giant tubercle of Zuckerkandl with retrosternal extension encountered during total thyroidectomy. BMJ Case Rep 2015; 2015:bcr-2015-210307. [PMID: 26113593 DOI: 10.1136/bcr-2015-210307] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Dhalapathy Sadacharan
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India Department of Endocrinology and Endocrine Surgery, Endocrine and Speciality Clinic, Chennai, Tamil Nadu, India
| | - Shriraam Mahadevan
- Department of Endocrinology, Sri Ramachandra Medical College, Chennai, Tamil Nadu, India Department of Endocrinology and Endocrine Surgery, Endocrine and Speciality Clinic, Chennai, Tamil Nadu, India
| | - Sankaran Muthukumar
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
| | - Krishnan Ravikumar
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
| |
Collapse
|
27
|
Sridhar B, Nanubolu JB, Ravikumar K. Four cocrystals of thymine with phenolic coformers: influence of the coformer on hydrogen bonding. Acta Crystallogr C Struct Chem 2015; 71:602-9. [PMID: 26146400 DOI: 10.1107/s2053229615011614] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 06/15/2015] [Indexed: 11/10/2022]
Abstract
Cocrystals are molecular solids composed of at least two types of neutral chemical species held together by noncovalent forces. Crystallization of thymine [systematic name: 5-methylpyrimidine-2,4(1H,3H)-dione] with four phenolic coformers resulted in cocrystal formation, viz. catechol (benzene-1,2-diol) giving thymine-catechol (1/1), C5H6N2O2·C6H6O2, (I), resorcinol (benzene-1,3-diol) giving thymine-resorcinol (2/1), 2C5H6N2O2·C6H6O2, (II), hydroquinone (benzene-1,4-diol) giving thymine-hydroquinone (2/1), 2C5H6N2O2·C6H6O2, (III), and pyrogallol (benzene-1,2,3-triol) giving thymine-pyrogallol (1/2), C5H6N2O2·2C6H6O3, (IV). The resorcinol molecule in (II) occupies a twofold axis, while the hydroquinone molecule in (III) is situated on a centre of inversion. Thymine-thymine base pairing is common across all four structures, albeit with different patterns. In (I)-(III), the base pair is propagated into an infinite one-dimensional ribbon, whereas it exists as a discrete dimeric unit in (IV). In (I)-(III), the two donor N atoms and one carbonyl acceptor O atom of thymine are involved in thymine-thymine base pairing and the remaining carbonyl O atom is hydrogen bonded to the coformer. In contrast, in (IV), just one donor N atom and one acceptor O atom are involved in base pairing, and the remaining donor N atom and acceptor O atom of thymine form hydrogen bonds to the coformer molecules. Thus, the utilization of the donor and acceptor atoms of thymine in the hydrogen bonding is influenced by the coformers.
Collapse
Affiliation(s)
- Balasubramanian Sridhar
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Jagadeesh Babu Nanubolu
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Krishnan Ravikumar
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| |
Collapse
|
28
|
Affiliation(s)
- Dhalapathy Sadacharan
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India Department of Endocrinology and Endocrine Surgery, Endocrine and Speciality Clinic, Chennai, Tamil Nadu, India
| | - Shriraam Mahadevan
- Department of Endocrinology and Endocrine Surgery, Endocrine and Speciality Clinic, Chennai, Tamil Nadu, India Department of Endocrinology, Sri Ramachandra Medical College, Chennai, Tamil Nadu, India
| | - Krishnan Ravikumar
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
| | - Sankaran Muthukumar
- Department of Endocrine Surgery, Madras Medical College, Chennai, Tamil Nadu, India
| |
Collapse
|
29
|
Ravikumar K, Sridhar B, Nanubolu JB, Rajasekaran T, Reddy BVS. Four oxoindole-linked α-alkoxy-β-amino acid derivatives. Acta Crystallogr C Struct Chem 2015; 71:322-9. [PMID: 25836294 DOI: 10.1107/s2053229615005604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 03/18/2015] [Indexed: 11/11/2022]
Abstract
Four structures of oxoindolyl α-hydroxy-β-amino acid derivatives, namely, methyl 2-{3-[(tert-butoxycarbonyl)amino]-1-methyl-2-oxoindolin-3-yl}-2-methoxy-2-phenylacetate, C24H28N2O6, (I), methyl 2-{3-[(tert-butoxycarbonyl)amino]-1-methyl-2-oxoindolin-3-yl}-2-ethoxy-2-phenylacetate, C25H30N2O6, (II), methyl 2-{3-[(tert-butoxycarbonyl)amino]-1-methyl-2-oxoindolin-3-yl}-2-[(4-methoxybenzyl)oxy]-2-phenylacetate, C31H34N2O7, (III), and methyl 2-[(anthracen-9-yl)methoxy]-2-{3-[(tert-butoxycarbonyl)amino]-1-methyl-2-oxoindolin-3-yl}-2-phenylacetate, C38H36N2O6, (IV), have been determined. The diastereoselectivity of the chemical reaction involving α-diazoesters and isatin imines in the presence of benzyl alcohol is confirmed through the relative configuration of the two stereogenic centres. In esters (I) and (III), the amide group adopts an anti conformation, whereas the conformation is syn in esters (II) and (IV). Nevertheless, the amide group forms intramolecular N-H···O hydrogen bonds with the ester and ether O atoms in all four structures. The ether-linked substituents are in the extended conformation in all four structures. Ester (II) is dominated by intermolecular N-H···O hydrogen-bond interactions. In contrast, the remaining three structures are sustained by C-H···O hydrogen-bond interactions.
Collapse
Affiliation(s)
- Krishnan Ravikumar
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Balasubramanian Sridhar
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Jagadeesh Babu Nanubolu
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Tamilselvan Rajasekaran
- Natural Product Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Basi Venkata Subba Reddy
- Natural Product Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| |
Collapse
|
30
|
Avasthi K, Shukla L, Kant R, Ravikumar K. Conformational control due to arene interactions in dissymmetrical diaryl 2-methylenepropylidene both in solution and solid state. J STRUCT CHEM+ 2015. [DOI: 10.1134/s0022476614080289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
31
|
Sridhar B, Nanubolu JB, Ravikumar K. The first polymorph in the family of nucleobases: a second form of cytosine. Acta Crystallogr C Struct Chem 2015; 71:128-35. [DOI: 10.1107/s2053229615000492] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/09/2015] [Indexed: 11/11/2022]
Abstract
A new polymorph of cytosine, C4H5N3O, is reported half a century after the report of its first known crystal structure [Barker & Marsh (1964).Acta Cryst.17, 1581–1587]. Cytosine thus provides the first polymorphic example in the category of parent nucleobases. The new form, denoted (Ib), was observed unexpectedly during an attempt to cocrystallize cytosine with catechol. Form (Ib) crystallizes in the orthorhombic centrosymmetric space groupPccnwith two molecules in the asymmetric unit. The previously known form, denoted (Ia), crystallizes in the orthorhombic noncentrosymmetric space groupP212121. The cytosine molecule is planar in both forms. Hydrogen-bonding interactions are also similar for both forms. Infinite one-dimensional ribbons composed of cytosine base-pair dimers inR22(8) arrangements are observed in both (Ia) and (Ib). However, the way that the ribbons are packed differs in (Ia) and (Ib). This appears to guide the centrosymmetricversusnoncentrosymmetric space-group selection through the formation of an inversion-related motif in polymorph (Ib) and a helical propagation in polymorph (Ia). A few selected polymorphic systems have been gathered from the Cambridge Structural Database to understand possible structural features responsible for achiral molecules adopting centro- and noncentrosymmetric space groups.
Collapse
|
32
|
Nanubolu JB, Sridhar B, Ravikumar K. Polymorphism in R-tamsulosin (an alpha blocker): The unexpected manifestation of a sulfonamide⋯o-diethoxybenzene heterosynthon. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2014.03.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
33
|
Sridhar B, Nanubolu JB, Ravikumar K. Observation of neutral, ionic and intermediate states in lamotrigine-acid complexes- inference from crystallographic bond geometries. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2014.06.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
34
|
Ravikumar K, Balachandran N, Begum SN, Patchaimal P, Bhanja M, Lohitasyudu K. Interesting plant records from Visakhapatnam District, Andhra Pradesh, India. J Threat Taxa 2014. [DOI: 10.11609/jott.o3144.6108-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
35
|
Avasthi K, Shukla L, Kant R, Ravikumar K. Folded conformations due to arene interactions in dissymmetric and symmetric butylidene-linker models based on pyrazolo[3,4-d]pyrimidine, purine and 7-deazapurine. Acta Crystallogr C Struct Chem 2014; 70:555-61. [PMID: 24898957 DOI: 10.1107/s2053229614009449] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 04/26/2014] [Indexed: 11/10/2022]
Abstract
The butylidene-linker models 1-[2-(2,6-dimethylsulfanyl-9H-purin-9-yl)-2-methylidenepropyl]-4,6-bis(methylsulfanyl)-1H-pyrazolo[3,4-d]pyrimidine, C18H20N8S4, (XI), 7,7'-(2-methylidenepropane-1,3-diyl)bis[3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one], C20H22N6O2S2, (XIV), and 7-[2-(4,6-dimethylsulfanyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)-2-methylidenepropyl]-3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one, C19H21N7OS3, (XV), show folded conformations in solution, as shown by (1)H NMR analysis. This folding carries over to the crystalline state. Intramolecular π-π interactions are observed in all three compounds, but only (XIV) shows additional intramolecular C-H···π interactions in the solid state. As far as can be established, this is the first report incorporating the pyrrolo[2,3-d]pyrimidine nucleus for such a study. In addition to the π-π interactions, the crystal structures are also stabilized by other weak intermolecular C-H···S/N/O and/or S···N/S interactions.
Collapse
Affiliation(s)
- Kamlakar Avasthi
- Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow 226 031, India
| | - Lakshmi Shukla
- Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow 226 031, India
| | - Ruchir Kant
- Molecular and Structural Biology Division, Central Drug Research Institute, Lucknow 226 031, India
| | - Krishnan Ravikumar
- Department of X-ray Crystallography, IICT Hydeabad, Hyderabad 500 007, India
| |
Collapse
|
36
|
Swamy GYSK, Ravikumar K. Molecular and crystal structures of bis-tetrazolate ammonium salt and bis-tetrazole monohydrate. J STRUCT CHEM+ 2014. [DOI: 10.1134/s0022476614030287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
37
|
|
38
|
Babu Nanubolu J, Sridhar B, Ravikumar K. Understanding the amino ↔ imino tautomeric preference in (imidazole)imidazolidine-N-aryl(alkyl) systems: a case study of moxonidine drug and insights from the Cambridge structural database (CSD). CrystEngComm 2014. [DOI: 10.1039/c4ce01541j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Moxonidine drug crystallizes exclusively as its imino tautomer. Conjugation plays a key role in the tautomer stability.
Collapse
Affiliation(s)
- Jagadeesh Babu Nanubolu
- Centre for X-ray Crystallography
- CSIR - Indian Institute of Chemical Technology
- Hyderabad, India
| | - Balasubramanian Sridhar
- Centre for X-ray Crystallography
- CSIR - Indian Institute of Chemical Technology
- Hyderabad, India
| | - Krishnan Ravikumar
- Centre for X-ray Crystallography
- CSIR - Indian Institute of Chemical Technology
- Hyderabad, India
| |
Collapse
|
39
|
Sridhar B, Ravikumar K, Varghese B. Tetra- and hexahydrates of bis(adeninium) zoledronate. Acta Crystallogr C Struct Chem 2013; 70:67-74. [DOI: 10.1107/s2053229613033172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 12/07/2013] [Indexed: 11/11/2022]
Abstract
The present paper reports the structures of bis(adeninium) zoledronate tetrahydrate {systematic name: bis(6-amino-7H-purin-1-ium) hydrogen [1-hydroxy-2-(1H-imidazol-3-ium-1-yl)-1-phosphonatoethyl]phosphonate tetrahydrate}, 2C5H6N5+·C5H8N2O7P22−·4H2O, (I), and bis(adeninium) zoledronate hexahydrate {systematic name: a 1:1 cocrystal of bis(6-amino-7H-purin-1-ium) hydrogen [1-hydroxy-2-(1H-imidazol-3-ium-1-yl)-1-phosphonatoethyl]phosphonate hexahydrate and 6-amino-7H-purin-1-ium 6-amino-7H-purine dihydrogen [1-hydroxy-2-(1H-imidazol-3-ium-1-yl)ethane-1,1-diyl]diphosphonate hexahydrate}, 2C5H6N5+·C5H8N2O7P22−·6H2O, (II). One of the adenine molecules and one of the phosphonate groups of the zoledronate anion of (II) are protonated on a 50% basis. The zoledronate group displays its usual zwitterionic character, with a protonated imidazole ring; however, the ionization state of the phosphonate groups of the anion for (I) and (II) are different. In (I), the anion has both singly and doubly deprotonated phosphonate groups, while in (II), it has one singly deprotonated phosphonate group and a partially deprotonated phosphonate group. In (I), the cations form anR22(10) base pair, while in (II), they formR22(8) andR22(10) base pairs. Two water molecules in (I) and five water molecules in (II) are involved in water–water interactions. The presence of an additional two water molecules in the structure of (II) might influence the different ionization state of the anion as well as the different packing mode compared to (I).
Collapse
|
40
|
Ravikumar K, Sridhar B, Nanubolu JB, Bhujanga Rao AKS, Jyothiprasad R. Tosylate salts of the anticancer drug lapatinib. Acta Crystallogr C 2013; 69:1516-23. [PMID: 24311503 DOI: 10.1107/s0108270113028965] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/21/2013] [Indexed: 11/10/2022] Open
Abstract
Two tosylate salts of an anticancer drug lapatinib, viz. a monotosylate [systematic name: ({5-[4-({3-chloro-4-[(3-fluorophenyl)methoxy]phenyl}amino)quinazolin-6-yl]furan-2-yl}methyl)[2-(methylsulfonyl)ethyl]azanium 4-methylbenzenesulfonate], C29H27ClFN4O4S(+)·C7H7O3S(-), (I), and a ditosylate [systematic name: 4-({3-chloro-4-[(3-fluorophenyl)methoxy]phenyl}amino)-6-]5-({[2-(methylsulfonyl)ethyl]azaniumyl}methyl)furan-2-yl[quinazolin-1-ium bis(4-methylbenzenesulfonate)], C29H28ClFN4O4S(2+)·2C7H7O3S(-), (II), were obtained during crystallization attempts for polymorphism. In both structures, the lapatinib cation is in a distorted U-like conformation and the tosylate anion is clamped between the aniline N atom and methylamine N atom through N-H···O hydrogen bonds, forming an R2(2)(15) ring motif. The 4-anilinoquinazoline ring system is essentially planar in (I), while it is twisted in (II), controlled by an intramolecular C-H···N interaction. In (I), alternating cations and anions are linked by N-H···O hydrogen bonds into C2(2)(6) chains. These chains are linked by cations in a helical manner. The presence of the additional tosylate anion in (II) results in the formation of one-dimensional tapes of fused hydrogen-bonded rings through N-H···O and C-H···O interactions. These studies augment our understanding of the role of nonbonded interactions in the solid state, which is useful for correlation to the physicochemical properties of drug products.
Collapse
Affiliation(s)
- K Ravikumar
- Centre for X-ray Crystallography, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | | | | | | | | |
Collapse
|
41
|
Selvanayagam S, Ravikumar K, Kathiravan S, Raghunathan R. 2-[(Ferrocen-1-yl)(hydroxy)methyl]prop-2-enenitrile. Acta Crystallogr Sect E Struct Rep Online 2013; 69:m669. [PMID: 24454176 PMCID: PMC3885001 DOI: 10.1107/s1600536813031218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 11/14/2013] [Indexed: 11/10/2022]
Abstract
In the title ferrocene derivative, [Fe(C5H5)(C9H8NO)], the dihedral angle between the enenitrile group and the substituted cyclopentadienyl ring is 71.2 (1)°. The cyclopentadienyl rings of the ferrocene moiety are arranged in an eclipsed conformation. The hydroxy group, and the corresponding methine H atom, are disordered over two sets of sites with site-occupancy factors of 0.744 (4) and 0.256 (4). An intramolecular C—H...O close contact is observed. In the crystal, O—H...N hydrogen bonds form aC(6) chain along [100].
Collapse
|
42
|
Sridhar B, Ravikumar K, Hariharakrishnan V. Zolmitriptan oxalate and zolmitriptan camphorsulfonate: the first structural study of salt complexes of the antimigraine drug zolmitriptan. Acta Crystallogr C 2013; 69:1186-91. [PMID: 24096513 DOI: 10.1107/s0108270113024323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 08/30/2013] [Indexed: 11/10/2022] Open
Abstract
Zolmitriptan hydrogen oxalate [(S)-dimethyl(2-{5-[(2-oxo-1,3-oxazolidin-4-yl)methyl]-1H-indol-3-yl}ethyl)azanium hydrogen oxalate], C16H22N3O2(+)·C2HO4(-), (I), and zolmitriptan camphorsulfonate [(S)-dimethyl(2-{5-[(2-oxo-1,3-oxazolidin-4-yl)methyl]-1H-indol-3-yl}ethyl)azanium (S,R)-{2-hydroxy-7,7-dimethylbicyclo[2.2.1]heptan-1-yl}methanesulfonate], C16H22N3O2(+)·C10H15O4S(-), (II), are the first reported salt complexes of the antimigraine drug zolmitriptan. Compound (I) crystallizes in the space group P2(1) with two molecules of protonated zolmitriptan and two oxalate monoanions in the asymmetric unit, while compound (II) crystallizes in the space group P2(1)2(1)2(1) with one protonated zolmitriptan molecule and one camphorsulfonate anion in the asymmetric unit. The orientations of the ethylamine side chain and the oxazolidinone ring with respect to the indole ring of the zolmitriptan cation are different for (I) and (II). In (I), they are oriented in opposite directions and the molecule adopts a step-like appearance, while in (II) the corresponding side chains are folded in the same direction, giving the molecule a cup-like appearance. The zolmitriptan molecules of (I) form an R2(2)(8) dimer, while in (II) they form a helical chain with a C(11) motif. The oxalate monoanions of (I) interact with the zolmitriptan cations and extend the dimer into a three-dimensional hydrogen-bonded network. In (II), the camphorsulfonate anion forms an R2(2)(15) ring motif with the zolmitriptan cation.
Collapse
Affiliation(s)
- Balasubramanian Sridhar
- X-ray Crystallography Division, CSIR - Indian Institute of Chemical Technology, Hyderabad 500 607, India
| | | | | |
Collapse
|
43
|
Sridhar B, Nanubolu JB, Ravikumar K. Solvent-mediated pseudo-quadruple hydrogen-bond motifs in three lamotrigine–carboxylic acid complexes. Acta Crystallogr C 2013; 69:1164-9. [DOI: 10.1107/s0108270113023573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/21/2013] [Indexed: 11/10/2022] Open
Abstract
Lamotrigine, an antiepileptic drug, has been complexed with three aromatic carboxylic acids. All three compounds crystallize with the inclusion ofN,N-dimethylformamide (DMF) solvent,viz.lamotriginium [3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazin-2-ium] 4-iodobenzoateN,N-dimethylformamide monosolvate, C9H8Cl2N5+·C7H4IO2−·C3H7NO, (I), lamotriginium 4-methylbenzoateN,N-dimethylformamide monosolvate, C9H7Cl2N5+·C8H8O2−·C3H7NO, (II), and lamotriginium 3,5-dinitro-2-hydroxybenzoateN,N-dimethylformamide monosolvate, C9H8Cl2N5+·C7H3N2O7−·C3H7NO, (III). In all three structures, proton transfer takes place from the acid to the lamotrigine molecule. However, in (I) and (II), the acidic H atom is disordered over two sites and there is only partial transfer of the H atom from O to N. In (III), the corresponding H atom is ordered and complete proton transfer has occurred. Lamotrigine–lamotrigine, lamotrigine–acid and lamotrigine–solvent interactions are observed in all three structures and they thereby exhibit isostructurality. The DMF solvent extends the lamotrigine–lamotrigine dimers into a pseudo-quadruple hydrogen-bonding motif.
Collapse
|
44
|
Gupta S, Koley D, Ravikumar K, Kundu B. Counter Ion Effect in Au/Ag-Catalyzed Chemoselective 6-endo-dig N- and O-Cyclizations of Enyne–Urea System: Diversity-Oriented Synthesis of Annulated Indoles. J Org Chem 2013; 78:8624-33. [DOI: 10.1021/jo4013332] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sahaj Gupta
- Medicinal and Process
Chemistry
Division, CSIR-Central Drug Research Institute, Lucknow 226001, India
| | - Dipankar Koley
- Medicinal and Process
Chemistry
Division, CSIR-Central Drug Research Institute, Lucknow 226001, India
- Academy of Scientific and Innovative Research, New Delhi 110001, India
| | - Krishnan Ravikumar
- X-ray Crystallography Division, CSIR-Indian Institute of Chemical Technology, Tarnaka,
Hyderabad 500607, India
| | - Bijoy Kundu
- Medicinal and Process
Chemistry
Division, CSIR-Central Drug Research Institute, Lucknow 226001, India
- Academy of Scientific and Innovative Research, New Delhi 110001, India
| |
Collapse
|
45
|
Ravikumar K, Sridhar B, Nanubolu JB, Hariharakrishnan V, Rao BV. Frovatriptan salts of aliphatic carboxylic acids. Acta Crystallogr C 2013; 69:428-35. [PMID: 23579721 DOI: 10.1107/s0108270113005878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 02/28/2013] [Indexed: 11/10/2022] Open
Abstract
The interaction of the antimigraine pharmaceutical agent frovatriptan with acetic acid and succinic acid yields the salts (±)-6-carbamoyl-N-methyl-2,3,4,9-tetrahydro-1H-carbazol-3-aminium acetate, C14H18N3O(+)·C2H3O2(-), (I), (R)-(+)-6-carbamoyl-N-methyl-2,3,4,9-tetrahydro-1H-carbazol-3-aminium 3-carboxypropanoate monohydrate, C14H18N3O(+)·C4H5O4(-)·H2O, (II), and bis[(R)-(+)-6-carbamoyl-N-methyl-2,3,4,9-tetrahydro-1H-carbazol-3-aminium] succinate trihydrate, 2C14H18N3O(+)·C4H4O4(2-)·3H2O, (III). The methylazaniumyl substitutent is oriented differently in all three structures. Additionally, the amide group in (I) is in a different orientation. All the salts form three-dimensional hydrogen-bonded structures. In (I), the cations form head-to-head hydrogen-bonded amide-amide catemers through N-H···O interactions, while in (II) and (III) the cations form head-to-head amide-amide dimers. The cation catemers in (I) are extended into a three-dimensional network through further interactions with acetate anion acceptors. The presence of succinate anions and water molecules in (II) and (III) primarily governs the three-dimensional network through water-bridged cation-anion associations via O-H···O and N-H···O hydrogen bonds. The structures reported here shed some light on the possible mode of noncovalent interactions in the aggregation and interaction patterns of drug molecule adducts.
Collapse
Affiliation(s)
- Krishnan Ravikumar
- Centre for X-ray Crystallography, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.
| | | | | | | | | |
Collapse
|
46
|
Srinivasan BR, Khandolkar SS, Jyai RN, Ravikumar K, Sridhar B, Natarajan S. Structural and spectral characterization of a new non-centrosymmetric organic thiosulfate. Spectrochim Acta A Mol Biomol Spectrosc 2013; 102:235-241. [PMID: 23220662 DOI: 10.1016/j.saa.2012.09.103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/30/2012] [Accepted: 09/09/2012] [Indexed: 06/01/2023]
Abstract
Aqueous reaction of ammonium thiosulfate with ethylenediamine (en) results in the formation of the title compound (enH(2))[S(2)O(3)] (1) (enH(2)=ethylenediammonium) in good yields. Compound 1 was characterized by analytical data, IR, Raman and NMR spectra, X-ray powder pattern and its crystal structure was determined. The structure of 1 which crystallizes in the non-centrosymmetric orthorhombic space group P2(1)2(1)2(1), consists of two crystallographically independent (enH(2))(2+) dications and two unique thiosulfate anions, which are interlinked by three varieties of H-bonding interactions, namely N-H⋯O, N-H⋯S, and C-H⋯O. (1)H and (13)C NMR spectra reveal the purity of 1 while its transparent nature can be evidenced from the UV-Vis-NIR spectral data. In compound 1 which exhibits SHG property, the infrared and Raman spectra confirm the presence of the organic dication and the thiosulfate anion.
Collapse
|
47
|
Swamy G, Ravikumar K, Ramakrishna K. Synthesis and crystal structure of bis [2-(4-methylphenyl)-1-phenethyl-4(1H)-quinazolinone] dichlorocopper (II). Polyhedron 2013. [DOI: 10.1016/j.poly.2012.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
48
|
Nanubolu JB, Sridhar B, Ravikumar K, Cherukuvada S. Adaptability of aripiprazole towards forming isostructural hydrogen bonding networks in multi-component salts: a rare case of strong O–H⋯O− ↔ weak C–H⋯O mimicry. CrystEngComm 2013. [DOI: 10.1039/c3ce00022b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
49
|
Nanubolu JB, Sridhar B, Ravikumar K, Sawant KD, Naik TA, Patkar LN, Cherukuvada S, Sreedhar B. Polymorphism in metformin embonate salt – recurrence of dimeric and tetrameric guanidinium–carboxylate synthons. CrystEngComm 2013. [DOI: 10.1039/c3ce26986h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
50
|
Ravikumar K, Sridhar B, Hariharakrishnan V, Singh AN. Three novel benzothiazine-fused triazoles as potential centrally acting muscle relaxants. Acta Crystallogr C 2012; 68:o475-80. [PMID: 23124467 DOI: 10.1107/s0108270112040759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 09/27/2012] [Indexed: 11/11/2022] Open
Abstract
The structures of the novel triazolobenzothiazines 2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]thiazin-1-one (IDPH-791), C(9)H(7)N(3)OS, (I), a potential muscle relaxant, its benzoyl derivative, 2-(2-oxo-2-phenylethyl)-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]thiazin-1-one, C(20)H(17)N(3)O(4)S, (II), and the β-keto ester derivative, ethyl 3-oxo-2-(1-oxo-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]thiazin-2-yl)-3-phenylpropanoate, C(17)H(13)N(3)O(2)S, (III), are the first examples of benzothiazine-fused triazoles in the crystallographic literature. The heterocyclic thiazine rings in all three structures adopt a distorted half-chair conformation. Compound (III) exists in the trans-β-diketo form. Other than N-H···O hydrogen bonds in (I) forming dimers, no formal intermolecular hydrogen bonds are involved in the crystal packing of any of the three structures, which is dominated by C-H···O/N and π-π stacking interactions.
Collapse
Affiliation(s)
- Krishnan Ravikumar
- Laboratory of X-ray Crystallography, CSIR Indian Institute of Chemical Technology, Hyderabad 500 007, India.
| | | | | | | |
Collapse
|