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Adalat B, Rahim F, Rehman W, Ali Z, Rasheed L, Khan Y, Farghaly TA, Shams S, Taha M, Wadood A, Shah SAA, Abdellatif MH. Biologically Potent Benzimidazole-Based-Substituted Benzaldehyde Derivatives as Potent Inhibitors for Alzheimer's Disease along with Molecular Docking Study. Pharmaceuticals (Basel) 2023; 16:208. [PMID: 37259358 PMCID: PMC9958709 DOI: 10.3390/ph16020208] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/27/2023] [Accepted: 01/28/2023] [Indexed: 09/29/2023] Open
Abstract
Twenty-one analogs were synthesized based on benzimidazole, incorporating a substituted benzaldehyde moiety (1-21). These were then screened for their acetylcholinesterase and butyrylcholinesterase inhibition profiles. All the derivatives except 13, 14, and 20 showed various inhibitory potentials, ranging from IC50 values of 0.050 ± 0.001 µM to 25.30 ± 0.40 µM against acetylcholinesterase, and 0.080 ± 0.001 µM to 25.80 ± 0.40 µM against butyrylcholinesterase, when compared with the standard drug donepezil (0.016 ± 0.12 µM and 0.30 ± 0.010 µM, against acetylcholinesterase and butyrylcholinesterase, respectively). Compound 3 in both cases was found to be the most potent compound due to the presence of chloro groups at the 3 and 4 positions of the phenyl ring. A structure-activity relationship study was performed for all the analogs except 13, 14, and 20, further, molecular dynamics simulations were performed for the top two compounds as well as the reference compound in a complex with acetylcholinesterase and butyrylcholinesterase. The molecular dynamics simulation analysis revealed that compound 3 formed the most stable complex with both acetylcholinesterase and butyrylcholinesterase, followed by compound 10. As compared to the standard inhibitor donepezil both compounds revealed greater stabilities and higher binding affinities for both acetylcholinesterase and butyrylcholinesterase.
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Affiliation(s)
- Bushra Adalat
- Department of Chemistry, Hazara University, Mansehra 21300, Pakistan
| | - Fazal Rahim
- Department of Chemistry, Hazara University, Mansehra 21300, Pakistan
| | - Wajid Rehman
- Department of Chemistry, Hazara University, Mansehra 21300, Pakistan
| | - Zarshad Ali
- Department of Chemistry, Hazara University, Mansehra 21300, Pakistan
| | - Liaqat Rasheed
- Department of Chemistry, Hazara University, Mansehra 21300, Pakistan
| | - Yousaf Khan
- Department of Chemistry, COMSATS University, Islamabad 45550, Pakistan
| | - Thoraya A. Farghaly
- Department of Chemistry, Faculty of Applied Science, Umm Al-Qura University, P.O. Box 715, Makkah Almukkarramah 24382, Saudi Arabia
| | - Sulaiman Shams
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Muhammad Taha
- Department of Clinical Pharmacy, Institute for Research and Medical Consultations (IRMC), Imam Abdul Rahman Bin Faisal University, P.O. Box 31441, Dammam 11099, Saudi Arabia
| | - Abdul Wadood
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Syed A. A. Shah
- Faculty of Pharmacy, Universiti Teknologi MARA Cawangan Selangor Kampus Puncak Alam, Bandar, Puncak Alam 42300, Malaysia
| | - Magda H. Abdellatif
- Department of Chemistry, College of Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
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Ejaz S, Zubair M, Rasool N, Ahmed F, Bilal M, Ahmad G, Altaf AA, Shah SAA, Rizwan K. N-([1,1'-biaryl]-4-yl)-1-naphthamide-based scaffolds synthesis, their cheminformatics analyses, and screening as bacterial biofilm inhibitor. J Basic Microbiol 2021; 62:1143-1155. [PMID: 34724237 DOI: 10.1002/jobm.202100288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 06/24/2021] [Revised: 09/07/2021] [Accepted: 09/26/2021] [Indexed: 11/07/2022]
Abstract
Naphthamides have pharmacological potential as they express strong activities against microorganisms. The commercially available naphthoyl chloride and 4-bromoaniline were condensed in dry dichloromethane (DCM) in the presence of Et3 N to form N-(4-bromophenyl)-1-naphthamide (86%) (3). Using a Pd(0) catalyzed Suzuki-Miyaura Cross-Coupling reaction of (3) and various boronic acids, a series of N-([1,1'-biaryl]-4-yl)-1-naphthamide derivatives (4a-h) were synthesized in moderate to good yields. The synthesized derivatives were evaluated for cytotoxicity haemolytic assay and biofilm inhibition activity through in silico and in vitro studies. Molecular docking, ADME (absorption, distribution, metabolism, and excretion), toxicity risk, and other cheminformatics predict synthesized molecules as biologically active moieties, further validated through in vitro studies in which compounds (4c) and (4f) showed significant haemolytic activity whereas (4e) exhibited an efficient biofilm inhibition activity against Gram-negative bacteria Escherichia coli and Gram-positive bacteria Bacillus subtilis. When forming biofilms, bacteria become resistant to various antimicrobial treatments. Currently, research is focused on the development of agents that inhibit biofilm formation, thus the present work is valuable for preventing future drug resistance.
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Affiliation(s)
- Saba Ejaz
- Department of Chemistry, Government College, University of Faisalabad, Faisalabad, Pakistan
| | - Muhammad Zubair
- Department of Chemistry, Government College, University of Faisalabad, Faisalabad, Pakistan
| | - Nasir Rasool
- Department of Chemistry, Government College, University of Faisalabad, Faisalabad, Pakistan
| | - Faiz Ahmed
- Department of Chemistry, Government College, University of Faisalabad, Faisalabad, Pakistan
| | - Muhammad Bilal
- Department of Chemistry, Government College, University of Faisalabad, Faisalabad, Pakistan
| | - Gulraiz Ahmad
- Department of Chemistry, Government College, University of Faisalabad, Faisalabad, Pakistan
| | - Ataf A Altaf
- Department of Chemistry, University of Okara, Okara, Pakistan
| | - Syed A A Shah
- Faculty of Pharmacy, Universiti Teknologi MARA Cawangan Selangor Kampus Puncak Alam, Bandar Puncak Alam, Selangor, Malaysia.,Atta-ur-Rahman Institute for Natural Products Discovery (AuRIns), Universiti Teknologi MARA Cawangan Selangor Kampus Puncak Alam, Bandar Puncak Alam, Malaysia
| | - Komal Rizwan
- Department of Chemistry, University of Sahiwal, Sahiwal, Pakistan
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Hussain M, Ahmed Z, Khan SN, Shah SAA, Razi R, Imran S, Khalid M, Ali B, Irshad MB, Nawaz F, Chaudhry MI. α-Glucosidase Inhibition and Docking Studies of 5-Deoxyflavonols and Dihydroflavonols Isolated from Abutilon pakistanicum. CURR ORG CHEM 2019. [DOI: 10.2174/1385272823666191001224741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Three new 5-deoxyflavonoid and dihydroflavonoids 2, 3 and 4 have been isolated
from the methanolic extract of Abutioln pakistanicum aerial parts, for which structures
were elucidated explicitly by extensive MS- and NMR-experiments. In addition to
these, 3,7,4′-trihydroxy-3′-methoxy flavonol (1) is reported for the first time from Abutioln
pakistanicum. Compound 2 and 4 are p-coumaric acid esters while compounds 2–4
exhibited α-glucosidase inhibitory activity. Docking studies indicated that the ability of
flavonoids 2, 3 and 4 to form multiple hydrogen bonds with catalytically important residues
is decisive hence is responsible for the inhibition activity. The docking results signified
the observed in-vitro activity quite well which is in accordance with previously obtained
conclusion that phenol moiety and hydroxyl group are critical for the inhibition of
α-glucosidase enzyme.
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Affiliation(s)
- Munawar Hussain
- Department of Chemistry, Faculty of Natural Sciences, Khwaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, Pakistan
| | - Zaheer Ahmed
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan
| | - Shamsun N. Khan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan
| | - Syed A. A. Shah
- Faculty of Pharmacy, Universiti Teknologi MARA (UiTM), Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor Darul Ehsan, Malaysia
| | - Rizwana Razi
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan
| | - Syahrul Imran
- Atta-ur-Rahman Institute for Natural Products Discovery (AuRIns), Universiti Teknologi MARA (UiTM), Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor Darul Ehsan, Malaysia
| | - Muhammad Khalid
- Department of Chemistry, Faculty of Natural Sciences, Khwaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, Pakistan
| | - Bakhat Ali
- Department of Chemistry, Faculty of Natural Sciences, Khwaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, Pakistan
| | - Muhammad B. Irshad
- Department of Chemistry, Faculty of Natural Sciences, Khwaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, Pakistan
| | - Faisal Nawaz
- Department of Chemistry, University of Wah, Quaid Avenue, Wah Cantt47040, Pakistan
| | - Muhammad I. Chaudhry
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan
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Tahlan S, Narasimhan B, Lim SM, Ramasamy K, Mani V, Shah SAA. 2-Mercaptobenzimidazole Schiff Bases: Design, Synthesis, Antimicrobial Studies and Anticancer Activity on HCT-116 Cell Line. Mini Rev Med Chem 2019; 19:1080-1092. [PMID: 30306865 DOI: 10.2174/1389557518666181009151008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [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: 12/21/2017] [Revised: 04/24/2018] [Accepted: 08/20/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Increased rate of mortality due to the development of resistance to currently available antimicrobial and anticancer agents initiated the need to develop new chemical entities for the treatment of microbial infections and cancer. OBJECTIVE The present study was aimed to synthesize and evaluate antimicrobial and anticancer activities of Schiff bases of 2-mercaptobenzimidazole. METHODS The Schiff bases of 2-mercaptobenzimidazole were synthesized from 4-(2-(1H-benzo[d]- imidazol-2-ylthio)acetamido)benzohydrazide. The synthesized compounds were evaluated for antimicrobial and anticancer activities by tube dilution method and Sulforhodamine-B (SRB) assay, respectively. RESULTS Compounds 8 (MICpa, an = 2.41, 1.20 µM/ml), 10 (MICse, sa = 2.50 µM/ml), 20 (MICec = 2.34 µM/ml) and 25 (MICca = 1.46 µM/ml) showed significant antimicrobial activity against tested bacterial and fungal strains and compounds 20 (IC50 = 8 µg/ml) and 23 (IC50 = 7 µg/ml) exhibited significant anticancer activity. CONCLUSION In general, the synthesized derivatives exhibited moderate antimicrobial and anticancer activities. Compounds 8 and 25 having high antifungal potential among the synthesized compounds may be taken as lead molecules for the development of novel antifungal agents.
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Affiliation(s)
- Sumit Tahlan
- Faculty of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak-124001, India
| | | | - Siong Meng Lim
- Faculty of Pharmacy, Universiti Teknologi MARA (UiTM), 42300 Bandar Puncak Alam, Selangor Darul Ehsan, Malaysia.,Collaborative Drug Discovery Research (CDDR) Group, Pharmaceutical Life Sciences Community of Research, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor Darul Ehsan, Malaysia
| | - Kalavathy Ramasamy
- Faculty of Pharmacy, Universiti Teknologi MARA (UiTM), 42300 Bandar Puncak Alam, Selangor Darul Ehsan, Malaysia.,Collaborative Drug Discovery Research (CDDR) Group, Pharmaceutical Life Sciences Community of Research, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor Darul Ehsan, Malaysia
| | - Vasudevan Mani
- Department of Pharmacology and Toxicology, College of Pharmacy, Qassim University, Buraidah 51452, Saudi Arabia
| | - Syed A A Shah
- Faculty of Pharmacy, Universiti Teknologi MARA (UiTM), 42300 Bandar Puncak Alam, Selangor Darul Ehsan, Malaysia.,Atta-ur-Rahman Institute for Natural Products Discovery (AuRIns), Universiti Teknologi MARA (UiTM), Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor Darul Ehsan, Malaysia
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Chan GCY, Kamble R, Muller H, Shah SAA, Tang TB, Meriaudeau F. Fusing Results of Several Deep Learning Architectures for Automatic Classification of Normal and Diabetic Macular Edema in Optical Coherence Tomography. Annu Int Conf IEEE Eng Med Biol Soc 2019; 2018:670-673. [PMID: 30440485 DOI: 10.1109/embc.2018.8512371] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Diabetic Macular Edema (DME) is a severe eye disease that can lead to irreversible blindness if it is left untreated. DME diagnosis still relies on manual evaluation from opthalmologists, thus the process is time consuming and diagnosis may be subjective. This paper presents two novel DME detection frameworks: (1) combining features from three pre-trained Convolutional Neural Networks: AlexNet, VggNet and GoogleNet and performing feature space reduction using Principal Component Analysis and (2) a majority voting scheme based on a plurality rule between classifications from AlexNet, VggNet and GoogleNet. Experiments were conducted using Optical Coherence Tomography datasets retrieved from the Singapore Eye Research Institute and the Chinese University Hong Kong. The results are evaluated using a Leave-Two-Patients-Out Cross Validation at the volume level. This method improves DME classification with an accuracy of 93.75%, which is similar to the best algorithms so far on the same data sets.
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Abbasi MA, Nazir M, Ur-Rehman A, Siddiqui SZ, Hassan M, Raza H, Shah SAA, Shahid M, Seo SY. Bi-heterocyclic benzamides as alkaline phosphatase inhibitors: Mechanistic comprehensions through kinetics and computational approaches. Arch Pharm (Weinheim) 2019; 352:e1800278. [PMID: 30624805 DOI: 10.1002/ardp.201800278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [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: 09/20/2018] [Revised: 11/29/2018] [Accepted: 12/05/2018] [Indexed: 12/12/2022]
Abstract
Novel bi-heterocyclic benzamides were synthesized by sequentially converting 4-(1H-indol-3-yl)butanoic acid (1) into ethyl 4-(1H-indol-3-yl)butanoate (2), 4-(1H-indol-3-yl)butanohydrazide (3), and a nucleophilic 5-[3-(1H-indol-3-yl)propyl]-1,3,4-oxadiazole-2-thiol (4). In a parallel series of reactions, various electrophiles were synthesized by reacting substituted anilines (5a-k) with 4-(chloromethyl)benzoylchloride (6) to afford 4-(chloromethyl)-N-(substituted-phenyl)benzamides (7a-k). Finally, the nucleophilic substitution reaction of 4 was carried out with newly synthesized electrophiles, 7a-k, to acquire the targeted bi-heterocyclic benzamides, 8a-k. The structural confirmation of all the synthesized compounds was done by IR, 1 H NMR, 13 C NMR, EI-MS, and CHN analysis data. The inhibitory effects of these bi-heterocyclic benzamides (8a-k) were evaluated against alkaline phosphatase, and all these molecules were identified as potent inhibitors relative to the standard used. The kinetics mechanism was ascribed by evaluating the Lineweaver-Burk plots, which revealed that compound 8b inhibited alkaline phosphatase non-competitively to form an enzyme-inhibitor complex. The inhibition constant Ki calculated from Dixon plots for this compound was 1.15 μM. The computational study was in full agreement with the experimental records and these ligands exhibited good binding energy values. These molecules also exhibited mild cytotoxicity toward red blood cell membranes when analyzed through hemolysis. So, these molecules might be deliberated as nontoxic medicinal scaffolds to render normal calcification of bones and teeth.
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Affiliation(s)
- Muhammad A Abbasi
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Gongju, South Korea
- Department of Chemistry, Government College University, Lahore, Pakistan
| | - Majid Nazir
- Department of Chemistry, Government College University, Lahore, Pakistan
| | - Aziz Ur-Rehman
- Department of Chemistry, Government College University, Lahore, Pakistan
| | - Sabahat Z Siddiqui
- Department of Chemistry, Government College University, Lahore, Pakistan
| | - Mubashir Hassan
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Gongju, South Korea
| | - Hussain Raza
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Gongju, South Korea
| | - Syed A A Shah
- Faculty of Pharmacy and Atta-ur-Rahman Institute for Natural Products Discovery (AuRIns), Level 9, FF3, Universiti Teknologi MARA, Puncak Alam Campus, Selangor Darul Ehsan, Malaysia
| | - Muhammad Shahid
- Department of Biochemistry, University of Agriculture, Faisalabad, Pakistan
| | - Sung-Yum Seo
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Gongju, South Korea
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Rehman AU, Ahtzaz N, Abbasi MA, Siddiqui SZ, Saleem S, Manzoor S, Iqbal J, Virk NA, Chohan TA, Shah SAA. Synthesis of some new propanamide derivatives bearing 4- piperidinyl-1,3,4-oxadiazole, and their evaluation as promising anticancer agents. TROP J PHARM RES 2018. [DOI: 10.4314/tjpr.v17i6.22] [Citation(s) in RCA: 2] [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] Open
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K. Lim C, Tho LY, M. Lim Y, A. A. Shah S, F. Weber JF. Synthesis of 1,3,6-Trioxygenated Prenylated Xanthone Derivatives as Potential Antitumor Agents. LETT ORG CHEM 2012. [DOI: 10.2174/157017812802850230] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Shah SAA, Aslam A, Mirza AI, Ali S. Bisphosphonate related osteonecrosis of the jaws. J Ayub Med Coll Abbottabad 2010; 22:214-217. [PMID: 22338459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Bisphosphonates are used widely for a variety of bone conditions, most notably intravenous bisphosphonate in the treatment of metastatic bone lesions and multiple myeloma and oral bisphosphonates for osteoporosis. Recently, a peculiar form of osteonecrosis limited to the jaws has been discovered especially with the use of intravenous bisphosphonates. We review briefly the mechanism of action of these drugs, the clinical features and staging of the disease, prevention strategies and management options.
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Affiliation(s)
- S A A Shah
- Department of Oral & Maxillofacial Surgery, de'Montmorency College of Dentistry/Punjab Dental Hospital, Lahore, Pakistan.
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Ormerod AD, Shah SAA, Copeland P, Omar G, Winfield A. Treatment of psoriasis with topical sirolimus: preclinical development and a randomized, double-blind trial. Br J Dermatol 2005; 152:758-64. [PMID: 15840110 DOI: 10.1111/j.1365-2133.2005.06438.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Systemically administered sirolimus has demonstrated efficacy in psoriasis in a multicentre European study. OBJECTIVES To determine the efficacy and safety of topically applied sirolimus in treating psoriasis. METHODS In vitro studies were followed by a pilot study designed to determine if sirolimus penetrates human skin, and by a randomized, double-blind, left-right comparative, dose-ranging study consisting of treatment with 2.2% sirolimus for 6 weeks and 8% sirolimus for an additional 6 weeks in 24 patients with stable, chronic plaque psoriasis. The primary outcome measure was clinical score. Secondary measures were ultrasound plaque thickness, plaque erythema, and computerized image analysis of immunohistochemical stains for immunocytes and proliferating cells. Pharmacokinetics and blood chemistry monitoring for safety were also performed. RESULTS A significant reduction in the clinical score (P = 0.03) (mean score 9.1 following sirolimus vs. 11.2 in control) was achieved with topical sirolimus. Measurements of plaque thickness and erythema did not show significant improvement with treatment. Computerized image analysis of biopsies showed a significant reduction in CD4+ cells (P = 0.0054) and proliferating cells (stained by Ki-67) in the epidermis (P = 0.0153) with sirolimus treatment compared with control. CONCLUSIONS Topically applied sirolimus penetrates normal skin and may have some antipsoriatic and immunosuppressive activity.
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Affiliation(s)
- A D Ormerod
- Department of Dermatology, Aberdeen Royal Infirmary, Aberdeen AB25 2ZN, UK.
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Motevalli M, Shah D, Shah SAA, Sullivan AC. Synthesis, Structure, and Homogeneous Catalytic Activity of the Novel (Cyclosiloxy)oxovanadium(IV) complex VO{O(SiPh2O)2}2-.mu.-(Li(THF)2)2. Organometallics 2002. [DOI: 10.1021/om00022a056] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Shah SAA, Dorn H, Roesky HW, Lubini P, Schmidt HG. Novel Cyclopentadienyl-Free Organolanthanides: The First Examples of Five-Membered Amidolanthanide Heterocycles. Inorg Chem 1997; 36:1102-1106. [PMID: 11669675 DOI: 10.1021/ic961033b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reactions of LnCl(3) (Ln = Nd, Gd, Yb) and [{Me(2)SiN(R)Li}(2)] (R = t-Bu, Ph) give the chloride-bridged dimers [{{(t-Bu)NSiMe(2)SiMe(2)N(t-Bu)}Ln(&mgr;-Cl)(THF)}(2)] (1, Ln = Nd; 2, Ln = Gd; 3, Ln = Yb) and [{{(Ph)NSiMe(2)SiMe(2)N(Ph)}Ln(&mgr;-Cl)(THF)(2)}(2)] (4, Ln = Nd; 5, Ln = Gd; 6, Ln = Yb) in good yields. Compounds 2 and 5 were structurally characterized by X-ray crystallography: 2, triclinic, P&onemacr;, a = 10.321(2) Å, b = 11.116(2) Å, c = 13.434(3) Å, alpha = 107.57(3) degrees, beta = 111.31(3) degrees, gamma = 90.67(3) degrees, V = 1356.1(5) Å(3), Z = 1, R = 0.0233; 5, monoclinic, P2(1)/n, a = 13.913(13) Å, b = 12.914(9) Å, c = 16.434(14) Å, beta = 105.64(3) degrees, V = 2843(4) Å(3), Z = 2, R = 0.0281. The chloro functions in 1-6 remain reactive, demonstrated by the isolation of the trifluoroacetate derivatives of 1 and 2. Treatment of 1 or 2 with 2 equiv of NaOCOCF(3) gives [{{(t-Bu)NSiMe(2)SiMe(2)N(t-Bu)}Ln(&mgr;-OCOCF(3))(THF)}(2)] (7, Ln = Nd; 8, Ln = Gd). The structure of 8 was determined by a single-crystal X-ray diffraction analysis. Crystal data for 8: triclinic, P&onemacr;, a = 11.045(2) Å, b = 16.120(3) Å, c = 16.949(3) Å, alpha = 66.17(3) degrees, beta = 85.51(3) degrees, gamma = 78.27(3) degrees, V = 2702.9(9) Å(3), Z = 2, R = 0.0311. The structure of 8 shows the trifluoroacetate group adopting a bridging bidentate mode of coordination.
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Affiliation(s)
- Syed A. A. Shah
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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Dorn H, Shah SAA, Parisini E, Noltemeyer M, Schmidt HG, Roesky HW. Organometallic Fluorides of Zirconium and Hafnium in the Synthesis of Carboxylate Complexes: Molecular Structures of [{(eta(5)-C(5)Me(5))ZrF(OCOCF(3))(2)}(2)] and [(eta(5)-C(5)Me(5))(2)Zr(OCOCF(3))(2)]. Inorg Chem 1996; 35:7181-7184. [PMID: 11666903 DOI: 10.1021/ic9604977] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction of [(eta(5)-C(5)Me(5))ZrF(3)] and [(eta(5)-C(5)Me(5))HfF(3)] with Me(3)SiOCOCF(3) yields the dinuclear complexes [{(eta(5)-C(5)Me(5))ZrF(OCOCF(3))(2)}(2)] (1) and [{(eta(5)-C(5)Me(5))HfF(OCOCF(3))(2)}(2)] (2), regardless of the molar ratio employed. [(eta(5)-C(5)Me(5))(2)ZrF(2)] reacts with 1 and 2 equiv of Me(3)SiOCOCF(3) to form the mononuclear compounds [(eta(5)-C(5)Me(5))(2)Zr(OCOCF(3))(2)] (3) and [(eta(5)-C(5)Me(5))(2)ZrF(OCOCF(3))] (4), respectively. The molecular structures of 1 and 3 have been determined by single-crystal X-ray analysis: 1, triclinic, P&onemacr;, a = 9.508(3) Å, b = 11.002(4) Å, c = 17.528(3) Å, alpha = 78.55(4), beta = 76.80(2), gamma = 87.51(2) degrees, V = 1750(1) Å(3), Z = 2, R = 0.0378; 3, monoclinic, C2/c, a = 18.553(4) Å, b = 9.110(2) Å, c = 16.323(3) Å, beta = 114.88(3) degrees, V = 2503(1) Å(3), Z = 4, R = 0.0457. Compound 1 shows bridging bidentate and chelating carboxylate ligands as well as bridging fluorine atoms. The zirconium atoms are seven coordinated and have an 18-electron configuration. X-ray studies of 3 reveal two structural components where the carboxylate ligands coordinate in a monodentate (major component) and a chelating manner (minor component).
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Affiliation(s)
- Hendrik Dorn
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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Shah SAA, Dorn H, Voigt A, Roesky HW, Parisini E, Schmidt HG, Noltemeyer M. Group 4 Metal Amido Fluorides and Chlorides: Molecular Structures and the First Comparison in Ethylene Polymerization Catalysis. Organometallics 1996. [DOI: 10.1021/om960177v] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Syed A. A. Shah
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Hendrik Dorn
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Andreas Voigt
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Herbert W. Roesky
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Emilio Parisini
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Hans-Georg Schmidt
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Mathias Noltemeyer
- Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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Lazell M, Motevalli M, Shah SAA, Simon CKS, Sullivan AC. Formation of ring-expanded products from certain combinations of tetraphenyldisiloxanediolates [(Ph2SiOM′)2O](M′= Li or Na) and group 4 metal chlorides MCl4. ACTA ACUST UNITED AC 1996. [DOI: 10.1039/dt9960001449] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Motevalli M, Shah D, Shah SAA, Sullivan AC. Synthesis and structural characterisation of the cyclosiloxymagesium compound [(py)2Li]2-µ-Mg[{Ph2SiO}2O][{Ph2SiO}3O] having both six- and eight-membered magnesiasiloxane rings. ACTA ACUST UNITED AC 1994. [DOI: 10.1039/c39940002427] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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