Formation of R44(8)$R_4^4(8)$ ring in chloride salts of 8-hydroxyquinolinium derivatives: synthesis, structural, and theoretical studies

The molecular structures of chloride salts of 2- and 5-substituted derivatives of 8-hydroxyquinoline, Me–H2Q+·Cl– ([C10H10NO]Cl) and Cl–H2Q+·Cl– ([C9H7ClNO]+·Cl–), were determined by single crystal X-ray diffraction methods; the latter is a new polymorph. In the crystal structures of these salts, several intra- and inter-molecular interactions result in a step-shaped centrosymmetric R 4 4 ( 8 ) $R_4^4(8)$ ring. Unlike most quinolinium salts, there was no solvent present in these structures. Protonation of the quinoline N atom had an effect on the N···O bite distances and C–N–C angle and greater conjugation of the benzene ring with a hydroxyl group was also observed. π–π Interactions between each pair of quinolinium rings were observed in Me–H2Q+·Cl– but not in Cl–H2Q+·Cl–. In addition, the quantum chemical calculations were performed on the new structures as well as similar compounds for comparison. The optimized structures were compared with the experimental observations for the effect of protonation and of hydrogen bonding interactions.

Reaction of selected carbohydrate aldehydes with benzylmagnesium halides: benzyl versus o-tolyl rearrangement

The Grignard reaction of 2,3-O-isopropylidene-α-D-lyxo-pentodialdo-1,4-furanoside and benzylmagnesium chloride (or bromide) afforded a non-separable mixture of diastereomeric benzyl carbinols and diastereomeric o-tolyl carbinols. The latter resulted from an unexpected benzyl to o-tolyl rearrangement. The proportion of benzyl versus o-tolyl derivatives depended on the reaction conditions. Benzylmagnesium chloride afforded predominantly o-tolyl carbinols while the application of benzylmagnesium bromide led preferably to the o-tolyl carbinols only when used in excess or at higher temperatures. The structures of the benzyl and o-tolyl derivatives were confirmed unambiguously by NMR spectral data and X-ray crystallographic analysis of their 5-ketone analogues obtained by oxidation of the corresponding mixture of diastereomeric carbinols. A possible mechanism for the Grignard reaction leading to the benzyl→o-tolyl rearrangement is also proposed.

Synthesis Methods For Ce(CrO4)2 · χH2O And Crystal Structures Of K2CrSO7, (NH4)2Cr2O7 And Na2Cr2O7 · 2H2O

New and quick methods to synthesize Ce(CrO4)2 · 2H2O and Ce(CrO4)2 ·H2O, giving high yields, are described. The methods are based on exchange reactions by refluxing in water or on solid state reactions. The first crystal structure containing a chromatosulfato ion is presented. K2CrSO7 belongs to space group P21/n with a = 7.4024(1), b = 7.3908(1), c = 12.9883(2) Å , β = 90.021(1)° and Z = 4. The CrSO7 2− ion, consisting of one chromate group sharing one oxygen atom with one sulfate group, has a pseudo syn-C2v conformation with eclipsed oxygen atoms. K2CrSO7 forms a three dimensional network of CrSO7 2− ions held together by the charge balancing potassium ions, with the general structural features common with dichromate-like structures. The redetermination of the structures of (NH4)2Cr2O7 (space group C2/c, with hydrogen atoms located) and Na2Cr2O7 ·2H2O (space group P21, with hydrogen atoms located and the absolute structure established) are reported

Ca10(Cr(V)O4)6(Cr(VI)O4), a disordered mixed-valence chromium compound exhibiting inversion twinning

The structure analysis of so-called 9CaO·4CrO(3)·Cr(2)O(3) proved it to be the title compound, decacalcium hexakis[chromate(V)] chromate(VI), with the simultaneous presence of unusual chromium oxidation states. The structure determination was carried out on a crystal that had inversion twinning. The Cr(VI)O(4) tetrahedron is situated on a threefold axis and is disordered over two possible orientations that share three O atoms, while the Cr(V)O(4) tetrahedra are in general positions and are ordered. The charge is balanced by Ca(2+) cations, one of which is located on a threefold axis. The Ca(2+) ions are coordinated by six, seven or eight O atoms. The compound is a significant phase in the CaO-CrO(x) system and its formation reduces the refractoriness of calcium-rich compositions in an oxidizing atmosphere.

X-ray and DFT studies of a mono- and binuclear copper(II) ionic compound containing a Schiff base

In the structure of trans-bis(ethanol-κO)tetrakis(1H-imidazole-κN(3))copper(II) bis[μ-N-(2-oxidobenzylidene)-D,L-glutamato]-κ(4)O(1),N,O(2'):O(2');κ(4)O(2'):O(1),N,O(2')-bis[(1H-imidazole-κN(3))cuprate(II)], [Cu(C(3)H(4)N(2))(4)(C(2)H(6)O)(2)][Cu(2)(C(15)H(14)N(3)O(5))(2)], both ions are located on centres of inversion. The cation is mononuclear, showing a distorted octahedral coordination, while the anion is a binuclear centrosymmetric dimer with a square-pyramidal copper(II) coordination. An extensive three-dimensional hydrogen-bonding network is formed between the ions. According to B3LYP/6-31G* calculations, the two equivalent components of the anion are in doublet states (spin density located mostly on Cu(II) ions) and are coupled as a triplet, with only marginal preference over an open-shell singlet.

Perforator flap: A novel method for providing skin cover to lower limb defects

BACKGROUND

Soft tissue defects in the lower limb pose a formidable challenge due to lack of reliable local flap options. Due to thin non-expendable soft tissues and predisposition to massive edema formation, even small defects become problematic. Perforator flaps represent the latest trends in soft tissue coverage. The aim of this study was to evaluate the effectiveness of perforator flaps as coverage of soft tissue defects in lower limbs.

MATERIAL AND METHODS

A series of patients with soft tissue defects of various etiologies in the lower limb were treated using perforator flap at a tertiary care service hospital. Six were free flaps and fourteen pedicled flaps. Doppler ultrasound was used to identify recipient and donor vessels pre-operatively.

RESULTS

Only one flap was lost due to venous congestion. In another case of carcinoma penis there was delayed healing due to persistent lymphorrhoea as a result of post-operative status following lymph node dissection and radiotherapy. Fifteen donor sites required split skin grafting, as they could not be closed directly.

CONCLUSION

Perforator flaps are a reliable option for closure of soft tissue defects of lower limb irrespective of size, location and depth. There is minimal donor site morbidity. It has the advantage of rapid dissection, flap elevation and reliable skin territory. As no special equipment is required it can be replicated in smaller centers also.

Synthesis and structure elucidation of novel fused 1,2,4-triazine derivatives as potent inhibitors targeting CYP1A1 activity

Synthesis and structure elucidation of new series of novel fused 1,2,4-triazine derivatives 3a-3f, 4a-4i and 6a-6b and their inhibitory activities are presented. Molecular structures of the synthesized compounds were confirmed by (1)H NMR, (13)C NMR, MS spectra and elemental analyses. X-ray crystallographic analysis was performed on 2-acetyl-8-(N,N-diacetylamino)-6-(4-methoxybenzyl)-3-(4-methoxy-phenyl)-7-oxo-2,3-dihydro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazine 3d and 2-acetyl-8-(N-acetylamino)-6-benzyl-3-(4-chlorophenyl)-3-methyl-7-oxo-2,3-dihydro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazine 4e to secure their structures. The inhibitory effect of these compounds toward the CPY1A1 activity was screened to determine their potential as promising anticancer drugs. Our data showed that compounds 4e, 5a, 5b and 6b possess the highest inhibitory effects among all tested compounds. Furthermore, analysis of triazolotriazine derivatives docking showed that these compounds bind only at the interface of substrate recognition site 2 (SRS2) and (SRS6) at the outer surface of the protein. Amino-acids ASN214, SER216 and ILE462 participate in the binding of these compounds through H-bonds.

Stemodin-derived analogues with lipid peroxidation, cyclooxygenase enzymes and human tumour cell proliferation inhibitory activities

A series of analogues, derived from the antiviral and cytotoxic diterpene stemodin, were prepared and evaluated for their lipid peroxidation (LPO), cyclooxygenase enzyme-1 (COX-1) and -2 (COX-2), and tumour cell proliferation inhibitory activities. Oxidation of stemodin produced stemodinone, which was then converted to stemod-12-en-2-one. Reaction of the latter under Petrow conditions (bromine; silver acetate/pyridine) yielded mainly dibrominated abeo-stachanes. Solvolysis of the dibromo compounds gave products of hydrolysis, some with rearranged skeleta. In the lipid peroxidation inhibitory assay three of the compounds exhibited prominent activity. Interestingly, all the analogues showed higher COX-1 enzyme inhibition than COX-2. Although a few of the diterpenes limited the growth of some human tumour cell lines, most compounds induced proliferation of such cells.

Ethyl 1-ethyl-7-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate: X-ray and DFT studies

The basic building unit in the structure of the title compound, C(14)H(14)FNO(3), is pairs of molecules arranged in an antiparallel fashion, enabling weak C-H···O interactions. Each molecule is additionally involved in π-π interactions with neighbouring molecules. The pairs of molecules formed by the C-H···O hydrogen bonds and π-π interactions form ribbon-like chains running along the c axis. Theoretical calculations based on these pairs showed that, although the main intermolecular interaction is electrostatic, it is almost completely compensated by an exchange-repulsion contribution to the total energy. As a consequence, the dominating force is a dispersion interaction. The F atoms form weak C-F···H-C interactions with the H atoms of the neighbouring ethyl groups, with H···F separations in the range 2.59-2.80 Å.

A new Mo Schiff base complex: methanol[N'-(3-meth-oxy-2-oxidobenzyl-idene)benzohydrazidato]dioxido-molybdenum(VI)

In the title benzil-idene Schiff base molybdenum(VI) complex, [Mo(C(15)H(12)N(2)O(3))O(2)(CH(3)OH)], the Mo(VI) ion is coordinated by two oxide O atoms and by two O atoms and one N atom of the tridentate N'-(3-meth-oxy-2-oxidobenzyl-idene)benzo-hydrazidate (L) Schiff base ligand. The methanol O atom completes the distorted octa-hedral configuration of the Mo(VI) atom. Strong O-H⋯N hydrogen bonds form a C(5) chain around a 2(1) screw axis. Weak C-H-O hydrogen bonds are also present.

Hexaaqua-zinc(II) bis-[tris-(3-carb-oxy-pyridine-2-carboxyl-ato)zincate(II)]

The title compound, [Zn(H(2)O)(6)][Zn(C(7)H(4)NO(4))(3)](2), consists of two [Zn(py-2,3-dcH)(3)](-) anions (py-2,3-dcH is 3-carboxy-pyridine-2-carboxylate) and one [Zn(H(2)O)(6)](2+) cation. The anion is a six-coordinate complex located on a threefold rotation axis with a slightly distorted octa-hedral geometry around Zn(2+) ion. The cation is also six-coordinate with an octa-hedral geometry around the Zn atom, located at a axis. Non-covalent inter-actions such as π-π stacking [centroid-centroid distance = 3.828 (4)Å] and O-H⋯O hydrogen bonds play important roles in stabilizing the supra-molecular structure.

Reconstruction in Warfare Injuries

Traumatic injuries, especially in the combat setting, stress the surgical team that may be sited in a remote forward area, battling against paucity of time, resources and infrastructure. The lone surgeon may be faced with the arduous challenge of saving life. There is seldom thought given to reconstruction in this high-pressure situation. If the patient survives, morbidity for want of reconstruction can be severe and quality of life can suffer significantly. Reconstruction after 3 to 5 days is fraught with complications and usually does compromise outcome in the post-operative phase. The reconstructive surgeon should be involved early in the management as he can provide coverage for large soft tissue defects after aggressive debridement with panache. If the patient is haemodynamically stable, he should be transferred urgently, preferrably by air, to a higher centre with multi-specialty care, especially being equipped with an orthopaedic and trauma reconstructive surgeon. It has been proved beyond doubt that the healing improves significantly and there is marked decrease in morbidity if coverage of wounds is provided early, before colonized wounds get infected.

Synthesis and X-ray structure of a C5-C4-linked glucofuranose-oxazolidin-2-one

The formation of (4R)-4-carbamoyl-4-[(4R)-3-O-benzyl-1,2-O-isopropylidene-beta-l-threofuranos-4-C-yl]-oxazolidin-2-one instead of expected imidazolidin-2,4-dione (hydantoin) derivative from 5-amino-5-cyano-5-deoxy-3-O-benzyl-1,2-O-isopropylidene-alpha-d-glucofuranose or 3-O-benzyl-1,2-O-isopropylidene-alpha-d-xylo-hexofuranos-5-ulose under Bucherer-Bergs reaction conditions is reported. Single crystal X-ray diffraction data revealed that (3)T(4) is the prefered conformation for the furanose ring, while E(2) and (2)T(1) conformations are adopted by the 1,3-dioxolane and 2-oxazolidinone five-membered rings, respectively.

Intramolecular hydrogen bond and proton transfer in 3-(2-benzimidazolylthio)-2,4-pentanedione. Crystallographic evidence and theoretical calculations

Crystal structure of the title compound is orthorhombic, Pbca, a=7.8689(2) Å, b=9.6519(3) Å, c=31.3579(9) Å. The structure was solved by direct methods and refined by a full-matrix least squares procedure to final R (all)=0.0682 for 2853 unique diffractions merged from 24459 measured at 183(2)K. The molecule is formed by two planar moieties joined through an atom of sulphur. The short intramolecular O...O contact is 2.430(2) Å, the intramolecular hydrogen bond is slightly asymmetric. Theoretical ab initio calculations done at B3LYP/SVP and ONIOM(MP2/SVP:B3LYP/SVP) levels showed that the experimental geometry of pentanedione pseudoring is close to the geometry corresponding to a transition state on the asymmetric potential energy curve. Calculated energy difference between two minima is only –4.72 kJ/mol and the energy barrier –6.02 kJ/mol, which agrees well to ~6.6kJ/mol found in microwave spectroscopic study of malonaldehyde.

A new Rietveld refinement of κ-Al2O3

Rietveld refinement and the final model for pure κ-alumina are presented. The starting model was obtained through total energy calculations based on first principles. The resulting geometry parameters are within intervals of expected values for octahedral and tetrahedral coordina-tions. This result thus serves as a validation of the compu-tational approach as a useful alternative to classical methods in the first step of structure determination.

Crystal and electronic structure of aqua(N-salicylidene-methylester-l-glutamato)Cu(II) monohydrate

The absolute structure of the title compound, CuNC13H17O7, has been determined. The crystal structure consists of the molecular units Cu(N-sal-5-met-L-glu)(H2O) connected by a three-dimensional network of hydrogen bonds. The coordination polyhedron in the complex is approximately square-pyramidal with a pentacoordinated Cu(II) atom. The base of the pyramid is formed by nitrogen and oxygen atoms belonging to the molecule, while the apex of the pyramid contains a weakly bonded oxygen atom of the carboxylic group of another molecule. The B3LYP/SVP method and basis set in Gaussian98 was used for quantum chemical calculation of the nature of Cu–X (X = O, N) bonds. While the calculated dissociation energy of the weakly bonded crystalline water is only 17.2 kJ/mol, the bonding energy of the water molecule coordinating to the Cu atom is 62.3 kJ/mol.

Bis[4-(dimethylamino)pyridine-kappaN1]silver(I) nitrate dihydrate

The title compound, [Ag(C(7)H(10)N(2))(2)]NO(3).2H(2)O or [Ag(dmap)(2)]NO(3).2H(2)O, where dmap is 4-(dimethylamino)pyridine, has a distorted linear coordination geometry around the Ag(I) ion. A novel pattern of water-nitrate hydrogen-bonded anionic strands is formed in the c direction, with the cationic [Ag(dmap)(2)](+) monomers trapped between them. The Ag(I) ion and the nitrate group atoms, as well as the water molecules (including the H atoms), are on a crystallographic mirror plane (Wyckoff position 4a). The influence of bulky methyl substituents in position 4 of the 4-(dimethylamino)pyridine ligand on packing is discussed. The absolute structure was determined unequivocally.

3D echocardiography: "The most powerful predictor of masked CVD in metabolic syndrome"

AIMS & OBJECTIVE: To evaluate the impact of the Metabolic Syndrome (MetS) on various echo variables by 3D Echocardiography.

MATERIALS AND METHODS

100 patients of MetS from indoor and outdoor patient departments were subjected to Echocardiographic and Carotid Doppler evaluation. They were divided into three groups: Group A, Group B and Group C on the basis of age <40 yrs, 40-60 yrs and >60 yrs respectively. The echo variables included left ventricular myocardial performance index (LVMPI), left ventricular mass index (LVMi), left ventricular diastolic dysfunction (LVDD), systolic function (LVEF), left atrial volume index (LAVi) and composite common carotid intima media thickness (CCIMT).

RESULTS

The mean LVMPI was abnormal in all the groups and showed an increasing trend with prolonged LVMPI (> 0.4) in 74% of the total population. Prolonged LVMPI in Group A, Group B and Group C were 12.1%, 52.7% and 35.1% respectively. There was also a strong correlation between LVMPI & LVDD (p-value < 0.0001). Only 9% had systolic dysfunction (LVEF < 50%), but 68% of patients had abnormal diastolic function, of which 53% had grade I LVDD, 12% had grade II LVDD and 3% had grade III diastolic dysfunction. None of our patients had grade IV diastolic dysfunction. The mean LA Vi was normal in all the groups, but LAVi increased with worsening LVDD. The mean LVMi indexed to Body Surface Area (BSA) was normal in all the groups, but showed a statistically significant increasing trend from Group A to Group C (p-value < 0.05). Statistically significant higher LVMi values were observed for males as compared to females (p-value < 0.0001). On analysis of patients having left ventricular hypertrophy (LVH), 76% had concentric remodeling; only 11 % had concentric hypertrophy, but none had eccentric hypertrophy. Most of our patients in Group B & Group C had higher mean Composite CCIMT (0.73 +/- 0.33 & 0.84 +/- 0.42 respectively) which was statistically very significant (p-value < 0.001)

CONCLUSION

Metabolic Syndrome is associated with masked cardiovascular disease (CVD) as evident by 3D Echo in this series of patients. LVMPI was an early indicator and the most robust marker of early LVDD. Impaired relaxation was highly prevalent; while LAVi was less robust predictor of LVDD in this series of patients. Concentric left ventricular remodeling was the most common pattern of LVH. Most of our series of patients had increased Composite CCIMT. Thus 3D Echocardiography has great potential and is very useful for early detection and timely therapeutic interventions in patients with subclinical CVD in MetS.