S. Madan Kumar

Crystal structure of {[2-hy-droxy-2-(3-meth-oxy-phen-yl)cyclo-hex-yl]meth-yl}di-methyl-ammonium benzoate.

The title compound, C16H26NO2 +·C7H5O2 −, is a benzoate salt of the painkiller Tramadol. The six-membered cyclohexane ring of the cation adopts a slightly distorted chair conformation and carries OH and 3-methoxyphenyl substituents at the 2-position and a protonated methylazaniumylmethyl group at the 3-position. In addition, a weak intramolecular C—H⋯O hydrogen bond is observed in the cation. In the crystal, weak O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds link the components into chains along [010]. A C—H⋯π contact is also observed.

Crystal structure of 4-[(E)-(4-fluoro-benzyl-idene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione.

The title compound, C10H9FN4S, crystallizes with two molecules (A and B) in the asymmetric unit. The dihedral angle between the planes of the trizole and fluorobenzene rings is 7.3 (3)° in molecule A and 41.1 (3)° in molecule B. Molecule A features an intramolecular C—H⋯S hydrogen bond, which closes an S(6) ring. In the crystal, A+B dimers linked by pairs of N—H⋯S hydrogen bonds occur, generating R 2 2(8) loops. Weak π–π stacking contacts [centroid–centroid separation = 3.739 (6) Å] are also observed.

Crystal structure of (E)-3-(4-hy-droxy-benz-yl)-4-{[4-(methyl-sulfan-yl)benzyl-idene]amino}-1H-1,2,4-triazole-5(4H)-thione.

In the title compound, C17H16N4OS2, the triazole and methylthiobenzylidene rings are nearly coplanar, making a dihedral angle of 6.52 (12)°. An intramolecular C—H⋯S hydrogen bond forms an S(6) ring motif. The hydroxybenzyl ring is almost normal to the triazole and methylthiobenzylidene rings, making dihedral angles of 78.56 (12) and 84.79 (11)°, respectively. In the crystal, molecules are linked through O—H⋯N and N—H⋯O hydrogen bonds, forming layers parallel to the ac plane. The layers are linked via C—H⋯N hydrogen bonds, forming a three-dimensional structure. In addition, a short π–π interaction is observed [inter-centroid distance = 3.764 (3) Å], involving inversion-related methylthiobenzylidene rings.

Synthesis and in-vitro antioxidant activities of some coumarin derivatives containing 1,2,3-triazole ring

ABSTRACT A new green protocol was developed for the S-alkylation of 2-mercapto-1,3,4-oxadiazole by the reaction of 5-substituted-2-mercapto-1,3,4-oxadiazole with propargyl bromide in sodium bicarbonate in water. The newly synthesized 5-[(substitutedphenoxy)methyl]-2-[(prop-2-yn-1-yl)sulfanyl]-1,3,4-oxadiazole when reacted with azidomethyl coumarins underwent regioselective reaction yielding 4-(((4-((5-((substitutedphenoxy)methyl)-1,3,4-oxadiazol-2-yl)sulfanylmethyl)-1H-1,2,3-triazol-1-yl)methyl)-6-methyl)-2H-chromene-2-one or 1-((4-((5-((substitutedphenoxy)methyl)-1,3,4-oxadiazol-2-yl)sulfanylmethy)-1H-1,2,3-triazol-1-yl-)methyl)-3H-benzo[f]chromene-3-one. Structures of the newly synthesized compounds were confirmed by spectral and analytical data. The compounds were screened for their in-vitro antioxidant property. GRAPHICAL ABSTRACT

Synthesis, Characterization, Crystal Structure, and Hirshfeld Surface Analysis of Ethyl 2-(4-bromophenyl)-1-cyclohexyl-1H-benzo[d]imidazole-5-carboxylate

The title compound, C22H23N2BrO2 was synthesized via one-pot reductive cyclization method and characterized by CNH analysis, FT-IR, UV-visible, mass, 1H and 13C NMR spectra, thermogravimetric analysis (TGA) and single crystal X-ray diffraction method. The compound crystallizes in monoclinic crystal system: sp. gr. P21/c, Z = 4. The crystal data reveals that the intermolecular interactions of the C–H···π and π···π type connect the molecules which was also visualized with the help of Hirshfeld surface analysis.

Design, synthesis and pharmacological studies of some new quinoline Schiff bases and 2,5-(disubstituted-[1,3,4])-oxadiazoles

Our aim with the present work was to design and synthesize quinoline Schiff bases and quinolinyloxadiazole hybrid molecules and assess them for in vitro antioxidant activities and antimicrobial properties against clinical isolates. Synthesized compounds were characterized using FT-IR, 1H NMR, 13C NMR, mass spectra, and single crystal X-RD techniques. All compounds viz., 4a–g and 5a–g were efficiently synthesized in good yields in ranges of 76–84% and 80–85%, respectively. Newly synthesized compounds were screened for their antioxidant and antimicrobial potentials. Results were compared with standard antibacterial (amoxicillin and streptomycin) and antifungal (fluconazole) compounds which served as positive controls. Compounds 4b and 5g showed free radical scavenging activity of 26.55% (IC50 value 288.38 μg mL−1) and 27.22% (IC50 value of 167.69 μg mL−1), respectively. Compounds 4a, 4f, 5c, and 5e exhibited pronounced antimicrobial activity among all other synthesized compounds with zones of inhibition ranging between 10 ± 1 to 21 ± 1 mm and MIC 17 to 33.5 μg mL−1. Molecular docking studies of the synthesized compounds revealed good binding via hydrogen bond interactions with key residues on active sites as well as neighboring residues with an active site of glucosamine-6-phosphate (G6P) synthase, the target protein which is essential for formation of bacterial or fungal cell walls, and indicating inhibition of G6P synthase. Among the synthesized compounds 4f, 5c, and 5b show the least binding energies of −9.31, −6.7 and −6.21 kcal mol−1, respectively. Results from in silico investigation as well as in vitro antimicrobial studies suggest that the synthesized compounds may act as potential antimicrobial agents.

Synthesis, anticancer, structural, and computational docking studies of 3-benzylchroman-4-one derivatives

A series of 3-Benzylchroman-4-ones were synthesized and screened for anticancer activity by MTT assay. The compounds were evaluated against two cancerous cell lines BT549 (human breast carcinoma), HeLa (human cervical carcinoma), and one noncancerous cell line vero (normal kidney epithelial cells). 3b was found to be the most active molecule against BT549 cells (IC50 = 20.1 µM) and 3h against HeLa cells (IC50 = 20.45 µM). 3b also exhibited moderate activity against HeLa cells (IC50 = 42.8 µM). The molecular structures of 3h and 3i were solved by single crystal X-ray crystallographic technique. Additionally, the molecular docking studies between the tumour suppressor protein p53 with the lead compound 3h, which exhibited better anticancer activity against HeLa cells was examined.

Crystal structure of SAM-dependent methyltransferase from Pyrococcus horikoshii

Methyltransferases (MTs) are enzymes involved in methylation that are needed to perform cellular processes such as biosynthesis, metabolism, gene expression, protein trafficking and signal transduction. The cofactor S-adenosyl-L-methionine (SAM) is used for catalysis by SAM-dependent methyltransferases (SAM-MTs). The crystal structure of Pyrococcus horikoshii SAM-MT was determined to a resolution of 2.1 Å using X-ray diffraction. The monomeric structure consists of a Rossmann-like fold (domain I) and a substrate-binding domain (domain II). The cofactor (SAM) molecule binds at the interface between adjacent subunits, presumably near to the active site(s) of the enzyme. The observed dimeric state might be important for the catalytic function of the enzyme.

Crystal structures of N,N-dimethyl-(2-(2,2-diphenyl)-2-prop-2-ynyloxy)acetoxy)ethylamine and N,N-dimethyl-(2-(2,2-diphenyl)-2-prop-2-ynyloxy)acetoxy)ethylammonium 2,4,6-trinitrophenolate

The molecule of the neutral title compound and the cation in the title salt both exhibit a similar kind of disorder, even though their overall conformations are different. There are no direction-specific interactions between the molecules of the neutral compound, but the ions in the salt are linked into hydrogen-bonded sheets.

Crystal structure of ebastinium 3,5-dinitrobenzoate

In the cation of the title molecular salt, one of the non-H substituents on the piperidine ring occupies an equatorial site and the other an axial site. The ions are linked into sheets by a combination of one N—H⋯O and two C—H⋯O hydrogen bonds.