Akkarapalli Muralikrishna

Synthesis and antioxidant activity of oxazolyl/thiazolylsulfonylmethyl pyrazoles and isoxazoles.

A new class of oxazolyl/thiazolylsulfonylmethyl pyrazoles (10-13) and isoxazoles (14, 15) were prepared from the synthetically vulnerable intermediate E-styrylsulfonylacetic acid methyl ester (1) and studied their antioxidant activity.

Synthesis and antioxidant activity of amido-linked benzoxazolyl/benzothiazolyl/benzimidazolyl-pyrroles and pyrazoles

The amido-linked benzoxazolyl/benzothiazolyl/benzimidazolyl-pyrroles and benzoxazolyl/benzothiazolyl/benzimidazolyl-pyrazoles were prepared from the synthetic intermediates (E)-N-(benzoxazol-2-yl)cinnamamide/(E)-N-(benzothiazol-2-yl)cinnamamide/(E)-N-(1H-benzimidazol-2-yl)cinnamamides adopting simple and versatile synthetic methodologies. All the new compounds were tested for antioxidant activity. The compounds 5b, 8b and 14b displayed greater antioxidant activity when compared with the standard drug ascorbic acid. It was also observed that benzoxazolyl amido-linked derivatives displayed greater radical scavenging activity than the benzothiazolyl and benzimidazolyl amido-linked derivatives.Graphical AbstractThe amido-linked benzoxazolyl/benzothiazolyl/benzimidazolyl-pyrroles and benzoxazolyl/benzothiazolyl/benzimidazolyl-pyrazoles were prepared from the synthetic intermediates (E)-N-(benzoxazol-2-yl)cinnamamide/(E)-N-(benzothiazol-2-yl)cinnamamide/(E)-N-(1H-benzimidazol-2-yl)cinnamamides adopting simple and versatile synthetic methodologies. All the new compounds were tested for antioxidant activity. The compounds 5b, 8b and 14b displayed greater antioxidant activity when compared with the standard drug Ascorbic acid. It was also observed that benzoxazolyl amido-linked derivatives displayed greater radical scavenging activity than the benzothiazolyl and benzimidazolyl amido-linked derivatives.

Synthesis and antioxidant activity of a new class of bis and tris heterocycles.

A series of novel heterocycles, bisbenzoxazolyl/benzothiazolyl/benzimidazolyl pyrazoles/isoxazoles/pyrimidines were synthesized and evaluated for their antioxidant activity. The bisbenzoxazolylisoxazole 10 exhibited good antioxidant activity when compared with the standard ascorbic acid.

N-(4-Chloro­phen­yl)-1-(5-{[(2-phenyl­ethen­yl)sulfon­yl]meth­yl}-1,3,4-oxadiazol-2-yl)methane­sulfonamide

In the title compound, C18H16ClN3O5S2, the dihedral angles between the oxadiazole ring and the phenyl and chlorobenzene rings are 23.4 (2) and 45.4 (2)°, respectively. The C—S—N—C and Cox—C—S—C (ox = oxadiazole) torsion angles are 89.3 (5) and −69.1 (3)°, respectively. A short intramolecular C—H⋯O contact closes an S(6) ring. In the crystal, molecules are linked by N—H⋯O hydrogen bonds, generating C(10) chains propagating in [001]. The packing is consolidated by C—H⋯O, C—H⋯π and very weak aromatic π–π stacking interactions [centroid–centroid separation = 4.085 (2) Å].