A. Padmaja

Synthesis, antimicrobial and cytotoxic activities of 1,3,4-oxadiazoles, 1,3,4-thiadiazoles and 1,2,4-triazoles.

A new class of 1,3,4-oxadiazoles were prepared from acid hydrazides on treatment with different carboxylic acids in the presence of phosphorus oxychloride. Interconversion of oxadiazoles to thiadiazoles and triazoles was carried out with appropriate reagents. The antimicrobial and cytotoxic activities of compounds 7a-d to 12a-d were tested. Compounds 10d and 12d showed pronounced antimicrobial activity. Further, compound 10d exhibited maximum cytotoxicity.

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 antimicrobial activity of amido linked pyrrolyl and pyrazolyl-oxazoles, thiazoles and imidazoles.

A new class of amido linked bis heterocycles viz., pyrrolyl/pyrazolyl-oxazoles, thiazoles and imidazoles were prepared by 1,3-dipolar cycloaddition of TosMIC and diazomethane to the respective cinnamamide derivatives and screened for antimicrobial activity. The chlorosubstituted imidazolyl cinnamamide (6c) is the most potential antimicrobial agent as it displayed strong antibacterial activity against Bacillus subtilis and antifungal activity against Penicillium chrysogenum.

Synthesis, antimicrobial and cytotoxic activities of pyrimidinyl benzoxazole, benzothiazole and benzimidazole.

A variety of pyrimidinyl benzoxazoles, benzothiazoles and benzimidazoles linked by thio, methylthio and amino moieties were prepared and studied their antimicrobial and cytotoxic activities. The compound pyrimidinyl bis methylthio benzimidazole 22 was a potent antimicrobial agent particularly against Staphylococcus aureus (29 mm, MIC 12.5 μg/mL) and Penicillium chrysogenum (38 mm, MIC 12.5 μg/mL). The amino linked pyrimidinyl bis benzothiazole 24 exhibited cytotoxic activity on A549 cells with IC50 value of 10.5 μM.

Synthesis, antimicrobial and cytotoxic activities of sulfone linked bis heterocycles.

A new class of sulfone linked bis heterocycles viz., pyrrolyl/pyrazolyl arylaminosulfonylmethyl 1,3,4-oxadiazoles, 1,3,4-thiadiazoles, and 1,2,4-triazoles were prepared and tested for antimicrobial activity and cytotoxicity. The chloro-substituted compounds 5c, 8c and 14c showed comparable antibacterial activity to chloramphenicol against Pseudomonasaeruginosa and compound 5c exhibited comparable antifungal activity to ketoconazole against Penicilliumchrysogenum. One of the compounds, vinylsulfonyl oxadiazole showed appreciably cytotoxic activity on A549 lung carcinoma cells with an IC(50) at a concentration of 31.7 μM.

AN EFFICIENT SYNTHESIS OF 6,8-DIARYLCARBAZOLES VIA FISCHER INDOLE CYCLIZATIONS

6,8Diaryl 6,7-dihydrocarba/.ole (4), 6,8diaryl 6,7,8,9, terahydrocarbazole (7), 6,8diary 1 carba/.olc (8) were obtaüied from the Fischer indole cyclization of 6 carbcthoxy3,5diarylcyclohex2-enI -one (1).

A simple strategy for styryl sulfonyl ethynylogues and 1,4-diarylbut-1-en-3-ynes

Abstract A general and simple strategy for 2-arylethenyl-2′-arylethynyl sulfones ( 9 ) and 1,4-diarylbut-1-en-3-ynes ( 10 ) has been developed by the lability of carbon-heteroatom bond in heterocycles, 1,2,3-selenadiazole ( 3 ) as the basis.

Synthesis and bioassay of pyrrolyl oxazolines and thiazolines.

A new class of sulfone linked pyrrolyl oxazolines and thiazolines were synthesized from E-arylsulfonylethenesulfonylacetic acid methyl ester and studied their antimicrobial and antioxidant activities.

REGIOSPECIFIC AND REGIOSELECTIVE 1,3-DIPOLAR CYCLOADDITION OF DIPOLAR REAGENTS TO UNSYMMETRICAL BISOLEFINIC KETONES IN THE PRESENCE OF CHLORAMINE-T (CAT)

ABSTRACT The reaction of 1,5-diaryl-3-methyl-1,4-pentadien-3-one with araldehyde phenylhydrazone/araldoxime in the presence of chloramine-T proceeds regiospecifically in MeOH and regioselectively in AcOH leading to mono- and bis-pyrazolines/ isoxazolines.

Synthesis and antimicrobial activity of amine linked bis- and tris-heterocycles

A series of amine linked bis- and tris-heterocycles were prepared from heteroaryl cinnamamides and tested for antimicrobial activity. The compounds 11c and 12c exhibited excellent antibacterial activity while 12a and 12c displayed excellent antifungal activity.