Synthesis and pharmacological evaluation of 3,5-disubstituted indole-2-[N beta-(substituted benzopyran-2 '-one-3 '-carboxyl)]carboxy hydrazides and 2H-3-(various substituted indol-3 '-yl)methyl-1,3-benzothiazoles

Abstract

Equimolar quantities of 3,5-disubstituted indole-2-carboxy hydrazides 1a-j and diethyl malonate 2 when refluxed in dry xylene for 10hr afford 3,5-disubstituted indole-2-[N beta -mono(carbethoxy malonoyl)]carboxy hydrazides 3a-j, which on reaction with Bz-substituted salicylaldehydes 4a-d in ethanol under reflux conditions in the presence of catalytic amount of piperidine for 5hr give 3,5-disubstituted indole-2-[N beta-(substituted benzopyran-2'-one-3'-carboxyl)]carboxy hydrazides 5a-z, 5a', b'. 2-(Various substituted indol-3'-yl)methyliminothiophenols 8a-d have been synthesised by reacting various substituted indole-3-carboxaldehydes 6a-d and o-aminothiophenol 7. Compounds 8a-d on reduction with sodium borohydride followed by treatment with formaldehyde yield the desired 2H-3-(various substituted indol-3'-yl)methyl-1,3-benzothiazoles 10a-d. All the newly synthesised compounds have been tested for their antimicrobial activity against E. coli, S. aureus, P. vulgaris and A. niger. Also compounds 3b-c, 5b, c, d, h 1, s, w and a' and 10a-d have been screened for their analgesic and anticatatonic activity. Some of the compounds exhibit significant activities.