Heterocyclic amplifiers of phleomycin. V. Thiadiazolylpyridines and related compounds; preliminary antitumour results

Abstract

Syntheses are described for N,N-dimethyl-2-[5'-(pyridin-2''-yl)-1',3',4'-thiadiazol-2'-ylthio]ethylamine; the homologous propylamine; the N,N-diethyl homologue; the 5'-phenyl analogue; and some substituted phenyl, pyrazinyl and pyrimidinyl analogues.

Unlike the pyridin-4''-yl isomer previously described, these compounds proved but mediocre amplifiers of phleomycin-G in vitro against Escherichia coli. Testing in vivo against Ehrlich's tumour in mice was therefore confined to the pyridin-4''-yl compound and to N,N-dimethyl-2-(6'-methyl-2'-phenylpyrimidin-4'-ylthio)ethylamine: the first showed considerable amplifying power towards two phleomycins and a bleomycin; the second, only marginally less amplification towards the same phleomycins.