Synthesis and antimicrobial activity of some novel thiazoline and thiazolidinone derivatives of 2,6-di-tertbutyl-1,4-benzoquino.

Three novel series of 2,6-di-tert-butyl-1,4-benzoquinone derivatives were synthesized: 4-[(3,4-disubstituted-2,3-dihydrothiazol-2-ylidene) hydrazono]-2,6-di-tert-butyl-2,5-cyclohexadien-1-ones, 4-[(3-substituted-5-carbethoxy-4-methyl-2,3-dihydrothiazol-2- ylidene)hydrazono]-2,6-di-tert-butyl-2,5-cyclohexadien-1-one s, and 4-[(3-substituted-4-oxothiazolidin-2-ylidene)hydrazono]-2,6- di-tert- butyl-2,5-cyclohexadien-1-ones. These compounds were prepared by cyclization of the new 4-(N-substituted thiocarbamoylhydrazono)-2,6-di-tert-butyl-2,5-cyclohexadien- 1-ones with phenacyl bromides, ethyl alpha-chloroacetoacetate and ethyl bromoacetate, respectively. Antimicrobial testing of the prepared compounds and of the key intermediate thiosemicarbazones was performed. Some of the compounds revealed higher activity than streptomycin.