New synthesis of 4-(1-adamantyl)-2-aryl-1,3-thiazoles from 4-(1-adamantyl)-1,2,3-thiadiazole

Treatment of 4-(1-adamantyl)-1,2,3-thiadiazole with potassium tert-butoxide generated potassium 2-(1-adamantyl)ethynethiolate which reacted with aromatic carboxylic acid chlorides to give unstable S-[2-(1-adamantyl)ethynyl] arenecarbothioates whose acid hydrolysis afforded S-[2-(1-adamantyl)-2-oxoethyl] arenecarbothioates. The latter reacted with ammonium acetate in acetic acid yielding 4-(1-adamantyl)-2-aryl-1,3-thiadiazoles. Reactions of 4-(1-adamantyl)-2-(4-chloro-3-nitrophenyl)-1,3-thiadiazole with cyclic secondary amines gave the corresponding products of nucleophilic replacement of the chlorine atom in the aromatic ring.