Synthesis and antifungal activity of some new derivatives of 5-{4′-(2",4"-dichlorobenzyloxy)-phenyl}-1,3,4-oxadiazole-2(3H)-thione

5-{4'-(2 '',4 ''-Dichlorobenzyloxy)-phenyl}-1,3,4-oxadiazole-2(3H)-thione (2) was prepared by the reaction of 4(2',4'-dichlorobenzyloxy)-benzoylhydrazine (1) with potassium isopropylxanthate in isopropyl alcohol. 5-{4'-(2 '',4 ''-Dichlorobenzyloxy)-phenyl}-1,3,4-oxadiazole-2(3H)-thione (2) on being subjected to aminomethylation with secondary amines in the presence of formaldehyde gave 3-aminomethy1-5-{4'-(2 '',4 ''-dichlorobenzyloxy)-phenyl}-1,3,4-oxadiazole-2(313)-thiones (3-8). Compound 2 was treated with alkyl/aralkyl/aryl halides in dry acetone in the presence of potassium carbonate to get 3-alkyl/aralkyl/ary1-5-{4'-(2 '',4 ''-dichlorobenzyloxy)-phenyl}-1,3,4-oxadiazole-2(3H)-thiones (9-14) while when compound 2 was treated with same halides in the presence of alcoholic potassium hydroxide, yielded 2-alkyl/aralkyl/arylthio-5-{4'(2 '',4 ''-dichlorobenzyloxy)-phenyl)-1,3,4-oxadiazoles (15-20). Oxadiazole 2 on reaction with acid chlorides in aqueous sodium hydroxide resulted in 2-aroyl/phenylacetylthio-5-{4'-(2 '',4 ''-dichlorobenzyloxy)-phenyl}-1,3,4-oxadiazoles (21-24). 2-Aryl5-{4'-(2 '',4 ''-dichlorobenzyloxy)-phenyl}-1,3,4-oxadiazoles (25-29) were obtained by refluxing benzoyl hydrazine 1 with aromatic acids in phosphorus oxychloride. The structures of the compounds were established by elemental analysis and spectral data (IR, H-1 NMR and Mass). The compounds were screened for their antifungal potential against human pathogenic fungi.