SYNTHESIS OF SUBSTITUTED 5-HYDROTHIAZOLO[4,3-B]-1,3,4-OXADIAZOLES, 5-HYDROTHIAZOLO[4,3-B]-1,3,4-THIADIAZOLES, AND 5-HYDROTHIAZOLO[3,4-B]-1,2,4-TRIAZOLES AS POTENTIAL ANTIFUNGAL AGENTS

2-Aryl-3-(3-arylthioureido)-4-thiazolidinones (IIIa-d) were prepared by addition-condensation of aldehyde 4-arylthiosemicarbazones(IIa-d)and mercaptoacetic acid. 5-Aryl-2-(arylamino)-5-hydrothiazolo-[4,3-b]1,3,4-thiadiazoles (IVa-d), the corresponding thiazolo[4,3-b]-1,3,4-oxadiazoles (Va-d), and 1,5-diaryl-5-hydro-2-mercaptothiazolo[3,4-b]-1,2,4-triazoles were obtained by chemoselective intramolecular heterocyclization of IIIa-d with concentrated H2SO4, CH3I, and NaOH, respectively. Compounds IIIa-d-VIa-d were compared with Dithane M-45, a commercial fungicide, for their antifungal action against Aspergillus flavus and Fusarium solani. The screening results have been correlated with the structural features of the tested compounds.