Hetero Diels-Alder Synthesis and Fungitoxicity of New 1,3,4-Thiadiazolo-s-triazine-5(H)-thiones

Article abstract of DOI:10.1021/jf00042a020

Hetero Diels-Alder synthesis involving conjugated azomethines, 5-(arylideneamino)-2-mercapto-1,3,4-thiadiazoles IIa-c, as dienes (azadienes) and aryl isothiocyanates as dienophiles affords 2,6,7-trisubstituted 6,7-dihydro-1,3,4-thiadiazolo<3,2-a>-s-triazine-5(H)-thiones IIIa-f.The azomethines IIa-c on ethylation followed by hetero Diels-Alder reaction furnish 6,7-diaryl-2-(ethylthio)-6,7-dihydro-1,3,4-thiadiazolo<3,2-a>-s-triazine-5(H)-thiones IVa-f.Fungitoxicities of the compounds II-IV were evaluated in vitro against Aspergillus niger and Fusarium oxysporum.Someof the compounds displayed activities comparable with that of the commercial fungicide Dithane M-45.Structure-activity relationships for the screened compounds are discussed.