SYNTHESIS AND FUNGITOXICITY OF NEW PEPTIDYL 1,3,4-OXADIAZOLO[3,2-A]PYRIMIDIN-5-ONES

摘要

Michael addition of nitrogen nucleophiles 2-amino-5-aryl-1,3,4-oxadiazoles IIa,b to 4-arylidene-5-oxazolones Ia,b followed by ring transformation of the resultant Michael adducts IIIa-d yielded 6-acetamido-2,7-diaryl-6,7-dihydro-5H-1,3,4-oxadiazolo[3,2-a]pyrimidin-5-o nes IVa-d in a one-pot procedure. The compounds IVa-d on deacetylation furnished their g-amino analogues Va-d, which were converted into their 6-peptidyl (Gly-Gly and Gly-L-Phe) amino derivatives VIIa-h. The compounds III-V and VII were evaluated in vitro for their fungitoxicities against Aspergillus niger and Fusarium oxysporum. Some of the compounds displayed activities comparable with that of the commercial fungicide Dithane M-45. Structure-activity relationships for the screened compounds are discussed.