Preparation of Sydnone-4-carboxamide Oximes and Their Conversion into 4-(1,2,4-Oxadiazol-3-yl)sydnones
作者:Mou-Yung Yeh、Tsutomu Nonaka、Takushi Goto、Ming-Ching Hsu、Toshio Fuchigami、Hsien-Ju Tien
DOI:10.1246/bcsj.56.3535
日期:1983.11
3-Arylsydnone-4-carboxamide oximes (2) were prepared from the corresponding 3-arylsydnone-4-carbonitriles and hydroxylamine in high yields. The amide oximes 2 reacted with orthoesters to give 3-aryl-4-(1,2,4-oxadiazol-3-yl)sydnones.
Pyrazole-based DHODase inhibitors have been efficient and conveniently synthesized in 51-60% yield from 3-(p-aryl)-4-cyanosydnone via regioselective 1,3-diploar cycloaddition followed by an amidation and a Ritter reaction.