Synthesis of 5-Amino-3,3-dimethyl-7-phenyl-3H-[1,2]oxathiolo[4,3-b]pyridine-6-carbonitrile 1,1-Dioxides

The reaction of 4-amino-5,5-dimethyl-5H-1,2-oxathiole 2,2-dioxide (1) with 2-(arylidene)malononitriles 2 in ethanol, at reflux, using piperidine as catalyst, afforded 5-amino-3,3-dimethyl-7-aryl-3H-[1,2]oxathiolo[4,3-b]pyridine-6-carbonitrile 1,1-dioxides (3) in moderate chemical yields.