Reaction of 2-Aryl-4-Cyano-1,3-Oxazole-5-Sulfonyl Chlorides With 5-Amino-1H-Pyrazoles and 5-Amino-1H-1,2,4-Triazole

The reaction of 2-aryl-4-cyano-1,3-oxazole-5-sulfonyl chlorides with 5-amino-3-R-1 H -pyrazoles and 5-amino-1 H -1,2,4-triazole gave 5-[(3-R-5-amino-1 H -pyrazol-1-yl)sulfonyl]-2-aryl-1,3-oxazole-4-carbo- nitriles and 5-[(5-amino-1 H -1,2,4-triazol-1-yl)sulfonyl]-2-aryl-1,3-oxazole-4-carbonitriles. The action of sodium hydride on these carbonitriles leads to the elimination of sulfur dioxide and cyclocondensation to give new heterocyclic systems, namely, [1,3]oxazolo[5,4- d ]pyrazolo[1,5- a ]-pyrimidine and [1,3]oxazolo[5,4- d ][1,2,4]triazolo[1,5- a ]pyrimidine.