The use of enamines in the synthesis of heterocycles

The reaction of the enamine N-styryl pyrrolidine with 4,6-dichloro-5-nitropyrimidine and 4-amino-6-chloro-5-nitropyrimidine was investigated. Reduction of resultant compounds was followed by spontaneous ring closure to the pyrrolo3,2-d]pyrimidine ring system. This reaction sequence should provide a general method for the preparation of 4,7-disubstituted pyrrolo3,2-d]-pyrimidines.