Reactivities of 6-Amino-1, 3-dimethyl-5-thioformyluracil toward Nucleophiles and Its Application to Synthesis of Pyrido[2, 3-d]pyrimidines

Abstract

The reaction of the 5-thioformyluracil 1 with phenylhydrazine and various amines readily afforded the hydrazone 3a and Schiff bases 3b-d, respectively. Further, carbanions and Wittig reagents reacted with 1 to give pyrido[2, 3-d]pyrimidines 4 and 9. The corresponding 5-formyluracil 2 possessed much lower reactivities toward these nucleophiles than did 1.