2-Aminonicotinic acid reacts with formamide, urea and thiourea to yield 4-hpdroxy-(I), 2, 4- dihydroxy-(IX) and X-mercapto--i-hydroxy-(VI) pyrido [2, 3-d] pyrimidines, respectively. These substances serve as starting materials for transformation reactions leading to a variety of pyrido-[2, 3-d] pyrimidines with one or two functional groups in the pyrimidine moiety. Some similarities and differences between the pyrido [2, 3-d]-pyrimidines and ...
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