Studies on uracils: A facile one-pot synthesis of pyrazolo[3,4-d]pyrimidines
The reaction of 6-hydrazino uracils 1 and nitrones 2 result in an efficient one-pot synthesis of pyrazolo[3,4-d]pyrimidines 3 in excellent yields. The isolation of the by-product aniline from the reaction mixture supported the plausible mechanism for the formation of pyrazolo[3,4-d]pyrimidines.
Bhuyan,Borah,Lekhok,Sandhu
p. 491 - 493
(2007/10/03)
Studies on Uracils. 10. A Facile One-Pot Synthesis of Pyrido- and Pyrazolopyrimidines
The reaction of functionalised uracils bearing amino and hydroxyamino groups at C-6 position (4 and 5) with strongly electrophilic cyano olefins (1,2 and 3) gave rise to pyridopyrimidines 7-9 in excellent yields.Hydrazine-substituted uracil 6 gave access to an efficient one-step synthesis of pyrazolopyrimidines 10.The capture of an eliminated hydrogen molecule by cyano olefins in the case of their reaction with 4 and 6 was confirmed by the isolation of dihydrocyano olefins.This fact further supported the plausible mechanism for the formation of compounds 7-10 via dihydropyrido- and dihydropyrazolopyrimidine intermediates A and C.