Concise Pyrimido4,5-dpyrimidine Synthesis via Direct Annulation of N-Uracil Amidines with Benzaldehydes Under Transition Metal Free Conditions

摘要

abstract_textpA novel and concise route towards the synthesis of pyrimido4,5-dpyrimidines via a direct annulation reaction of N-uracil amidines with benzaldehydes under transition metal free conditions has been described. The requisite precursors N-uracil amidines are obtained via S(N)AE reaction on 6-chlorouracil with amidines. A series of pyrimido4,5-dpyrimidines has been synthesized in good to excellent yields by the direct annulation of N-uracil amidines with benzaldehydes using Cs2CO3 as base and molecular oxygen as oxidant in (BuOH)-Bu-t at 100 C-0. This synthetic protocol has a number of advantages such as- operational simplicity, use of green oxidant, avoidance of transition metal catalysts or ligands, and easy accessibility of the starting materials, making it a highly practical approach to access various pyrimido4,5-dpyrimidines of biological interest./p/abstract_text