one-pot green synthesis of derivatives of pyrimido[۵',۴':۵,۵]pyrido[۳,۲-d] pyrimidines catalyzed by boron nitride nanosheets

In this work, one-pot reaction of ۳,۱-dimethylbarbituric acid, aromatic aldehydes, and ammonium acetate using Boron nitride nanosheets as an efficient and recyclable catalyst has been investigated. While aromatic aldehydes substituted with electron‐withdrawing group or none reacted successfully with ۳,۱-dimethylbarbituric acid and ammonium acetate to give new pyrimido[۵',۴':۵,۵]pyrido[۳,۱-d]pyrimidine derivatives (can be also named as pyrido[۳,۲-d:۵,۶-d']dipyrimidines) in high yields over relatively short reaction times, Knoevenagel condensation products are isolated from the reaction mixture using aromatic aldehydes bearing electron‐donating substituents. The catalyst could be efficiently used at least four times without substantial reduction in its catalytic activity.The new products were characterized on the basis of FT-IR, ۳H NMR, and ۳۱C NMR spectral data.

Keywords:

Pyrimidopyridopyrimidines , Pyridodipyrimidines , Boron nitride nanosheets