Synthesis of New Pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidines and Their Use in the Preparation of Tetraheterocyclic Systems

Abstract

8,10-Dimethyl-3-(unsubstituted, methyl, ethyl, n-butyl, phenyl)-4-hydroxypyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidin-2(1H)-ones and 3-(2-hydroxyethyl)-2,8,10-trimethylpyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidin-4-ol were synthesized by cyclocondensation of 3-amine-4,6-dimethyl-1H-pyrazolo[3,4-b]pyridine with ethyl malonates and α-acetyl-γ-butyrlolactone. Dichloro- and diazido- derivatives were obtained from the reaction of pyridopyrazlopyrimidine derivatives with POCl₃ followed by NaN₃. The tetrahetrocyclic systems were formed by cyclization of 4-chloro-3-(2-chloroethyl)-2,8,10-trimethylpyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine with the appropriate primary amines. The structures of all compounds were established by NMR and mass spectra.

Keywords:

• Cyclocondensation
• dichloride
• pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidin-2(1H)-ones
• tetrahetrocyclic systems

ACKNOWLEDGMENTS

I express my gratitude to Professor Magdy Kamal, head of my department, for his encouragement. I am also indebted to Professor Adel Nassar for his assistance in spectral measurements.