Facile Synthesis of 12‐Ketoquino[2,1‐b]Quinazolines via the Vilsmeier–Haack Reaction of 6‐Nitro‐2‐Methyl‐3‐Aryl‐4(3H)Quinazolones

Abstract

Unlike the diformylation of the 2‐methyl group in 2‐methyl‐3‐aryl‐4(3H)quinazolone during the Vilsmeier reaction, the 2‐methyl group in 6‐nitro‐2‐methyl‐3‐aryl‐4(3H)quinazolones underwent monoformylation. An unprecedented attack of the iminium species generated in situ under the Vilsmeier conditions on the 3‐aryl ring of 6‐nitro‐2‐methyl‐3‐aryl‐4(3H)quinazolones provided a facile approach to the synthesis of tetracyclic 12‐ketoquino[2,1‐b]quinazolines.

Keywords:

• 12‐ketoquino[2,1‐b]quinazoline
• 6‐nitro‐2‐methyl‐4(3H)quinazolone
• Vilsmeier–Haack reaction

Acknowledgment

H.S.B. is grateful to Colour Chem Limited, Thane, India, for financial support.