Molecular Rearrangement of 2-Substituted Indazolones: Unorthodox Access to 2-Carboxylate-2,3-dihydroquinazolin-4-(1H)-one Scaffold

We disclose a practical and efficient strategy for the expedient synthesis of 2,3-dihydroquinazolin-4-(1H)-one derivatives by one carbon insertion into cyclic N-N bond. Spontaneous manipulations with operationally simple procedures furnishing pharmaceutically useful compounds are key features of the developed protocol. Mechanistic studies reveal that the predicted intramolecular rearrangement occurs via consecutive ring-opening and cyclization sequences. A gram-scale reaction and synthetic transformation of products to quinazolinone derivatives have also been demonstrated during the course of the study.

Automated summary

We disclose a practical and efficient strategy to synthesize 2,3-dihydroquinazolin-4-(1H)-one derivatives by inserting one carbon into a cyclic N-N bond. The developed protocol is characterized by its simple operation procedures and the ability to produce pharmaceutically useful compounds. Mechanistic studies demonstrate that the predicted intramolecular rearrangement occurs through consecutive ring-opening and cyclization sequences. Additionally, a gram-scale reaction and synthetic transformation of products to quinazolinone derivatives have been presented.