Design and synthesis of [1,2,4]-triazolo isoquinoline derivatives via 1, 3-dipolar [3+2] cycloaddition: Reaction of azomethine imine with ethyl cyanoformate as unknown protocol

A series of novel 1, 2, 4-triazolo isoquinoline derivatives (8a-8p) were synthesized starting from 2-phenylethan-1-ol derivative (1) in a 7 step synthetic sequence. The key step in the scheme involves 1, 3-dipolar [3 + 2] cycloaddition of azomethine imine and ethyl cyanoformate as unknown reaction protocol. We have demonstrated the hydrolysis of both ester and benzoyl group in a single step and the corresponding carboxylic acid derivatives were coupled with various amines to generate unknown 1, 2, 4-triazolo isoquinoline derivatives The structures of the compounds (8a-8p) were characterized by H-1 NMR, C-13 NMR and HRMS analysis. (C) 2019 Elsevier Ltd. All rights reserved.