Highly regioselective one-step synthesis of 1-benzyl-5-formyl-1,2,3-triazole-4-carboxylates

A novel methodology has been developed to afford 1,4,5-trisubstituted 1-benzyl-5-formyl-1,2,3-triazole-4-carboxylates in one step under mild conditions. This method includes the reduction of the ester functional group to an aldehyde using lithium tri-tert-butoxyaluminum hydride. Especially, this method offers a different perspective for fully substituted 1,2,3-triazoles with high regioselectivity and high yields. The structure of fully substituted triazoles was verified using FTIR, H-1, C-13 NMR spectroscopy, HRMS, advanced NMR techniques (COSY, C-APT, HSQC, and HMBC), and X-ray crystallography.