An Effective Nitrilimine Cycloaddition for the Synthesis of 1,3,5-Trisubstituted 1,2,4-Triazoles from Oximes with Hydrazonoyl Hydrochlorides
摘要:
An effective 1,3-dipolar cycloaddition for the synthesis of 1,3,5-trisubstituted 1,2,4-triazole derivatives was developed by reacting oximes with hydrazonoyl hydrochlorides using triethylamine as a base. The desired 1,3,5-trisubstituted 1,2,4-triazoles were obtained in good yields and the reaction was applicable to aliphatic, cyclic aliphatic, aromatic and heterocyclic oxime substrates.
‘One-flask’ synthesis to 3,5-disubstituted 1,2,4-triazoles from aldehydes with hydrazonoyl hydrochlorides via 1,3-dipolar cycloaddition
摘要:
A new 'one-flask' synthesis of 3,5-disubstituted 1,2,4-triazoles has successfully been developed to synthesize a series of 3,5-disubstituted 1,2,4-triazoles. The transformation involves the 1,3-dipolar cycloaddition reaction of hydrazonoyl hydrochlorides with oxime intermediates prepared from aldehydes with hydroxylamine hydrochloride in the presence of excess amount of triethylamine. In this 'one-flask' 1,3-dipolar reaction, hydrazonoyl hydrochlorides was concerned as the masked 1,3-dipole nitrilimine under basic condition. Furthermore, this newly developed methodology can be applied to various aldehyde substrates including aliphatic, cyclic aliphatic, aromatic, and heterocyclic aldehydes. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.