Regioselective One‐Pot Synthesis of 9‐Alkyl‐6‐chloropyrido[3,2‐e][1,2,4]triazolo[4,3‐a]pyrazines. Reactivity of Aliphatic and Aromatic Hydrazides.

Abstract

Pyrazine derivatives R 0550Regioselective One-Pot Synthesis of 9-Alkyl-6-chloropyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrazines. Reactivity of Aliphatic and Aromatic Hydrazides. -A new method to prepare the title pyrazines is reported. However, the reaction with aromatic hydrazides and electron-withdrawing substituted aliphatic hydrazides results in formation of keto analogues such as (VI) and (VIII). In the presence of an excess of hydrazide, tetracyclic systems like (IV) are obtained. -(UNCITI-BROCETA, A.; PINEDA-DE-LAS-INFANTAS, M. J.; DIAZ-MOCHON, J. J.; ROMAGNOLI, R.; BARALDI, P. G.; GALLO, M. A.; ESPINOSA*, A.; J.