Recyclization of Hydrazides of 2-Carboxyphenyldifurylmethanes: Synthesis of Novel 4,10-Dihydro-3H-pyridazino[1,6-b]isoquinolin-10-one System - Butin, Alexander V; Dmitriev, Artem S; Abaev, Vladimir T; Zavodnik, Valery E (Synlett, 2006)