A DIVERSITY ORIENTED SYNTHESIS OF 2,10-DIOXO-10H-1,2,3,4,4a,5-HEXAHYDROPYRIDAZINO[3,2-b]QUINAZOLINES

摘要

A parallel method for the synthesis of the title compounds is described.Thus,methyl anthranilates(5)are transformed into 2-aminobenzohydrazides(3)which were treated with 4-oxo acids(4)to afford in high yields and acceptable purity of piridazino[3,2-b]quinazolines(1).Compounds(1)present four diversity centers(R_1,R_2,R_3,and R_4).The range of chemically acceptable substituents at each center has been evaluated.The isolation of a possible intermediate in the formation of 1,which presents an aminol structure(10),has allowed proposing a complete mechanistic rationalization for the formation of structures(1).