Pyrimido [4, 5-c] pyridazines. 3. Preferential formation of 8-amino-1H-pyrimido [4, 5-c]-1, 2-diazepin-6 (7H)-ones by cyclizations with. alpha.,. gamma.-dioxo esters

WR Mallory, RW Morrison Jr…

Index: Mallory, W. Revill; Morrison, Robert W.; Styles, Virgil L. Journal of Organic Chemistry, 1982 , vol. 47, # 4 p. 667 - 674

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Citation Number: 15

Abstract

Reactions of la with a, y-Diketo Esters We previously reported2 that simple a-keto esters cyclize straightforwardly with (l-alkylhydrazino) isocytosines 1 in methanol or water to give pyrimido [4, 5-c] pyridazine-4, 5-(lH, GH)-diones 2. Only with diethyl oxomalonate was the product 3 of reversed orientation obtained (Scheme I). Extension of this synthesis by reaction of 6-(l-methylhydrazino) isocytosine la and a,?-diketo esters (4, Table I) in ...