New synthesis of 7??bromo??1, 3??dihydro??3??hydroxy??5??(2′??pyridyl)??2H??1, 4??benzodiazepin??2??one

T Kovač, B Belin, T Fajdiga…

Index: Kovac, Tomislav; Belin, Branka; Fajdiga, Tatjana; Sunjic, Vitomir Journal of Heterocyclic Chemistry, 1981 , vol. 18, p. 59 - 62

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Citation Number: 6

Abstract

Abstract A new synthesis of 7-bromo-1, 3-dihydro-3-hydroxy-5-(2′-pyridyl)-2H-1, 4- benzodiazepin-2-one (5) is described. Starting from bromazepam (3), C (3) acylation with lead tetraacetate/potassium iodide in acetic acid affords 4, while its mild hydrolysis according to our recently described method (5) gives 5. Improved hexamine cyclization of 1 into 3, via quaternary hexaminium salt 2, is discussed, and identification of the ...