Benz azepinones

A careful study of the fragmentation of a series of TV-p- toluenesulfonamides, that includes several TV-(p-tosyl)-benz- and -dibenz-azepinones, reveals that loss of (M-S02) occurs only in certain systems, and is diagnostic for those structures in which the carbonyl and tosylamino groups are both attached directly to the benzene ring at positions ortho to each other, e.g. the l-benzazepin-5-one (31 R = p-Ts) (690MS(2)337). 

A key step in the asymmetric synthesis of the angiotensin converting enzyme inhibitor, benazepril HCl 32, was the reduction of the ketoester 28 with baker s yeast to afford the chiral a-hydroxy ester 29 in high chemical yield and ee. Formation of the benz[i]azepinone 31 directly from 29 proceeded in 42% yield (without racemization at C-3) or in 74% yield in two steps via 30, again with no racemization <03TA2239>. 

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