title: Rearrangements encountered in the attempted syntheses of pyridoazepinone carboxylic acids.
abstract: Attempts to synthesize pyridoazepinone carboxylic acids such as 33 by standard methodologies resulted exclusively in unusual and unexpected rearrangement products. Seven-membered ring formation was attempted by ring expansion of a six-membered ring and by aldol ring closure. In each case, the major product resulted from rearrangement of the starting material without detection of the desired product. Ultimately, an isomeric pyridoazepinone ethyl ester was prepared; however, attempted saponification resulted in another unusual rearrangement. [reaction: see text]
authors.affiliation: Infectious Disease Research, Abbott Laboratories, 200 Abbott Park Road, Abbott Park, IL 60064-6217, USA. will.sanders@abbott.com
authors.forename: William J
authors.initials: WJ
authors.lastname: Sanders
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhang
authors.forename: Rolf
authors.initials: R
authors.lastname: Wagner