Structures of Saturated 5 H ‐Pyrrolo[1,2‐ a ][3,1]benzoxazin‐1(2 H )‐ones Prepared from 4‐Oxopentanoic Acid and Cyclic Amino Alcohols

Saturated heterocycles containing two condensed heterocyclic rings and a carbo(bi)cyclic ring have been prepared by the reaction of 4‐oxopentanoic acid ( 1 ) with (bi)cyclic amino alcohols. 5 H ‐Pyrrolo[1,2‐ a ][3,1]benzoxazin‐1(2 H )‐ones 2 − 5 were formed in the reaction of 1 with trans ‐ or cis ‐2‐(hydroxymethyl)cyclohexylamines or ‐cyclohexenylamines. With di‐ endo ‐ or di‐ exo ‐3‐aminobicyclo[2.2.1]hept‐2‐yl‐ or ‐hept‐5‐en‐2‐ylmethanols, 1 yielded the corresponding derivatives 6 − 9 that are methylene‐bridged in the cyclohexane or cyclohexene rings. The stereoselectivity of the syntheses were high; only for 5 , 7 and 9 were both C‐3a epimers produced in observable amounts. The structures were established by means of NMR spectroscopic methods by applying standard pulse techniques. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)