New TRANS/CIS tetrahydroisoquinolines. 3. [1,3]‐oxazolo‐[3,2‐B]‐tetrahydroisoquinolinones having an angular aryl substituent

Abstract

Abstractmagnified imageThe parent compound 5‐oxo‐10a‐phenyl‐2,3,10,10a‐tetrahydro‐5H‐[1,3]‐oxazolo‐[3,2‐b]‐isoquinoline‐10‐carboxylic acid (5) was prepared in large scale and a good yield by reaction between homophthalic anhydride (3) and 4,5‐dihydro‐2‐phenyl‐1,3‐oxazole (4). Thus, the closure of the isoquinoline ring and fusion of the 1,3‐oxazol ring occur in one step. Trans configuration was assumed for the product. The parent acid 5 was converted in four steps to the target aminomethyl derivatives 9a‐1. The latter contain four features that make them interesting from pharmaceutical point of view.