In 1946 Elderfield and his collaborators' reinvestigated the synthesis and cyclization of@- anilinopropionic acid derivatives (like IV). 2 Although they realized substantial improvement in the method of preparing these acids, attempts to effect ring closure with a number of variously substituted acids under a variety of conditions were either unsuccessful or gave low yields. Since the cyclization products-formerly presumed to be dihydro-4-quinolones ( ...