ANOMALOUS REACTION COURSE IN THE AMIDOALKYLATION WITH 4-SUBSTITUTED 2-METHOXY N-TRIFLUOROACETYL PIPERIDINES
Amidoalkylation of suitably substituted benzofurans and benzothiophenes with 2-methoxy-N-acyl-piperidines and -morpholines gave very low yields of the 2-(2'-benzofuranyl)-, and 2-(2'-benzothienyl)piperidine derivatives.The amidoalkylation of 3-phenyl-benzofuran with the isomeric mixture of the 4-methyl-2-methoxy-N-trifluoroacetyl piperidines however gave a good conversion but trans-4-methyl-2-(2'-(3'-phenyl)benzofuranyl)-N-trifluoroacetyl piperidine is only the minor product formed.Mass spectroscopy, 1H and 13C NMR spectroscopy proved that the major product is 1-trifluoroacetylamino-3-methyl-5,5-bis(2'-(3'-phenyl)-benzofuranyl)-pentane.