Reactions of some <i>N</i>-acyl-1-alkylamines with poly phosphoric ester PPE: nuclear magnetic resonance and stereochemistry of reaction products

Abstract

Phenylindanes were obtained from the reaction of N-acyl-1-arylalkylamines with polyphosphoric ester (PPE). cis-1-Methyl-3-(3,4-dimethoxyphenyl)-5,6-dimethoxyindane was synthesized to determine which stereoisomer was produced by N-formyl and N-acetyl-1-(3,4-dimethoxyphenyl)ethylamine with PPE. Nuclear magnetic resonance specra ( 1 H and 13 C) of several mono-, 1,3-di-, and 1,2,3-tri-substituted indanes were fully analyzed to provide information on steric interactions and conformation of the cyclopentene ring. Possible cyclodimerization pathways are proposed.