New <i>trans/cis</i> tetrahydroisoquinolines. 2. <i>trans‐ and cis</i>‐3‐(1‐methyl‐1h‐pyrrol‐2‐<i>y</i>l)‐1‐(2<i>H</i>)‐oxo‐2‐phenethyl‐1,2,3,4‐tetrahydroisoquino‐lin‐4‐carboxylic acids and subsequent transformations

Abstract

Abstract Stereochemical course of the reaction of homophthalic anhydride and N ‐(1‐methyl‐1 H ‐pyrrol‐2‐yl‐methylidene)‐phenethylamine was studied. Mixtures of the expected trans ‐ and cis ‐1,2,3,4‐tetrahydroiso‐quinoline‐4‐carboxylic acids trans‐ 4 and cis‐ 4 were obtained along with by‐products 5 and 6 . The ratios of all products and the diastereomers, obtained under different reaction conditions, were established by pmr. THF as a solvent and ultrasonic treatment are applied for the first time in the reaction of this type. The reaction was made diastereoselective towards any isomer. The carboxylic group of trans‐ 4 was transformed in four steps into various cyclic amino‐methyl groups yielding numerous new tetrahydroisoquinolinones trans‐ 10a‐i incorporating a given fragment of pharmacological interest. Reduction of 10a‐i was studied.