New trans/cis Tetrahydroisoquinolines. 2. trans- and cis-3-(1-Methyl-1H-pyrrol-2-yl)-1-(2H)-oxo-2-phenethyl-1,2,3, 4-tetrahydroisoquinolin-4-carboxylic Acids and Subsequent Transformations

Article abstract of DOI:10.1002/jhet.5570400508

Stereochemical course of the reaction of homophthalic anhydride and N-(1-methyl-1H-pyrrol-2-yl-methylidene)-phenethylamine was studied. Mixtures of the expected trans- and cis-1,2,3,4-tetrahydroisoquinoline-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.