Reaction of 6-Hydroxytetrahydro-β-carboline-3-carboxylic Acids with Isocyanates and Isothiocyanates

Abstract

The reaction of (-)-(3S)-6-hydroxy-1, 2, 3, 4-tetrahydro-β-carboline-3-carboxylic acid (3a) with isocyanates and isothiocyanates gave the (±)-β-carboline-hydantoin (4a-d) and -thiohydantoin systems (5a-d). The treatment of (-)-(1S, 3S)-6-hydroxy-1-methyl-1, 2, 3, 4-tetrahydro-β-carboline-3-carboxylic acid (3b) with isocyanates yielded the (±)-cis disatereomer of the β-carboline-hydantoin rings (4e-h). However, the reaction of 3b with isothiocyanates provided the corresponding trans isomer (5e-h). These results have been confirmed by ¹³C-NMR data and nuclear Overhauser effect (NOE) experiments. The new compounds were tested for in vitro binding affinity to the central-type benzodiazepine receptors.