Hydantoins and thiohydantoins derived from 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid

The reaction of methyl (S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate with isocyanates (phenyl, naphthalen-1-yl, cyclohexyl, (S)-1-methylbenzyl) in ether has been used to prepare N-substituted methyl (3S)-2-aminocarbonyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylates. These compounds were cyclised by action of CF3COOH to give the corresponding 2-substituted (10aS)-10,10a-dihydroimidazo[1,5-b]isoquinoline-1,3(2H,5H)-diones (hydantoins Tic-H). Hydantoins Tic-H were also prepared by the reaction of methyl (S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate with isocyanates (methyl, (1S)-1-methylbenzyl, 4-methylphenyl, 3-methylphenyl, 4-chlorophenyl, 2,4-dichlorophenyl, 4-methoxyphenyl, 5-chloro-2-methoxyphenyl, 3-chloro-4-ethoxyphenyl) and triethylamine in CH2Cl2. 2-Substituted (10aS)-3-thioxo-1,2,3,5,10,10a-hexahydroimidazo[1,5-b]isoquinolin-1-ones (thiohydantoins Tic-TH) were prepared analogously by the reaction of methyl (S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate with isothiocyanates (methyl, ethyl, allyl, phenyl). The optical purity of selected substances was determined chromatographically.