Resolution of racemic R.S-α-arylethylamine by a new resolving agent (R)thiazolidine-2-thione-4-carboxylic acid

Racemic R.S α arylethylamine was resolved by R（-）thiazolidine 2 thione 4 carboxylic acid, a new resolving agent abbreviated as , by which R（-）TTCA·S（-） arylethylamine salts 2a - 2e, 20 D= -47.24°\-64.40° and optically active R（+） α arylethylamines 3a - 3e , 74.54%\94.45% e.e., were obtained. Optically active S（-） α arylethylamines 4a - 4e , 72.84%\90.36% e.e., were obtained by the decomposition of 2a - 2e in basic solutions. The influence of substitutive group of the benzene ring on the basicity of the amino group was studied by semiempirical PM3 method. The structures of the R（-）TTCA·S（-） α phenylethylamine salt （2a（R S） configuration） and R（-）TTCA·R（+） α phenylethylamine salt （2a′（R R） configuration） have been established by means of X ray diffraction. They crystallize in a monoclinic system. Space group is P 2 l. The cell constants of 2a（R S） configuration were obtained as follows: a =1.387 8（2）, b =0.664 05（10）, c =1.580 0（2） nm; β =90 844（10）°, Z=4 ; those obtained for 2a′（R R） configuration were a= 1.080 6（2）, b =0.584 80（12）, c = 1.218 8（2） nm, β =110.38（3）°, V =0.722 0 nm 3, Z =2. There are intermolecular hydrogen bonds in the crystals of the two kinds of configurations of the amine salt. The hydrogen bond number in the unit cell of R（-）TTCA·S（-） α phenylethylamine salt is twice as much as that of R（-）TTCA·R（+） α phenylethylamine salt.

Racemic R.S-α-arylethylamine was resolved by R (-) thiazolidine-2-thione-4-carboxylic acid, a new resolving agent abbreviated as [R (-) TTCA], by which R (-) TTCA.S(-) arylethylamine salts2a-2e, [α] D 20 =-47.24° — 64.40° and optically active R(+)-a-arylethylamines3a – 3e, 74. 54%-94. 45% e, e., were obtained. Optically active S (-) -α-arylethylamines4a-4e, 72.84%-90.36% e.e., were obtained by the decomposition of2a-2e in basic solutions. The influence of substitutive group of the benzene ring on the basicity of the amino group was studied by semiempirical PM3 method. The structures of the R (-) TTCA.S (-) -α-phenylethylamine salt (2a(R-S) configuration) and R (-) TTCA-R(+)-a-phenylethylamine salt (2a(R-R) configuration) have been established by means of X-ray diffraction. They crystallize in a monoclinic system. Space group isP21. The cell constants of2a(R-S) configuration were obtained as follows: α = 1.387 8(2), b = 0.664 05(101,c = 1.580 O(2) nm; β = 90.844(10)° Z = 4; those obtained for2a(R-R) configuration were α = 1.080 6(2),b = 0.584 80(12),c = 1.2188(2) nm, β= 110.38(3)dg, V = 0.7220nm3,Z = 2. There are intermolecular hydrogen bonds in the crystals of the two kinds of configurations of the amine salt. The hydrogen bond number in the unit cell of R (-) TTCA.S (-)-α-phenylethylamine salt is twice as much as that of R (-) TTCA.R(+)-a-phenylethylamine salt.