94133-42-3

Herein we report the syntheses and structural analyses of three coordination compounds Co(L)2 (3), Ni(L)2, (4) and Cu(L)2 (5) (L = bis[(4R,5R)-4-methyl-5-phenyl-4,5-dihydro-thiazol-2-yl]-amine) prepared by template reactions from the optically active ligand (4R,5R)-4-methyl-5-phenyl-4,5-dihydro-thiazol-2-yl-amine (1) and CoCl2·6H2O, NiBr2·3H2O or Cu(OAc)2·H2O The template reactions involve the condensation of two molecules of thiazol-2-yl-amine and elimination of one NH3. The resulting bidentate ligand coordinates to the metal ion through the imine nitrogen atoms forming a six-membered ring, presenting an electronic delocalization which averages the four M-N bond lengths. The distorted tetrahedral geometry of the metal atoms gives place to complex electronic spectra for compounds 3-5. A mixed ionic compound (6) formed by three cations (4S,5S)-3,4-dimethyl-5-phenyl-thiazolidin-2-ylidene ammonium, one dianion tris-(thiocyano)bromide cobaltate and one bromide, obtained from reaction of (4S,5S)-3,4-dimethyl-5-phenyl-thiazolidin-2-ylidene ammonium thiocyanate (2) and CoBr2 is also described. Compounds 3-6 were characterized in the solid state by UV-Vis-NIR and IR spectroscopy, mass spectrometry and X-ray diffraction analyses. Metal···H-C, S···H-C interactions were observed in 3-6, whereas in 6, also Br···H-N, Br···H-C and Br···S, S···S short contacts were found.

The reaction of chlorodeoxypseudoephedrine or chlorodeoxynorpseudoephedrine hydrochlorides with sodium dithiocarbonate in stirring ethanol at 0 °C to stereoselectively afford the corresponding cis-thiazolidinethiones in good yields (81% and 95%) is reported. The in situ formation of a cis-aziridine to explain the presence of trans-thiazolidinethione as a side product is proposed when the same reaction was carried out at room temperature. In addition, a 70:30 mixture of trans-isomers of a thiazolidinethione/isothiazolidinethione was formed when a cis-aziridine NH was reacted with carbon disulfide in refluxing ethanol. The analogous reaction with cis-aziridine N-Me stereoselectively affords the corresponding cis-thiazolidinethione. The 1H and 13C NMR data of the thiazolidinethiones were assigned. cis-3,4-Dimethyl-5-phenylthiazolidine-2-thione was crystallized from ethanol and its X-ray diffraction structure was analyzed.

The reaction of chlorodeoxyephedrine hydrochlorides with one, two, and three molar equivalents of base was studied. Isochlorodeoxypseudoepherines were identified and assigned by 1H and 13C NMR data as intermediate compounds in the formation of cis-aziridines. Erythro and threo ephedrinethylethers were isolated as new compounds and analyzed by spectroscopic data. In addition, the erythro isomer was studied by X-ray diffraction.

The stereochemistry of the chlorination reactions with SOCl2 of free ephedrine and pseudoephedrine and their hydrochlorides, examides and sulfonamides was analyzed. Chlorination of free and hydrochloride erythro isomers occurs with 100% inversion of configuration at C-1 (S(N)2 mechanism). Chlorination of examides and sulfonamides of erythro isomers occurs with retention of the configuration at C-1, (S(N)i mechanism). Chlorination reactions in all three isomers and derivatives hydrochlorides, examides or sulfonamides gave the same ratio of erythro (40%) and three isomers (60%) (S(N)1 mechanism). Treatment of the isomeric mixture of the chlorodeoxyephedrine and chlorodeoxypseudoephedrine hydrochloride in DMSO with HCl changes the isomeric ratio, increasing the erythro isomer content (65%). Using the erythro ethanolamines it is possible to arrive stereoselectively at the erythro chloroamines if the compound is previously tosylated or converted to the amide, or to the three chloroamines if the compound is directly chlorinated with SOCl2.

Determination of the stereochemical makeup of forensic samples can provide information about the source of the sample and a basis for intersample comparisons.The clandestine synthesis of methamphetamine and related amines continues to be a major source of these drugs of abuse.Most synthetic methods employ carbon-nitrogen bond formation and produce a racemic mixture; however, the individual enantiomers of ephedrine and pseudoephedrine contain the structural components of methamphetamine in chiral form.This paper will focus on the stereochemical course of the synthesis of methamphetamine via hydrogenolysis of the benzylic hydroxyl group in ephedrine and pseudoephedrine.The configurations of these amines were determined by liquid chromatography on an achiral C18 stationary phase following precolumn derivatization with 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate.