Patent ID: 7501514

Claim:
A process for the preparation of single enantiomers of a compound of formula (B), and pharmaceutically acceptable salts thereof, in the cis configuration, wherein R 1 is selected from the following formulae: R 2 is hydrogen or R 3 —(CO); R 3 is hydrogen, straight or branched chain alkyl, alkoxyalkyl, aralkyl, aryloxyalkyl, aryl, substituted dihydro pyridinyl, sulphonate esters, sulfate esters, amino acid esters and mono, di- or triphosphate esters; R 4 and R 5 are in each case independently H, straight, branched or cyclic C 1-6 alkyl, straight, branched or cyclic C 2-6 alkenyl, C 6-14 aryl, or 5-10 membered heteroaromatic ring containing 1-3 heteroatoms selected from O, N, and S; and R 6 is hydrogen, hydroxymethyl, trifluoromethyl, straight, branched or cyclic C 1-6 alkyl, straight, branched or cyclic C 2-6 alkenyl, bromine, chlorine, fluorine, or iodine; said process comprising: forming a conglomerate salt of a racemic mixture or an enantiomerically enriched mixture of Compound (B) with an acid wherein the resulting conglomerate salt has the following characteristics: the IR spectrum of the salt of the racemic compound, a 1:1 mixture of (−) and (+) crystals, is identical to each of the single enantiomers, and the salt of the racemic compound has a melting point lower than that of either single enantiomer; and resolving said mixture by preferential crystallization.