Chiral salt resolution.

A method for resolving enantiomers of a compound containing the structure of the formula: wherein r4 or r5 may contain one or more asymmetric centres, by mixing a racemic mixture of enantioners of a compound, containing the structure of said formula; in a solvent, with a resolving compound having a defined stereospecificity, to form a solution and with said resolving agent being capable of binding with at least one but not all of said enantiomers to form a precipitate, containing said at least one of said enantiomers in stereospecific form and collecting either the precipitate and purifying it or collecting the solution with contained other of said enantiomers and recrystallizing the enantiomer contained in said solution.