altogether 150 mmol of the desired lpe sss diastereomer i were in it was largely concentrated by evaporation in a vacuum at 45 u00b0 c bath temperature the residue was taken up in 1400 ml water and briefly stripped in a vacuum after the addition of 120 ml toluene and 30 ml ethyl acetate the ph was adjusted with concentrated hydrochloric acid to 1 the mixture was then agitated 10 min and the phases subsequently separated a ph of 4 was now adjusted at 40 u00b0 c in the aqueous phase and the latter extracted with 450 ml methyl isobutyl ketone the phases were separated the organic phase mixed with 110 ml water and adjusted with sodium hydroxide solution 50 to a ph of 5 8 after phase separation the organic phase was evaporated to low bulk in a vacuum at max 40 u00b0 c bottom temperature to 230 g the bottom was mixed with 185 ml methyl cyclohexane and cooled down to 5 u00b0 c a crystalline precipitate was produced which was filtered washed and subsequently dried in an oil pump vacuum 4 h at rt ______________________________________ u03b1 25 dsss diastereomer c 1 meoh content melting point residual solvent 0 in hcl by weight u00b0 c mg kg degrees ______________________________________97 6 0 6 87 91 91 methyl isobutyl 25 5 ketone 253 methyl cyclohexane______________________________________ a reductive amination according to patent application ep 05 23 449 is carried out analogously to example 3 page 10 the reaction solution for which the dosage for the workup was selected in such a manner that in addition to the typical byproduct profile altogether 150 mmol of the desired lpe sss diastereomer i were in it.