28 g (64.57 mmole) 2-(acetylamino)-2-[2(4-octylphenyl)ethyl]propanedioic acid diethylester (=compound according to formula (III)) was added to 450 ml ethanol. A solution of 17.91 g calcium chloride in 125 ml water was added in one lot. 12.21 g (322.7 mmole) sodium borohydride was added to the reaction mixture at 0° C. in 1 hr 20 min. The reaction mixture was left overnight for stirring. 100 ml of 1 N HCl was added to neutralize the reaction mixture and inorganic solids were filtered and washed with 200 ml ethanol. Filtrate was evaporated under vacuum. 300 ml water was added to the residue obtained and was extracted with 2×250 ml EtOAC. The organic extract was washed with brine, dried over sodium sulphate and evaporated to give 23 g semisolid.
