Enantioselective lipase-catalysed kinetic resolution of acyloxymethyl and ethoxycarbonylmethyl esters of 1,4-dihydroisonicotinic acid derivatives

The lipase-catalysed kinetic resolution of four derivatives of 4-[(acyloxy)methyl] and 4-ethoxycarbonylmethyl 3-methyl 5-propyl 2,6-dimethyl-1,4-dihydro-3,4,5-pyridinetricarboxylates has been investigated. Whereas the enantioselectivity of lipases towards the acyloxymethyl derivatives was rather low, the Candida antarctica lipase B (Novozym 435?, CAL-B)-catalysed hydrolysis of the ethoxycarbonylmethyl ester of 1,4-dihydroisonicotinic acid was enantioselective. In water-saturated diisopropyl ether at 45°C the enantioselectivity of CAL-B toward the ethoxycarbonylmethyl ester was rather moderate (E=13.8), but it was enhanced at rt and 4°C (E=21.5 and E=28.9, respectively). A high enantiomeric ratio (E=45.3) was reached at subzero temperatures, although at the expense of the reaction rate.