Flordipine → 1,4-Dihydro-2,6-dimethyl-1-[2-(4-morpholinyl)ethyl]-4-[2-(trifluoromethyl)phenyl]-3,5-pyridinedicarboxylate maleate

Participants

Reaction Steps

A solution of 1.2 g (0.010 mol) of maleic acid in 6 ml of acetone was poured into a solution of 5.1 g (0.010 mole) of diethyl 1,4-dihydro-2,6-dimethyl-1-[2-(4-morpholinyl)ethyl]-4-[2-(trifluoromethyl)phenyl]-3,5-pyridinedicarboxylate in 30 ml of toluene. The precipitated solid was collected, washed with toluene, and dried to yield 6.1 g (97%) of 1,4-dihydro-2,6-dimethyl-1-[2-(4-morpholinyl)ethyl]-4-[2-(trifluoromethyl)phenyl]-3,5-pyridinedicarboxylate maleate. This material was partitioned between 30 ml of toluene and 25 ml of 10% aqueous NaOH and the separated toluene phase was diluted with 60 ml of heptane. Chilling overnight yielded 3.4 g (67%) of diethyl 1,4-dihydro-2,6-dimethyl-1-[2-(4-morpholinyl)ethyl[4-[2-(trifluoromethyl)phenyl]-3,5-pyridinedicarboxylate. Recrystallization from 10 ml of 2-propanol yielded 2.9 g of the title compound which contained, as determined by HPLC, 0.19% of ##STR11##

Provenance & Evidence