Oxalic Acid → HCID 20065666, compound

Participants

Reaction Steps

75 cc of trifluoroacetic acid is added in the course of 45 minutes to 2-[3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)propyl]-3-hydroxy-3-benzyl-1-isoindolinone (15.2 g) and sodium cyanoborohydride (4.6 g) cooled to a temperature close to -25° C. Agitation is continued for 4 hours at a temperature close to 20° C. The solution is diluted with methylene chloride (150 cc) then washed with saturated aqueous sodium bicarbonate solution (200 cc). The aqueous phase is extracted with methylene chloride (4×150 cc). The organic extracts are combined, washed with 1N hydrochloric acid solution (3×50 cc), dried over anhydrous magnesium sulphate, treated with animal charcoal, filtered and concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C. The residue obtained is dissolved in tetrahydrofuran (150 cc). Tetramethylethylenediamine (3.1 cc) is added and the solution heated to a temperature close to 65° C. for 1 hour. After cooling to a temperature close to 20° C., the solution is diluted with methylene chloride (300 cc), and washed with distilled water (5×50 cc). The organic extract is dried over anhydrous magnesium sulphate, filtered and evaporated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 50° C. The residue obtained is dissolved in acetonitrile (20 cc). A solution of oxalic acid (0.7 g) in acetonitrile (20 cc) is added and agitation is continued for 1 hour at a temperature close to 20° C. The precipitate formed is separated by filtration and recrystallized from boiling methanol (280 cc). 4.6 g of 3-benzyl-2-[3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)propyl]-1-isoindolinone oxalate are thus obtained, melting at 219° C.

Provenance & Evidence