Oxalic Acid → HCID 20065658, compound

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Reaction Steps

15 A solution of 2-[3-(4-phenyl-1,2,3,6-tetrahydro-1pyridyl)propyl]-3-hydroxy-1-isoindolinone (7 g) in anhydrous dimethylformamide (75 cc) is added to a suspension of sodium hydride (as a 50% suspension in oil) (1 g) in anhydrous dimethylformamide (25 cc) at a temperature close to 20° C. in the course of 10 minutes and agitation is continued for 2 hours. Then, 2.3 g of isobutyryl chloride is added in the course of 5 minutes, and agitation is continued for a further 20 hours. The suspension obtained is poured into distilled water (100 cc) and extracted with methylene chloride (4×50 cc). The organic extracts are combined, dried over anhydrous magnesium sulphate, filtered and concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C. The residue obtained is dissolved in methyl ethyl ketone (45 cc). A solution of oxalic acid (1.5 g) in methyl ethyl ketone (35 cc) is added and agitation continued for 1 hour at a temperature close to 20° C. The precipitate formed is separated by filtration and recrystallized from boiling methanol (200 cc). 3 g of 3-isobutyryloxy-2-[3-(4-phenyl-1,2,3,6-tetrahydro-1-pyridyl)propyl]-1-isoindolinone oxalate are thus obtained, melting at 164° C.

Provenance & Evidence