Gabapentin hydrochloride → Gabapentin

Participants

Reaction Conditions

Reaction Steps

Gabapentin hydrochloride was dissolved in 130 ml of dry isopropanol at 25° C. by mixing, then 1.1 g of active carbon was added and the suspension was heated to 40° C. and maintained for two hours at 40° C. The suspension was filtered at 40° C. and the filter cake was washed twice with additional 15 ml of isopropanol. The washings were added to the already separated solution of gabapentin hydrochloride in isopropanol. The solution was concentrated to dryness in vacuum (˜10 mm Hg) to constant weight. The temperature of the heating bath was maintained at a maximum temperature of 35° C. during this operation. Next, 245 ml of acetonitrile was added to the dry residue of gabapentin hydrochloride and mixing commenced. After half an hour of mixing at 250° C., an amount of 19.5 g of tributylamine was added during 30 minutes and the mixing was continued for two hours at the same temperature. The formed gabapentin base was separated from the suspension by filtration. The filter cake was washed with 23 ml of acetonitrile and 23 ml of methanol to give gabapentin crude. After reslurry as in Example 1B, gabapentin pure was obtained having a yield of 67.8%, and anion content of 142 ppm.

Provenance & Evidence