Hydrochloric Acid → Gabapentin hydrochloride

Temperature

108 °C

22.3 1 of water and 22.3 1 of concentrated hydrochloric acid are mixed in a T100 reactor and 6.41 kg gabapentin lactam added thereto, while stirring. The clear brown solution formed is subsequently boiled under reflux for six hours at 108° C. and the reaction mixture is left to stand until it has cooled to 28° C.. The white precipitate obtained is again dissolved by the addition of a further 40 l of water. For the removal of still undissolved lactam, the reaction mixture is extracted three times with, in each case, 30 l dichloromethane. The pale yellow aqueous phase is evaporated to dryness in a vacuum evaporator (QVF 100 L), the temperature finally reaching to 80° C. at 133 Pa. The almost dry crystal mass is stirred in 12.8 l acetone and filtered off with suction. It is then washed with 2 l acetone and dried for four hours at 60° C. The yield is about 60% of theory.

1. additionadded
2. customThe clear brown solution formed
3. waitthe reaction mixture is left
4. temperaturehas cooled to 28° C.
5. customThe white precipitate obtained
6. customFor the removal of still undissolved lactam
7. extractionthe reaction mixture is extracted three times with, in each case, 30 l dichloromethane
8. customThe pale yellow aqueous phase is evaporated to dryness in a vacuum evaporator (QVF 100 L)
9. customfinally reaching to 80° C. at 133 Pa
10. stirringThe almost dry crystal mass is stirred in 12.8 l acetone
11. filtrationfiltered off with suction
12. washIt is then washed with 2 l acetone
13. customdried for four hours at 60° C

ORD record

ord-ee0add09e1bd428886e70278d5e3da2e

Source dataset

uspto-grants-1991_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05068413