Trimethylamine → DL-Carnitine

Temperature

10 °C

In a 1 liter flask with a cooling jacket equipped with a mechanical stirrer and a thermometer, 295.5 gm. of aqueous trimethylamine solution (TMA) (40.0 percent, 2.00 moles) was prepared and cooled to 10° C. (in a cryometer, or tap water). With a hose-equipped perpex compression pump and a teflon hose, which was submerged (extended) into the TMA solution, 73.50 gm. of γ-chloroacetoacetic ethyl ester (89.6 percent, 40 moles) was added in doses during 3.5 hours at 10° C., while stirring well. The vessel and the teflon hose were flushed with 5 gm. of ethanol. After 1 hour of continued stirring, the excess TMA was sucked off on a rotavapor and condensed. The reaction solution was adjusted from pH 7.5 to pH 6.0 (using 11 ml of concentrated HC1). The brown solution was reacted with 2.2 gm. of platinum on activated charcoal (ex Fluka, 5% purest) and was hydrogenated in a 1 liter SFS laboratory autoclave during 5 hours at 10° C., 10 atm. and 750 rpm. The solution was filtered off from the catalyst. The resultant bright yellow solution was hydrolyzed with approximately 10 ml of concentrated hydrochloric acid (at most the pH was 0.5) in distillation apparatus. Subsequently this was evaporated to dryness and the residue was dried at 40° C. under high vacuum. The residue was suspended in 330 ml of absolute ethanol during 1.5 hours, was filtered and dried to a constant weight. 72.55 gm. of carnitine hdrochloride, with a melting point of 198° to 199° C, were obtained - this corresponded to a 90.5 percent yield, related to the starting γ-chloroacetoacetic ethyl ester.

1. customIn a 1 liter flask with a cooling jacket equipped with a mechanical stirrer
2. customThe vessel and the teflon hose were flushed with 5 gm
3. customthe excess TMA was sucked off on a rotavapor and condensed
4. customThe brown solution was reacted with 2.2 gm
5. filtrationThe solution was filtered off from the catalyst
6. distillationin distillation apparatus
7. customSubsequently this was evaporated to dryness
8. customthe residue was dried at 40° C. under high vacuum
9. waitThe residue was suspended in 330 ml of absolute ethanol during 1.5 hours
10. filtrationwas filtered
11. customdried to a constant weight

ORD record

ord-a8e96e82cd30441a818b3eaf93b246ac

Source dataset

uspto-grants-1977_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04018821