Tributylamine → N-Acetyl-L-carnosine

Participants

Reaction Steps

On the other hand, 52.4 g of L-histidine hydrochloride monohydrate was dissolved in 400 ml of water and the solution was adjusted to pH 10.5 with about 112 ml of 4 N aqueous sodium hydroxide solution. To this solution were simultaneously added dropwise 370 ml of methyl isobutyl ketone solution containing 148.6 g of tri-n-butylamine salt of 3-acetylaminopropionic acid-sulfuric acid mixed acid anhydride which has been prepared previously and 330 ml of 4 N aqueous sodium hydroxide solution while the reaction medium was stirred and maintained to a pH of 10.3-10.5 and a temperature of 5°-10° C. After stirring for 30 minutes at room temperature, the reaction was adjusted to pH 13.0 with about 300 ml of 4 N aqueous sodium hydroxide solution and allowed to stand. The upper methyl isobutyl ketone layer was separated out and the lower aqueous layer was treated by a similar manner as in Example 4 to obtain 49.6 g of N-acetyl-L-carnosine crystals.

Provenance & Evidence