Hydrochloric Acid → Boc-Thr(Bzl)-Lys(COCH2CH2COOH)-OCH3

Participants

Reaction Steps

3.60 Grams of Z-Lys(COCH2CH2COOH)-OCH3 was dissolved in 30 ml of methanol, to this solution was added 100 mg of 5%-palladium-carbon and 9.13 ml of 1N-hydrochloric acid, and the mixture was subjected to a catalytic reduction in a hydrogen gas stream. After finishing the reaction, the catalyst was removed by filtration, and the filtrate was concentrated under reduced pressure, the residue thus obtained was dried over sodium hydroxide under reduced pressure. Then the residue thus obtained was dissolved in a mixture of 30 ml of THF and 5 ml of water, and under ice-cooling condition, the pH of this mixture was adjusted to pH 6-7 by adding triethylamine. To this mixture was added 4.08 g of Boc-Thr(Bzl)-OSu, then the pH of this mixture was adjusted to pH 7-8 by adding N-methylmorpholine, and stirred under ice-cooling condition for 1 hour, next at room temperature for 18 hours. The reaction mixture was concentrated under reduced pressure, and the residue thus obtained was extracted with 50 ml of ethyl acetate. The ethyl acetate layer was washed with 1N-hydrochloric acid, next with a saturated sodium chloride aqueous solution three times, then was dried over anhydrous sodium sulfate, and was concentrated under reduced pressure. The residue thus obtained was dissolved in chloroform and was added to a silica gel column, eluted with 200 ml of chloroform, next with 500 ml of 2%-methanol/chloroform to obtain the fraction containing the objective product, then concentrated under reduced pressure, and the residue thus obtained was solidified by adding diethyl ether. 960 Milligrams (yield: 19.1%) of the above-mentioned objective product was obtained.

Provenance & Evidence