Citric Acid → N-Boc-serinol

Participants

Reaction Steps

Boc—Ser(Bzl)-ol (300 mg, 1.07 mmol) was dissolved in DMF (2 ml), and NaH (50% oil suspension; 77.3 mg, 1.61 mmol) was added under ice-cooling thereto followed by stirring for 30 minutes. After addition of benzyl bromide (165 μl, 1.39 mmol), the mixture was stirred for 10 minutes under ice-cooling, and stirred for 1 hour at room temperature. Aqueous solution of 10% citric acid was added to the reaction mixture, and ethyl acetate added for extraction. The ethyl acetate layer was washed with saturated aqueous solution of sodium hydrogen carbonate, then saturated aqueous solution of NaCl, dried over magnesium sulfate, and concentrated under reduced pressure, yielding the dibenzyl derivative of Boc—Ser-ol. The Boc group of this compound was removed and sequentially coupled to Boc—Val—OH and then to Boc—Ala—OH. The Boc group of the product was removed. The product (9.5 mg, 16.9 μmol) obtained was coupled to the compound (5.7 mg, 11.1 μmol) obtained in the step 1) of the synthesis of compound (4), and the protecting groups were removed by an ordinary method, yielding compound (8) (0.5 mg) shown in Table 1 as colorless oil.

Provenance & Evidence