Ethyl orthoformate → HCID 10964674, compound

Temperature

70 °C

To a suspension of D-cysteine 1.5 hydrate hydrochloride (Q-1, Scheme Q where RQ-1 and RQ-1 are equal to hydrogen, RQ-3 is hydrogen and stereochemistry is (S)) (5 g, 27.1 mmol) in absolute ethyl alcohol (50 mL) was added triethylorthoformate (13.5 mL, 81.2 mmol) at ambient temperature. A stream of anhydrous HCl gas was bubbled through the solution for 30 min. The stream of anhydrous HCl gas was maintained as the mixture heated to 70° C. for 2 h. The reaction mixture was concentrated in vacuo and the resulting residue triturated with diethyl ether to afford D-cysteine ethyl ester (4.43 g) as a white solid which was used without further purification. Physical data as follows: 1H NMR (300 MHz, D2O) 4.36 (1H), 4.27 (2H), 3.12 (2H), 1.25 (3H); MS (ESI+) for C5H11NO2S m/z 150.0 (M+H)+.

1. customA stream of anhydrous HCl gas was bubbled through the solution for 30 min
2. temperatureThe stream of anhydrous HCl gas was maintained as the mixture
3. concentrationThe reaction mixture was concentrated in vacuo
4. customthe resulting residue triturated with diethyl ether

ORD record

ord-0148b6fb37474773ae8e6594902e5f86

Source dataset

uspto-grants-2004_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06685617B1