Hydrochloric Acid → N,S-Bis[(phenylmethoxy)carbonyl]-L-cysteine

HRID 341759

Reaction equation

HRID 341759 reaction equation
Cl.[NH2:2][C@H:3]([C:6]([OH:8])=[O:7])[CH2:4][SH:5].Cl[C:10]([O:12][CH2:13][C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)=[O:11].Cl>[OH-].[Na+]>[C:10]([NH:2][C@H:3]([C:6]([OH:8])=[O:7])[CH2:4][S:5][C:10]([O:12][CH2:13][C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)=[O:11])([O:12][CH2:13][C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)=[O:11]

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 10387Benzyl chloroformateHCID 60960Cysteine Hydrochloride

Product 1

HCID 7021869N,S-Bis[(phenylmethoxy)carbonyl]-L-cysteineYield 80%

Reagents, catalysts & solvents 1

HCID 14798Sodium HydroxideSolvent2×

Conditions

Temperature
0 °C

Procedure

Cysteine HCl (2.0 g, 12.6 mmol) was dissolved in 2N NaOH and benzyl chloroformate (4.5 mL) was slowly added over 15 min. The pH value of the solution was kept at 9-10 by addition of 2 N NaOH (~7 mL) at 0° C. After vigorous stirring for 1 h at 0° C., the aqueous solution was acidified with 2N HCl at pH ~2 to form a colorless syrup. The aqueous solution was decanted and the sticky syrup was triturated with petroleum ether (100 ml×3) to give N,S-diCBZ-cysteine (3.94 g, 80%) as a white solid. Analytically pure sample could also be obtained by flash chromatography (on silica gel, 5% CH3OH in EtOAc):mp.93°-94° C.; 1H NMR (CDCl3) δ7.33 (10H, m), 5.67 (1H, d, J=7.7 Hz), 5.21 (2H, s), 5.12 (2H, s), 4.66 (1H, ddd, J=7.7, 6.7, 4.4 Hz), 3.31 (1H, dd, J=6.7, 14.5 Hz).

Workup

  1. customto form a colorless syrup
  2. customThe aqueous solution was decanted
  3. customthe sticky syrup was triturated with petroleum ether (100 ml×3)

Sources & evidence

ORD record
ord-1360925152c1482681108626c9474932
Source dataset
uspto-grants-1999_01
Patent number
US05856310

Linked notes

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