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

HRID 1450168

Reaction equation

HRID 1450168 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 2N 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-31e16a25b12c4e04b7d10dfbbe948e00
Source dataset
uspto-grants-1997_02
Patent number
US05602098

Linked notes

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