L-(+)-Cysteine → 2-Phenyl-4,5-dihydro-1,3-thiazole-4-carboxylic acid

HRID 982887Notes

Reaction equation

HRID 982887 reaction equation
[NH2:1][C@H:2]([C:5]([OH:7])=[O:6])[CH2:3][SH:4].[C:8](#N)[C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1.C(N(CC)CC)C>C(O)C>[C:9]1([C:8]2[S:4][CH2:3][CH:2]([C:5]([OH:7])=[O:6])[N:1]=2)[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1

Participants

5

Reactant 3

HCID 5862L-(+)-CysteineHCID 7505BenzonitrileHCID 8471Triethylamine

Product 1

HCID 883272-Phenyl-4,5-dihydro-1,3-thiazole-4-carboxylic acidYield 66%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Cysteine, benzonitrile, and 5 equivalents of triethylamine were refluxed in ethanol for 6-8 hours to obtain a 66-70% yield of 2-phenylthiazoline-4-carboxylic acid. The 2-phenylthiazoline-4 carboxylic acid was reacted with 2.05 equivalents of base and 1 equivalent of methyl iodide in tetrahydrofuran at 0° C. to form 2-phenyl-4-methylthiazoline-4 carboxylic acid. The 2-phenyl-4-methylthiazoline-4 carboxylic acid can be resolved and isolated as the (S)-enantiomer using emulsion crystallization, and subsequently hydrolyzed with hydrochloric acid, thereby obtaining (S)-2-methylcysteine hydrochloride.

Sources & evidence

ORD record
ord-fb65e38ffce848cf8addba9f7755a32d
Source dataset
uspto-grants-2005_03
Patent number
US06861532B2

Reaction notes

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