Hydrochloric Acid → N-Acetyl-S-methyl-L-cysteine

HRID 325330

Reaction equation

[CH3:1][S:2][CH2:3][C@@H:4]([C:6]([OH:8])=[O:7])[NH2:5].[OH-].[Na+].[C:11](OC(=O)C)(=[O:13])[CH3:12].Cl>>[CH3:1][S:2][CH2:3][C@@H:4]([C:6]([OH:8])=[O:7])[NH:5][C:11](=[O:13])[CH3:12]

Participants

Reactant 4

HCID 313Hydrochloric Acid

HCID 7918Acetic Anhydride

HCID 14798Sodium Hydroxide

HCID 24417(-)-S-Methyl-L-cysteine

Product 1

HCID 13893975N-Acetyl-S-methyl-L-cysteineYield 80.6%

Procedure

S-Methyl-L-cysteine (119.6 g, 0.89 mole) was dissolved in 1.87 l (1.87 mole) of 1 N sodium hydroxide solution and then ice-cooled. Thereafter, 92.6 ml (0.98 mole) of acetic anhydride was added dropwise and the mixture was stirred for 2.0 hours at room temperature. The reaction mixture was acidified to pH 1.0 with 6 N hydrochloric acid and extracted with 1 liter of ethyl acetate five times. The extracts were dried over anhydrous magnesium sulfate and concentrated in vacuo to give 126.4 g of S-methyl-N-acetyl-L-cysteine as an oil (80.6% yield). A second crop of 5.17 g (3.3%) was recovered by reextraction of the aqueous layer.

Workup

temperatureice-cooled
extractionextracted with 1 liter of ethyl acetate five times
dry with materialThe extracts were dried over anhydrous magnesium sulfate
concentrationconcentrated in vacuo

Sources & evidence

ORD record: ord-2aaa495b46bc4d9b8a75a64dde900409
Source dataset: uspto-grants-1984_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04440788

Linked notes

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