2-methyl-3-sulfanylpropanoic acid

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To the cold (5°) solution of 1.2 g. (10 mMol.) of 3-mercapto-2-methylpropanoic acid and 1.7 g. (10 mMol.) of L-proline tert.butyl ester in 25 ml. dichloromethane 2.26 g. of dicyclohexylcarbodiimide in 5 ml. dichloromethane is added in portions. After 2 hours at room temperature, 5 drops of acetic acid are added, the mixture is filtered and the filtrate evaporated to an oily residue. This residue is taken up in 20 ml. of petroleum ether-ethyl acetate (3:1) and applied to a 150 ml. silica gel column prepared in petroleum ether. The fraction eluted with petroleum ether-ethyl acetate (1:1) contains the product, 1-(3-Mercapto-2-methylpropanoyl)-L-proline tert.butyl ester. This fraction (0.6 g.) is dried over P2O5 in vacuo for 12 hours. Rf 0.6 (Silica gel, Benzene/Acetic acid 3:1), Rf 0.8 (Silica gel, Methyl-ethylketone/acetic acid/pyridine/water 14:1:2:1). To the cold (5°) solution of 1.2 g the mixture is filtered the filtrate evaporated to an oily residue silica gel column prepared in petroleum ether The fraction eluted with petroleum ether-ethyl acetate (1:1) This fraction (0.6 g.) is dried over P2O5 in vacuo for 12 hours

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To the cold (5°) solution of 1.2 g. (10 mMol.) of 3-mercapto-2-methylpropanoic acid and 1.7 g. (10 mMol.) of L-proline tert.butyl ester in 25 ml. dichloromethane 2.26 g. of dicyclohexylcarbodiimide in 5 ml. dichloromethane is added in portions. After 2 hours at room temperature, 5 drops of acetic acid are added, the mixture is filtered and the filtrate evaporated to an oily residue. This residue is taken up in 20 ml. of petroleum ether-ethyl acetate (3:1) and applied to a 150 ml. silica gel column prepared in petroleum ether. The fraction eluted with petroleum ether-ethyl acetate (1:1) contains the product, 1-(3-Mercapto-2-methylpropanoyl)-L-proline tert.butyl ester. This fraction (0.6 g.) is dried over P2O5 in vacuo for 12 hours. Rf 0.6 (Silica gel, Benzene/Acetic acid 3:1), Rf 0.8 (Silica gel, Methyl-ethylketone/acetic acid/pyridine/water 14:1:2:1). To the cold (5°) solution of 1.2 g the mixture is filtered the filtrate evaporated to an oily residue silica gel column prepared in petroleum ether The fraction eluted with petroleum ether-ethyl acetate (1:1) This fraction (0.6 g.) is dried over P2O5 in vacuo for 12 hours

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3-Mercapto-2-methylpropanoic acid (2.4 g.) and N-hydroxymethylacetamide (1.8 g.) are dissolved in trifluoroacetic acid and the solution is stored at room temperature for one hour. The trifluoroacetic acid is removed in vacuo and the residue is dried in vacuo over potassium hydroxide to yield 3-acetamidomethylthio-2-methylpropanoic acid. The trifluoroacetic acid is removed in vacuo the residue is dried in vacuo over potassium hydroxide

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3-Mercapto-2-methylpropanoic acid (2.4 g.) and N-hydroxymethylacetamide (1.8 g.) are dissolved in trifluoroacetic acid and the solution is stored at room temperature for one hour. The trifluoroacetic acid is removed in vacuo and the residue is dried in vacuo over potassium hydroxide to yield 3-acetamidomethylthio-2-methylpropanoic acid. The trifluoroacetic acid is removed in vacuo the residue is dried in vacuo over potassium hydroxide

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 3-mercapto-2-methylpropanoic acid (2.4 g.) and freshly distilled 2,3-dihydro-4H-pyrane (1.9 g.) in benzene (60 ml.), boron trifluoride etherate (2.8 g.) is added. After two hours, potassium carbonate (4 g.) is added, the mixture is stirred and filtered. The filtrate is concentrated to dryness to yield 3-(tetrahydropyran-2-ylthio)-2-methylpropanoic acid. filtered The filtrate is concentrated to dryness

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 3-mercapto-2-methylpropanoic acid (2.4 g.) and freshly distilled 2,3-dihydro-4H-pyrane (1.9 g.) in benzene (60 ml.), boron trifluoride etherate (2.8 g.) is added. After two hours, potassium carbonate (4 g.) is added, the mixture is stirred and filtered. The filtrate is concentrated to dryness to yield 3-(tetrahydropyran-2-ylthio)-2-methylpropanoic acid. filtered The filtrate is concentrated to dryness