methyl (2S)-2-(methylamino)-3-phenylpropanoate

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

Procedure: To 100 ml of acetone, 2.2 g of N-methylphenylalanine methyl ester was dissolved, and 2.0 g of 2-methylthio-1,3-dithiolium iodide was gradually added thereto under stirring at room temperature. The mixture was stirred at room temperature for 1 hour, and then concentrated under reduced pressure. The residue was dissolved in water. The aqueous layer was washed with ethyl acetate, and then water was distilled off under reduced pressure, whereby 1.7 g (yield: 52%) of N-(1,3-dithiol-2-ylidene)-N-methyl-N-(2-phenyl-1-methoxycarbonylethyl)ammonium iodide (Compound No. 5) was obtained as oily substance. The mixture was stirred at room temperature for 1 hour concentrated under reduced pressure The residue was dissolved in water The aqueous layer was washed with ethyl acetate

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

Procedure: Condensation of BocProOH (4.30 g.) and HMePheOMe (2.74 g.) by the mixed anhydride method using diphenylphosphinyl chloride gave BocPro-MePheOMe in 77% yield. Demethylation of BocPro-MePheOMe (3.0 g.) using aqueous sodium hydroxide gave BocPro-MePheOH in 83% yield. Condensation of BocPro-MePheOH (1.71 g.) and HPheOBz (2.14 g.) using dicyclohexylcarbodiimide and N-hydroxysuccinimide gave BocPro-MePhe-PheOBz in 76% yield. Debenzylation of BocPro-MePhe-PheOBz (2.0 g.) by hydrogenation with palladium catalyst gave BocPro-MePhe-PheOH in 100% yield.

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

Procedure: Condensation of BocProOH (4.30 g.) and HMePheOMe (2.74 g.) by the mixed anhydride method using diphenylphosphinyl chloride gave BocPro-MePheOMe in 77% yield. Demethylation of BocPro-MePheOMe (3.0 g.) using aqueous sodium hydroxide gave BocPro-MePheOH in 83% yield. Condensation of BocPro-MePheOH (1.71 g.) and HPheOBz (2.14 g.) using dicyclohexylcarbodiimide and N-hydroxysuccinimide gave BocPro-MePhe-PheOBz in 76% yield. Debenzylation of BocPro-MePhe-PheOBz (2.0 g.) by hydrogenation with palladium catalyst gave BocPro-MePhe-PheOH in 100% yield.

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

Procedure: N-(Toluene-4-sulfonyl)sarcosine was coupled to N-methyl-L-phenylalanine methyl ester using the procedure described in Method 3 to give N-(toluene-4-sulfonyl)sarcosyl-N-methylphenylalanine methyl ester. The title compound was prepared via hydrolysis of the methyl ester using LiOH in THF/water. Proton and carbon NMR analysis indicated a mixture of amide bond rotomers in about a 65:35 ratio.

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

Procedure: To 100 ml of acetone, 2.2 g of N-methylphenylalanine methyl ester was dissolved, and 2.0 g of 2-methylthio-1,3-dithiolium iodide was gradually added thereto under stirring at room temperature. The mixture was stirred at room temperature for 1 hour, and then concentrated under reduced pressure. The residue was dissolved in water. The aqueous layer was washed with ethyl acetate, and then water was distilled off under reduced pressure, whereby 1.7 g (yield: 52%) of N-(1,3-dithiol-2-ylidene)-N-methyl-N-(2-phenyl-1-methoxycarbonylethyl)ammonium iodide (Compound No. 5) was obtained as oily substance. The mixture was stirred at room temperature for 1 hour concentrated under reduced pressure The residue was dissolved in water The aqueous layer was washed with ethyl acetate