benzyl (2S)-2-aminopropanoate

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

Procedure: By substituting L-tyrosine benzyl ester for the L-alanine benzyl ester in the procedure of Example 23, and then treating the product by the procedure of Examples 24 and 26, N-(4-methoxycarbonyl-2-methylbutanoyl)-L-tyrosine benzyl ester, N-(4-methoxycarbonyl-2-methylbutanoyl)-L-tyrosine, and N-(4-carboxy-2-,ethylbutanoyl)-L-tyrosine are obtained. are obtained

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

Procedure: By substituting L-tyrosine benzyl ester for the L-alanine benzyl ester in the procedure of Example 23, and then treating the product by the procedure of Examples 24 and 26, N-(4-methoxycarbonyl-2-methylbutanoyl)-L-tyrosine benzyl ester, N-(4-methoxycarbonyl-2-methylbutanoyl)-L-tyrosine, and N-(4-carboxy-2-,ethylbutanoyl)-L-tyrosine are obtained. are obtained

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

Procedure: By substituting Nε -benzyloxycarbonyl-L-lysine benzyl ester for the L-alanine benzyl ester in the procedure of Example 23 and then treating the product by the procedure of Examples 24 and 26, Nα -(4-methoxycarbonyl-2-methylbutanoyl)-Nε -benzyloxycarbonyl-L-lysine benzyl ester, Nα -(4-methoxycarbonyl-2-methylbutanoyl)-L-lysine and Nα -(4-carboxy)-2-methylbutanoyl)-L-lysine are obtained. are obtained

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

Procedure: By substituting Nε -benzyloxycarbonyl-L-lysine benzyl ester for the L-alanine benzyl ester in the procedure of Example 23 and then treating the product by the procedure of Examples 24 and 26, Nα -(4-methoxycarbonyl-2-methylbutanoyl)-Nε -benzyloxycarbonyl-L-lysine benzyl ester, Nα -(4-methoxycarbonyl-2-methylbutanoyl)-L-lysine and Nα -(4-carboxy)-2-methylbutanoyl)-L-lysine are obtained. are obtained

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

Procedure: 4-methoxycarbonyl-2-methylbutanoic acid (3.1 g.), L-alanine benzyl ester (3.58 g.) and hydroxybenzotriazole (2.7 g.) are dissolved in dichloromethane. The solution is chilled in the ice bath and dicyclohexylcarbodiimide (4.12 g.) is added. After stirring 15 minutes in the ice bath and 18 hours at room temperature the precipitate is filtered off and the filtrate is concentrated to dryness. The residue is dissolved in ethyl acetate and washed neutral. The organic phase is dried over magnesium sulfate and concentrated to dryness to yield N-(4-methoxycarbonyl-2-methylbutanoyl)-L-alanine benzyl ester. is added is filtered off the filtrate is concentrated to dryness The residue is dissolved in ethyl acetate washed neutral The organic phase is dried over magnesium sulfate concentrated to dryness

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

Procedure: 4-methoxycarbonyl-2-methylbutanoic acid (3.1 g.), L-alanine benzyl ester (3.58 g.) and hydroxybenzotriazole (2.7 g.) are dissolved in dichloromethane. The solution is chilled in the ice bath and dicyclohexylcarbodiimide (4.12 g.) is added. After stirring 15 minutes in the ice bath and 18 hours at room temperature the precipitate is filtered off and the filtrate is concentrated to dryness. The residue is dissolved in ethyl acetate and washed neutral. The organic phase is dried over magnesium sulfate and concentrated to dryness to yield N-(4-methoxycarbonyl-2-methylbutanoyl)-L-alanine benzyl ester. is added is filtered off the filtrate is concentrated to dryness The residue is dissolved in ethyl acetate washed neutral The organic phase is dried over magnesium sulfate concentrated to dryness

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

Procedure: L-alanine benzyl ester (44.7 g.) and hydroxybenzotriazole (34 g.) are dissolved in dioxane (750 ml.) and the solution is chilled with stirring in an ice-water bath. Dicyclohexylcarbodiimide (51.5 g.) and 3-methoxycarbonyl-2-methylpropanoic acid (36 g.), prepared by hydrogenation of 3-methoxycarbonyl-2-methylene propanoic acid, are added in that order and the mixture is stirred at room temperature for 18 hours. The precipitate is filtered off, and the filtrate is concentrated to dryness in vacuo. The residue is dissolved in ethyl acetate and washed neutral. The ethyl acetate is dried over magnesium sulfate and concentrated to dryness in vacuo to yield N-(3-methoxycarbonyl-2-methylpropanoyl)-L-alanine benzyl ester. the solution is chilled are added in that order the mixture is stirred at room temperature for 18 hours The precipitate is filtered off the filtrate is concentrated to dryness in vacuo The residue is dissolved in ethyl acetate washed neutral The ethyl acetate is dried over magnesium sulfate concentrated to dryness in vacuo

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

Procedure: L-alanine benzyl ester (44.7 g.) and hydroxybenzotriazole (34 g.) are dissolved in dioxane (750 ml.) and the solution is chilled with stirring in an ice-water bath. Dicyclohexylcarbodiimide (51.5 g.) and 3-methoxycarbonyl-2-methylpropanoic acid (36 g.), prepared by hydrogenation of 3-methoxycarbonyl-2-methylene propanoic acid, are added in that order and the mixture is stirred at room temperature for 18 hours. The precipitate is filtered off, and the filtrate is concentrated to dryness in vacuo. The residue is dissolved in ethyl acetate and washed neutral. The ethyl acetate is dried over magnesium sulfate and concentrated to dryness in vacuo to yield N-(3-methoxycarbonyl-2-methylpropanoyl)-L-alanine benzyl ester. the solution is chilled are added in that order the mixture is stirred at room temperature for 18 hours The precipitate is filtered off the filtrate is concentrated to dryness in vacuo The residue is dissolved in ethyl acetate washed neutral The ethyl acetate is dried over magnesium sulfate concentrated to dryness in vacuo

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

Procedure: Using the procedure described in Example 60, but starting with 2-acetylthiomethyl-3-(4-hydroxyphenyl)butanoic acid and alanine benzyl ester, N-[2-acetylthiomethyl-3-(4-hydroxyphenyl)-1-oxobutyl]alanine benzyl ester is obtained in a 69% yield, the characteristics of which are as follows: Rf= 0.22 [hexane/ethyl acetate (65:35 by volume)].

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

Procedure: Using the procedure described in Example 60, but starting with 3-acetylthio-2-(1-indanyl)propanoic acid and alanine benzyl ester, N-[3-acetylthio-2-(1-indanyl)-1-oxopropyl)alanine benzyl ester is obtained in a 72% yield in the form of a white solid, having the following characteristics: m.p.: 95° C.; Rf =0.17 [cyclohexane/ethyl acetate (4:1 by volume)].

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

Procedure: Using the procedure described in Example 60, starting with 2-acetylthiomethyl-3-phenylbutanoic acid and alanine benzyl ester, and after purification by chromatography, eluting with a cyclohexane/ethyl acetate (75:25 by volume) mixture, N-(2-acetylthiomethyl-1-oxo-3-phenylbutyl)alanine benzyl ester is obtained in a 68% yield, the characteristics of which are as follows: Rf =0.31 [hexane/ethyl acetate (75:25 by volume)]. after purification by chromatography eluting with a cyclohexane/ethyl acetate (75:25 by volume) mixture

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

Procedure: The product of example 20A and L-alanine benzyl ester were processed as in examples 1E to yield (2RS,3R)-3-(tert-butoxycarbonylamino)-2-hydroxy-4-cyclohexyl)butanoyl-L-alanine benzyl ester. 0.5 g of the above product was hydrogenated in 2 mL of isopropyl alcohol in the presence of 20 mg of 10%-palladium on charcoal to yield (2RS,3R)-3-(tert-butoxycarbonylamino)-2-hydroxy-4-cyclohexyl)butanoyl-L-alanine (0.4 g).