sodium;4-methyl-2-oxopentanoate

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

Procedure: A mixture of 2-Oxo-4-methyl pentanoic acid sodium salt (10 g, 65.7 mmol) and benzyl chloride (8 g, 63 mmol) in 300 ml DMF was stirred at 40°-50° C. for 5 h. It was filtered, and the filtrate was evaporated under reduced pressure to provide an oil. The oil was dissolved in chloroform, washed with water, dried, filtered, and evaporated to provide the desired product (13 g, 94%). 1H NMR (CDCl3, TMS) δ0.95 (d,6H), 2.15 (m,1H), 2.7 (d,2H), 5.28 (s,2H), 7.4 (m,5H). Mass spectrum: (M+H)+ =221. It was filtered the filtrate was evaporated under reduced pressure to provide an oil washed with water dried filtered evaporated

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

Procedure: A mixture of 2-Oxo-4-methyl pentanoic acid sodium salt (10 g, 65.7 mmol) and benzyl chloride (8 g, 63 mmol) in 300 ml DMF was stirred at 40°-50° C. for 5 h. It was filtered, and the filtrate was evaporated under reduced pressure to provide an oil. The oil was dissolved in chloroform, washed with water, dried, filtered, and evaporated to provide the desired product (13 g, 94%). 1H NMR (CDCl3, TMS) δ0.95 (d,6H), 2.15 (m,1H), 2.7 (d,2H), 5.28 (s,2H), 7.4 (m,5H). Mass spectrum: (M+H)+ =221. It was filtered the filtrate was evaporated under reduced pressure to provide an oil washed with water dried filtered evaporated

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

Procedure: A mixture of 2-Oxo-4-methyl pentanoic acid sodium salt (10 g, 65.7 mmol) and benzyl chloride (8 g, 63 mmol) in 300 ml DMF was stirred at 40°-50° C. for 5 h. It was filtered, and the filtrate was evaporated under reduced pressure to provide an oil. The oil was dissolved in chloroform, washed with water, dried, filtered, and evaporated to provide the desired product (13 g, 94%). 1H NMR (CDCl3, TMS) δ0.95 (d,6H), 2.15 (m,1H), 2.7 (d,2H), 5.28 (s,2H), 7.4 (m,5H). Mass spectrum: (M+H)+ =221. It was filtered the filtrate was evaporated under reduced pressure to provide an oil washed with water dried filtered evaporated

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

Procedure: A solution of L-alanyl-L-isoleucine (150 mg) and 4-methyl-2-oxopentanoic acid sodium salt (564 mg) in water was adjusted to pH 7 and treated with 140 mg of sodium cyanoborohydride at room temperature for several days. The reaction was quenched with strong acid ion-exchange resin, added to a column of the same resin, and eluted with 2% pyridine in water. Freeze drying afforded 200 mg (84.9%) of white fluffy solid, N-(1-carboxy-3-methylbutyl)-L-alanyl-L-isoleucine. Mass spectrum showed peaks at 460 for the disilylated derivative, and 445 for disilyl molecular ion minus methyl (460-15). The nmr spectrum showed a broad doublet centered at 0.95 ppm, complex absorption in the 1.2-1.8 ppm range, and a broad weak singlet at 3.7 ppm. The reaction was quenched with strong acid ion-exchange resin added to a column of the same resin eluted with 2% pyridine in water Freeze drying

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

Procedure: A solution of L-alanyl-L-isoleucine (150 mg) and 4-methyl-2-oxopentanoic acid sodium salt (564 mg) in water was adjusted to pH 7 and treated with 140 mg of sodium cyanoborohydride at room temperature for several days. The reaction was quenched with strong acid ion-exchange resin, added to a column of the same resin, and eluted with 2% pyridine in water. Freeze drying afforded 200 mg (84.9%) of white fluffy solid, N-(1-carboxy-3-methylbutyl)-L-alanyl-L-isoleucine. Mass spectrum showed peaks at 460 for the disilylated derivative, and 445 for disilyl molecular ion minus methyl (460-15). The nmr spectrum showed a broad doublet centered at 0.95 ppm, complex absorption in the 1.2-1.8 ppm range, and a broad weak singlet at 3.7 ppm. The reaction was quenched with strong acid ion-exchange resin added to a column of the same resin eluted with 2% pyridine in water Freeze drying

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

Procedure: A solution of dicyclohexylcarbodiimide (DCC) (157 g) in dichloromethane (200 ml) was added dropwise over 2 hours to an efficiently stirred mixture of powdered sodium 4-methyl-2-oxopentanoate (115.5 g), 2-aminoacetophenone hydrochloride (130.4 g) and HOBT (103 g) in dichloromethane (1 liter). The mixture was stirred overnight and the insoluble dicyclohexylurea removed by filtration. The filtrate was concentrated and the residue redissolved in dichloromethane (500 ml). The mixture was filtered to remove a further quantity of dicyclohexylurea, and the filtrate was washed with saturated sodium hydrogen carbonate solution (500 ml), water (500 ml) and saturated sodium chloride solution (500 ml). The organic phase was dried and concentrated to give 4-methyl-2-oxo-N-(2-oxo-2-phenylethyl)pentanamide (C), as a foam (183.6 g), which was used without further purification; NMR (CDCl3) : 1.0 (d, 6H), 2.2 (m, 1H), 2.8 (d, 2H), 4.75 (d, 2H), 7.4-7.7 (m, 3H), 7.9 (br, 1H), 8.0 (m, 2H). the insoluble dicyclohexylurea removed by filtration The filtrate was concentrated the residue redissolved in dichloromethane (500 ml) The mixture was filtered to remove a further quantity of dicyclohexylurea the filtrate was washed with saturated sodium hydrogen carbonate solution (500 ml), water (500 ml) and saturated sodium chloride solution (500 ml) The organic phase was dried concentrated

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

Procedure: A mixture of 2-Oxo-4-methyl pentanoic acid sodium salt (10 g, 65.7 mmol) and benzyl chloride (8 g, 63 mmol) in 300 ml DMF was stirred at 40°-50° C. for 5 h. It was filtered, and the filtrate was evaporated under reduced pressure to provide an oil. The oil was dissolved in chloroform, washed with water, dried, filtered, and evaporated to provide the desired product (13 g, 94%). 1H NMR (CDCl3, TMS) δ0.95 (d,6H), 2.15 (m,1H), 2.7 (d,2H), 5.28 (s,2H), 7.4 (m,5H). Mass spectrum: (M+H)+ =221. It was filtered the filtrate was evaporated under reduced pressure to provide an oil washed with water dried filtered evaporated