tert-butyl N-[(3S)-1-chloro-4-methyl-2-oxopentan-3-yl]carbamate

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. Solvent was evaporated the resulting residue was triturated with ether

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. The resulting mixture was filtered the retained material was washed with 40 mL of cold THF The combined filtrates were added to 200 mL of diazomethane solvent was removed by evaporation to yield an oil washed with 5% sodium bicarbonate dried over sodium sulfate Evaporation of solvent left 6.4 g of an oil The oil was dissolved in 100 mL of ether the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0° This solution was washed with cold water dried over sodium sulfate After evaporation of solvent, product was washed with hexane

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. Solvent was evaporated the resulting residue was triturated with ether

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. Solvent was evaporated the resulting residue was triturated with ether

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. The resulting mixture was filtered the retained material was washed with 40 mL of cold THF The combined filtrates were added to 200 mL of diazomethane solvent was removed by evaporation to yield an oil washed with 5% sodium bicarbonate dried over sodium sulfate Evaporation of solvent left 6.4 g of an oil The oil was dissolved in 100 mL of ether the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0° This solution was washed with cold water dried over sodium sulfate After evaporation of solvent, product was washed with hexane

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. Solvent was evaporated the resulting residue was triturated with ether

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. The resulting mixture was filtered the retained material was washed with 40 mL of cold THF The combined filtrates were added to 200 mL of diazomethane solvent was removed by evaporation to yield an oil washed with 5% sodium bicarbonate dried over sodium sulfate Evaporation of solvent left 6.4 g of an oil The oil was dissolved in 100 mL of ether the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0° This solution was washed with cold water dried over sodium sulfate After evaporation of solvent, product was washed with hexane

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

Procedure: Boc-ValCHN2 was prepared by a procedure substantially similar to that described for preparation of Boc-TyrCHN2 (Procedure C) except that Boc-Tyr-OH was replaced with Boc-Val-OH. Boc-ValCHN2 was treated with 3.45N ethanolic:HCl, as described in Procedure C, to give Boc-ValCH2Cl. After crystallization from hexane, product melted at 70°-73°.

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. Solvent was evaporated the resulting residue was triturated with ether

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. The resulting mixture was filtered the retained material was washed with 40 mL of cold THF The combined filtrates were added to 200 mL of diazomethane solvent was removed by evaporation to yield an oil washed with 5% sodium bicarbonate dried over sodium sulfate Evaporation of solvent left 6.4 g of an oil The oil was dissolved in 100 mL of ether the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0° This solution was washed with cold water dried over sodium sulfate After evaporation of solvent, product was washed with hexane

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. Solvent was evaporated the resulting residue was triturated with ether

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

Procedure: First, precursor H-ValCH2Cl.HCl was prepared by dissolving Boc-Val-OH (6.5 g, 30 mmol) in 10 mL of THF and treating it with N-methylmorpholine (3.3 mL, 30 mmol) and isobutyl chloroformate (3.9 mL, 30 mmol) for 10 minutes at -20°. The resulting mixture was filtered and the retained material was washed with 40 mL of cold THF. The combined filtrates were added to 200 mL of diazomethane:ether. The resulting solution was stirred for 2 hours at 0°, and then solvent was removed by evaporation to yield an oil. The oil was dissolved in ethyl acetate, washed with 5% sodium bicarbonate followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. Evaporation of solvent left 6.4 g of an oil. The oil was dissolved in 100 mL of ether, and the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0°. This solution was washed with cold water followed by saturated aqueous sodium chloride, and then dried over sodium sulfate. After evaporation of solvent, product was washed with hexane to yield 2.7 g of Boc-ValCH2Cl (m.p. 70°-73°). Boc-ValCH2Cl (1.0 g) was deblocked by stirring with 5 mL of 3N ethanolic HCl for 30 minutes at about 23°. Solvent was evaporated and the resulting residue was triturated with ether to yield 0.69 g of H-ValCH2Cl.HCl. The resulting mixture was filtered the retained material was washed with 40 mL of cold THF The combined filtrates were added to 200 mL of diazomethane solvent was removed by evaporation to yield an oil washed with 5% sodium bicarbonate dried over sodium sulfate Evaporation of solvent left 6.4 g of an oil The oil was dissolved in 100 mL of ether the resulting solution was treated with a 5% excess of ethanolic HCl for 15 minutes at 0° This solution was washed with cold water dried over sodium sulfate After evaporation of solvent, product was washed with hexane