chloromethyl (2S)-3-methyl-2-[(2-methylpropan-2-yl)oxycarbonylamino]butanoate

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

Procedure: To a vigorously stirred mixture of (S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanoic acid (4 g, 18.41 mmol), tetrabutylammonium hydrogen sulfate (1.25 g, 3.68 mmol), and Na2CO3 (9.76 g, 92 mmol) in DCM 80 (mL) and water (80 mL), cooled in an ice/water bath, was slowly added chloromethyl chlorosulfate (3.8 mL, 36.8 mmol) over 4 min. After stirring in the ice/water bath for 30 min, the cold bath was removed and the reaction mixture was allowed to stir at room temperature. After stirring 16 h at room temperature, the reaction mixture was diluted with water and extracted with DCM. The aqueous layer was back extracted with DCM and the combined organic layers were dried over MgSO4, filtered and concentrated to afford Intermediate 38A (5.45 g). cooled in an ice/water bath over 4 min the cold bath was removed After stirring 16 h at room temperature the reaction mixture was diluted with water extracted with DCM The aqueous layer was back extracted with DCM the combined organic layers were dried over MgSO4 filtered concentrated

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

Procedure: To a vigorously stirred mixture of (S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanoic acid (4 g, 18.41 mmol), tetrabutylammonium hydrogen sulfate (1.25 g, 3.68 mmol), and Na2CO3 (9.76 g, 92 mmol) in DCM (80 mL) and water (80 mL) cooled in an ice/water bath was slowly added chloromethyl chlorosulfate (3.8 mL, 36.8 mmol) over 4 min. After stirring in the ice/water bath for 30 min, the cold bath was removed and the reaction was allowed to stir at room temperature. After stirring 16 h at room temperature the reaction was diluted with water and extracted with DCM. The aqueous layer was back extracted with DCM and the combined organic layers were dried over MgSO4, filtered and concentrated. The crude material (5.45 g) was used as is without purification. cooled in an ice/water bath over 4 min the cold bath was removed After stirring 16 h at room temperature the reaction was diluted with water extracted with DCM The aqueous layer was back extracted with DCM the combined organic layers were dried over MgSO4 filtered concentrated as is without purification

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

Procedure: A suspension of 50 mmole of 7-[[(2,3-dihydro-5-benzofuranyl)acetyl]amino]-3-[[(1-methyltetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid sodium salt and 50 mmole of N-tert-butoxycarbonyl-L-valine chloromethyl ester, prepared by the procedure described in W. German Offen. No. 2,236,620, are mixed in 100 ml of dimethylformamide and stirred for about 72 hours. The mixture is diluted with ethyl acetate, washed with water, with aqueous sodium bicarbonate, and with water a second time. The organic layer is dried over magnesium sulfate, filtered and evaporated to give 7-[[(2,3-dihydro-5-benzofuranyl)acetyl]amino]-3-[[(1-methyltetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid N-tert-butoxycarbonyl-2-amino-3-methylbutyrylmethyl ester from which the amine protecting group is removed by standard procedures to give the title compound. prepared by the procedure washed with water, with aqueous sodium bicarbonate The organic layer is dried over magnesium sulfate filtered evaporated

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

Procedure: A suspension of 50 mmole of 7-[[(2,3-dihydro-5-benzofuranyl)acetyl]amino]-3-[[(1-methyltetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid sodium salt and 50 mmole of N-tert-butoxycarbonyl-L-valine chloromethyl ester, prepared by the procedure described in W. German Offen. No. 2,236,620, are mixed in 100 ml of dimethylformamide and stirred for about 72 hours. The mixture is diluted with ethyl acetate, washed with water, with aqueous sodium bicarbonate, and with water a second time. The organic layer is dried over magnesium sulfate, filtered and evaporated to give 7-[[(2,3-dihydro-5-benzofuranyl)acetyl]amino]-3-[[(1-methyltetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid N-tert-butoxycarbonyl-2-amino-3-methylbutyrylmethyl ester from which the amine protecting group is removed by standard procedures to give the title compound. prepared by the procedure washed with water, with aqueous sodium bicarbonate The organic layer is dried over magnesium sulfate filtered evaporated

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

Procedure: A suspension of 5 grams of 7-[[2-carbethoxy-2-(1H-indol-1-yl)acetyl]amino]-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid sodium salt and 8.5 grams of N-tert-butoxycarbonyl-L-valine chloromethyl ester, prepared by the general procedure described in W. German Offen. No. 2,236,620 are mixed in 100 ml of dimethylformamide (DMF) and stirred for 72 hours. The mixture is diluted with ethyl acetate, washed with water, aqueous sodium bicarbonate and again with water. The ethyl acetate portion is dried over magnesium sulfate, filtered and evaporated to dryness to give 7-[[2-carbethoxy-2-(1H-indol-1-yl)acetyl]amino]-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid N-tert-butoxycarbonyl-2-amino-3-methylbutyryloxymethyl ester from which the protecting group can be removed by standard procedures to give the title compound. prepared by the general procedure washed with water, aqueous sodium bicarbonate and again with water The ethyl acetate portion is dried over magnesium sulfate filtered evaporated to dryness

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

Procedure: A suspension of 5 grams of 3-[(acetyloxy)methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid sodium salt and 8.5 grams of N-tert-butoxycarbonyl-L-valine chloromethyl ester, which is prepared by the general procedure described in W. German Offen. No. 2,236,620, are mixed in 100 ml of dimethyl formamide and stirred for 72 hours. The mixture is diluted with ethyl acetate, washed with water with aqueous bicarbonate and again with water. The organic layer is dried over magnesium sulfate, filtered, and evaporated to dryness to give 3-[(acetyloxy)-methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2carboxylic acid N-tert-butoxycarbonyl-2-amino-3-methylbutyryloxymethyl ester from which the amine protecting group is removed by standard procedures to give the title product. is prepared by the general procedure washed with water with aqueous bicarbonate and again with water The organic layer is dried over magnesium sulfate filtered evaporated to dryness

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

Procedure: A suspension of 5 grams of 3-[(acetyloxy)methyl]-7-amino-8-amino-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid sodium salt and 8.5 grams of N-tert-butoxycarbonyl-L-valine chloromethyl ester, which is prepared by the general procedure described in W. German Offen. 2,236,620, are mixed in 100 ml of dimethyl formamide and stirred for 72 hours. The mixture is diluted with ethyl acetate, washed with water with aqueous bicarbonate and again with water. The organic layer is dried over magnesium sulfate, filtered, and evaporated to dryness to give 3-[(acetyloxy)methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid N-tert-butoxycarbonyl-2-amino-3-methylbutyryloxymethyl ester from which the amine protecting group is removed by standard procedures to give the title product. is prepared by the general procedure washed with water with aqueous bicarbonate and again with water The organic layer is dried over magnesium sulfate filtered evaporated to dryness

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

Procedure: To a stirred solution of (S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanoic acid (1 g, 4.60 mmol), sodium carbonate (2.439 g, 23.01 mmol) and tetrabutylammonium hydrogen sulfate (0.313 g, 0.921 mmol) in a mixture of DCM (10 mL) and water (5 mL) at 0° C., was added chloromethyl chlorosulfate (1.519 g, 9.21 mmol). The reaction mixture was allowed to warm to room temperature overnight. The mixture was diluted with DCM and water, and the organic layer was separated, washed with a brine solution, and dried over Na2SO4. The solution was filtered and concentrated in vacuo and the residue obtained was purified by a flash chromatography (SiO2, 0-10% EtOAc in hexane) to afford Preparation 52A (0.9 g, 73.6%) as a colorless oil. 1H NMR (400 MHz, CDCl3) δ 0.93 (d, J=6.80 Hz, 3H), 1.00 (d, J=6.80 Hz, 3H), 1.43 (s, 9H), 2.17-2.18 (m, 1H), 4.25-4.27 (m, 1H), 4.96 (d, J=7.60 Hz, 1H), 5.62 (d, J=6.00 Hz, 1H), 5.88 (d, J=6.00 Hz, 1H). the organic layer was separated washed with a brine solution dried over Na2SO4 The solution was filtered concentrated in vacuo the residue obtained was purified by a flash chromatography (SiO2, 0-10% EtOAc in hexane) to afford

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

Procedure: To a stirred solution of (S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanoic acid (1 g, 4.60 mmol), sodium carbonate (2.439 g, 23.01 mmol) and tetrabutylammonium hydrogen sulfate (0.313 g, 0.921 mmol) in a mixture of DCM (10 mL) and water (5 mL) at 0° C., was added chloromethyl chlorosulfate (1.519 g, 9.21 mmol). The reaction mixture was allowed to warm to room temperature overnight. The mixture was diluted with DCM and water, and the organic layer was separated, washed with a brine solution, and dried over Na2SO4. The solution was filtered and concentrated in vacuo and the residue obtained was purified by a flash chromatography (SiO2, 0-10% EtOAc in hexane) to afford Preparation 52A (0.9 g, 73.6%) as a colorless oil. 1H NMR (400 MHz, CDCl3) δ 0.93 (d, J=6.80 Hz, 3H), 1.00 (d, J=6.80 Hz, 3H), 1.43 (s, 9H), 2.17-2.18 (m, 1H), 4.25-4.27 (m, 1H), 4.96 (d, J=7.60 Hz, 1H), 5.62 (d, J=6.00 Hz, 1H), 5.88 (d, J=6.00 Hz, 1H). the organic layer was separated washed with a brine solution dried over Na2SO4 The solution was filtered concentrated in vacuo the residue obtained was purified by a flash chromatography (SiO2, 0-10% EtOAc in hexane) to afford

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (R)-3-[N′-(5-Acetyl-2H-pyrazole-3-carbonyl)-N-(5′-chloro-2′-fluorobiphenyl-4-ylmethyl)hydrazino]-2-hydroxypropionic acid (95.5 mg, 0.2 mmol) was dissolved in acetone (886 μL, 12.1 mmol). Et3N (70 μL, 503 μmol) and (S)-2-t-butoxycarbonylamino-3-methyl-butyric acid chloromethyl ester (56.1 mg, 211 μmol) were added, and the resulting mixture was stirred at 60° C. for 6 hours. The solvent was removed in vacuo and the residue was purified using flashy chromatography (normal phase; MeOH:EtOAc=0:50). The pure fractions were collected, concentrated, then dissolved in MeCN (630 μL, 12.1 mmol). A solution of 4.0 M HCl in 1,4-dioxane (503 μL, 2.0 mmol) was added, and the resulting mixture was stirred at room temperature for 2 hours. The solvent was removed in vacuo to yield the title compound (90 mg). The solvent was removed in vacuo the residue was purified The pure fractions were collected concentrated the resulting mixture was stirred at room temperature for 2 hours The solvent was removed in vacuo

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

Procedure: To a mixture of (S)-2-(t-butoxycarbonylamino)-3-methylbutanoic acid (28.6 g, 130 mmol) and NaHCO3 (44 g, 520 mmol) and Bu4NHSO4 (4.4 g, 13 mmol) in DCM (200 mL) and water (200 mL) was added chloromethyl sulfochloridate (26 g, 158 mmol) at 0° C. The mixture was stirred at room temperature for 24 hours, and then was extracted with DCM (3×150 mL). The combined organic layers were washed with water (2×300 mL), and the DCM layer was purified by flash column (PE:EtOAc=15:1) to yield the title compound as a yellow solid (35 g). LC-MS: 266 [M+H]+. was added chloromethyl sulfochloridate (26 g, 158 mmol) at 0° C was extracted with DCM (3×150 mL) The combined organic layers were washed with water (2×300 mL) the DCM layer was purified by flash column (PE:EtOAc=15:1)

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

Procedure: To a mixture of (S)-2-(t-butoxycarbonylamino)-3-methylbutanoic acid (28.6 g, 130 mmol) and NaHCO3 (44 g, 520 mmol) and Bu4NHSO4 (4.4 g, 13 mmol) in DCM (200 mL) and water (200 mL) was added chloromethyl sulfochloridate (26 g, 158 mmol) at 0° C. The mixture was stirred at room temperature for 24 hours, and then was extracted with DCM (3×150 mL). The combined organic layers were washed with water (2×300 mL), and the DCM layer was purified by flash column (PE:EtOAc=15:1) to yield the title compound as a yellow solid (35 g). LC-MS: 266 [M+H]+. was added chloromethyl sulfochloridate (26 g, 158 mmol) at 0° C was extracted with DCM (3×150 mL) The combined organic layers were washed with water (2×300 mL) the DCM layer was purified by flash column (PE:EtOAc=15:1)