tert-butyl pentanoate

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: Reaction operations were carried out according to the first step of Example 1 by using 2-(trans-4-(4-ethylphenyl)cyclohexyl)oxetane (42) (7.5 g, 30.9 mmol) and tert-butyl pentanoate (43) (15.6 g, 98.9 mmol) as starting materials to obtain tert-butyl 2-propyl-5-hydroxy-5-(trans-4-(4-ethylphenyl)cyclohexyl)pentanoate (44) (11.6 g, 28.8 mmol). The yield based on the compound (42) was 93%. Reaction operations

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

Procedure: Reaction operations were carried out according to the first step of Example 1 by using 2-(trans-4-(4-ethylphenyl)cyclohexyl)oxetane (42) (7.5 g, 30.9 mmol) and tert-butyl pentanoate (43) (15.6 g, 98.9 mmol) as starting materials to obtain tert-butyl 2-propyl-5-hydroxy-5-(trans-4-(4-ethylphenyl)cyclohexyl)pentanoate (44) (11.6 g, 28.8 mmol). The yield based on the compound (42) was 93%. Reaction operations

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

Procedure: Potassium fluoride (21.6 mg, 0.37 mmol) was added to a solution of N-[(1-methyl-3-isobutyl-indole-2-carbonyl)valinyl]-3-amino-5-bromo-4-oxo-pentanoic acid, tert-butyl ester (86.1 mg, 0.149 mmol) and 2,3,5, 6-tetrafluorophenol (27.0 mg, 0.163 mmol) in DMF (2.0 ml). After stirring at room temperature for 3 hours, the reaction mixture was partitioned between ethyl acetate and water. The aqueous layer was back-extracted with ethyl acetate. The organic layers were combined, washed with saturated NaHCO3 solution, and brine, dried over sodium sulfate, and concentrated. The residue was triturated with ether to give the titled product, N-(1-methyl-3-isobutyl-indole-2-carbonyl)-valinyl-3-amino-4-oxo-5-(2,3,5,6-tetral]uorophenyloxy)-pentanoic acid, tert-butyl ester as a white solid (43.8 mg, 44%). TLC (hexane/EtOAc, 50/50): Rf=0.50. the reaction mixture was partitioned between ethyl acetate and water The aqueous layer was back-extracted with ethyl acetate washed with saturated NaHCO3 solution, and brine dried over sodium sulfate concentrated The residue was triturated with ether

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

Procedure: Potassium fluoride (21.6 mg, 0.37 mmol) was added to a solution of N-[(1-methyl-3-isobutyl-indole-2-carbonyl)valinyl]-3-amino-5-bromo-4-oxo-pentanoic acid, tert-butyl ester (86.1 mg, 0.149 mmol) and 2,3,5, 6-tetrafluorophenol (27.0 mg, 0.163 mmol) in DMF (2.0 ml). After stirring at room temperature for 3 hours, the reaction mixture was partitioned between ethyl acetate and water. The aqueous layer was back-extracted with ethyl acetate. The organic layers were combined, washed with saturated NaHCO3 solution, and brine, dried over sodium sulfate, and concentrated. The residue was triturated with ether to give the titled product, N-(1-methyl-3-isobutyl-indole-2-carbonyl)-valinyl-3-amino-4-oxo-5-(2,3,5,6-tetral]uorophenyloxy)-pentanoic acid, tert-butyl ester as a white solid (43.8 mg, 44%). TLC (hexane/EtOAc, 50/50): Rf=0.50. the reaction mixture was partitioned between ethyl acetate and water The aqueous layer was back-extracted with ethyl acetate washed with saturated NaHCO3 solution, and brine dried over sodium sulfate concentrated The residue was triturated with ether

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

Procedure: Reaction operations were carried out according to the first step of Example 1 by using 2-(trans-4-(4-ethylphenyl)cyclohexyl)oxetane (42) (7.5 g, 30.9 mmol) and tert-butyl pentanoate (43) (15.6 g, 98.9 mmol) as starting materials to obtain tert-butyl 2-propyl-5-hydroxy-5-(trans-4-(4-ethylphenyl)cyclohexyl)pentanoate (44) (11.6 g, 28.8 mmol). The yield based on the compound (42) was 93%. Reaction operations

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: To a suspension of 160 mg (0.74 mmol) of rac-5-amino-2-propylpentanoic acid 1,1-dimethylethyl ester (8) in 1 mL of water and 1 mL of dichloromethane, 153 mg (0.76 mmol) of 4-nitrophenylchloroformate and 267 mg of sodium bicarbonate were added at 0° C. The mixture was stirred at room temperature overnight and then diluted with 50 mL of dichloromethane and 30 mL of water. The organic part was separated. The aqueous part was extracted with 2×50 mL of dichloromethane. The organic parts were combined and washed with 2×50 mL of 5% sodium bicarbonate followed by 50 mL of water, dried over MgSO4 and concentrated. The residue was purified by preparative thin layer chromatography using 1:1 ethyl acetate:hexane as the eluent to yield 185 mg (0.48 mmol, 66%) of rac-5-[[(4-nitrophenoxy)carbonyl]amino]-2-propyl]pentanoic acid 1,1-dimethylethyl ester (9) asan offwhite solid. NMR, IR and MS data confirmed compound identity. were added at 0° C The organic part was separated The aqueous part was extracted with 2×50 mL of dichloromethane washed with 2×50 mL of 5% sodium bicarbonate dried over MgSO4 concentrated The residue was purified by preparative thin layer chromatography

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

Procedure: Reaction operations were carried out according to the first step of Example 1 by using 2-(trans-4-(4-ethylphenyl)cyclohexyl)oxetane (42) (7.5 g, 30.9 mmol) and tert-butylpentanoate (43) (15.6 g, 98.9 mmol) as starting materials to obtain tert-butyl 2-propyl-5-hydroxy-5-(trans-4-(4-ethylphenyl)cyclohexyl)pentanoate (44) (11.6 g, 28.8 mmol). The yield based on the compound (42) was 93%. Reaction operations

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

Procedure: Potassium fluoride (21.6 mg, 0.37 mmol) was added to a solution of N-[(1-methyl-3-isobutyl-indole-2-carbonyl)valinyl]-3-amino-5-bromo-4-oxo-pentanoic acid, tert-butyl ester (86.1 mg, 0.149 mmol) and 2,3,5, 6-tetrafluorophenol (27.0 mg, 0.163 mmol) in DMF (2.0 ml). After stirring at room temperature for 3 hours, the reaction mixture was partitioned between ethyl acetate and water. The aqueous layer was back-extracted with ethyl acetate. The organic layers were combined, washed with saturated NaHCO3 solution, and brine, dried over sodium sulfate, and concentrated. The residue was triturated with ether to give the titled product, N-(1-methyl-3-isobutyl-indole-2-carbonyl)-valinyl-3-amino-4-oxo-5-(2,3,5,6-tetral]uorophenyloxy)-pentanoic acid, tert-butyl ester as a white solid (43.8 mg, 44%). TLC (hexane/EtOAc, 50/50): Rf=0.50. the reaction mixture was partitioned between ethyl acetate and water The aqueous layer was back-extracted with ethyl acetate washed with saturated NaHCO3 solution, and brine dried over sodium sulfate concentrated The residue was triturated with ether

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

Procedure: Reaction operations were carried out according to the first step of Example 1 by using 2-(trans-4-(4-ethylphenyl)cyclohexyl)oxetane (42) (7.5 g, 30.9 mmol) and tert-butyl pentanoate (43) (15.6 g, 98.9 mmol) as starting materials to obtain tert-butyl 2-propyl-5-hydroxy-5-(trans-4-(4-ethylphenyl)cyclohexyl)pentanoate (44) (11.6 g, 28.8 mmol). The yield based on the compound (42) was 93%. Reaction operations