methyl 2,2-dimethyl-4-oxobutanoate

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

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

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

Procedure: Step D In a manner similar to the method described in Example 1a, glycine tert-butyl ester (1.09 g, 8.32 mmol) was reacted with 2,2-dimethyl-4-oxo-butyric acid methyl ester (1.2 g, 8.32 mmol) in CH2Cl2 at room temperature for 18 h to give 4-[(E)-tert-butoxycarbonylmethylimino]-2,2-dimethyl-butyric acid methyl ester as a colorless oil (2.1 g, 100%).

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Step C To a solution of oxalyl chloride (1.09 mL, 12.5 mmol) (Aldrich) in dichloromethane (20 mL) at −78° C. was added the solution of dimethyl sulfoxide (1.77 mL, 25 mmol) in dichloromethane (5 mL) dropwise. After 5 mins, the solution of 4-hydroxy-2,2-dimethyl-butyric acid methyl ester (1.5 g, 11.3 mmol) in dichloromethane (5 mL) was added dropwise. The reaction mixture was stirred at −78° C. for 15 min. Triethylamine (5.7 mL, 41 mmol) was added and the reaction mixture was slowly warmed up to room temperature and stirred at room temperature for 45 min. Then water was added. The organic layers were separated, and the aqueous layer was extracted with dichloromethane. The organic layers were combined, washed with 10% of HCl, saturated NaHCO3, brine, dried over MgSO4, and concentrated to give 2,2-dimethyl-4-oxo-butyric acid methyl ester as a light yellow oil (Yield: 1.2 g, 81%). the reaction mixture was slowly warmed up to room temperature stirred at room temperature for 45 min The organic layers were separated the aqueous layer was extracted with dichloromethane washed with 10% of HCl, saturated NaHCO3, brine dried over MgSO4 concentrated

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