Trimethyl borate → B-[2-[[(4,5-dimethyl-3-isoxazolyl)[(2-methoxyethoxy)methyl]amino]sulfonyl]phenyl]Boronic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of the title compound of step C (22.16 g, 52.85 mmol) in 264 ml THF at -95° C., n-butyl lithium (2M solution in pentane, 29.07 ml, 58.14 mmol) was added. The mixture was stirred at -95° C. for 10 minutes and trimethylborate (6.59 g, 63.42 mmol) was added and stirred at -78° C. for 15 minutes. The cold bath was removed and the mixture was warmed to room temperature slowly and stirred at room temperature for 0.5 hr. The mixture was then cooled to 0° C. and 100 ml 3N HCl was added dropwise. After stirring for 30 minutes, the mixture was extracted with CH2Cl2 (300 ml, 100 ml). The combined organic extracts were washed with 30 ml brine, dried and concentrated to give 2-borono-N-(4,5-dimethyl-3-isoxazolyl)-N-[(2-methoxyethoxy)methyl]benzenesulfonamide as a gum.

Provenance & Evidence