Acetic Acid → HCID 68470916, compound

Participants

Reaction Steps

The acetyl-imine (Example 5, 9.37 g, 30.0 mmol) and methylboronic acid (1.796 g, 30.0 mmol) were dissolved into acetic acid (75 mL) and treated with NaBO3 (˜2.45 g, 30.0 mmol). After 40 minutes, more NaBO3 (˜2.45 g, 30.0 mmol) was added while the reaction vessel was in a water bath. More NaBO3 (2.45+g, 30.0 mmol) was added after a total of 80 minutes and again at 120 minutes (600 mg, 7.3 mmol). The mixture was stirred at room temperature overnight, transferred to a larger flask with an EtOAc rinse, and concentrated three times from toluene. The residue was mixed with water and basified with concentrated aqueous NH4OH, and then partitioned into 2:1 EtOAc/hexanes (150 mL). The aqueous phase was separated and extracted three times with more 2:1 EtOAc/hexanes. The combined organic phases were washed with a mixture of water (30 mL), concentrated aqueous NH4OH (5 mL) and brine (5 mL), then dried (Na2SO4), concentrated, and chromatographed on silica (15 to 30 to 50% EtOAc/hexanes) to give the titled compound. 1H NMR (400 MHz, CD3OD) δ ppm 4.77 (2H), 5.16 (1H), 5.32 (1H), 7.19 (1H), 7.23 (1H), 7.46 (1H); MS (ESI) 271 (M+H)+.

Provenance & Evidence