3,3-diMethyl-6-nitrobenzo[c][1,2]oxaborol-1(3H)-ol

Yellow solid

At -40°C, to 100% fuming nitric acid (10 mL) was added dropwise a solution of 3,3-dimethylbenzo[c][l,2]oxaborol-l(3H)-ol (XCVI) (1.37 g, 0.0085 mol) in carbon tetrachloride (40 mL), maintaining the temperature below -40°C. After 20 min, the yellow solution was poured into ice and was stirred for 10 min at RT. The mixture was extracted with EtOAc. 1M aqueous NaOH was added to the organic layer to adjust the pH=7. The organic layer was separated, and washed with water, dried over MgS04, and filtered, and the solvent was removed in vacuo to give an orange viscous oil. The oily residue was triturated with hexane to give pure 3,3-diMethyl-6-nitrobenzo[c][1,2]oxaborol-1(3H)-ol.