反应详情

温度

-42.5 °C

To 106 mL fuming HNO3 at −45° C. was slowly added a solution of 3,3-dimethyl-3H-benzo[c][1,2]oxaborol-1-ol (16.9 g, 104.3 mmol) in 10.5 mL nitrobenzene via a syringe while maintaining the reaction temperature between −40 to −45° C. Once the addition was complete the resulting solution was allowed to stir at −45° C. for an additional 45 min before poured into crushed ice. The ice mixture was allowed to melt and the aqueous solution was extracted with DCM (3×). The combined DCM extracts were dried over Na2SO4 then evaporated. The crude oil remaining was mixed with one liter 1:1 DCM/heptanes. The volume of the solution was reduced under reduced pressure by half and the resulting solution was allowed to stand overnight in a −20° C. freezer. The precipitate formed was filtered out, washed with heptanes and vacuum dried to give the titled compound as a white solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 1.46 (s, 6 H) 7.69 (d, J=8.4 Hz, 1 H) 8.28 (dd, J=8.4, 2.3 Hz, 1 H) 8.48 (d, J=2.2 Hz, 1 H) 9.41 (br. s., 1 H). Amount obtained: 11.2 g (51.8% yield).

1. additionOnce the addition
2. additionbefore poured
3. custominto crushed ice
4. extractionthe aqueous solution was extracted with DCM (3×)
5. dry with materialThe combined DCM extracts were dried over Na2SO4
6. customthen evaporated
7. additionThe crude oil remaining was mixed with one liter 1:1 DCM/heptanes
8. waitto stand overnight in a −20° C.
9. customThe precipitate formed
10. filtrationwas filtered out
11. washwashed with heptanes and vacuum
12. customdried