1-hydroxy-3,3,6-trimethyl-2,1-benzoxaborole

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a solution of 3,3,6-trimethylbenzo[c][1,2]oxaborol-1(3H)-ol (6.87 g, 39 mmol) in CCl4 (100 mL) at rt was added benzoyl peroxide (0.944 g, 3.9 mmol) followed by NBS (13.9 g, 78 mmol). The reaction mixture was refluxed for 16 h, cooled to rt and treated with Na2CO3. The aqueous layer was acidified with 3 N HCl to pH of 3 and extracted with EA. The organic layer was washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel eluted with DCM-MeOH (20:1) to give 1-hydroxy-3,3-dimethyl-1,3-dihydrobenzo[c][1,2]oxaborole-6-carbaldehyde (4.85 g; yield 65.4%) as a pale yellow solid. 1H NMR (500 MHz, CDCl3) δ 10.06 (s, 1H), 8.15 (s, 1H), 8.01 (d, J=8.0 Hz, 1 H), 7.42 (d, J=8.0 Hz, 1 H), 1.58 (s, 6H) ppm. MS: m/z=191.1 (M+1, ESI+). The reaction mixture was refluxed for 16 h extracted with EA The organic layer was washed with brine dried over Na2SO4 filtered concentrated under reduced pressure The residue was purified by column chromatography over silica gel eluted with DCM-MeOH (20:1)

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a solution of compound 2-(2-(2-(ethoxymethoxy)propan-2-yl)-5-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (76.2 mmol) in THF (100 mL) was added 6 N HCl (381 mL). The reaction mixture was stirred at rt overnight, and the obtained mixture was extracted three times with ethyl acetate. The combined extracts were washed with water and brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel eluted with PE-EA (20:1) to give 3,3,6-trimethylbenzo[c][1,2]oxaborol-1(3H)-ol (6.87 g; yield 51.2% over 2 steps) as a white solid. MS: m/z=177.1 (M+1, ESI+). the obtained mixture was extracted three times with ethyl acetate The combined extracts were washed with water and brine dried over Na2SO4 filtered concentrated under reduced pressure The residue was purified by column chromatography over silica gel eluted with PE-EA (20:1)

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a solution of compound 2-(2-(2-(ethoxymethoxy)propan-2-yl)-5-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (76.2 mmol) in THF (100 mL) was added 6 N HCl (381 mL). The reaction mixture was stirred at rt overnight, and the obtained mixture was extracted three times with ethyl acetate. The combined extracts were washed with water and brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel eluted with PE-EA (20:1) to give 3,3,6-trimethylbenzo[c][1,2]oxaborol-1(3H)-ol (6.87 g; yield 51.2% over 2 steps) as a white solid. MS: m/z=177.1 (M+1, ESI+). the obtained mixture was extracted three times with ethyl acetate The combined extracts were washed with water and brine dried over Na2SO4 filtered concentrated under reduced pressure The residue was purified by column chromatography over silica gel eluted with PE-EA (20:1)

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a solution of 3,3,6-trimethylbenzo[c][1,2]oxaborol-1(3H)-ol (6.87 g, 39 mmol) in CCl4 (100 mL) at rt was added benzoyl peroxide (0.944 g, 3.9 mmol) followed by NBS (13.9 g, 78 mmol). The reaction mixture was refluxed for 16 h, cooled to rt and treated with Na2CO3. The aqueous layer was acidified with 3 N HCl to pH of 3 and extracted with EA. The organic layer was washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel eluted with DCM-MeOH (20:1) to give 1-hydroxy-3,3-dimethyl-1,3-dihydrobenzo[c][1,2]oxaborole-6-carbaldehyde (4.85 g; yield 65.4%) as a pale yellow solid. 1H NMR (500 MHz, CDCl3) δ 10.06 (s, 1H), 8.15 (s, 1H), 8.01 (d, J=8.0 Hz, 1 H), 7.42 (d, J=8.0 Hz, 1 H), 1.58 (s, 6H) ppm. MS: m/z=191.1 (M+1, ESI+). The reaction mixture was refluxed for 16 h extracted with EA The organic layer was washed with brine dried over Na2SO4 filtered concentrated under reduced pressure The residue was purified by column chromatography over silica gel eluted with DCM-MeOH (20:1)

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a solution of compound 2-(2-(2-(ethoxymethoxy)propan-2-yl)-5-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (76.2 mmol) in THF (100 mL) was added 6 N HCl (381 mL). The reaction mixture was stirred at rt overnight, and the obtained mixture was extracted three times with ethyl acetate. The combined extracts were washed with water and brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel eluted with PE-EA (20:1) to give 3,3,6-trimethylbenzo[c][1,2]oxaborol-1(3H)-ol (6.87 g; yield 51.2% over 2 steps) as a white solid. MS: m/z=177.1 (M+1, ESI+). the obtained mixture was extracted three times with ethyl acetate The combined extracts were washed with water and brine dried over Na2SO4 filtered concentrated under reduced pressure The residue was purified by column chromatography over silica gel eluted with PE-EA (20:1)