2-amino-5-bromo-4-methylphenol

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2-amino-5-bromo-4-methylphenol (42) (290 mg), trifluoromethanesulfonic acid Ytterbium (III) salt (20 mg, 1% mol) and trimethyl orthoacetate (216 μl, 1.5 eq.) in 2 ml EtOH was heated at 90° C. for 2 h. After cooling down to r.t., the reaction mixture was taken up in EA, washed with aq. NaHCO3 and brine, dried over Na2SO4, concentrated to dryness. The resulting brown solid was dissolved in DCM and subjected to silica gel column purification using 0-60% B (A: hexane; B: 50% EA in hexane) to furnish 148 mg 6-bromo-2,5-dimethylbenzoxazole (48) as pale brown solid. After cooling down to r.t. washed with aq. NaHCO3 and brine dried over Na2SO4 concentrated to dryness The resulting brown solid was dissolved in DCM subjected to silica gel column purification

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2-amino-5-bromo-4-methylphenol (42) (290 mg), trifluoromethanesulfonic acid Ytterbium (III) salt (20 mg, 1% mol) and trimethyl orthoacetate (216 μl, 1.5 eq.) in 2 ml EtOH was heated at 90° C. for 2 h. After cooling down to r.t., the reaction mixture was taken up in EA, washed with aq. NaHCO3 and brine, dried over Na2SO4, concentrated to dryness. The resulting brown solid was dissolved in DCM and subjected to silica gel column purification using 0-60% B (A: hexane; B: 50% EA in hexane) to furnish 148 mg 6-bromo-2,5-dimethylbenzoxazole (48) as pale brown solid. After cooling down to r.t. washed with aq. NaHCO3 and brine dried over Na2SO4 concentrated to dryness The resulting brown solid was dissolved in DCM subjected to silica gel column purification

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of 4-bromo-6-methoxy-3-methylaniline (41). (500 mg, 2.3 mmol) in 6 ml DCM was added 1 M BBr3 in DCM (4.6 ml, 4.6 mmol). The reaction mixture was stirred at r.t. for 2 h, which turned to a brown solution and back to a brown suspension. After quenched with aq. sodium bicarbonate solution, the mixture was extracted with EA. The org. phase was washed with brine, dried over sodium sulfate, concentrated to dryness to give 581 mg 2-amino-5-bromo-4-methylphenol as dark oil. After quenched with aq. sodium bicarbonate solution the mixture was extracted with EA phase was washed with brine dried over sodium sulfate concentrated to dryness

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2-amino-5-bromo-4-methylphenol (42) (290 mg), trifluoromethanesulfonic acid Ytterbium (III) salt (20 mg, 1% mol) and trimethyl orthoacetate (216 μl, 1.5 eq.) in 2 ml EtOH was heated at 90° C. for 2 h. After cooling down to r.t., the reaction mixture was taken up in EA, washed with aq. NaHCO3 and brine, dried over Na2SO4, concentrated to dryness. The resulting brown solid was dissolved in DCM and subjected to silica gel column purification using 0-60% B (A: hexane; B: 50% EA in hexane) to furnish 148 mg 6-bromo-2,5-dimethylbenzoxazole (48) as pale brown solid. After cooling down to r.t. washed with aq. NaHCO3 and brine dried over Na2SO4 concentrated to dryness The resulting brown solid was dissolved in DCM subjected to silica gel column purification

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2-amino-5-bromo-4-methylphenol (42) (290 mg), trifluoromethanesulfonic acid Ytterbium (III) salt (20 mg) and trimethyl orthoformate (185 μl, 1.5 eq.) in 2 ml EtOH was heated at 90° C. for 2 h. After cooling down to r.t., the reaction mixture was taken up in EA, washed with aq. NaHCO3 and brine, dried over Na2SO4, concentrated to dryness. The resulting brown solid was dissolved in DCM and subjected to silica gel column purification using 0-60% B (A: hexane; B: 50% EA in hexane) to furnish 91.9 mg 6-bromo-5-methylbenzoxazole (43) as yellow solid (yield: 38%) After cooling down to r.t. washed with aq. NaHCO3 and brine dried over Na2SO4 concentrated to dryness The resulting brown solid was dissolved in DCM subjected to silica gel column purification

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of 4-bromo-6-methoxy-3-methylaniline (41) (500 mg, 2.3 mmol) in 6 ml DCM was added 1 M BBr3 in DCM (4.6 ml, 4.6 mmol). The reaction mixture was stirred at r.t. for 2 h, which turned to a brown solution and back to a brown suspension. After quenched with aq. sodium bicarbonate solution, the mixture was extracted with EA. The org. phase was washed with brine, dried over sodium sulfate, concentrated to dryness to give 581 mg 2-amino-5-bromo-4-methylphenol as dark oil. After quenched with aq. sodium bicarbonate solution the mixture was extracted with EA phase was washed with brine dried over sodium sulfate concentrated to dryness

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2-amino-5-bromo-4-methylphenol (42) (290 mg), trifluoromethanesulfonic acid Ytterbium (III) salt (20 mg, 1% mol) and trimethyl orthoacetate (216 μl, 1.5 eq.) in 2 ml EtOH was heated at 90° C. for 2 h. After cooling down to r.t., the reaction mixture was taken up in EA, washed with aq. NaHCO3 and brine, dried over Na2SO4, concentrated to dryness. The resulting brown solid was dissolved in DCM and subjected to silica gel column purification using 0-60% B (A: hexane; B: 50% EA in hexane) to furnish 148 mg 6-bromo-2,5-dimethylbenzoxazole (48) as pale brown solid. After cooling down to r.t. washed with aq. NaHCO3 and brine dried over Na2SO4 concentrated to dryness The resulting brown solid was dissolved in DCM subjected to silica gel column purification

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2-amino-5-bromo-4-methylphenol (42) (290 mg), trifluoromethanesulfonic acid Ytterbium (III) salt (20 mg) and trimethyl orthoformate (185 μl, 1.5 eq.) in 2 ml EtOH was heated at 90° C. for 2 h. After cooling down to r.t., the reaction mixture was taken up in EA, washed with aq. NaHCO3 and brine, dried over Na2SO4, concentrated to dryness. The resulting brown solid was dissolved in DCM and subjected to silica gel column purification using 0-60% B (A: hexane; B: 50% EA in hexane) to furnish 91.9 mg 6-bromo-5-methylbenzoxazole (43) as yellow solid (yield: 38%) After cooling down to r.t. washed with aq. NaHCO3 and brine dried over Na2SO4 concentrated to dryness The resulting brown solid was dissolved in DCM subjected to silica gel column purification

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of 4-bromo-6-methoxy-3-methylaniline (41) (500 mg, 2.3 mmol) in 6 ml DCM was added 1 M BBr3 in DCM (4.6 ml, 4.6 mmol). The reaction mixture was stirred at r.t. for 2 h, which turned to a brown solution and back to a brown suspension. After quenched with aq. sodium bicarbonate solution, the mixture was extracted with EA. The org. phase was washed with brine, dried over sodium sulfate, concentrated to dryness to give 581 mg 2-amino-5-bromo-4-methylphenol as dark oil. After quenched with aq. sodium bicarbonate solution the mixture was extracted with EA phase was washed with brine dried over sodium sulfate concentrated to dryness

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2-amino-5-bromo-4-methylphenol (42) (290 mg), trifluoromethanesulfonic acid Ytterbium (III) salt (20 mg, 1% mol) and trimethyl orthoacetate (216 μl, 1.5 eq.) in 2 ml EtOH was heated at 90° C. for 2 h. After cooling down to r.t., the reaction mixture was taken up in EA, washed with aq. NaHCO3 and brine, dried over Na2SO4, concentrated to dryness. The resulting brown solid was dissolved in DCM and subjected to silica gel column purification using 0-60% B (A: hexane; B: 50% EA in hexane) to furnish 148 mg 6-bromo-2,5-dimethylbenzoxazole (48) as pale brown solid. After cooling down to r.t. washed with aq. NaHCO3 and brine dried over Na2SO4 concentrated to dryness The resulting brown solid was dissolved in DCM subjected to silica gel column purification

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of 4-bromo-6-methoxy-3-methylaniline (41). (500 mg, 2.3 mmol) in 6 ml DCM was added 1 M BBr3 in DCM (4.6 ml, 4.6 mmol). The reaction mixture was stirred at r.t. for 2 h, which turned to a brown solution and back to a brown suspension. After quenched with aq. sodium bicarbonate solution, the mixture was extracted with EA. The org. phase was washed with brine, dried over sodium sulfate, concentrated to dryness to give 581 mg 2-amino-5-bromo-4-methylphenol as dark oil. After quenched with aq. sodium bicarbonate solution the mixture was extracted with EA phase was washed with brine dried over sodium sulfate concentrated to dryness

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 2-amino-5-bromo-4-methylphenol (42) (290 mg), trifluoromethanesulfonic acid Ytterbium (III) salt (20 mg, 1% mol) and trimethyl orthoacetate (216 μl, 1.5 eq.) in 2 ml EtOH was heated at 90° C. for 2 h. After cooling down to r.t., the reaction mixture was taken up in EA, washed with aq. NaHCO3 and brine, dried over Na2SO4, concentrated to dryness. The resulting brown solid was dissolved in DCM and subjected to silica gel column purification using 0-60% B (A: hexane; B: 50% EA in hexane) to furnish 148 mg 6-bromo-2,5-dimethylbenzoxazole (48) as pale brown solid. After cooling down to r.t. washed with aq. NaHCO3 and brine dried over Na2SO4 concentrated to dryness The resulting brown solid was dissolved in DCM subjected to silica gel column purification