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O-Demethylation

(BBr3)







Examples:


Example 1



A mixture of the SM (1.01 g, 4.54 mmol) in dry DCM (36 mL) at 0 C under N2 was treated dropwise with BBr3 (1M in DCM, 13.6 mL, 13.6 mmol). The resulting mixture was allowed to warm to RT and stir O/N, after which time it was added dropwise to a stirring mixture of ice water (50 mL). The mixture was stirred for 30 min at RT then filtered to provide the product as a yellow solid. [0.77 g, 82%] [WO2012112946, page 128]



Example 2



To 0.55M solution of the SM in DCM at 0 C was added BBr3 (1.0M in DCM, 2.2 equiv) over 5 min. The reaction mixture was stirred at RT for 22 h, and then cooled to -5 C for 30 min. The solids were filtered and then stirred in ice/H2O for 30 min. The solids were filtered, rinsed with IPA, and dried in a desiccator to provide the product as an off-white solid. [79%] [WO2007117607, page 305]



Example 3



To a suspension of the SM (1.26 g, 4.6 mmol) in DCM (20 mL) at 0 C was added BBr3 (1M in DCM , 28 mL, 28 mmol) dropwise. The reaction was stirred at 45 C for O/N, after which time it was concentrated and diluted with cold sat aq NaHCO3. The resulting solids were collected, dried, and used without further purification. [WO2007117607, page 314]



Example 4



To a solution of the SM (260 mg, 1.5 mmol) in DCM (5 mL) was added BBr3 (750 mg, 3.0 mmol) at 0 C. The reaction mixture was stirred at 0 C for 12 h. The mixture was diluted with DCM (20 mL), washed with sat aq NaHCO3 (2 x 20 mL), brine, dried (Na2SO4), and concentrated to provide the product as a yellow oil. [200 mg, 84%] [WO2015140133, page 109]



Example 5



To a solution of the SM (21 g, 90 mmol) in DCM (100 mL) at -78 C was slowly added BBr3 (46 g, 180 mmol). The reaction mixture was stirred at RT for 2 h, after which time the mixture was quenched with H2O (50 mL). The mixture was filtered and the solids were washed with DCM (2 x 200 mL). The filtrate was washed with H2O (2 x 100 mL). The org layer was dried (Na2SO4) and concentrated to provide the product was a yellow oil. [13.0 g, 66%] [WO2016011390, page 282]



Example 6



To a suspension of the SM (8.0 g, 24.0 mmol) in DCM (100 mL) at 0 C was slowly added BBr3 (3M in DCM, 24 mL, 72.0 mmol). The reaction mixture was strirred at RT for 6 h, after which time it was quenched with MeOH (50 mL). The solids were collected by filtration and washed with MeOH (2 x 5 mL) to provide the product as a yellow solid. [6.2 g, 80%] [WO2016011390, page 370]