ChemicalBook CAS DataBase List 3,3-diMethylbenzo[c][1,2]oxaborol-1(3H)-ol

3,3-diMethylbenzo[c][1,2]oxaborol-1(3H)-ol synthesis

10synthesis methods

Product Name:3,3-diMethylbenzo[c][1,2]oxaborol-1(3H)-ol
CAS Number:221352-10-9
Molecular formula:C9H11BO2
Molecular Weight:161.99

To a solution of 2-(2-bromo-phenyl)-propane-2-ol (4.0 g, 18.6 mmol) in anhydrous THF (60 mL) under argon was slowly added n-butyl lithium (15 mL, 2.5 M). The mixture was stirred at -78° C for 2 h, and then triisopropylborate (5.5 mL, 24.2 mmol) was added to the mixture. The mixture was heated to room temperature and stirred for 12 h and then cooled to 0° C. Hydrochloric acid (10 mL, 1N) was added to the mixture until pH<5. The reaction system was then stirred at RT for 1 h. Until the solution was separated, the aqueous layer was extracted twice with ethyl acetate. The organic layers were combined, dried with anhydrous sodium sulfate, and filtered. The filtrate was concentrated under reduced pressure to afford a yellow oil. The oil was purified by chromatography (silica, EtOAc: hexanes,1:3) to afford 3,3-diMethylbenzo[c][1,2]oxaborol-1(3H)-ol which is a white solid.

3,3-diMethylbenzo[c][1,2]oxaborol-1(3H)-ol

7073-69-0 Synthesis

7073-69-0
87 suppliers
$22.00/250mg

221352-10-9
76 suppliers
$40.00/100mg

Yield:221352-10-9 82.4%

Reaction Conditions:

Stage #1:2-(2-bromophenyl)propanol with methylmagnesium bromide in tetrahydrofuran at 0;Cooling with ice;
Stage #2: with n-butyllithium in tetrahydrofuran;hexane at -40;Cooling with acetone-dry ice;
Stage #3: with Triisopropyl borate in tetrahydrofuran;hexane at 20;Product distribution / selectivity;

Steps:

82
82c[0384] A 50 mL round-bottomed-flask equipped with a magnetic stir bar and ice- H₂O bath was charged with 82b (860 mg, 4.0 mmol) and anhydrous THF (20 mL). MeMgBr (1.3 mL, 2.0 M in THF) was slowly added via a syringe. The mixture was stirred at 0 ⁰C for 10 minute and the ice bath was replaced with a dry ice-acetone bath at -40 ⁰C. BuLi (1.9 mL, 2.5 M in hexanes) was added dropwise via a syringe. The resulting mixture was stirred at -40 ⁰C for another 2h before B(O-ipr)₃ (1.4 mL, 4.8 mmol) was added dropwise. The mixture was allowed to warm up to rt gradually and stirred overnight. After carefully quenched the reaction with H₂O (1 mL), HCl (3M, 10 mL) was added and the mixture was stirred at rt for Ih. The mixture was extracted with EtOAc (20 mL) 3 times. Combined extracts was washed with H₂O (20 mL), brine (20 mL), dried over MgSO₄, filtered and concentrated under reduced pressure to give a clear oil. The oil solidified overnight to give 82c as a pale yellow waxy solid (544mg, 82.4%).

References:

ANACOR PHARMACEUTICALS, INC.;CHEN, Daitao;ORR, Matthew;SLIGAR, Jessica;JACOBS, Robert;PLATTNER, Jacob, J. WO2011/19618, 2011, A1 Location in patent:Page/Page column 137-138