Electric Literature of 99548-54-6,Some common heterocyclic compound, 99548-54-6, name is Methyl 3-bromo-2-methylbenzoate, molecular formula is C9H9BrO2, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
Example 110 methyl { (3S) -6- [ (3-bromo-2-methylbenzyl) amino] -2, 3-dihydro-l- benzofuran-3-yl } acetate; [0990][0991]Methyl 3-bromo-2-methylbenzoate (2.29 g, 10.0 mmol) was dissolved in tetrahydrofuran (50 mL) , under ice-cooling, lithium aluminum hydride (0.285 g, 7.50 mmol) was added by small portions, and the mixture was stirred under a nitrogen atmosphere for 2 hr. Sodium sulfate 10 hydrate (2.42 g, 7.50 mmol) was added to the reaction mixture, and the mixture was stirred at room temperature for 2 hr. Insoluble material was filtered off through celite, and the filtrate was concentrated under reduced pressure. The obtained solid was recrystallized from heptane-ethyl acetate to give 3-bromo-2-methylbenzyl alcohol (1.76 g, yield 88%) as colorless crystals. This product (0.943 g, 4.69 mmol) was dissolved in acetonitrile (25 mL) , a Dess-Martin reagent (2.39 g, 5.63 mmol) was added by small portions under ice-cooling, and the mixture was stirred at room temperature for 0.5 hr. The reaction mixture was treated with saturated aqueous sodium hydrogen carbonate and aqueous sodium thiosulfate solution, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. A solution of the obtained colorless oil, methyl [ (3S) -6-amino-2, 3-dihydro-l- benzofuran-3-yl] acetate (0.972 g, 4.69 mmol) and acetic acid(0.537 mL, 9.38 mmol) in acetonitrile (25 mL) was stirred under a nitrogen atmosphere at room temperature for 0.5 hr. Sodium triacetoxyborohydride (1.99 g, 9.38 mmol) was added to the reaction mixture, and the mixture was further stirred for 12 hr. The reaction mixture was treated with water and saturated aqueous ammonium chloride solution, and extracted with ethyl acetate. The extract was washed successively with saturated aqueous sodium hydrogen carbonate and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate rhexane = 5:95-40:60) to give the title compound (1.59 g, yield 87%, 2 steps) as a colorless oil.1H NMR (300 MHz, CDCl3) delta 2.42 (3H, s) , 2.48-2.59 (IH, m) , 2.68-2.78 (IH, m) , 3.68-3.83 (4H, m) , 3.89 (IH, br s) , 4.18- 4.30 (3H, m) , 4.71 (IH, t, J = 9.1 Hz), 6.07-6.16 (2H, m) , 6.93 (IH, d, J = 8.0 Hz), 7.01 (IH, t, J = 7.9 Hz), 7.23-7.30(IH, m) , 7.49 (IH, dd, J = 7.9, 1.1 Hz). MS m/z 390 (M + H)+.
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route Methyl 3-bromo-2-methylbenzoate, its application will become more common.
Reference:
Patent; TAKEDA PHARMACEUTICAL COMPANY LIMITED; NEGORO, Nobuyuki; TERAO, Yoshito; MIKAMI, Satoshi; YUKAWA, Tomoya; WO2010/143733; (2010); A1;,
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics