At the same time, in my other blogs, there are other synthetic methods of this type of compound,625-92-3, 3,5-Dibromopyridine, and friends who are interested can also refer to it.
Adding a certain compound to certain chemical reactions, such as: 625-92-3, 3,5-Dibromopyridine, can increase the reaction rate and produce products with better performance than those obtained under traditional synthetic methods. Here is a downstream synthesis route of the compound, Quality Control of 3,5-Dibromopyridine, blongs to pyridine-derivatives compound. Quality Control of 3,5-Dibromopyridine
3-(Benzyloxy)-5-bromopyridine [1099] (Zhu. G.-D. et al., Bioorg. Med. Chem. Lett. 2006, 16, 3150-3155) [1100] A 500 mL three-necked flask was charged with sodium hydride (60% dispersion in oil; 9.6 g, 240 mmol, 2.0 equiv.) and fitted out with stir bar, dropping funnel, N2 balloon, and septa. The sodium hydride was washed with hexane (2¡Á150 mL), then anhydrous DMF (110 mL) was added. With stifling and intermittent ice cooling, benzyl alcohol (25 mL, 240 mmol, 2.0 equiv.) was added dropwise within 105 min. The temperature was kept high enough to permit efficient stifling and prevent excessive frothing. After the addition was finished, the dropping funnel was rinsed with anhydrous DMF. Stirring was continued at room temperature for 20 min. The flask was briefly opened to add 3,5-dibromopyridine (28.4 g, 120 mmol) all at once. The atmosphere was again replaced with N2, and the reaction mixture was stirred at room temperature for 15 h. A thin layer chromatogram (small aliquot quenched into EtOAc/H2O; silica gel, EtOAc/hexane 15:85) taken shortly before the end of this period demonstrated the near-absence of starting material (Rf 0.6) and the formation of a product (Rf 0.25); benzyl alcohol was detected at Rf 0.15. The bulk of DMF was distilled in an oil pump vacuum at a bath temperature of 40 C. into a receiver cooled with acetone/dry ice. Initial foaming was due to the evaporation of residual hexane. The receiver was subsequently changed to maintain a high vacuum. The residue was taken up in diethyl ether (300 mL) and the resulting suspension poured into ice water (300 mL). The phases were separated, and the aqueous phase was twice extracted with ether (100 mL each). The combined organic phases were washed with brine (100 mL) and dried over MgSO4 (15 g). Evaporation furnished an orange-colored liquid together with a colorless solid. After transfer into a 200 mL flask, benzyl alcohol was distilled off in an oil pump vacuum into a -78 C. receiver. The product began to crystallize after partial cooling, whereon methanol (60 mL) was added. Crystallization was initially allowed to proceed at room temperature, then in the freezer overnight. [1101] The product was isolated by suction filtration, washed with two portions of freezer-chilled methanol (20 mL each), and dried (40 C./oil pump) to obtain 23.2 g (73%) of light-tan crystals (mp 67-68.5 C.). The mother liquor was concentrated to a few mL, diluted with methanol (15 mL), seeded, and placed in the freezer. Isolation as above gave 1.7 g of a solid which upon TLC examination revealed contamination with polar material. The second mother liquor still contained substantial amounts of benzyl alcohol, which was removed by evaporation into a 50 mL flask and bulb-to-bulb distillation at 80 C. in an oil pump vacuum until by visual appearance no further distillate was formed. The dark residue (2.7 g) together with the impure second crystal fraction was taken up in CH2Cl2 (3 mL) and chromatographed on silica gel (25¡Á3.8 cm, EtOAc/hexane 1:9) to yield, after evaporation and drying, another 2.4 g (8%) of the product 2. 1H NMR (CDCl3, 300 MHz) delta 8.33 (narrow m, 2H), 7.50-7.32 (m, 6H), 5.11 (s, 2H).
At the same time, in my other blogs, there are other synthetic methods of this type of compound,625-92-3, 3,5-Dibromopyridine, and friends who are interested can also refer to it.
Reference:
Patent; The Board of Trustees of the University of Illinois; PsychoGenics, Inc.; Chandrasekhar, Jayaraman; Kozikowski, Alan P.; Liu, Jianhua; Tueckmantel, Werner; Walker, Joel R.; Yuen, Po-wai; US2013/184313; (2013); A1;,
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