28342-75-8,Some common heterocyclic compound, 28342-75-8, name is 1,5-Dibromo-2,4-difluorobenzene, molecular formula is C6H2Br2F2, 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.
A mixture of 2-(2-methoxy-1-naphthalenyl)-boronic acid (3.24 g, 16 mmole), 1,5-dibromo-2,4-difluorobenzene (1.78 g, 6.55 mmole), Pd(PPh3)4 (0.33 g, 0.29 mmole) and potassium carbonate (4.53 g, 32.8 mmole) in 1,2-dimethoxyethane (120 ml) and water (30 ml) was stirred with heating at reflux temperature under nitrogen atmosphere for 4 hours. After that reaction mixture cooled down, precipitate collected by filtration to give 1.12 g of the product. Organic phase of the filtrate was evaporated further and the second precipitate collected by filtration, dried in vacuum to give 1.8 g of the product. Crude product as a mixture of diastereomers was used for the next step without further purification. Crude product can be purified by chromatography on silica gel column using gradient elution with mixtures of hexanes and dichlromethane to isolate pure isolated diastereomers. MS: MH+ = 427.1H-NMR of diastereomer 1 (CDCl3, 500 MHz): 3.95 (s, 6H), 7.14 (t, 1H, J = 9 Hz), 7.34-7.37 (m, 3H), 7.38 (d, 2H, J = 9 Hz), 7.43 (td, 2H, J1 = 1 Hz, J2 = 8 Hz), 7.68 (d, 2H, J = 9 Hz), 7.83 (d, 2H, J = 8 Hz), 7.92 (d , 2H, J = 9 Hz).1H-NMR of diastereomer 2 (CDCl3, 500 MHz): 3.91 (s, 6H), 7.14 (t, 1H, J = 9 Hz), 7.31-7.38 (m, 3H), 7.38 (d, 2H, J = 9 Hz), 7.44 (td, 2H, J1 = 1 Hz, J2 = 8 Hz), 7.64 (d, 2H, J = 9 Hz), 7.83 (d, 2H, J = 9 Hz), 7.92 (d, 2H, J = 9 Hz).
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 28342-75-8, its application will become more common.
Reference:
Patent; E. I. DU PONT DE NEMOURS AND COMPANY; SKULASON, Hjalti; DIEV, Viacheslav V.; VO, Giang Dong; GAO, Weiying; WU, Weishi; HERRON, Norman; HOWARD, Michael Henry, Jr.; DOGRA, Kalindi; ZOU, Yunlong; (195 pag.)WO2018/97937; (2018); A1;,
Bromide – Wikipedia,
bromide – Wiktionary