1996-29-8, These common heterocyclic compound, 1996-29-8, name is 1-Bromo-4-chloro-2-fluorobenzene, its 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.
Reference Example-10 A solution of 1-bromo-4-chloro-2-fluoro benzene (10.0 g, 47.8 mmol) in THF was added dropwise to a suspension of magnesium (1.28 g, 52.5 mmol) in THF (50 mL) at 40 C. (oil bath temperature) in the presence of a catalytic amount of iodine in an argon gas atmosphere, whereby a Grignard reagent was prepared. The Grignard reagent was added dropwise to a solution of diethyl oxalate (8.37 g, 57.3 mmol) in THF at -50 C., and the temperature was slowly raised to room temperature, followed by stirring for 18 hours. After the reaction was completed, the reaction solution was poured into ice, then, acidified with concentrated hydrochloric acid, and the resultant product was extracted with ether (100 mL*2, 50 mL*1). The organic layer was dried over anhydrous magnesium sulfate, and concentrated under reduced pressure, whereby an orange oily crude product (12.9 g) was obtained. This was purified by silica gel column chromatography (hexane:ethyl acetate=10:1), whereby ethyl 2-(4-chloro-2-fluorophenyl)-2-oxoacetate (4.17 g, yield: 41%) was obtained as a yellow oily material. 1H-NMR (400 MHz, CDCl3): delta1.40 (t, J=7.1 Hz, 3H), 4.43 (q, J=7.1 Hz, 2H), 7.22 (dd, J=1.8 and 10.2 Hz, 1H), 7.31 (dd, J=1.8 and 8.4 Hz, 1H), 7.89 (dd, J=7.6 and 8.4 Hz, 1H). 19F-NMR (376 MHz, CDCl3): delta-109 (s, 1F).
Chemical properties determine the actual use. Each compound has specific chemical properties and uses. We look forward to more synthetic routes in the future to expand reaction routes of 1996-29-8.
Reference:
Patent; KAKEN PHARMACEUTICAL CO., LTD.; SAGAMI CHEMICAL RESEARCH INSTITUTE; KOBAYASHI, Osamu; NIIKURA, Naoko; INOUE, Tomoko; MIZUTA, Satoshi; TAKATSUNA, Reiko; HIRAI, Kenji; SHIROUZU, Kentaro; OBATA, Miyoo; (183 pag.)US2016/24110; (2016); A1;,
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