Reference of 6919-61-5, A common heterocyclic compound, 6919-61-5, name is N-Methoxy-N-methylbenzamide, molecular formula is C9H11NO2, 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.
To a solution of 5.0g (25.4 mmol) of tetaut-butyldimethyl-pent-4-ynylochiy-silane (prepared by the method of Koseki, Y.; Sato, H.; Watanabe, Y.; Nagasaka, T. Org. Lett. 2002, 4, 885-888) in 10OmL of THF at -78C under an atmosphere of N2 was added dropwise 10.2 mL (25.4 mmol) of 2.5 M nBuLi in hexane. After stirring for Ih at that temperature, 4.0 g (24.2 mmol) of N-methoxy-N-methyl benzamide (2-1) in 20 mL of THF was added, the cooling bath was removed, and stirring was continued for 3h at room temperature. The reaction was quenched with saturated aqueous NH4Cl, extracted with 2 x EtOAc, washed with brine, dried over Na2SO4, and concentrated. The crude material was loaded onto a 4Og silica gel cartridge and eluted with a gradient of 0 to 55% EtOAc in hexanes over 25 minutes to provide 6.3g (20.9 mmol, 87%) of the propargylic ketone (2-2) as a pale yellow oil. To a suspension of 2.2g (10.7 mmol) of CuBrOMS in 30 mL of THF at -78C was added 10.7 mL (21.4 mmol) of a 2.0 M solution of PhLi in dibutylether. After stirring for 1.5h, 2.7g (8.9 mmol) of the above prepared ketone 2-2 in 5mL of THF was added, and the mixture was allowed to stir for an additional 3h at -78C, and warmed to 00C for 15 minutes before being quenched with saturated aqueous NH4Cl. The mixture was partitioned with EtOAc, the layers were separated, the aqueous was extracted with 2 x EtOAc, the organics were combined, washed with brine, dried over Na2SO4, and concentrated. The crude material was loaded onto a 4Og silica gel cartridge and eluted with a gradient of 0 to 25% EtOAc in hexanes to provide 2.89g (7.6 mmol, 85%) of 2-3 as a yellow oil; NMR analysis indicated that there was a 1.1:1 mixture of E:Z isomers. Careful separation of a fraction of this material provided the pure isomers, whose identities were determined by ID NOE analysis. Data for 2-3-(E) (first to elute): 1HNMR (500 MHz, CDCl3) delta 8.0 (m, 2H), 7.6 – 7.4 (m, 8H), 7.1 (s, IH), 3.7 (t, J = 6.3 Hz, 2H), 3.1 (m, 2H), 1.75 (m, 2H), 0.9 (s, 9H), 0.01 (s, 6H) ppm. Data for 2-3-(Z) (second to elute): 1HNMR (500 MHz, CDCl3) delta 7.8 (m, 2H) 7.45 (m, IH), 7.35 (m, 2H), 7.25 – 7.1 (m, 5H), 6.7 (s, IH), 3.65 (t, J = 6.3 Hz, 2H), 2.65 (t, J = 7.6 Hz, 2H), 1.7 (m, 2H), 0.9 (s, 9H), 0.05 (s, 6H) ppm. Data for mixture 2-3: HRMS (ES) calc’d M + H for C24H32O2Si: 381.2245. Found: 381.2251
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.
Reference:
Patent; MERCK & CO., INC.; WO2006/7501; (2006); A2;,
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