Ethyl Acetate → 1-[3,5-Bis(trifluoromethyl)phenyl]ethoxy-3-(4-fluorophenyl)-1,4-oxazine

Participants

Reaction Steps

A solution of (2R-cis)-2-[[1-[3.5-bis(trifluoromethyl)phenyl]-ethenyl]oxy]-3-(4-fluorophenyl)-4-(phenylmethyl)mopholine (1082 g, 94% pure, 1.94 moles) in 1:1 ethyl acetate:ethanol (13 L) was mixed with 10% palladium-on-carbon (165 g). The resulting slurry was treated with hydrogen (40 psi, 20-25° C.) for 12 hours. The reaction was monitored by hydrogen uptake and HPLC. The vessel was vented, and the catalyst was removed by filtration. After washing the catalyst with 1:1 ethyl acetate:ethanol (6 L) followed by ethyl acetate (2 L), the combined organic phases containing crude product were vacuum concentrated. A second batch, starting with 1078 g of (2R-cis)-2-[[1-[3.5-bis(trifluoromethyl)phenyl]ethenyl]oxy]-3-(4-fluorophenyl)-4-(phenylmethyl)mopholine (1.93 moles) was prepared. The resulting crude product was vacuum concentrated and combined with the first batch. The combined batches of crude product were flushed with methyl-t-butyl ether (2×3 L) in order to remove residual ethyl acetate and ethanol, then were dissolved in methyl-t-butyl ether (3 L). The solution was assayed to contain 1348 g (3.09 moles, 80% yield) of the title compound (as the free base). Alternatively, 60 g of the vinyl ether, 650 mL of methyl t-butyl ether (MTBE), and 18 g of 5% Pd on alumina were stirred under 40 psi hydrogen pressure at 40° for 12 H. Assay yield was 87%, with a 91:9 ratio of diastereomers. At the end of the reaction age, the catalyst was removed by filtration through Solka-Floc, then the filtrate was concentrated to 140 mL.

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