反应详情

Racemic (I) was synthesized as described by Quintana, et al. [J. Pharm. Sci. Vol. 54, Pages 785-787 (1965)] which is specifically incorporated herein by reference. Briefly, α,α'-dibromo-p-xylene (30.0 g, 0.11 36 mole) in 400 ml acetone was added to a solution of N,N-diethylnicotinamide (41.93 g, 0.2353 mole) in 700 ml absolute ethanol and refluxed (8.5 h) to yield α,α'-bis[3-(N,N-diethylcarbamoyl)pyridinium]-p-xylene dihydrobromide (36.3 g, 0.0585 mole, mp 267.4°-268.1° C.). Hydrogenation (PtO2,/H2, 50 psi) of the quaternary compound (25.0 g, 0.0403 mole) afforded I.2HBr (25.0 g, 0.0395 mole). The crude product (25.0 g) was dissolved in hot absolute ethanol and allowed to cool to room temperature. After three days, the separated crystals were filtered off to yield 9.4 g (0.0149 mole) of the "first crop", mp 280°-281° C. (decomp). The mother liquor, upon standing for 7-10 days afforded 6.5 g (0.0103 mole) of the "second crop", mp 279.0°-279.8° C. (decomp).

1. temperaturerefluxed (8.5 h)