反应详情

A mixture of 2-methoxy-5-nitrobenzaldehyde, 16 g, (U.S. Pat. No. 4,367,234), 2,4,4-trimethyl-2-oxazoline, 30 ml, (Aldrich Chemical Company), para toluenesulfornic acid, 0.5 g, in toluene, 100 ml, is refluxed overnight under a water separator. The mixture is evaporated, the residue dissolved in diethylether, 800 ml, and washed with water. The diethyl ether layer is separated, concentrated, and filtered to give 11.1 g of 4,5-dihydro-2-[2-(2-methoxy-5-nitrophenyl)ethenyl]-4,4-dimethyloxazole after recrystallization from diisopropyl ether; mp 115°-116° C.

1. customThe mixture is evaporated
2. dissolutionthe residue dissolved in diethylether
3. wash800 ml, and washed with water
4. customThe diethyl ether layer is separated
5. concentrationconcentrated
6. filtrationfiltered