反应详情

To a stirred solution of ammonium thiocyanate (3.06 g., 0.04 mole) in 2M aqueous sulfuric acid (20 ml) at 0° C., methyl 3-bromopropiolate (3.26 g., 0.02 mole) was added dropwise, neat, over 5 minutes. After keeping the temperature at 0° C. for 1 hour, the mixture, consisting of a solid precipitate in the aqueous solution, was extracted with ether which was washed with water, dried (MgSO4), and concentrated. The residual solid was suspended in hexane and removed by filtration, yielding 2.4 g. of product. The solid recrystallized from ethanol as yellowish microcrystals; mp 139°-142.5° C.; IR (KBr) 2170, 1680 cm-1.

1. customat 0° C.
2. customfor 1 hour
3. extractionwas extracted with ether which
4. washwas washed with water
5. dry with materialdried (MgSO4)
6. concentrationconcentrated
7. customremoved by filtration
8. customyielding 2.4 g
9. customThe solid recrystallized from ethanol as yellowish microcrystals