反应详情

800 gm (2.61 mol) of the difficultly soluble diastereoisomer of [1-(2'-fluoro-4-biphenylyl)-ethylsulfinyl]-acetic acid, m.p. 164°-165° C., were suspended in 4 liters of benzene and 125.5 gm (3.92 mol) of methanol, and a solution of 648 gm (3.14 mol) of dicyclohexyl-carbodiimide in 650 ml of benzene was added while stirring and cooling at 20°-25° C. The acid dissolved, and dicyclohexylurea precipitated out. The mixture was allowed to stand overnight at room temperature, then the excess of carbodiimide was decomposed by addition of glacial acetic acid, and then 2 liters of water were added, the dicyclohexylurea was suction-filtered off, the organic phase was separated from the filtrate and evaporated in vacuo after drying. The obtained oil (969 gm) was recrystallized from 2.9 liters of isopropanol. Yield: 736 gm (88% of theory); m.p. 75°-77° C.

1. temperaturecooling at 20°-25° C
2. dissolutionThe acid dissolved
3. customdicyclohexylurea precipitated out
4. additionthe excess of carbodiimide was decomposed by addition of glacial acetic acid
5. addition2 liters of water were added
6. filtrationthe dicyclohexylurea was suction-filtered off
7. customthe organic phase was separated from the filtrate
8. customevaporated in vacuo
9. customafter drying
10. customThe obtained oil (969 gm) was recrystallized from 2.9 liters of isopropanol