反应详情

温度

50 °C

10N Sodium hydroxide solution (71.4 cc.) is added to a solution of ethyl (5,6-dihydro-1,4-dithiin-2-yl)acetate (121.3 g.) in ethanol (800 cc.). The reaction mixture is heated for 3 hours at about 50° C. After evaporating the solvent under reduced pressure (25 mm.Hg), the residue is dissolved in distilled water (500 cc.). The alkaline aqueous solution is washed twice with ether (total 100 cc.), treated with decolourizing charcoal (0.2 g.), filtered and then acidified with excess hydrochloric acid (d = 1.19). The oil which separates out is extracted three times with diethyl ether (total 450 cc.). The combined ether solutions are washed three times with distilled water (total 300 cc.), dried over anhydrous magnesium sulphate and evaporated. The residue (102.2 g.) is dissolved in boiling diisopropyl ether (150 cc.) and then petroleum ether (b.p. 40°-60° C.) (50 cc.) is added. After 3 hours at 2° C., the crystals which have appeared are filtered off, washed twice with ice-cold diisopropyl ether (total 60 cc.) and dried under reduced pressure (25 mm.Hg) to give (5,6-dihydro-1,4-dithiin-2-yl)acetic acid (82.2 g.) melting at 82° C.

1. customAfter evaporating the solvent under reduced pressure (25 mm.Hg)
2. dissolutionthe residue is dissolved in distilled water (500 cc.)
3. washThe alkaline aqueous solution is washed twice with ether (total 100 cc.)
4. additiontreated with decolourizing charcoal (0.2 g.)
5. filtrationfiltered
6. extractionThe oil which separates out is extracted three times with diethyl ether (total 450 cc.)
7. washThe combined ether solutions are washed three times with distilled water (total 300 cc.)
8. dry with materialdried over anhydrous magnesium sulphate
9. customevaporated
10. dissolutionThe residue (102.2 g.) is dissolved
11. additionpetroleum ether (b.p. 40°-60° C.) (50 cc.) is added
12. filtrationthe crystals which have appeared are filtered off
13. washwashed twice with ice-cold diisopropyl ether (total 60 cc.)
14. customdried under reduced pressure (25 mm.Hg)