反応 #5248

反応方程式

sulfuric acid

1,4-dichloro-2,3-butanediol

trioxane

1,4-dichloro-2,3-butanediol

→

4,5-Dichloromethyl-1,3-dioxolane

収率 89.5%

溶媒

1,2-dichloroethane

反応条件

後処理

1. 1
   その他A three-neck 500-mL flask equipped with a thermometer, a mechanical stirrer, an addition funnel, a condenser
2. 2
   workup.ADDITIONDuring the addition period
3. 3
   その他the flask was immersed in an ice bath
4. 4
   温度to maintain the reaction temperature at 21.5° C. to 25.5° C. for 2.1 hours
5. 5
   その他The acid layer was removed
6. 6
   洗浄washed once with 30 mL EDC
7. 7
   その他The combined EDC solutions were quenched with 2% NaHCO3 (600 mL)
8. 8
   洗浄washed with deionized water (400 mL), 1% NaHCO3 solution (400 mL), deionized water (400 mL

実験手順

A three-neck 500-mL flask equipped with a thermometer, a mechanical stirrer, an addition funnel, a condenser, and a positive nitrogen atmosphere was charged with 1,4-dichloro-2,3-butanediol (50.0 g, 0.314 mole), trioxane (9.43 g, 0.314 mole), and 1,2-dichloroethane (EDC) (300 mL). The 1,4-dichloro-2,3-butanediol was not totally dissolved. Concentrated sulfuric acid (46.3 g, 0.455 mole) was then added dropwise over eight minutes. During the addition period, a slight exotherm was noticed and the flask was immersed in an ice bath to maintain the reaction temperature at 21.5° C. to 25.5° C. for 2.1 hours. The reaction mixture was permitted to settle overnight. The acid layer was removed, washed once with 30 mL EDC, and discarded. The combined EDC solutions were quenched with 2% NaHCO3 (600 mL), washed with deionized water (400 mL), 1% NaHCO3 solution (400 mL), deionized water (400 mL, twice), and stripped in vacuo. The resulting light yellow liquid weighed 48.9 g (89.5% yield), and contained 1.8% EDC and 98.2% dl- and meso-(4,5-dichloromethyl)-1,3-dioxolane, as determined by GC analysis and proton NMR (CDCl3) δ (s, --OCH2O--), 4.1 (m, ClCH2CHCHCH2Cl), 3.6(d, ClCH2CHCHCH2Cl).

出典