تفاعل #564828

معادلة التفاعل

sodium

3

2-(1-bromoethyl)-2-(5-bromo-6-methoxy-2-naphthyl)-1,3- dioxolane-4(R),5(R)-dicarboxylic acid dimethyl ester

→

2-(1(S)-bromoethyl)-2-(5-bromo-6-methoxy-2-naphthyl)-1,3-dioxolane-4(R),5(R)-dicarboxylic acid

المذيبات

water

methanol

ظروف التفاعل

المعالجة

1. 1
   أخرىthen methanol was removed under reduced pressure
2. 2
   workup.ADDITIONby addition of water
3. 3
   أخرىThe aqueous solution, so obtained
4. 4
   استخلاصwas extracted with dichloromethane
5. 5
   استخلاصextracted with diethylether (3×100 ml)
6. 6
   غسيلThe combined organic extracts were washed with water
7. 7
   ترشيحfiltered
8. 8
   تركيزconcentrated in vacuo
9. 9
   أخرىCrystallization of the residue from dichloromethane

الإجراء التجريبي

A solution of sodium hydroxyde (5.32 g, 0.133 mol) in water (70 ml) was added dropwise in 1 hour, under stirring, to a solution of the diastereoisomer 3 (35.4 g, 0.0665 mol) in methanol (250 ml) at 20° C. The reaction mixture was kept at 20° C. for 2 hours; then methanol was removed under reduced pressure mantaining the initial volume of the solution by addition of water. The aqueous solution, so obtained, was extracted with dichloromethane, acidified with conc HCl to pH 1, and extracted with diethylether (3×100 ml). The combined organic extracts were washed with water, anhydrified over sodium sulfate, filtered, and concentrated in vacuo. Crystallization of the residue from dichloromethane gave the pure 2-(1(S)-bromoethyl)-2-(5-bromo-6-methoxy-2-naphthyl)-1,3-dioxolane-4(R),5(R)-dicarboxylic acid (diastereoisomer 7).

المصدر