反应详情

To a solution of ethyl 2-methoxyimino-3,3-ethylenedioxy-4-chlorobutyrate (syn isomer, 10.4 g) in ethanol (30 ml) was added an aqueous solution (10 ml) of sodium hydroxide (3.3 g) under ice-cooling, and the mixture was stirred for 30 minutes at ambient temperature. The reaction mixture was adjusted to pH 7 with 20% sulfuric acid under ice-cooling and stirring, and water (30 ml) was added thereto, and then the solvents are distilled off. To the residue was added water (30 ml), and the resultant solution was washed with diisopropyl ether (50 ml). To the aqueous solution was added diisopropyl ether (100 ml), adjusted to pH 2 with 20% sulfuric acid under ice-cooling and stirring and then saturated with sodium chloride. The diisopropyl ether layer was separated, and the remaining aqueous layer was further extracted with diisopropyl ether. The diisopropyl ether layer and extracts were combined together, washed with a saturated aqueous solution of sodium chloride, dried over magnesium sulfate, treated with an activated carbon and then filtered. The filtrate was concentrated and the remaining oil was allowed to stand for 1 hour under reduced pressure to give crystals of 2-methoxyimino-3,3-ethylenedioxy-4-chlorobutyric acid (syn isomer), mp 80°-81° C. in yield of 99.6%.

1. temperaturecooling
2. temperaturecooling
3. stirringstirring
4. distillationthe solvents are distilled off
5. additionTo the residue was added water (30 ml)
6. washthe resultant solution was washed with diisopropyl ether (50 ml)
7. additionTo the aqueous solution was added diisopropyl ether (100 ml)
8. temperaturecooling
9. stirringstirring
10. customThe diisopropyl ether layer was separated
11. extractionthe remaining aqueous layer was further extracted with diisopropyl ether
12. washwashed with a saturated aqueous solution of sodium chloride
13. dry with materialdried over magnesium sulfate
14. additiontreated with an activated carbon
15. filtrationfiltered
16. concentrationThe filtrate was concentrated
17. waitto stand for 1 hour under reduced pressure