Acetic Anhydride → Propanedioic acid, 2-(1-methoxyethylidene)-, 1,3-dimethyl ester

HRID 2248979Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 2248979
[C:1]([O:8][CH3:9])(=[O:7])[CH2:2][C:3]([O:5][CH3:6])=[O:4].[C:10](OC)(OC)([O:12][CH3:13])[CH3:11].C(OC(=O)C)(=O)C>>[C:3]([C:2](=[C:10]([O:12][CH3:13])[CH3:11])[C:1]([O:8][CH3:9])=[O:7])([O:5][CH3:6])=[O:4]

Komponenten

4

Edukt 3

HCID 7918Acetic AnhydrideHCID 7943Dimethyl malonateHCID 15050Trimethyl orthoacetate

Produkt 1

HCID 13508544Propanedioic acid, 2-(1-methoxyethylidene)-, 1,3-dimethyl esterAusbeute 77,5 %

Reaktionsbedingungen

Temperatur
130 °C

Versuchsvorschrift

264 g (2 mol) of dimethyl malonate, 961 g (8 mol) of trimethyl orthoacetate and 1 g of catalyst from Example 1 were put into the pressure apparatus described in Example 2. The mixture was heated to 130° C., whereupon an internal pressure of 1.5 bar developed. 100 g of acetic anhydride were then metered in over the course of 12 hours, the low-boiling component was distilled off at a head temperature of 82° to 87° C. and the reaction temperature was gradually increased to 160° C. After complete distillation of the low-boiling component, the mixture was cooled, the excess trimethyl orthoacetate distilled off at reduced pressure and the crude product was fractionated through a short column at a head temperature of 110° C. under a high vacuum of 0.3 mbar. In this way methyl 2-carbomethoxy-3-methoxy-2-butenoate was obtained in a yield of 77.5% and methyl 2-carbomethoxy-3,3-dimethoxy-butanoate was obtained in a yield of 11% of the theoretical yield.

Aufarbeitung

  1. customwere then metered in over the course of 12 hours
  2. distillationthe low-boiling component was distilled off at a head temperature of 82° to 87° C.
  3. temperaturethe reaction temperature was gradually increased to 160° C
  4. distillationAfter complete distillation of the low-boiling component
  5. temperaturethe mixture was cooled
  6. distillationthe excess trimethyl orthoacetate distilled off at reduced pressure
  7. customwas fractionated through a short column at a head temperature of 110° C. under a high vacuum of 0.3 mbar

Quellen und Nachweise

ORD-Eintrag
ord-df954916ab8743ca8579b62c3222c085
Quelldatensatz
uspto-grants-1991_08
Patentnummer
US05041619

Notizen zur Reaktion

Wird geladen…