Acetic Anhydride → Propanedioic acid, 2-(1-methoxyethylidene)-, 1,3-dimethyl ester
Reaction equation
[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]Participants
Conditions
- Temperature
- 130 °C
Procedure
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.
Workup
- customwere then metered in over the course of 12 hours
- distillationthe low-boiling component was distilled off at a head temperature of 82° to 87° C.
- temperaturethe reaction temperature was gradually increased to 160° C
- distillationAfter complete distillation of the low-boiling component
- temperaturethe mixture was cooled
- distillationthe excess trimethyl orthoacetate distilled off at reduced pressure
- customwas fractionated through a short column at a head temperature of 110° C. under a high vacuum of 0.3 mbar
Sources & evidence
- ORD record
- ord-df954916ab8743ca8579b62c3222c085
- Source dataset
- uspto-grants-1991_08
- Patent number
- US05041619
Reaction notes
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