Acetic Anhydride → Methyl 2-(methoxymethylidene)-3-oxopentanoate

Reaction equation

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

Participants

Reactant 3

HCID 7918Acetic Anhydride

HCID 9005Trimethyl orthoformate

HCID 121699Methyl 3-oxovalerate

Product 1

HCID 53662896Methyl 2-(methoxymethylidene)-3-oxopentanoate

Procedure

A mixture of methyl propionylacetate (112.2 g, 0.86 mol), trimethyl orthoformate (188 ml, 1.72 mol) and acetic anhydride (81 ml, 0.86 mol) was heated at reflux for 17 hours, then the volatile material removed in vacuo, finally at 70°/0.3 mm. The residue was predominantly methyl 2-propanoyl-3-methoxyacrylate, and was used without further purification.