how butenoic acid is prepared from diethyl malonate
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Diethyl malonate, also known as DEM, is the diethyl ester of malonic acid. It occurs naturally in grapes and strawberries as a colourless liquid with an apple-like odour, and is used in perfumes. It is also used to synthesize other compounds such as barbiturates, artificial flavourings, vitamin B1, and vitamin B6.
Diethyl malonateNamesPreferred IUPAC name
Diethyl propanedioate
Other names
Diethyl malonate
Identifiers
CAS Number
105-53-3 
3D model (JSmol)
Interactive image
AbbreviationsDEM
Beilstein Reference
774687ChEBI
CHEBI:391281 
ChEMBL
ChEMBL177114 
ChemSpider
13863636 
ECHA InfoCard100.003.006EC Number203-305-9MeSHDiethyl+malonate
PubChem CID
7761
RTECS numberOO0700000UNII
53A58PA183
reaction
One of the principal uses of this compound is in the malonic ester synthesis. The carbanion (2) formed by reacting diethyl malonate (1) with a suitable base can be alkylated with a suitable electrophile. This alkylated 1,3-dicarbonyl compound (3) readily undergoes decarboxylation with loss of carbon dioxide, to give a substituted acetic acid (4):
Sodium ethoxide is preferred as the base. The use of aqueous sodium hydroxide may give the base hydrolysis products: sodium malonate and ethanol. In comparison, when sodium ethoxide is used, any nucleophilic attack at the carboxylate by the ethoxide will not give any side product; other alkoxide salts will cause scrambling by transesterification.
Diethyl malonateNamesPreferred IUPAC name
Diethyl propanedioate
Other names
Diethyl malonate
Identifiers
CAS Number
105-53-3 
3D model (JSmol)
Interactive image
AbbreviationsDEM
Beilstein Reference
774687ChEBI
CHEBI:391281 
ChEMBL
ChEMBL177114 
ChemSpider
13863636 
ECHA InfoCard100.003.006EC Number203-305-9MeSHDiethyl+malonate
PubChem CID
7761
RTECS numberOO0700000UNII
53A58PA183
reaction
One of the principal uses of this compound is in the malonic ester synthesis. The carbanion (2) formed by reacting diethyl malonate (1) with a suitable base can be alkylated with a suitable electrophile. This alkylated 1,3-dicarbonyl compound (3) readily undergoes decarboxylation with loss of carbon dioxide, to give a substituted acetic acid (4):
Sodium ethoxide is preferred as the base. The use of aqueous sodium hydroxide may give the base hydrolysis products: sodium malonate and ethanol. In comparison, when sodium ethoxide is used, any nucleophilic attack at the carboxylate by the ethoxide will not give any side product; other alkoxide salts will cause scrambling by transesterification.
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