Dimethyl acetylenedicarboxylate

Dimethyl acetylenedicarboxylate

IUPAC name	Dimethyl acetylenedicarboxylate
Other names	DMAD Acetylenedicarboxylic acid, dimethyl ester
Identifiers
CAS number	762-42-5
RTECS number	ES0175000
SMILES	O=C(OC)C#CC(OC)=O
Properties
Molecular formula	C₆H₆O₄
Molar mass	142.11 g/mol
Appearance	Colorless liquid
Density	1.1564 g/cm³
Melting point	-117 °C
Boiling point	195–198 °C 96–98° at 8 mm Hg
Solubility in water	Insoluble
Solubility in other solvents	Soluble in most organic solvents
Refractive index (n_D)	1.447
Structure
Dipole moment	0 D
Hazards
Main hazards	Toxic gas
R-phrases	R34
S-phrases	S23 S26 S27 S36/37/39 S45
Flash point	187 °F
Related Compounds
Related compounds	Methyl propiolate, Hexafluoro-2-butyne, Acetylene
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Dimethyl acetylenedicarboxylate (DMAD) is the organic compound with the formula CH₃O₂CC₂CO₂CH₃. This alkyne, which exists as a liquid at room temperature, is highly electrophilic. As such, DMAD, as it is commonly called in the laboratory, is widely employed as a dienophile in cycloaddition reactions, such as the Diels-Alder reaction. It is also a potent Michael acceptor.^[1]^[2]

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Preparation

Although inexpensively available, DMAD is prepared today as it was originally.^[3] Maleic acid is brominated and the resulting dibromosuccinic acid is dehydrohalogenated.^[4] The dicarboxylic acid is then esterified with methanol and sulfuric acid as a catalyst.^[5]

Safety

DMAD is a lachrymator and a vesicant.

References

^ Stelmach, J. E.; Winkler, J. D. “Dimethyl Acetylenedicarboxylate”in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
^ Sahoo, Manoj Kumar: Dimethyl Acetylene Dicarboxylate SYNLETT 2007, No. 13, pp 2142–2143 doi:10.1055/s-2007-984894 Open access
^ Bandrowski, E. “Ueber Acetylendicarbonsäure” Chemische Berichte band 10, 838 (1877).
^ Abbott, T. W.; Arnold, R. T.; Thompson, R. B. “Acetylenedicarboxyltic acid” Organic Syntheses, Collective Volume 2, page 10.
^ Huntress, E. H. Lesslie, T. E.; Bornstein, J. “Dimethyl Acetylenedicarboxylate” Organic Syntheses, Collective Volume 4, page 329.