Dimethyl acetylenedicarboxylate

Dimethyl acetylenedicarboxylate
Names
IUPAC name
Dimethyl but-2-ynedioate
Other names
DMAD
Acetylenedicarboxylic
acid dimethyl ester
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.010.999
RTECS number ES0175000
Properties
C6H6O4
Molar mass 142.11 g/mol
Appearance Colorless liquid
Density 1.1564 g/cm3
Melting point -18°C
Boiling point 195 to 198 °C (383 to 388 °F; 468 to 471 K) (96–98° at 8 mm Hg)
Insoluble
Solubility in other solvents Soluble in most
organic solvents
1.447
Structure
0 D
Hazards
Main hazards Toxic gas
R-phrases (outdated) R34
S-phrases (outdated) S23 S26 S27
S36/37/39 S45
Flash point 187 °C (369 °F; 460 K)
Related compounds
Related compounds
 Methyl propiolate,
Hexafluoro-2-butyne,
Acetylene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Dimethyl acetylenedicarboxylate (DMAD) is an organic compound with the formula CH3O2CC2CO2CH3. It is a di-ester in which the ester groups are conjugated with a C-C triple bond. As such, the molecule is highly electrophilic, and is widely employed as a dienophile in cycloaddition reactions, such as the Diels-Alder reaction. It is also a potent Michael acceptor.[1][2] This compound exists as a colorless liquid at room temperature. This compound was used in the preparation of nedocromil.

Preparation

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

Safety

DMAD is a lachrymator and a vesicant.

References

  1. ↑ 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.
  2. ↑ Sahoo, Manoj (2007). "Dimethyl Acetylene Dicarboxylate". Synlett. 2007: 2142. doi:10.1055/s-2007-984894.
  3. ↑ Bandrowski, E. (1877). "Ueber Acetylendicarbonsäure". Berichte der deutschen chemischen Gesellschaft. 10: 838. doi:10.1002/cber.187701001231.
  4. ↑ Abbott, T. W.; Arnold, R. T.; Thompson, R. B. "Acetylenedicarboxylic acid". Organic Syntheses. ; Collective Volume, 2, p. 10
  5. ↑ Huntress, E. H. Lesslie, T. E.; Bornstein, J. "Dimethyl Acetylenedicarboxylate". Organic Syntheses. ; Collective Volume, 4, p. 329
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