Dimethyl acetylenedicarboxylate

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Dimethyl acetylenedicarboxylate
Chemical structure of DMAD
Ball-and-stick model
Identifiers
CAS number 762-42-5 YesY
ChemSpider 12440 YesY
RTECS number ES0175000
Jmol-3D images Image 1
Properties
Molecular formula C6H6O4
Molar mass 142.11 g/mol
Appearance Colorless liquid
Density 1.1564 g/cm3
Melting point c
Boiling point 195 to 198 °C (383 to 388 °F; 468 to 471 K) (96–98° at 8 mm Hg)
Solubility in water Insoluble
Solubility in other solvents Soluble in most
organic solvents
Refractive index (nD) 1.447
Structure
Dipole moment 0 D
Hazards
R-phrases R34
S-phrases S23 S26 S27
S36/37/39 S45
Main hazards Toxic gas
Flash point 187 °C (369 °F; 460 K)
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 (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.

Preparation[edit]

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]

Preparation of dimethyl acetylenedicarboxylate.png

Safety[edit]

DMAD is a lachrymator and a vesicant.

References[edit]

  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", Org. Synth. ; Coll. Vol. 2: 10 
  5. ^ Huntress, E. H. Lesslie, T. E.; Bornstein, J., "Dimethyl Acetylenedicarboxylate", Org. Synth. ; Coll. Vol. 4: 329