Dimethyl acetylenedicarboxylate

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.

Dimethyl acetylenedicarboxylate
Chemical structure of DMADuak
Ball-and-stick model
Names
Preferred IUPAC name
Dimethyl but-2-ynedioate
Other names
DMAD
Acetylenedicarboxylic
acid dimethyl ester
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.010.999
EC Number
  • 212-098-4
RTECS number
  • ES0175000
UNII
  • InChI=1S/C6H6O4/c1-9-5(7)3-4-6(8)10-2/h1-2H3 checkY
    Key: VHILMKFSCRWWIJ-UHFFFAOYSA-N checkY
  • InChI=1/C6H6O4/c1-9-5(7)3-4-6(8)10-2/h1-2H3
    Key: VHILMKFSCRWWIJ-UHFFFAOYAX
  • COC(=O)C#CC(=O)OC
Properties
C6H6O4
Molar mass 142.11 g/mol
Appearance Colorless liquid
Density 1.1564 g/cm3
Melting point −18 °C (0 °F; 255 K)
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
Occupational safety and health (OHS/OSH):
Main hazards
 Toxic
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
Danger
H302, H314
P260, P264, P270, P280, P301+P312, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P405, P501
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).
checkY verify (what is checkY☒N ?)
Infobox references

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:10.1002/047084289X.
  2. Sahoo, Manoj (2007). "Dimethyl Acetylene Dicarboxylate". Synlett. 2007 (13): 2142–2143. doi:10.1055/s-2007-984894.
  3. Bandrowski, E. (1877). "Ueber Acetylendicarbonsäure". Berichte der Deutschen Chemischen Gesellschaft. 10: 838–842. doi:10.1002/cber.187701001231.
  4. Abbott, T. W.; Arnold, R. T.; Thompson, R. B. (1938). "Acetylenedicarboxylic acid". Organic Syntheses. 18: 3. doi:10.15227/orgsyn.018.0003.; Collective Volume, vol. 2, p. 10
  5. Huntress, E. H.; Lesslie, T. E.; Bornstein, J. (1952). "Dimethyl Acetylenedicarboxylate". Organic Syntheses. 32: 55. doi:10.15227/orgsyn.032.0055.; Collective Volume, vol. 4, p. 329
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