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.
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| Names | |
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| Preferred IUPAC name
Dimethyl but-2-ynedioate | |
| Other names
DMAD
Acetylenedicarboxylic acid dimethyl ester | |
| Identifiers | |
3D model (JSmol)
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| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.010.999 |
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PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| 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 |
Refractive index (nD)
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1.447 |
| Structure | |
| 0 D | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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Toxic |
| GHS labelling: | |
 
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| 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
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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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Preparation
editAlthough 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
editDMAD is a lachrymator and a vesicant.[citation needed]
References
edit- ^ 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.
- ^ Sahoo, Manoj (2007). "Dimethyl Acetylene Dicarboxylate". Synlett. 2007 (13): 2142–2143. doi:10.1055/s-2007-984894.
- ^ Bandrowski, E. (1877). "Ueber Acetylendicarbonsäure". Berichte der Deutschen Chemischen Gesellschaft. 10: 838–842. doi:10.1002/cber.187701001231.
- ^ Abbott, T. W.; Arnold, R. T.; Thompson, R. B. (1938). "Acetylenedicarboxylic acid". Organic Syntheses. 18: 3. doi:10.15227/orgsyn.018.0003; Collected Volumes, vol. 2, p. 10.
- ^ Huntress, E. H.; Lesslie, T. E.; Bornstein, J. (1952). "Dimethyl Acetylenedicarboxylate". Organic Syntheses. 32: 55. doi:10.15227/orgsyn.032.0055; Collected Volumes, vol. 4, p. 329.