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Diethyl azodicarboxylate



Diethyl azodicarboxylate
IUPAC name Diethyl diazenedicarboxylate
Other names Diethyl azidoformate,
DEAD,
DAD
Identifiers
CAS number 1972-28-7
SMILES O=C(/N=N/C(=O)OCC)OCC
Properties
Molecular formula C6H10N2O4
Molar mass 174.15 g/mol
Density 1.106 g/cm³
Boiling point

106 °C at 13 mm Hg

Hazards
MSDS External MSDS
Flash point 85°C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Diethyl azodicarboxylate, often abbreviated DEAD, is the organic compound CH3CH2O2CN=NCO2CH2CH3. As indicated with this formula, the molecule consists of a central azo functional group, RN=NR, flanked by two ethyl ester groups. This red orange liquid is a valuable reagent but also quite dangerous.

Additional recommended knowledge

Contents

Preparation

Although widely available, diethyl azodicarboxylate can be prepared in the laboratory. A two-step synthesis starts from hydrazine, first by alkylation with ethyl chloroformate. followed by treating the resulting ethyl hydrazodicarboxylate with chlorine.[1]

2 CH3CH2O2CCl + N2H4 → CH3CH2O2CN(H)N(H)CO2CH2CH3 + 2 HCl
CH3CH2O2CN(H)N(H)CO2CH2CH3 + Cl2 → CH3CH2O2CN=NCO2CH2CH3 + 2 HCl

Red fuming nitric acid can also be used in the second step.[2]

Applications

DEAD is an efficient component in Diels-Alder reactions and in click chemistry, for example the synthesis of Bicyclo[2.1.0]pentane, which originates from Otto Diels.[3]

DEAD is an important reagent in the Mitsunobu reaction where it forms an adduct with phosphines. In one study[4] the compound together with triphenylphosphine and a chalcone formed a pyrazoline:

Safety

DEAD is toxic, shock sensitive, and thermally unstable. It is handled as a solution, rarely as the pure compound. This safety hazards have resulted in DEAD usage rapidly declining and being replaced with DIAD (Diisopropyl azo dicarboxylate).

References

  1. ^ Rabjohn, N.. "Diethyl azodicarboxylate". Org. Synth.; Coll. Vol. 3: 375. 
  2. ^ Kauer, J. C.. "Diethyl azodicarboxylate". Org. Synth.; Coll. Vol. 4: 411. 
  3. ^ Gassman, P. G.;Mansfield, K. T.. "Bicyclo(2.1.0)pentane]". Org. Synth.; Coll. Vol. 5: 96. 
  4. ^ A Novel Reaction of the “Huisgen Zwitterion” with Chalcones and Dienones: An Efficient Strategy for the Synthesis of Pyrazoline and Pyrazolopyridazine Derivatives Vijay Nair, Smitha C. Mathew, Akkattu T. Biju, and Eringathodi Suresh Angew. Chem. Int. Ed. 2007, 46, 2070 –2073 doi:10.1002/anie.200604025
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Diethyl_azodicarboxylate". A list of authors is available in Wikipedia.
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