Diethyl azodicarboxylate

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Template:Chembox header |Diethyl azodicarboxylate
Diethyl azodicarboxylate

File:Diethyl azodicarboxylate-3d.png

Chemical name Diethyl diazenedicarboxylate
Other names Diethyl azidoformate,
DEAD,
DAD
Chemical formula C6H10N2O4
Molecular mass 174.15 g/mol
Melting point xx.x°C
Boiling point 106 °C at 13 mm Hg
Density 1.106 g/cm³
CAS number [1972-28-7]
SMILES O=C(/N=N/C(=O)OCC)OCC
Flash point 85°C
Template:Chembox header | 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.

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:

reraction of DEAD / triphenylphosphine with chalcones

Safety

DEAD is toxic, shock sensitive, and thermally unstable. It is handled as a solution, rarely as the pure compound.

References

  1. Rabjohn, N. "Diethyl azodicarboxylate" Organic Syntheses 28:58; Coll. Vol. 3:375.
  2. "Diethyl azodicarboxylate]" Kauer, J. C. Organic Syntheses, Collective Volume 4, page 411.
  3. Gassman, P. G.;Mansfield, K. T. "Bicyclo(2.1.0)pentane". Org. Synth. 49:1; 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

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