Diethyl azodicarboxylate

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Diethyl azodicarboxylate
Chemical name Diethyl diazenedicarboxylate
Other names Diethyl azidoformate,
DEAD,
DAD
Chemical formula C6H10N2O4
Molecular mass 174.15 g/mol
Melting point °C
Boiling point 106 °C at 13 mm Hg
Density 1.106 g/cm3
CAS number [1972-28-7]
SMILES CC(=O)ON=NOC(=O)C
Image:DEAD.gif
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 ethylester groups. This red orange liquid is a valuable reagent but also quite dangerous.

The structure shown in the figure is correct, except that the predominant isomer is trans, not cis.

Contents

[edit] 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]

[edit] Applications

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

[edit] Safety

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

[edit] 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

[edit] External links