Diphenylphosphoryl azide

Diphenylphosphoryl azide
Names
IUPAC name
Diphenyl phosphorazidate
Other names
Diphenoxyphosphoryl azide
Diphenylphosphonic azide
Diphenyl azidophosphate
Phosphoric acid diphenyl ester azide
Identifiers
26386-88-9 YesY
3D model (Jmol) Interactive image
Abbreviations DPPA
ChemSpider 172597 YesY
ECHA InfoCard 100.043.298
PubChem 123414
Properties
C12H10N3O3P
Molar mass 275.20 g·mol−1
Appearance Colourless or faintly yellow liquid
Density 1.277 g/cm3
Boiling point 157 °C (315 °F; 430 K) (0.2 mmHg)
Hazards
Toxic (T)
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
1
4
0
Flash point 112 °C (234 °F; 385 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Diphenylphosphoryl azide (DPPA; alternative, more precise name: diphenoxyphosphoryl azide; IUPAC name: diphenyl phosphorazidate) is an organic compound. It is widely used in synthesis of other organic compounds.[1]

Uses

DPPA undergoes pseudohalogen replacement of the azido group by treatment with nucleophilic reagents, such as water, butanol, ammonia, and various amines.

This compound is used as a reagent for the synthesis of peptides by virtue of its reactions with carboxylic acids leading to either the urethane or the amide. The formation of the urethane is particularly valuable since it works with carboxylic acids which fail to undergo the Schmidt reaction, and is believed to involve transfer of the azido group to the carboxylic acid.

It is now suggested that this reaction proceeds through the intermediate mixed anhydride, resulting from attack by the nucleophilic carboxylate anion on the phosphorus atom, with expulsion of the azide ion. The latter then attacks the carbonyl carbon atom, to give the acyl azide and loss of the diphenylphosphate anion, known to be a good leaving group. Finally, the acyl azide reacts in the normal manner to give the urethane.

Studies show that DPPA reacts with amines giving the corresponding phosphoramidates; it therefore appears that formation of the amide similarly involves the intermediate anhydride, followed by nucleophilic substitution by the amine.

Safety

DPPA is very toxic and a potential explosive like most other azide compounds.

See also

References

  1. ↑ R. J. W. Cremlyn (1973). "Some Reactions of O,O-Diphenylphosporyl Azide". Australian Journal of Chemistry. 26 (7): 1591–3. doi:10.1071/CH9731591.
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