A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Org. Synth. 1984, 62, 187
DOI: 10.15227/orgsyn.062.0187
[Phosphorazidic acid, diphenyl ester]
Submitted by Takayuki Shioiri1 and Shun-ichi Yamada2.
Checked by Christina Bodurow and M. F. Semmelhack.
1. Procedure
A mixture of 56.8 g (0.21 mol) of diphenyl phosphorochloridate (Note 1), 16.3 g (0.25 mol) of sodium azide, and 300 mL of anhydrous acetone (Note 2) in a 500-mL round-bottomed flask fitted with a calcium chloride tube is stirred at 20–25°C for 21 hr. The lachrymatory mixture is filtered in a hood, and the filtrate is concentrated under reduced pressure. The residue is distilled through a short Vigreux column (Note 3). The yield of diphenyl phosphorazidate, bp 134–136°C (0.2 mm), is 49–52 g (84–89%) (Note 4).
2. Notes
1. Diphenyl phosphorochloridate (diphenyl chlorophosphate), from Aldrich Chemical Company, Inc., was used after purification by distillation at 165–168°C (5 mm).
2. Commercial acetone was dried over anhydrous potassium carbonate and distilled.
3. The bath temperature should be kept below 200°C to minimize decomposition of diphenyl phosphorazidate.3
4. Diphenyl phosphorazidate is a colorless nonexplosive oil that can be kept for a long time without decomposition if it is protected against light3 and moisture.
3. Discussion
The procedure described is essentially that of Shioiri and Yamada.4 Diphenyl phosphorazidate is a useful and versatile reagent in organic synthesis.5 6 It has been used for racemization-free peptide syntheses,4,7,8 thiol ester synthesis,9 a modified Curtius reaction,7,10,11 C-acylation of active methylene compounds,12 esterification of an α-substituted carboxylic acid,13 formation of diketopiperazines,14 an alkyl azide synthesis,15 phosphorylation of alcohols and amines,16 and polymerization of amino acids and peptides.17 Furthermore, diphenyl phosphorazidate acts as a nitrene source3 and as a 1,3-dipole.18,19 An example of the ring contraction of cyclic ketones to form cycloalkanecarboxylic acids is presented on page 135 in this volume.
This preparation is referenced from:

References and Notes
  1. Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467, Japan.
  2. Faculty of Pharmaceutical Sciences, Josai University, Saitama 350-02, Japan.
  3. Breslow, R.; Feiring, A.; Herman, F. J. Am. Chem. Soc. 1974, 96, 5937.
  4. Shioiri, T.; Yamada, S. Chem. Pharm. Bull. 1974, 22, 849. No spectral and/or analytical data appear to have been reported for diphenyl phosphorazidate. The checkers recorded the following spectral data: 1H NMR (CDCl3), δ: 7.0–7.3 (br, s, C6H5-); IR (neat) cm−1: 3060 (w, C-H), 2170 (s, -N3), 1590 (m), 1490 (s, arene C=C), 1270 (m, P=O), 960 (s, P-O-aryl).
  5. For a review, see (a) Shioiri, T.; Yamada, S. Yuki Gosei Kagaku Kyokai Shi (J. Synth. Org. Chem. Japan) 1973, 31, 666; Chem. Abstr. 1974, 81, 13781a;
  6. Shioiri, T. Nagoya Shiritsu Daigaku Yakugakubu Kenkyu Nempo (Ann. Rept. Pharm. Nagoya City University) 1977, 25, 1.
  7. Shioiri, T.; Ninomiya, K.; Yamada, S. J. Am. Chem. Soc. 1972, 94, 6203.
  8. Yamada, S.; Ikota, N.; Shioiri, T.; Tachibana, S. J. Am. Chem. Soc. 1975, 97, 7174.
  9. Yokoyama, Y.; Shioiri, T.; Yamada, S. Chem. Pharm. Bull. 1977, 25, 2423.
  10. Ninomiya, K.; Shioiri, T.; Yamada, S. Tetrahedron 1974, 30, 2151.
  11. Ninomiya, K.; Shioiri, T.; Yamada, S. Chem. Pharm. Bull. 1974, 22, 1398.
  12. Hamada, Y.; Shioiri, T. Tetrahedron Lett. 1982, 23, 235. For a review, see Shioiri, T.; Hamada, Y. Heterocycles 1988, 28, 1035.
  13. Ninomiya, K.; Shioiri, T.; Yamada, S. Chem. Pharm. Bull. 1974, 22, 1795.
  14. Yamada, S.; Yokoyama, Y.; Shioiri, T. Experientia 1976, 32, 398.
  15. Lal, B.; Pramanik, B. N.; Manhas, M. S.; Bose, A. K. Tetrahedron Lett. 1977, 1977.
  16. Cremlyn, R. J. W. Aust. J. Chem. 1973, 26, 1591.
  17. Nishi, N.; Nakajima, B.; Hasebe, N.; Noguchi, J. Int. J. Biol. Macromol. 1980, 2, 53.
  18. Yamada, S.; Hamada, Y.; Ninomiya, K.; Shioiri, T. Tetrahedron Lett. 1976, 4749; see p. 135 in this volume.
  19. Shioiri, T.; Kawai, N. J. Org. Chem. 1978, 43, 2936.

Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

Diphenyl phosphorochloridate (diphenyl chlorophosphate)

potassium carbonate (584-08-7)

acetone (67-64-1)

sodium azide (26628-22-8)

diphenyl phosphorochloridate (2524-64-3)

Diphenyl phosphorazidate,
Phosphorazidic acid, diphenyl ester (26386-88-9)