Synlett 2005(10): 1638-1639  
DOI: 10.1055/s-2005-869872
© Georg Thieme Verlag Stuttgart · New York

Cyanogen Bromide (CNBr)

Vinod Kumar*
Process Technology Development Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, 474002 (MP), India
Further Information

Publication History

Publication Date:
07 June 2005 (online)


Cyanamides are versatile synthons that can be transformed into many biologically active compounds such as ureas, thioureas, selenoureas, guanidines, hydroxy­guanidines, creatine, and a large number of heterocyclic compounds. Cyanogen bromide is a very useful and extensively used reagent for the synthesis of cyanamides. It is a colorless or white crystalline solid that decomposes in the presence of moisture and has a very small liquid range (mp 50-53 °C, bp 61-62 °C). It is cheap and can be ­obtained commercially, or it can be synthesized by the ­reaction of sodium cyanide with bromine in aqueous ­medium. [1] Caution! It is highly toxic. Reactions should be carried out in a well-ventilated hood.

CNBr produces electrophilic cyanide. Therefore, it is ­attacked by nucleophiles such as amines, alcohols and ­thiols. Organic chemists are fully utilizing this property of the reagent. CNBr has also been applied in molecular ­biology to digest some proteins, and as a coupling agent for phosphoramidate or pyrophosphate internucleotide bonds in DNA duplexes.


  • 1 Hartmann WW. Dreger EE. Org. Synth. Coll. Vol. 2   John Wiley & Sons; London: 1943.  p.150 
  • 2a Podesva CP. Tarlton EJ. McKay AP. Can. J. Chem.  1962,  40:  1403 
  • 2b Deaton DN. Hassell AM. McFadyen RB. Miller AB. Miller LR. Shewchuk LM. Tavares FX. Willard DH. Wright LL. Bioorg. Med. Chem. Lett.  2005,  15:  1815 
  • 3 Rosowsky A. Modest EJ. J. Heterocycl. Chem.  1966,  3:  387 
  • 4a Hageman HA. The von Braun Reactions, In Organic Reactions   Vol. 7:  Blatt AH. Cope AC. McGrew FC. Niemann C. Snyder A. Wiley; New York: 1953.  p.198 
  • 4b Furuya S. Okamoto T. Heterocycles  1988,  27:  2609 
  • 5 Snider BB. O’Hare SM. Tetrahedron Lett.  2001,  42:  2455 
  • 6 Cai T. Xian M. Wang PG. Bioorg. Med. Chem. Lett.  2002,  12:  1507 
  • 7 Scholl R. Kacer F. Ber. Dtsch. Chem. Ges.  1903,  36:  322 
  • 8 Companon P.-L. Gros B. Synthesis  1976,  448 
  • 9 Ho J.-L. Wong CM. Synth. Commun.  1973,  3:  63 
  • 10a Martin D. Bauer M. Org. Synth. Coll. Vol. 7   John Wiley & Sons; London: 1990.  p.435 
  • 10b Yan H. Chen S. Qi G. Polymer  2003,  44:  7861 
  • 11 von Braun J. Engelbertz P. Ber. Dtsch. Chem. Ges.  1923,  56:  1573 
  • 12a Gross E. Witkop B. J. Am. Chem. Soc.  1961,  83:  1510 
  • 12b Gross E. Witkop B. J. Biol. Chem.  1962,  237:  1856 
  • 12c Stadtmana ER. Van Remmen H. Richardson A. Wahr NB. Levine RL. Biochim. Biophys. Acta  2005,  1703:  135 
  • 13 Zhong H. Marcus SL. Li L. J. Am. Soc. Mass Spectrom.  2005,  16:  471