Skip to main content


The chloro-phosphonium coupling reagent PyCloP was developed as an alternative to the BOP reagent, avoiding the release of the toxic HMPA in the activation step.

CAS: 133894-48-1

Synonym: Chlorotripyrrolidinophosphonium hexafluorophosphate




Molecular Formula

C12H24ClN3P · PF6

Molecular Weight

421.73 [gr/mol]


White to off-white crystalline powder

Storage Conditions

Store in a cool and dry place (2-8oC)


  • PyCloP often gives better results than other phosphonium-HOBt reagents, for the coupling of N-methylated amino acids.
  • PyCloP, as other phosphonium salts, cannot react with free amine function and therefore does not terminate the peptide growing as the aminium salts do, through the formation of guanidine derivatives.


  • Coupling N-Methylated Amino Acids Using PyBroP and PyCloP Halogenophosphonium Salts: Mechanism and Fields of Application
    J. Coste, E. Frerot, P. Jouin J. Org. Chem., 1994, 59 (9), pp 2437–2446.

Request an Information or Quotation

Information Request

    Price Quote Request

      Skip to content