Editing Peptide synthesis (section)

==== Propanephosphonic acid anhydride ====
Since late 2000s, [[propanephosphonic acid anhydride]], sold commercially under various names such as "T3P", has become a useful reagent for amide bond formation in commercial applications. It converts the oxygen of the carboxylic acid into a leaving group, whose peptide-coupling byproducts are water-soluble and can be easily washed away. In a performance comparison between propanephosphonic acid anhydride and other peptide coupling reagents for the preparation of a nonapeptide drug, it was found that this reagent was superior to other reagents with regards to yield and low epimerization.<ref>{{Cite journal |last1=Hiebl |first1=J. |last2=Baumgartner |first2=H. |last3=Bernwieser |first3=I. |last4=Blanka |first4=M. |last5=Bodenteich |first5=M. |last6=Leitner |first6=K. |last7=Rio |first7=A. |last8=Rovenszky |first8=F. |last9=Alberts |first9=D.P. |last10=Bhatnagar |first10=P.K. |last11=Banyard |first11=A.F. |last12=Baresch |first12=K. |last13=Esch |first13=P.M. |last14=Kollmann |first14=H. |last15=Mayrhofer |first15=G. |date=1999 |title=Large-scale synthesis of hematoregulatory nonapeptide SK&F 107647 by fragment coupling |url=https://onlinelibrary.wiley.com/doi/10.1034/j.1399-3011.1999.00089.x |journal=The Journal of Peptide Research |language=en |volume=54 |issue=1 |pages=54–65 |doi=10.1034/j.1399-3011.1999.00089.x |pmid=10448970 |issn=1397-002X|url-access=subscription }}</ref>