Phosphoramidate
{{short description|Class of organophosphorous compounds}}
{{Distinguish|Phosphonamidate|Phosphoramidite}}
File:Fosthietan.svg is a phosphoramidate]]
In organophosphorus chemistry, phosphoramidates (sometimes also called amidophosphates) are a class of phosphorus compounds structurally related to phosphates (or organophosphates) via the substitution of an {{chem2|\sO-}} group for an amine group ({{chem2|\sN\s}}). They are derivatives of phosphoramidic acids, which possess the structure {{chem2|O\dP(OH)(NR2)2}} or {{chem2|O\dP(OH)2(NR2)}}.
A phosphorodiamidate is a phosphate that has two of its hydroxyl ({{chem2|\sOH}}) groups substituted by amine ({{chem2|NR2}}) groups to give a species with the general formula {{chem2|O\dP(OH)(NH2)2}}. The substitution of all three OH groups gives the phosphoric triamides ({{chem2|O\dP(NR2)3}}), which are commonly referred to as phosphoramides.{{GoldBookRef|title=phosphoramides| file = A00484}}
Synthesis
In the Stokes method, phosphoramidates are synthesized from phosphorus oxychloride. The compound reacts with phenol to form a chlorophosphonate ester or diester, depending on stoichiometry. The remaining chlorine substituents then react with an amine compound to give the phosphoramidate.{{cite encyclopedia|chapter=Phosphorus|first=R.|last=Klement|pp=579-590|chapter-url=https://archive.org/details/Handbook_of_Preparative_Inorganic_Chemistry_1_2_Brauer/page/n603/|year=1963|publisher=Academic Press|location=NY, NY|lccn=63-14307|title=Handbook of Preparative Inorganic Chemistry|volume=1|edition=2nd|editor-first=Georg|editor-last=Brauer|translator-first=Reed F.|translator-last=Riley}}
Examples
Two examples of natural phosphoramidates are phosphocreatine and the phosphoramidate formed when histidine residues in histidine kinases are phosphorylated.{{cite journal|title=Two-Component Signal Transduction |journal=Annual Review of Biochemistry |date=2000-07-01 |doi=10.1146/annurev.biochem.69.1.183 |last1=Stock |first1=Ann M. |last2=Robinson |first2=Victoria L. |last3=Goudreau |first3=Paul N. |volume=69 |pages=183–215 |pmid=10966457}}
An example of a phosphorodiamidate is morpholino which is used in molecular biology.