Propanephosphonic acid anhydride

Propanephosphonic acid anhydride
Names
	Preferred IUPAC name 2,4,6-Tripropyl-1,3,5,2λ5,4λ5,6λ5-trioxatriphosphinane-2,4,6-trione
	Other names PPACA; PPAA; T3P; Propylphosphonic anhydride
Identifiers
CAS Number	68957-94-8;
3D model (JSmol)	Interactive image;
ChemSpider	100355;
EC Number	422-210-5;
PubChem CID	111923;
UNII	I6EGD8839N;
	InChI InChI=1S/C9H21O6P3/c1-4-7-16(10)13-17(11,8-5-2)15-18(12,14-16)9-6-3/h4-9H2,1-3H3 Key: PAQZWJGSJMLPMG-UHFFFAOYSA-N;
	SMILES CCCP1(=O)OP(=O)(OP(=O)(O1)CCC)CCC;
Properties
Chemical formula	C9H21O6P3
Molar mass	318.182 g·mol−1
Hazards
GHS pictograms
GHS Signal word	Warning
GHS hazard statements	H290, H314
GHS precautionary statements	P234, P260, P264, P280, P301+330+331, P303+361+353, P304+340, P305+351+338, P310, P321, P363, P390, P404, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	Infobox references

Propanephosphonic acid anhydride (PPAA, T3P) is the trimeric anhydride of n-propylphosphonic acid. It is a useful reagent for peptide synthesis reactions, where it activates the carboxylic acid partner for subsequent reaction with a primary or secondary amine.^[1] It is commercially available as 50% solution in DMF or ethyl acetate as a slightly yellow mixture.^[2]^[3]

Examples of T3P being used in the industrial syntheses of pharmaceuticals include the Pfizer synthesis of dacomitinib, the Neurosearch synthesis of SNDRIs such as PC44156003,^[4] the last step of the synthesis of selinexor,^[5] and the synthesis of darolutamide.^[5]