Pyridinium p-toluenesulfonate

Pyridinium p-toluenesulfonate

IUPAC name 4-methylbenzenesulfonate; pyridin-1-ium
Other names pyridinium p-toluenesulfonate
Identifiers
Abbreviations	PPTS
CAS number	24057-28-1
PubChem	466102
ChemSpider	141806^Y
Jmol-3D images	Image 1
SMILES Cc1ccc(cc1)S(=O)(=O)[O-].c1cc[nH+]cc1
InChI InChI=1S/C7H8O3S.C5H5N/c1-6-2-4-7(5-3-6)11(8,9)10;1-2-4-6-5-3-1/h2-5H,1H3,(H,8,9,10);1-5H^Y Key: ZDYVRSLAEXCVBX-UHFFFAOYSA-N^Y InChI=1/C7H8O3S.C5H5N/c1-6-2-4-7(5-3-6)11(8,9)10;1-2-4-6-5-3-1/h2-5H,1H3,(H,8,9,10);1-5H Key: ZDYVRSLAEXCVBX-UHFFFAOYAE
Properties
Molecular formula	C₁₂H₁₃NO₃S
Molar mass	251.3 g mol⁻¹
Appearance	Colourless solid
Melting point	120 °C, 393 K, 248 °F (source^[2])
Acidity (pK_a)	5.21^[1]
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Pyridinium p-toluenesulfonate is a salt of pyridine and p-toluenesulfonic acid. It is often called PPTS. It appears a colourless solid.

Masaki Miyashita studied this compound and found it efficient to deprotect tetrahydropyranyl group (THP).^[3]

Uses

In organic synthesis, p-toluenesulfonate is used as a catalyst due to its weak acidity. For example, PPTS is available to deprotect silyl group or tetrahydropyranyl group when a substrate is unstable to strong acid.

^ David A. Evans (2005-11-04). "Evans pKa Table" (PDF). http://evans.harvard.edu/pdf/evans_pKa_table.pdf. Retrieved 2011-09-16.
^ TOKYO CHEMICAL INDUSTRY CO., LTD. "Pyridinium p-Toluenesulfonate". http://www.tokyokasei.co.jp/catalog/P0942.html. Retrieved 2011-09-16.
^ Miyashita, M.; Yoshikoshi, A.; Grieco, P. A. (1977). "Pyridinium p-toluenesulfonate. A mild and efficient catalyst for the tetrahydropyranylation of alcohols". J. Org. Chem. 42 (23): 3772–3774. doi:10.1021/jo00443a038.