Mosher's acid

Mosher's acid

Names
IUPAC names (R)-3,3,3-trifluoro-2-methoxy-2-phenylpropanoic acid (S)-3,3,3-trifluoro-2-methoxy-2-phenylpropanoic acid
Other names Methoxy(trifluoromethyl)phenylacetic acid, MTPA
Identifiers
CAS Number	81655-41-6 (racemic) Y 20445-31-2 (R) N 17257-71-5 (S) N
3D model (JSmol)	Interactive image
ChemSpider	78043 N
ECHA InfoCard	100.153.604
InChI InChI=1S/C10H9F3O3/c1-16-9(8(14)15,10(11,12)13)7-5-3-2-4-6-7/h2-6H,1H3,(H,14,15) N Key: JJYKJUXBWFATTE-UHFFFAOYSA-N N InChI=1/C10H9F3O3/c1-16-9(8(14)15,10(11,12)13)7-5-3-2-4-6-7/h2-6H,1H3,(H,14,15) Key: JJYKJUXBWFATTE-UHFFFAOYAJ
SMILES COC(C(O)=O)(c1ccccc1)C(F)(F)F
Properties
Chemical formula	C10H9F3O3
Molar mass	234.17
Appearance	solid
Melting point	46 to 49 °C (115 to 120 °F; 319 to 322 K)
Boiling point	105 to 107 °C (221 to 225 °F; 378 to 380 K) at 1 torr
Hazards
R-phrases (outdated)	R36/37/38
S-phrases (outdated)	S26/S36
Flash point	110 °C (230 °F; 383 K)
Related compounds
Related acyl chloride	Mosher's acid chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Mosher's acid, or α-methoxy-α-trifluoromethylphenylacetic acid (MTPA) is a carboxylic acid which was first used by Harry Stone Mosher as a chiral derivatizing agent. It is a chiral molecule, consisting of R and S enantiomers.

As a chiral derivatizing agent, it reacts with an alcohol or amine of unknown stereochemistry to form an ester or amide. The absolute configuration of the ester or amide is then determined by proton and/or ¹⁹F NMR spectroscopy.

Mosher's acid chloride, the acid chloride form, is sometimes used because it has better reactivity.