Title: Mosher's Reagent
CAS Registry Number: 81655-41-6
CAS Name: a-Methoxy-a-(trifluoromethyl)benzeneacetic acid
Synonyms: (±)-Mosher's acid; MTPA; 2-methoxy-2-(trifluoromethyl)phenylacetic acid
Molecular Formula: C10H9F3O3
Molecular Weight: 234.17
Percent Composition: C 51.29%, H 3.87%, F 24.34%, O 20.50%
Literature References: Chiral derivatizing reagent. Prepn: D. L. Dull, H. S. Mosher,
J. Am. Chem. Soc. 89, 4230 (1967); J. A. Dale
et al., J. Org. Chem. 34, 2543 (1969). Microscale prepn: D. E. Ward, C. K. Rhee,
Tetrahedron Lett. 32, 7165 (1991). Absolute configuration: S. S. Oh
et al., J. Org. Chem. 54, 4499 (1989); of the acid chloride: B. S. Joshi, S. W. Pelletier,
Heterocycles 51, 183 (1999). Enantiomeric purity of commerical samples: W. A. K?nig
et al., Tetrahedron Lett. 31, 6867 (1990). Use in determn of abs config: T. R. Hoye, M. K. Renner,
J. Org. Chem. 61, 2056 (1996); A. Ichikawa,
Enantiomer 3, 255 (1998); L. F. Tietze
et al., Eur. J. Org. Chem. 2000, 2247.
Derivative Type: (
R)-(+)-Form
CAS Registry Number: 20445-31-2
Properties: bp1.5 mm 116-118°. [a]D25 +68.5 ± 1.3° (c = 1.49 in CH3OH).
Boiling point: bp1.5 mm 116-118°
Optical Rotation: [a]D25 +68.5 ± 1.3° (c = 1.49 in CH3OH)
Derivative Type: (
S)-(-)-Form
CAS Registry Number: 17257-71-5
Properties: bp1.5 mm 115-117°. [a]D24 -71.8± 0.6° (c = 3.28 in CH3OH).
Boiling point: bp1.5 mm 115-117°
Optical Rotation: [a]D24 -71.8± 0.6° (c = 3.28 in CH3OH)
Derivative Type: (
R)-(-)-Acid chloride
CAS Registry Number: 39637-99-5
Synonyms: (
R)-MTPA-chloride
Properties: bp1 mm 54-56°. [a]D25 -10.0± 0.1° (neat, l = 1).
Boiling point: bp1 mm 54-56°
Optical Rotation: [a]D25 -10.0± 0.1° (neat, l = 1)
Derivative Type: (
S)-(+)-Acid chloride
CAS Registry Number: 20445-33-4
Properties: bp1 mm 54-56°. [a]D24 +129.0± 0.2° (c = 5.17 in CCl4).
Boiling point: bp1 mm 54-56°
Optical Rotation: [a]D24 +129.0± 0.2° (c = 5.17 in CCl4)
Use: Resolution of enantiomers primarily of alcohols and amines.
