Mosher's acid
| Mosher's acid | ||
|---|---|---|
/-/(S)-Mosher_Acid_Formula_V.1.svg.png) |
/-/(R)-Mosher_Acid_Formula_V.1.svg.png) | |
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| IUPAC name (R)-3,3,3-trifluoro-2- | ||
| Other names Methoxy(trifluoromethyl)phenylacetic acid, MTPA | ||
| Identifiers | ||
| CAS number | 81655-41-6, (racemic) 20445-31-2 (R) 17257-71-5 (S) | |
| Jmol-3D images | Image 1 | |
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| Properties | ||
| Molecular formula | C10H9F3O3 | |
| Molar mass | 234.17 | |
| Appearance | solid | |
| Melting point | 46-49°C (319-322 K) | |
| Boiling point | 105 - 107 °C at 1 torr | |
| Hazards | ||
| R-phrases | R36/37/38 | |
| S-phrases | S26/S36 | |
| Flash point | 110 °C; 230 °F; 383 K | |
| Related compounds | ||
| Related acyl chloride | Mosher's acid chloride | |
 (verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | ||
| 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.[1][2][3][4] It is a chiral molecule, consisting of R and S enantiomers.
Applications
As a chiral derivatizing agent, it reacts with an alcohol or amine[5] 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.[6]
References
- ↑ J. A. Dale, D. L. Dull, H. S. Mosher (1969). "α-Methoxy-α-trifluoromethylphenylacetic acid, a versatile reagent for the determination of enantiomeric composition of alcohols and amines". Journal of Organic Chemistry 34 (9): 2543–2549. doi:10.1021/jo01261a013.
- ↑ J. A. Dale, H. S. Mosher (1973). "Nuclear magnetic resonance enantiomer regents. Configurational correlations via nuclear magnetic resonance chemical shifts of diastereomeric mandelate, O-methylmandelate, and α-methoxy-α-trifluoromethylphenylacetate (MTPA) esters". Journal of the American Chemical Society 95 (2): 512–519. doi:10.1021/ja00783a034.
- ↑ Y. Goldberg, H. Alper (1992). "A new and simple synthesis of Mosher's acid". Journal of Organic Chemistry 57 (13): 3731–3732. doi:10.1021/jo00039a043.
- ↑ D. L. Dull, H. S. Mosher (1967). "Aberrant rotatory dispersion curves of α-hydroxy- and α-methoxy-α-trifluoromethylphenylacetic acids". Journal of the American Chemical Society 89 (16): 4230–4230. doi:10.1021/ja00992a053.
- ↑ See for example: Mosher Amides: Determining the Absolute Stereochemistry of Optically-Active Amines Allen, Damian A.; Tomaso, Anthony E., Jr.; Priest, Owen P.; Hindson, David F.; Hurlburt, Jamie L. J. Chem. Educ. 2008, 85, 698. Abstract
- ↑ D. E. Ward, C. K. Rhee (1991). "A simple method for the microscale preparation of Mosher's acid chloride". Tetrahedron Letters 32 (49): 7165–7166. doi:10.1016/0040-4039(91)80466-J.