Methoxy-a-trifluoromethylphenylacetic acid

The most important group of derivatives for the amino function (Fig. 7-4) is the carbamate group, which can be formed by reactions with acids, acid chlorides or acid anhydrides. A series of chlorides as 2-chloroisovalerylchloride [1], chrysanthe-moylchloride [2] and especially chloride compounds of terpene derivatives (cam-phanic acid chloride [3], camphor-10-sulfonyl chloride [4]) are used. The a-methoxy-a-trifluoromethylphenylacetic acid or the corresponding acid chloride introduced by Mosher in the 1970s are very useful reagents for the derivatization of amines and alcohols [5]. 

Enantiomeric purity is often determined by derivatization with an optically pure chiral agent. For alcohols and amines, a-methoxy-a-trifluoromethylphenylacetic acid (MTPA) and a-cyano-a-fluoropheny lace tic acid (CFPA) [45] work well. 

Methoxypropene, 328-329 6-Mcthoxy-1,2,3,4-tetrahy dronaphthalene-1 -carboxylic acid, 148 6-Methoxy-1 -tetralone, 148 Methoxythioanisoles, 473 a-Methoxy-a-trifluoromethylphenylacetic acid, 330... 

RESOLUTION Brucine. a-Methoxy-a-trifluoromethylphenylacetic acid. RING EXPANSION ... 

J. A. Dale, D. L. Dull and H. S. Mosher, a-Methoxy-a-trifluoromethylphenylacetic acid, a versatile reagent for the determination of enantiomeric composition of alcohols and amines, J. Org. Chem., 34 (1969) 2543-2549. 

---