| abstract |
A process for preparing (-)-(2R,4S)-4Ä(3,5-bis-trifluoromethyl-benzyl) -methoxycarbonyl-aminoÜ-2-ethyl-6-trifluoromethyl-3,4-dihydro-2H-quino line-1-carboxylic acid ethyl ester comprising combining (-)-(2R,4S)-4(3,5-bis-trifluoromethyl-benzylamino) -2-ethyl-6-trifluoromethyl-3,4-dihydro-2H-quinoline-1-carboxylic acid ethyl ester, 4-toluene-sulfonate and sodium carbonate in tetrahydrofuran at a temperature of about 20 DEG C to about 25 DEG C in the presence of methyl chloroformate. <CHEM> |