Patent ID: 6500986
Filing Date: 2002-12-31
Classification: C07C

Abstract:
A process for preparing a racemic amino acid derivative of the formula: in whichn represents the numbers 0, 1 or 2, R1 represents methyl, ethyl, n-propyl or isopropyl; R2 represents cyclohexyl, norbornyl or cyclohexenyl, or represents monosubstituted to tetrasubstituted cyclohexyl, norbornyl or cyclohexenyl, the substituents being identical or different and being, in each case, selected from the group consisting of fluorine, chlorine, methyl and ethyl, or represents furyl, pyridyl or thienyl, or represents mono-substituted to trisubstituted furyl, pyridyl or thienyl, the substituents being identical or different and being, in each case, selected from the group consisting of fluorine, chlorine, bromine, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, methoxy, ethoxy, n-propoxy, i-propoxy, trifluoromethyl and trifluoroethyl; or represents phenyl, naphthyl or monosubstituted to pentasubstituted phenyl or naphthyl, the substituents being identical or different and being, in each case, selected from the group consisting of fluorine, chlorine, bromine, nitro, amino hydroxy, formyl, carboxyl, carbamoyl, thiocarbamoyl, methyl, ethyl, n- or i-propyl, n-, i-, s- or t-butyl, methoxy, ethoxy, n- or i-propoxy, methylthio, ethylthio, n- or i-propylthio, methylsuphinyl, ethylsulphinyl, methylsulphonyl- or ethylsulphonyl, trifluoromethyl, trifluoroethyl, difluoromethoxy, trifluoromethoxy, difluorochloromethoxy, trifluoroethoxy, difluorochloromethylthio, difluoromethylthio, trifluoromethylthio, trifluoromethylsulphinyl or trifluoromethylsulphonyl, methylamino, ethylamino, n- or i-propylamino, dimethylamino, diethylamino, methoxycarbonyl, ethoxycarbonyl, phenyl, phenyloxy, phenylthio, benzyloxy, benzylthio or phenylethyloxy, or by in each case doubly linked trimethylene (propane-1,3-diyl), methylenedioxy or ethylenedioxy which may each be unsubstituted, mono-substituted or polysubstituted, identically or differently, by fluorine, chlorine, methyl, trifluoromethyl, ethyl, n- or i-propyl, and R3 represents hydrogen, amino, methyl, ethyl, n- or i- propyl, n-, i-, s-butyl, pentyl, hexyl, heptyl, octyl, methoxy, ethoxy, hydroxymethyl, 1-hydroxy-1-ethyl, methoxymethyl, methoxyethyl, methoxypropyl, ethoxymethyl, ethoxyethyl, 2-carboxy-1-hydroxy-1-ethyl, 2-carboxy-1-ethyl, 3-carboxy-1-propyl or benzyl; which process comprises reacting an optically active amide of the formula in which R1, R2, R3 and n are as defined above,with a strong base, optionally in the presence of an organic diluent.