| abstract |
In the compounds of the invention, R 1 is methyl or ethyl, R 2 is trifluoromethyl, R 3 is hydrogen, methyl or ethyl, R 4 is methyl, ethyl or n-propyl, R 5 is hydrogen, C 1-6 alkylcarbonylmethyl, C 1-4 alkylsulfonyl, phenylsulfonyl, benzyl, benzoylmethyl, C 1-3 alkylsulfonyl substituted with one or more halogens, phenylsulfonyl substituted with methyl or halogen, benzyl substituted with halogen, nitro or methoxy, or substituted with one or more halogen atoms, methyl, nitro or methyl, |