(1,2,4)triazolo[2,3-a]pyridines

Claim 1

A triazolopyridine of the formula I ##STR20## where R 1 is C 1 -C 20 -alkyl optionally substituted with phenyl, phenoxy, carboxy or C 1 -C6hd 20-alkoxycarboxyl whose alkyl chain may be interrupted by 1 to 4 oxygens or substituted by phenyl or phenoxy, and may be interrupted by one or more oxygens, phenyl optionally substituted with C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy, halogen, nitro or carboxyl, or hydroxyl, R 2 is hydrogen, formyl, nitroso, cyano, C 1 -C 4 -alkoxymethyl or CH 2 --NL 1 L 2 where L 1 and L 2 are identical or different and each, independently of one another, is hydrogen or C 1 -C 4 -alkyl, or they form together with the nitrogen connecting them a 5- or 6-membered saturated heterocyclic radical, R 3 is cyano, carbamoyl, carboxyl or C 1 -C 4 -alkoxycarbonyl and R 4 is hydroxyl, halogen, --NL 1 L 2 where L 1 and L 2 each have the abovementioned meaning, or the radical of a compound with an acidic CH derived from the nitromethane, nitroethane or compounds of the formulae V to X ##STR21## where X 1 is cyano, nitro, C 1 -C 4 -alkanoyl, benzoyl optionally substituted by C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy or halogen, C 1 -C 4 -alkylsulfonyl, phenylsulfonyl optionally substituted by C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy or halogen, carboxyl, C 1 -C 4 -alkoxycarbonyl, phenoxycarbonyl, carbamoyl, momo- or di-C 1 -C 4 -alklcarbamoyl, phenylcarbamoyl optionally substituted by C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy or halogen, phenyl optionally substituted by C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy, halogen or nitro, 2-benzothiazolyl, 2-benzimidazolyl, 5-phenyl-1,3,4-thiadiazol-2-yl or 2-hydroxy-3-quinoxalinyl, X 2 is C 1 -C 4 -alkoxy, X 3 is C 1 -C 4 -alkoxycarbonyl, phenylcarbamoyl or 2-benzimidazolyl, X 4 is hydrogen or C 1 -C 6 -alkyl, X 5 is hydrogen, C 1 -C 4 -alkyl or phenyl and X 6 is C 1 -C 4 -alkyl.