Phenolic benzothiazole derivatives and their use as corrosion inhibitors

Claim 1

A composition composed of a coating material and containing 0.1 to 20% by weight, based on the solids content of the coating material, of at least one compound of the formula I ##STR21## in which each R independently of one another is hydrogen, C 1 -C 12 -alkyl, C 1 -C 4 -halogenalkyl, C 1 -C 12 -alkoxy, C 1 -C 12 -alkylthio, phenylthio, benzylthio, C 1 -C 12 -alkylsulfonyl, phenyl, C 7 -C 15 -alkylphenyl, C 7 -C 10 -phenylalkyl, C 5 -C 8 -cycloalkyl, halogen, --NO 2 , --CN, --COOH, --COO--(C 1 -C 4 -alkyl), --OH, --NH 2 , --NHR 6 , --N(R 6 ) 2 , --CONH 2 , --CONHR 6 or --CON(R 6 ) 2 , R 1 is hydrogen, C 1 -C 12 -alkyl, phenyl, phenyl which is substituted by halogen, C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy or --NO 2 , pyridyl, thienyl, or furyl, R 2 is hydrogen or C 1 -C 4 -alkyl, R 3 and R 4 independently of one another are hydrogen, halogen, C 1 -C 4 -alkoxy, cyano, nitro, C 1 -C 20 -alkyl, --(CH 2 ) m --COOR 7 , --(CH 2 ) m --CONHR 6 , --(CH 2 ) m --CON(R 6 ) 2 , C 3 -C 20 -alkenyl, C 7 -C 10 -phenylalkyl, phenyl, cyclohexyl, cyclopentyl or a group of the formula II ##STR22## R 5 is hydrogen, C 1 -C 20 -alkyl, C 3 -C 20 -alkenyl or hydroxy, or R 3 and R 5 together or R 4 and R 5 together form a ring fused to the phenolic moiety which ring may be a carbocyclic or heterocyclic ring containing oxygen, nitrogen or sulfur as heteroatoms, each ring being optionally substituted by C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy or halogen, R 6 is C 1 -C 12 -alkyl, C 3 -C 12 -alkyl which is interrupted by one or more O atoms, C 5 -C 8 -cycloalkyl, benzyl, phenyl, or phenyl which is substituted by halogen, C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy or nitro, or --N(R 6 ) 2 is a pyrrolidino, piperidino or morpholino group, R 7 is hydrogen or C 1 -C 20 -alkyl, which may be substituted by halogen or hydroxyl or R 7 is C 3 -C 20 -alkyl which is interrupted by one or more oxygen atoms and may be substituted by hydroxyl and m is 0, 1 or 2.