Method of inducing tillering using pyridine derivatives, and some of the pyridines themselves, process for preparing them and agricultural compositions containing them

Claim 1

1 . A method of inducing tiller formation in a monocotyledonous plant, characterised by applying to the plant, to seed of the plant or to the locus surrounding the plant or seed, a compound of general formula (I) : wherein R 1 is hydrogen, halogen, optionally halo- or acetoxy- substituted C l-4 alkyl, hydroxy, amino, phenyl or (C 1-5 alkoxy) carbonyl; R 2 is cyano, or a group of general formula -CO R 4 wherein R 4 is -O- l/m M m+ , -OR 5 , -SR 6 , -NR 7 R 8 or -NR 9 -NR 10 R 11 wherein M is an m-valent cation; R 5 is C 1-8 alkyl optionally substituted with halogen, hydroxy, cyano, C 1-4 alkoxy, C 1-4 alkylthio, carboxy, (C 1-4 alkoxy)carbonyl, C 3-6 cycloalkyl, amino, mono- or di- C 1-4 alkylamino, a 5- or 6-membered heterocyclic ring or optionally halo- or C 1-4 alkylsubstituted phenyl; C 3-6 cycloalkyl; optionally halo- substituted C 2-6 alkenyl; C 3-6 alkynyl; or phenyl optionally substituted with halogen, C 1-4 alkyl, C l-4 alkoxy, C l-4 alkylthio, cyano or nitro; R 6 is C 1-8 alkyl optionally substituted with C 3-6 cycloalkyl, (C l-4 alkoxy)carbonyl, halogen, cyano, a 5- or 6-membered heterocyclic ring or optionally halo- or C 1-4 alkyl- substituted phenyl; C 3-6 cycloalkyl; C 3-6 alkenyl; or phenyl optionally substituted with halogen, C 1-4 alkyl, C 1-4 alkoxy, C 1-4 alkylthio, cyano or nitro; each of R 7 and R 8 , which may be the same or different, is hydrogen; C 1-6 alkyl optionally substituted with hydroxy, halogen, cyano, (C 1-4 alkoxy)carbonyl, C 1-4 alkox y or C 3-6 cycloalkyl; Cl-4 alkox y ; C 3-6 alkenyl; C 3-6 alkynyl; C 3-6 cycloalkyl; (C 1-6 alkane)sulphonyl;hydroxy; or phenyl or benzyl optionally ring-substituted by halogen, C 1-4 alkyl, C 1-4 alkox y, C 1-4 alk y lthio, (C 1-4 alkoxy)carbonyl, cyano or nitro; or R 7 or R 8 together with the nitrogen atom to which they are bound form a 5- or 6-membered heterocyclic ring optionally containing a further hetero atom; R 9 is hydrogen, C 1-4 alkyl, phenyl or benzyl; each of R 10 and R 11 , which may be the same or different, is hydrogen; C 1-4 alkyl; (C l-4 alkoxy) (C l-4 alkyl); C 2-6 alkanoyl; or benzoyl or phenyl optionally substituted with halogen, C 1-4 alkyl or C 1-4 alkoxy, or R 10 and R 11 together with the nitrogen atom to which they are bound for a 5- or 6-membered heterocyclic ring optionally containing a further hetero atom; R 3 is optionally halo-, haloalkyl- haloalkoxy- nitro-, cyano-, hydroxy-, amino-, acylamino- mono- or di- alkylamino-, C l-4 alkyl-, C l-4 alk oxy-, C 1-4 alkylthio-, C 1-4 alkylsulphinyl-, C 1-4 alkylsulphonyl-, C 2-6 alkenyl-, carboxy-, C l-4 alkoxycarbonyl- or carboxamido- substituted phenyl; and n is 0 or 1; or, when n is O, an acid addition salt thereof.