PREPARATION OF NITROGUANIDINE DERIVATIVE

There is proposed a novel process for the preparation of 1,3-disubstituted 2-nitroguanidines of the formula I in which R1 is hydrogen or C1-C4-alkyl, R2 is hydrogen, C1-C6-alkyl, C3-C6-cycloalkyl or a radical -CH2B; A is an aromatic or nonaromatic, monocyclic or bicyclic heterocyclic radical which is unsubstituted or mono- to tetrasubstituted and can have one to two substituents from the series comprising C1-C3-haloalkyl having 1 to 7 halogen atoms, cyclopropyl, halocyclopropyl having 1 to 3 halogen atoms, C2-C3-alkenyl, C2-C3-alkynyl, C2-C3-haloalkenyl and C2-C3-haloalkynyl having 1 to 4 halogen atoms, C1-C3-haloalkoxy having 1 to 7 halogen atoms, C1-C3-alkylthio, C1-C3-haloalkylthio having 1 to 7 halogen atoms, allyloxy, propargyloxy, allylthio, propargylthio, haloallyloxy, haloallylthio, cyano and nitro, and one to four substituents from the series comprising C1-C3-alkyl, C1-C3-alkoxy and halogen; and B is phenyl, cyanophenyl, nitrophenyl, halophenyl having 1 to 3 halogen atoms, or phenyl, 3-pyridyl and 5-thiazolyl, each of which is substituted by C1-C3-alkyl, C1-C3-haloalkyl having 1 to 7 halogen atoms, C1-C3-alkoxy or C1-C3-haloalkoxy having 1 to 7 halogen atoms, or 5-thiazolyl which is substituted by one to two substituents from the series comprising C1-C3-alkyl, C1-C3-haloalkyl having 1 to 7 halogen atoms, cyclopropyl, halocyclopropyl, C2-C3-alkenyl, C2-C3-alkynyl, C1-C3-alkoxy, C2-C3-haloalkenyl and C2-C3-haloalkynyl having 1 to 4 halogen atoms, C1-C3-haloalkoxy having 1 to 7 halogen atoms, C1-C3-alkylthio, C1-C3-haloalkylthio having 1 to 7 halogen atoms, allyloxy, propargyloxy, allylthio, propargylthio, haloallyloxy, haloallylthio, halogen, cyano and nitro; or 3-pyridyl which is substituted by one to two radicals from the series comprising C1-C3-haloalkyl having 1 to 7 halogen atoms, cyclopropyl, halocyclopropyl, C2-C3-alkenyl, C2-C3-alkynyl, C2-C3-haloalkenyl C2-C3-haloalkynyl having 1 to 4 halogen atoms, C1-C3-haloalkoxy having 1 to 7 halogen atoms, C1-C3-alkylthio, C1-C3-haloalkylthio having 1 to 7 halogen atoms, allyloxy, propargyloxy, allylthio, propargylthio, haloallyloxy, haloallylthio, cyano and nitro or by one to four radicals from the series comprising C1-C3-alkyl, C1-C3-alkoxy and halogen, characterised in that a compound of the formula II in which R is unsubstituted or substituted C1-C10-alkyl, C3-C6-cycloalkyl, phenyl or benzyl, is hydrolysed. The compounds of the formula I are suitable as intermediates for the preparation o