Method for producing 1,3-disubstituted 2-nitroguanidines

Process for the preparation of compounds of the formula (I)

• 62
• in which
• R1 is hydrogen or C1-C4-alkyl,
• R2 is hydrogen, C1-C6-alkyl, C3-C6-cycloalkyl or a radical —CH2R3,
• R3 is C2-C5-alkenyl, C2-C5-alkinyl, phenyl, cyanophenyl, nitrophenyl, halogenophenyl having from 1 to 3 halogen atoms;
• phenyl substituted by C1-C3-alkyl, C1-C3-halogenoalkyl having from 1 to 7 halogen atoms, C1-C3-alkoxy or C1-C3-halogenoalkoxy having from 1 to 7 halogen atoms;
• 5-thiazolyl substituted by one to two (preferably one) substituents from the group consisting of C1-C3-alkyl, C1-C3-halogenoalkyl having from 1 to 7 halogen atoms, cyclopropyl, halogenocyclopropyl having from 1 to 3 halogen atoms, C2-C3-alkenyl, C2-C3-alkinyl, C1-C3-alkoxy, C2-C3-halogenoalkenyl having from 1 to 5 halogen atoms, C2-C3-halogenoalkinyl having from 1 to 3 halogen atoms, C1-C3-halogenoalkoxy having from 1 to 7 halogen atoms, C1-C3-alkylthio, C1-C3-halogenoalkylthio having from 1 to 7 halogen atoms, allyloxy, propargyloxy, allylthio, propargylthio, halogenoallyloxy having from 1 to 5 halogen atoms, halogenoallylthio having from 1 to 5 halogen atoms, halogen, cyano or nitro;
• or 3-pyridyl substituted by one to four (preferably one or two) radicals from the group consisting of C1-C3-halogenoalkyl having from 1 to 7 halogen atoms, cyclopropyl, halogenocyclopropyl having from 1 to 3 halogen atoms, C2-C3-alkenyl, C2-C3-alkinyl, C2-C3-halogenoalkenyl having from 1 to 5 halogen atoms, C2-C3-halogenoalkinyl having from 1 to 3 halogen atoms, C1-C3-halogenoalkoxy having from 1 to 7 halogen atoms, C1-C3-alkylthio, C1-C3-halogenoalkylthio having from 1 to 7 halogen atoms, allyloxy, propargyloxy, allylthio, propargylthio, halogenoallyloxy having from 1 to 5 halogen atoms, halogenoallylthio having from 1 to 5 halogen atoms, cyano, nitro, C1-C3-alkyl, C1-C3-alkoxy or halogen,
• Het is an unsubstituted or substituted aromatic or non-aromatic, monocyclic or bicyclic heterocyclic radical, preferably from the series
• 63
• which may include one to two substituents from the group consisting of C1-C3-halogenoalkyl having from 1 to 7 halogen atoms, cyclopropyl, halogenocyclopropyl having from 1 to 3 halogen atoms, C2-C3-alkenyl, C2-C3-alkinyl, C2-C3-halogenoalkenyl having from 1 to 5 halogen atoms, C2-C3-halogenoalkinyl having from 1 to 3 halogen atoms, C1-C3-halogenoalkoxy having from 1 to 7 halogen atoms, C1-C3-alkylthio, C1-C3-halogenoalkylthio having from 1 to 7 halogen atoms, allyloxy, propargyloxy, allylthio, propargylthio, halogenoallyloxy having from 1 to 5 halogen atoms, halogenoallylthio having from 1 to 5 halogen atoms, cyano, nitro, C1-C3-alkyl, C1-C3-alkoxy and halogen,
• characterized in that a compound of the formula (II)
• 64
• in which
• R1, R2 and Het are as defined above, and
• R4 is C1-C10-alkyl, C3-C6-cycloalkyl, phenyl, arylalkyl or heterocyclylmethyl, each of which may be unsubstituted or substituted, where heterocyclyl is an unsaturated or saturated 5- or 6-membered heterocycle containing one or more heteroatoms from the series nitrogen, oxygen and sulphur, such as, for example, furan, tetrahydrofuran, thiophene or pyridine,
• in the presence of a nitrile having from 3 to 5 carbon atoms, is reacted with anhydrous hydrogen halide.