Herbicidal 5H-furan-2-one derivatives

A 5H-furan-2-one of the formula ##STR188## in which X represents the radical OR.sup.1 or the radical ##STR189## where R.sup.1 represents straight-chain or branched alkyl having 1 to 4 carbon atoms, or represents in each case straight-chain or branched cyanoalkyl, alkoxyalkyl, alkylcarbonyl, halogenoalkylcarbonyl or alkoxycarbonyl having 1 to 6 carbon atoms in the individual alkyl moieties and where appropriate 1 to 9 identical or different halogen atoms,

• R.sup.4 represents hydrogen, in each case straight-chain or branched alkyl having 1 to 4 carbon atoms, alkenyl having 2 to 4 carbon atoms or alkoxyalkyl having in each case 1 to 4 carbon atoms in the alkoxy moiety and alkyl moiety or alkylcarbonyl having 1 to 4 carbon atoms, and
• R.sup.7 represents hydrogen, hydroxy, amino, formyl or in each case straight-chain or branched alkyl, alkoxy, alkoxyalkyl, cyanoalkyl, alkylcarbonyl, halogenoalkylcarbonyl, alkoxycarbonyl, alkylamino, alkylcarbonyloxy or aminocarbonylalkyl having 1 to 6 carbon atoms in the individual alkyl moieties and where appropriate 1 to 4 identical or different halogen atoms, or represents alkynyl having 2 to 8 carbon atoms, or represents cycloalkyl having 3 to 7 carbon atoms, or represents arylcarbonyl, aralkyl, aralkyloxy having 3 to 10 carbon atoms in the aryl part and 1 to 4 carbon atoms in the straight-chain or branched alkyl part, each of which is unsubstituted or monosubstituted or polysubstituted by identical or different substituents as mentioned in the definition of R.sup.5 hereinbelow, or represents the radical NR.sup.8 R.sup.9 in which R.sup.8 and R.sup.9 independently of each other represents alkyl or alkylcarbonyl having 1 to 4 carbon atoms, or R.sup.4 and R.sup.7 together with the nitrogen atom to which they are bonded represent a saturated heterocycle having 4 to 5 carbon atoms, and
• q represents the numbers 0 or 1,
• R.sup.2 represents phenyl which is unsubstituted or monosubstituted of polysubstituted by identical or different substituents selected from the group consisting of cyano, nitro, halogen, in each case straight-chain or branched alkyl or alkoxy having 1 to 6 carbon atoms in each case straight-chain or branched halogenoalkyl or halogenoalkoxy having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms, and phenethenyl or phenethynyl, each of which is unsubstituted or monosubstituted or polysubstituted by identical or different substituents, the substituents in each case being the phenyl substituents already mentioned above;
• or the radical --(CH.sub.2).sub.n --Z.sub.m --(CH.sub.2).sub.p --R.sup.5,where
• R.sup.5 represents aryl which has 6 to 10 carbon atoms and which is unsubstituted or monosubstituted or polysubstituted by identical or different substituents selected from the group consisting of cyano, nitro, halogen, C.sub.104 -alkyl, C.sub.1-4 -alkoxy, halogeno-C.sub.1-4 -alkyl and halogeno-C.sub.1-4 -alkoxy,
• Z represents oxygen or sulphur or represents the group >C.dbd.O and
• n, m and p independently of one another represent the numbers 0 or 1, and
• R.sup.3 and R.sup.6 represent hydrogen, straight-chain or branched alkyl having 1 to 6 carbon atoms, phenyl which is unsubstituted or monosubstituted to polysubstituted by identical or different substituents as defined hereinabove, or aralkyl which has 6 to 10 carbon atoms in the aryl moiety and 1 to 4 carbon atoms in the alkyl moiety and which is unsubstitute or monosubstituted to polysubstituted by identical or different substituents, the substituents being selected from the group consisting of cyano, nitro, halogen, C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, halogeno-C.sub.1-4 and halogen-C.sub.1-4 -alkoxy,
• with the proviso that if X represents the radical OR.sup.1 and simultaneously q represents O, R.sup.2 can only represent ortho-substituted phenyl when the substituents are halogen, halogenomethyl having 1 to 3 identical or different halogen atoms or phenyl, phenethenyl or phenethynyl each of which is unsubstituted or monosubstituted to polysubstituted by identical or different substituents, with the proviso that R.sup.2 represents substituted phenyl when q represents 1 and X simultaneously represents the radical OR.sup.1, and with the exception of the compounds 5-[(3,4-dimethoxyphenyl-methyl]-4-methoxy-3-(4-methoxyphenyl)-5H-furan-2-o ne, 4-methoxy-3-(3,4,5-trimethoxyphenyl)-5H-furan-2-one, 3-(3-chlorophenyl)-4-methoxy-5H-furan-2-one, 3-(4-chlorophenyl)-4-methoxy-5H-furan-2-one, 3-(3-fluorophenyl)-4-methoxy-5H-furan-2-one, 3-(4-fluorophenyl)-4-methoxy-5H-furan-2-one, 4-methoxy-3-(3-methoxyphenyl)-5H-furan-2-one, 4-(4-bromophenyl)-4-methoxy-5H-furan-2-one, 3-(3,4-dichlorophenyl)-4-methoxy-5H-furan-2-one, 3-[1,1'-biphenyl]-4-yl-4-methoxy-5H-furan-2-one, 4-methoxy-3-(4-methylphenyl)-5H-furan-2-one and 4-methoxy-3-(4-methoxyphenyl)-5H-furan-2-one, 3-(2-chlorophenyl)-4-methoxy-5H-furan-2-one, 3-(2-fluorophenyl)-4-methoxy-5H-furan-2-one and 4-methoxy-3-(2-methoxyphenyl)-5H-furan-2-one.