Herbicidal 5H-furan-2-one derivatives

A 5H-furan-2-one of the formula ##STR503## in which R.sup.4 and R.sup.7 together with the nitrogen atom to which they are bonded represent a saturated hetrocycle having 4 to 5 carbon atoms, and

• q represents the numbers 0 or 1,
• R.sup.2 represents phenyl which is unsubstituted or monosubstituted or 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, balogen, C.sub.1-4 -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 unsubstituted 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 halogeno-C.sub.1-4 -alkoxy.