Herbicidal 4-substituted isoxazol

A process for the preparation of a compound of the formula:

• ##STR65## wherein:
• R represents hydrogen;
• R.sup.1 represents:
• straight- or branched-chain alkyl, alkenyl or alkynyl having up to 6 carbon atoms, optionally substituted by one or more halogens;
• or cycloalkyl having from 3 to 6 carbon atoms, optionally bearing one or more substituents selected from the group consisting of R.sup.93, halogen and --CO.sub.2 R.sup.96, wherein R.sup.93 and R.sup.96 are as defined below;
• or
• cycloalkenyl having 5 or 6 carbon atoms, optionally bearing one or more substituents selected from the group consisting of R.sup.93, halogen and --CO.sub.2 R.sup.96, wherein R.sup.93 and R.sup.96 are as defined below;
• or
• an aryl or aralkyl group of the formula (R.sup.2).sub.q -phenyl-(--CR.sup.93 R.sup.94 --).sub.p, wherein R.sup.2, q, p, R.sup.93 and R.sup.94 are as defined below;
• or
• a member selected from the group consisting of --CO.sub.2 R.sup.93 and --COR.sup.93, wherein R.sup.93 is as defined below:
• R.sup.2 represents:
• a member selected from the group consisting of nitro, cyano, halogen, R.sup.95, --S(O).sub.m R.sup.95, --SO.sub.2 NR.sup.93 R.sup.94, --CO.sub.2 R.sup.93, --COR.sup.93, --CONR.sup.93 R.sup.94, --CSNR.sup.93 R.sup.94, --OR.sup.95 and C.sub.1 -C.sub.3 alkyl substituted by --OR.sup.95, wherein R.sup.93, R.sup.94, R.sup.95 and m are as defined below;
• n represents an integer from 1 to 5;
• Q represents C.dbd.O;
• R.sup.93 and R.sup.94, which are the same or different, each represents:
• hydrogen or straight- or branched-chain alkyl having up to 6 carbon atoms, optionally substituted by one or more halogens;
• R.sup.95 represents:
• straight- or branched-chain alkyl having up to 6 carbon atoms, optionally substituted by one or more halogens;
• R.sup.96 as defined for R.sup.93 but does not represent hydrogen;
• m represents zero or 1, or 2;
• q represents zero or an integer from 1 to 5;
• and
• p represents zero or 1;
• with the proviso that when R.sup.1 is methyl, then (R.sup.2).sub.n cannot be 4-fluoro;
• said process comprising reacting a compound of the formula ##STR66## wherein R.sup.1, R.sup.2 and n are as defined above, and X is O-alkyl or N,N-diakyl, with hydroxylamine or a salt of hydroxylamine, in the presence of a solvent.