Improved method for producing specific oximes and oximethers

Method for preparing an oxime of formula (Va) or an oxime O-methyl ether of formula (Vb)

• in which
• R3 is C1-C12-alkyl, C3-C12-cycloalkyl, C2-C20-alkenyl, C6-C14-aryl, C1-C6-alkylaryl, 5-10-membered heterocycles and C1-C6-alkylhetaryl, wherein the alkyl residue, the cycloalkyl residue, the alkenyl residue, the aryl residue, the alkylaryl residue or the heterocyclic residue or the alkylhetaryl residue may be substituted with one or more substituents selected from among halogen, CN, NO2, C1-C6-alkyl, C1-C6-haloalkyl, —OH, —OR, —COOR, ═N—OR, CONH2, CONHR, CONRR′, SR, RSO, RSO2, —OAr, carbonyl, ═NOH;
• R4 is hydrogen, C1-C18-alkyl, C3-C12-cycloalkyl, C6-C14-aryl, C1-C6-alkylaryl, COOR, CONH2, CONHR, CONRR′, wherein the alkyl residue, the cycloalkyl residue, the aryl residue, the alkylaryl residue or the group R or R′ may be substituted with one or more substituents selected from among halogen, CN, NO2, C1-C6-alkyl, C1-C6-haloalkyl, OH, OR, COOR, C═N—OR, CONH2, CONHR, CONRR′, SR, RSO, RSO2, OAr, carbonyl, ═N—OH and
• R and R′ are mutually independently unsubstituted or substituted C1-C6-alkyl;
• or
• R3 and R4 together form an unsubstituted or substituted cycloalkyl residue having 3 to 10 carbon atoms, or a substituted or unsubstituted 5-10-membered heterocycle;
• Comprising reacting a quinone, or a carbonyl compound of the formula (II)
• in which the residues R3 and R4 have the meanings mentioned above and the compounds (II) have a solubility in water of 0 to 30 g/l, optionally 0 to 20 g/l at 20° C.,
• with the free base of hydroxylamine of the formula (III) or with a salt of hydroxylamine or hydroxylamine O-methyl ether of the formula (IV)
• in which
• R5 is hydrogen,
• R′5 is hydrogen or methyl,
• B− is an anion, which is selected from among chloride, sulphate, phosphate, hydrogen phosphate, dihydrogen phosphate, carbonate, hydrogen carbonate and acetate, and
• in the presence of a phosphoric ester of formula (I) and/or a salt thereof,
• in which
• X is OH and
• R1 and R2 are mutually independently hydrogen, C1-C18-alkyl, C2-C20-alkenyl, C3-C12-cycloalkyl, phenyl or C1-C6-alkylphenyl, wherein the alkyl residue, the alkenyl residue or the cycloalkyl residue may be substituted in each case with one or more substituents selected from among halogen, CN and NO2 and wherein the phenyl residue may in addition be mono- or polysubstituted with C1-C6-alkyl and/or C1-C6-haloalkyl;
• in an at least biphasic mixture consisting of an aqueous and organic phase wherein the pH (at RT) in the aqueous phase during the reaction is in a range of 2 to 10.