The invention concerns a method of preparing α-methoxyiminocarboxylic acid methylamides of formula (I) (X = nitro, trifluoromethyl, halogen, alkyl or alkoxy; n = 0, 1, 2, 3 or 4; Y = an organic carbon group) by the Pinner reaction of a cyanoketone of formula (II) with an alcohol, followed by reaction of the ester of formula (IV) formed in the Pinner reaction with hydroxylamine to give an oxime of formula (V), methylation of (V) to give an oxime ether of formula (VI) and subsequent reaction of (VI) with methylamine. The invention also concerns the intermediates used in the method.