CARBOXYLIC ACID AMIDE AND HERBICIDE CONTAINING SAID COMPOUND

Carboxamides of the formula Ia to Ic in which the substituents have the following meanings: X is oxygen or sulphur; R is hydrogen or optionally substituted cycloalkyl or alkyl; R is hydroxyl, alkoxy, cyanoalkyl, optionally substituted alkenyl, alkynyl, phenyl or naphthyl, optionally substituted 5- to 6-membered heterocycle or one of the groups mentioned under R , or R and R together form a 4- to 7-membered chain which can contain, besides methylene groups, one of the following groups as ring members: oxygen, sulphur, N-methyl or carbonyl; R and R are nitro, cyano, halogen, optionally substituted amino, alkoxy, alkylthio, optionally substituted 5- to 6-membered heterocycle, optionally substituted alkenyl, alkynyl, phenyl, phenoxy or phenylthio, or one of the groups mentioned under R ; R is formyl, 4,5-dihydrooxazol-2-yl or a group COYR (Y = O,S); R is hydrogen, cycloalkyl, optionally substituted alkyl, alkenyl, alkynyl, cycloalkenyl or phenyl, a 5- to 6-membered heterocycle, phthalimido, tetrahydrophthalimido, succinimido, maleimido, benzotriazolyl or a group -N=CR R where R and R are hydrogen or alkyl, R is furthermore cycloalkyl, phenyl, furyl, or R and R together form a 4- to 7-membered alkylene chain; where, in the event that - R is carboxyl, methoxycarbonyl or ethoxycarbonyl and R is hydrogen, R does not represent hydrogen or R does not represent hydrogen or methyl, and in the event that - R is carboxyl, methoxycarbonyl or ethoxycarbonyl and R is hydrogen, R does not represent hydrogen or R does not represent one of the following groups: hydrogen; C1-C4-alkyl, phenyl; 2-(3,4-dimethoxyphenyl)ethyl or 2,5-dichlorothien-3-yl; the preparation of the compound I, and herbicides containing it.d