Process for the preparation of N-arylaminoacrylic acid derivatives and the use of N-arylaminoacrylic acid derivatives thus prepared for the preparation of 4-quinolone-3-carboxylic acid derivatives

A process for the preparation of a N-arylaminoacrylic acid derivative of the formula (I) ##STR5## in which R.sup.1 denotes hydrogen or C.sub.1 -C.sub.6 -alkyl,

• R.sup.2 and R.sup.3 independently of one another each denote fluorine, chlorine, bromine, trifluoromethyl, cyano, nitro, C.sub.1 -C.sub.6 -alkoxy, hydroxyl, imidazolyl, triazolyl or C.sub.7 -C.sub.10 -aralkoxy or
• R.sup.2 and R.sup.3 together denote an --O--, --CH.sub.2 --, --CH.sub.2 O--, --O--CH--O-- or --O--CH.sub.2 --CH.sub.2 --O-- radical,
• X.sup.1 and X.sup.2 independently of one another each denote fluorine, chlorine or bromine,
• A denotes CH, N or CR.sup.3, where R.sup.3 =fluorine, chlorine, bromine, trifluoromethyl, cyano, nitro, C.sub.1 -C.sub.6 -alkoxy, hydroxyl, imidazolyl, triazolyl or C.sub.7 -C.sub.10 -aralkoxy,
• B denotes CH, N or CR.sup.2, where R.sup.2 =fluorine, chlorine, bromine, trifluoromethyl, cyano, nitro, C.sub.1 -C.sub.6 -alkoxy, hydroxyl, imidazolyl, triazolyl or C.sub.7 -C.sub.10 -aralkoxy,
• m denotes zero, 1, 2 or 3 and
• n denotes zero, 1 or 2,
• in which a benzoylacetic acid derivative of the formula ##STR6## in which R.sup.1, R.sup.3, X.sup.1, X.sup.2, A and n have the meaning given for formula (I),
• is reacted with an N-arylimino ether of the formula ##STR7## in which R.sup.2, B and m have the meaning given for formula (I) and
• R.sup.4 represents C.sub.1 -C.sub.6 -alkyl.