Abstract: The present invention relates to a process for the preparation of compounds of the general Formula I ##STR1## and pharmaceutically acceptable salts thereof (wherein R stands for piperazinyl or 4-methyl-piperazinyl) which comprises reacting a compound of the general Formula II ##STR2## (wherein R.sup.1 and R.sup.2 stand for halogen; an aliphatic acyloxy group comprising 2-6 carbon atoms and optionally substituted by halogen; or an aromatic acyloxy group comprising 7-11 carbon atoms) with a piperazine of the general Formula III ##STR3## (wherein R.sup.3 represent hydrogen or methyl) or a salt thereof, hydrolysing the compound of the general Formula IV ##STR4## thus obtained (wherein R, R.sup.1 and R.sup.2 are as stated above) without or after hydrolysis and if desired converting the compound of the general Formula I thus obtained into a salt thereof or setting free the same from its salt.The compounds of the general Formula I are known antibacterial agents.

Abstract: The invention relates to new 6-fluoro-7-chloro-1-methylamino-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid/boric acid anhydrides of the general Formula I ##STR1## (wherein R and R.sup.1 stand for halogen; an aliphatic acyloxy group comprising 2-6 carbon atoms and optionally substituted by halogen; or an aromatic acyloxy group comprising 7-11 carbon atoms).The new compounds of the general Formula I are valuable intermediates useful in the preparation of the antibacterial agent 6-fluoro-1-methylamino-7-(4-methyl-piperazino)-4-oxo-1,4-dihydro-quinoline -3- carboxylic acid.The new compounds of the general Formula I may be prepared by reacting a compound of the Formula II ##STR2## or a compound of the general Formula III ##STR3## (wherein R.sup.2 stands for alkyl comprising 1-4 carbon atoms) with hydrogen fluoro borate of the Formula IVHBF.sub.4 /IV/or a borone trihalide of the general Formula VBX.sub.

Abstract: The invention relates to a process for the preparation of compounds of the Formula I ##STR1## (wherein R and R.sup.1 stand for an aliphatic acyloxy group comprising 2-5 carbon atoms and optionally substituted by halogen or for an aromatic acyloxy group comprising 7-11 carbon atoms), which comprises reacting a compound of the general Formula II ##STR2## (wherein R.sup.2 stands for hydrogen or alkyl comprising 1-4 carbon atoms) with a boron derivative of the Formula III ##STR3## (wherein R.sup.3, R.sup.4 and R.sup.5 stand for an alkyl group comprising 1-4 carbon atoms and optionally substituted by halogen or for an aryl group comprising 6-10 carbon atoms).The new compounds of the general Formula I are useful pharmaceutical intermediates.