Abstract: Process for the preparation of 9-fluoro-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de] [1,4]benzothiazine-6-carboxylic acid hydrochloride (Rufloxacin) by reaction of 2,3,5-trifluoro-4-(4-methyl-1-piperazinyl)benzoyl ethyl acetate with N,N-dimethylformamide dimethylacetal, followed by reaction with 2-aminoethanethiol, intramolecular cyclization by treatment with NaH, hydrolysis with H.sub.2 O and salification with HCl.

Abstract: The invention relates to antibacterially active pyrido-benzothiazine derivatives with long-term action, having the following general formula: ##STR1## in which R is ##STR2## Where R.sup.1 is H, C.sub.1 -C.sub.6 alkyl, p-fluorophenyl, m-fluorophenyl, o-fluorophenyl or 2-pyridyl; or ##STR3## where R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6 are lower alkyls. The invention also comprises the process for preparing compounds of general formula (I). Said process consists of a synthesis cycle using 2,4-difluoro-3-chloronitrobenzene and thiolactic acid as starting substances.The inventiona also comprises pharmaceutical compositions containing at least one of the compounds of general formula (I) as active principle.

Abstract: A new class of antimicrobial pyrido-benzothiazine compounds and processes for their preparation are described.

Abstract: Pyrido-benzothiazine compounds having anti-microbial activity are prepared by (a) reacting 3-chloro-4-fluoroaniline with potassium thiocyanate and bromine to produce 2-amino-6-fluoro-7-chlorobenzothiazole, (b) reacting 2-amino-6-fluoro-7-chlorobenzothiazole with sodium hydroxide to produce the disulfide of 2-amino-5-fluoro 6-chlorothiophenol, (c) reacting the disulfide with sodium monochloroacetate to produce 7-fluoro-8-chloro-2H-1,4-benzothiazin-3(4H)-one, (d) reducing 7-fluoro-8-chloro-2H-1,4-benzothiazin-3(4H)-one to produce 7-fluoro-8-chloro-3,4-dihydro-2H-1,4-benzothiazone, (e) reacting 7-fluoro-8-chloro-3,4-dihydro-2-H-1,4-benzothiazone with ethyl ethoxymethylenemalonate and cyclyzing the intermediate formed with polyphosphoric acid to produce ethyl 9-fluoro-10-chloro-7-oxo-2,3-dihydro-7H-pyrido[1,2,3 de] [1,4]-benzothiazine-6-carboxylate and (f) hydrolyizing the ethyl carboxylate to produce the corresponding carboxylic acid.

Abstract: Object of the invention is a class of new organic compounds derived from 1,4-benzothiazine through substitution of an hydrogen atom in position 6, 7 or 8 by an oxypropanolammine radical monosubstituted in N and furthermore a series of new phenyl derivatives of 1,4-benzothiazine, obtained as intermediate in the synthesis of oxypropanolammine derivatives, and process for obtained the new compounds in form suitable for the preparation of pharmaceutical compositions having antihypertensive, vasodilating and antiarrhythmic activity.