849744-52-1

Upstream product

• 98349-24-7 ethyl 2,4,5-trifluorobenzoylacetate 
• 154359-92-9 3,3-Bis-ethylsulfanyl-2-(2,4,5-trifluoro-benzoyl)-acrylic acid ethyl ester 
• 55084-17-8 diethyl[bis(ethylsulfanyl)methylene]malonate 
• 154330-71-9 diethyl [(3,4-difluorophenyl)amino](ethylthio) methylene malonate 
• 154330-70-8 2-(Ethanesulfinyl-ethylsulfanyl-methylene)-malonic acid diethyl ester 
• 105-53-3 diethyl malonate 

Downstream Products

• 154330-68-4 ethyl 4-acetoxy-6,7-difluoro-2-(ethylthio)quinoline-3-carboxylate 
• 113046-72-3 ethyl 6,7-difluoro-1-methyl-4-oxo-1H,4H-[1,3]thiazeto[3,2-a]quinoline-3-carboxylate 

Relevant academic research and scientific papers

PROCESS FOR THE PREPARATION OF HIGHLY PURE PRULIFLOXACIN

The present invention provides an industrially advantageous process for the preparation of highly pure prulifloxacin of formula I and its pharmaceutically acceptable salts. The present i innvention a also provides a novel process for the purification of prulifloxacin acid addition salt.

Studies on pyridonecarboxylic acids. V. A practical synthesis of ethyl 6,7-difluoro-1-methyl-4-oxo-4H-[1,3]thiazeto[3,2-α]quinoline 3-carboxylate, a key intermediate for the new tricyclic quinolone, prulifloxacin (nm441) and versatile new syntheses of the 2-thioquinoline skeleton

A practical synthesis of ethyl 6,7-difluoro-1-methyl-4-oxo4H- [1,3]thiazeto[3,2-α]quinoline-3-carboxylate (9), the key intermediate for 6- fluoro-1-methyl-7-[4-(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl-1-piperazinyl]- 4-oxo-4H-[1,3]thiazeto[3,2-α]quinoline-3-carboxylic acid (2), NM441, was developed. The crucial points of this synthetic mute are the chlorination of ethyl 4-acetoxy-2-(ethylthio)-6,7-difluoroquinoline-3-carboxylate (12) and the subsequent deacetylation of the resulting 2-(1-chloroethyl)thio compound 13 followed by the intramolecular cyclization reaction. Versatile new syntheses of 2-thioquinoline skeleton were also developed. The first mute includes the intramolecular cyclization of the N,S-acetal 22 which was prepared from 2,4,5-trifluorobenzoic acid in three steps. The second one contains the regioselective attack of lithium enolate of ethyl acetate to the novel 2-(methylthio)-4H-[3,1]benzothiazine-4-one 29 at the 4-position followed by the intramolecular cyclization of the resulting β-ketoester 30.