Quinolone antibiotics: Study of reactivity and impurity profile of piperazine with chloro-fluoro-quinolone carboxylic acid in aqueous medium
The reaction of 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,2-dihydroquinoline-3-carboxyli c acid with piperazine in water was studied. The product ciprofloxacin was isolated and the impurity formed in the reaction was isolated and characterized as 1-cyclopropyl-7-chloro-6-piperazinyl-4-oxo-1,2-dihydroquinoline-3-carb oxylic acid. Similarly norfloxacin was also synthesised.
Regioselective nucleophilic substitution of halogen derivatives of 1-substituted 4-oxo-1,4-dihydroquinoline-3-carboxylic acids
The rate of the nucleophilic displacement of the fluoro atom of 7-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate could be enhanced either by the introduction of further fluoro atom(s) into position(s) 6 and/or 8, or by the formation of a boron chelate (e.g. 3). The regioselectivity of the nucleophilic substitution of the chloro atom in 1-substituted 6-fluoro-7-chloro-4-oxo-1,4dihydroquinoline-3-carboxylic acids could also be enhanced by the formation of a boron chelate (e.g. 7).
Hermecz, Istvan,Vasvari-Debreczy, Lelle,Podanyi, Benjamin,Kereszturi, Geza,Balogh, Maria,Horvath, Agnes,Varkonyi, Peter
Convenient one pot synthesis of some fluoroquinolones in aqueous media
A one pot synthetic strategy for the preparation of fluoroquinolones from 1 is introduced. Product 3 was condensed with piperazine in an aqueous media to produce pharmaceutical grade ciprofloxacin in 86% yield. The method was extended to the synthesis of some other fluoroquinolones with pharmaceutical grade quality.
Abaee, M. Saeed,Sharifi, Ruhollah,Borhani, Shahin,Heravi, Majid M.,Motahari, Hossein