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Synthesis of fluorinated pyridines by the balz‐schiemann reaction. An alternative route to enoxacin, a new antibacterial pyridonecarboxylic acid
Author(s) -
Matsumoto JunIchi,
Miyamoto Teruyuki,
Minamida Akira,
Nishimura Yoshiro,
Egawa Hiroshi,
Nishimura Haruki
Publication year - 1984
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570210309
Subject(s) - chemistry , enoxacin , tetrafluoroborate , solvent , carboxylic acid , organic chemistry , medicinal chemistry , combinatorial chemistry , catalysis , ionic liquid , antibiotics , biochemistry , ciprofloxacin , norfloxacin
Fluorination of the 2,6‐disubstituted 3‐aminopyridines 5 and 12 by the Balz‐Schiemann reaction is described. 2,6‐Dichloro‐3‐pyridinediazonium tetrafluoroborate ( 6 ) and 2‐substituted 6‐acetylamino‐3‐pyridinediazonium tetrafluoroborates 13 were heated with or without a solvent to give the corresponding fluorinated pyridines 7 and 14 , respectively, in good yields. 2‐Substituted 6‐acetylamino‐3‐fluoropyridines ( 14 ) were converted by a known method into a series of 7‐substituted 1‐ethyl‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acids 21 including enoxacin [1‐ethyl‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐7‐(1‐piperazinyl)‐1,8‐naphthyridine‐3‐carboxylic acid [( 2 )], a new potential antibacterial agent.