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Synthesis of N ‐amino‐3‐hydroxy‐2‐phenyl‐4(1 H )‐quinolinone
Author(s) -
Spáčilová Lucie,
Hlaváč Jan,
Hradil Pavel,
Fryšová Iveta,
Soural Miroslav,
Krejčí Petr,
Maloň Michal
Publication year - 2006
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.5570430437
Subject(s) - chemistry , anthranilic acid , hydrochloric acid , benzoic acid , methylene , sodium hydroxide , boiling , medicinal chemistry , organic chemistry
2‐[(Disubstituted‐methylene)‐hydrazino] benzoic acid phenacylesters 2a‐2d , prepared from anthranilic acid phenacylester 1 , were unsuccesfully tried as starting materials for the synthesis of N ‐amino‐3‐hydroxy‐2‐phenyl‐4(1 H )‐quinolinone 8 . The desired compound 8 was prepared by cyclization of N ‐acetyl as well as N ‐benzoyl‐hydrazinobenzoic acid phenacylester 6a or 6b in polyphosphoric acid to afford N ‐acylamino‐3‐hydroxy‐2‐phenyl‐4(1 H )‐quinolinone 7a or 7b , respectively. Surprisingly, the acyl group was resistant to attack by both hydrochloric acid as well as sodium hydroxide solution. It could be removed by boiling the compounds 7a or 7b respectively in 50% sulphuric acid to afford the the target compound 8 .