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Synthesis of some 3‐substituted quino[3,2‐c][1,8]naphtyridines . A new heterocyclic ring system
Author(s) -
da Settimo Antonio,
Prirnofiore Giampaolo,
Livi Oreste,
Ferrarini Pier Luigi,
Spinelli Silvano
Publication year - 1979
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.5570160131
Subject(s) - chemistry , aromatization , quinoline , ring (chemistry) , ketone , medicinal chemistry , condensation , organic chemistry , catalysis , physics , thermodynamics
Isatoic acid reacts with 7‐mcthyl‐2,3‐dihydro‐1,8‐naphthyridin‐4(1 H ) one ( 8 ) to give 3‐methyl‐5,6‐dihvdroquino[3,2‐ c ][1,8]naphthyriclin‐7‐carboxylic acid ( 9a ), which was transformed into the 3‐methylquino[3,2‐ c ][1,8]naphthyridine ( 7a ) by refluxing with copper chromite in quinoline. The same product ( 7a ) was also obtained by aromatization of the 3‐methyl‐5,6‐dihydroquino‐[3,2‐ c ][1.8]naphthvridine ( 10a ), prepared by condensation of the ketone ( 8 ) and o ‐aminobenzaldehyde. Other 3‐substituted quino[3,2‐ c ][1,8]naphthyridines ( 7b,c,d,e ), which contain a new heterocyclic, ring structure, have been prepared using o‐aminobenzaldehyde and 7‐sub‐stituted‐2,3‐dihv dro‐1,8‐naphthyridin‐4(1 H ) ones ( 12 and 13 ) as starting materials. Also, the preparation of the parent nucleus ( 7f ) is described.