Transformations in the 2‐quinolone series

Abstract

The treatment of 1‐substituted‐1,2‐dihydro‐4‐hydroxy‐2‐oxo‐3‐quinoline carboxylic acid esters and 4‐hydroxy‐1‐methyl‐3‐nitro‐2‐(1H)quinolinone with phosphorus oxychloride resulted in the formation of the corresponding 4‐chloro‐2‐quinolones. Their reactions with a variety of carbon, nitrogen, oxygen, and sulfur nucleophiles is described.

Fused Quinoline Heterocycles V. Synthesis of Novel 1,2,3,5,6-Pentaazaaceanthrylene Derivatives

“…In addition, signals due to aromatic protons were observed in their expected positions. Furthermore, the 13 C NMR spectrum of 7 confirmed the presence of the C=S group at δ = 179.9 ppm. 17 Structure 7 is also supported by its mass spectrum which showed peak at m/z 393, consistent with M + for C 23 H 15 N 5 S.…”

“…The isomeric quinolin-4-one structure (5) could be excluded because the IR spectrum showed significantly an amide carbonyl function at 1665 cm -1 ; 11,12 4-quinolinones generally have carbonyl absorptions below 1600 cm -1 . [13][14][15] The pyrazolo [4,3-c]quinolines 2 served as a starting point for the construction of novel tetracyclic systems incorporating both a pyrimidine nucleus and a pyrazoloquinoline moiety. Thus, the reaction of compound 2 with phenyl isothiocyanate in dry pyridine at reflux for 15 min led to the novel 1,5diphenyl-1,5-dihydro-1,2,3,5,6-pentaazaaceanthrylene-4(3H)thione (7).…”