Novel heterocyclic derivatives of pyrano[3,2-c]quinolinone from 3-(1-ethy1-4-hydroxy-2-oxo-2(1H)-quinolin-3-yl)-3-oxopropanoic acid

Studies on the chemical behavior of 3-(nitroacetyl)-1-ethyl-4-hydroxyquinolin-2(1H)-one towards some electrophilic and nucleophilic reagents

“…In continuation to our work on the novel β-ketoacid 1, 11 we found that nitration of β-ketoacid 3 using a mixture of concentrated nitric acid and sulfuric acid gave the cyclized product, 6-ethyl-4-hydroxy-3-nitropyrano[3,2-c]quinoline-2,5(6H)-dione (3) via the non isolable intermediate 2 (Scheme 1). 12 The reaction proceeds via nitration at the active methylene carbon with concomitant cyclization under the strongly acidic reaction conditions.…”

“…6-Ethyl-2-methyl-3-nitro-4H-pyrano[3,2-c]quinoline-4,5(6H)-dione (11) 3-Nitroacetylquinolinone 4 (0.83 g, 3 mmol) in acetic anhydride (10 mL) and freshly fused sodium acetate was heated under reflux for 4 h. After cooling, the reaction mixture was poured onto ice/water. The solid obtained was filtered off, washed several times with water, air dried and crystallized from ethanol to give 11 as pale yellow crystals, yield 0.40 g (44%).…”

“…11 6-Ethyl-4-hydroxy-3-nitropyrano[3,2-c]quinoline-2,5(6H) dione (3) A mixture of β-ketoacid 1 (0.55 g, 2 mmol) in concentrated nitric acid (5 mL) and concentrated sulfuric acid (5 mL) was stirred at room temperature for 2h, then left continuous stirring at ambient temperature. After complete addition, the reaction mixture was heated on a boiling water bath under reflux for 2 h and left over night.…”

“…[1][2][3][4][5][6] The biological importance of quinolinones stimulated an intensive research work for the synthesis of many members of this class of compounds. [7][8][9][10] In continuation of our previous reports on the synthesis of novel 4-hydroxyquinolin-2(1H)-ones starting from 3-(1-ethy1-4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)-3-oxopropanoic acid (1), 11 the present work aims to synthesize the 3-(nitroacetyl)-1-ethyl-4-hydroxyquinolin-2(1H)-one (4) and to study its reactivity towards a variety of chemical reagents.…”

Heteroannulated pyranoquinolinediones: Part 1. An efficient and convenient synthesis of the novel heteroannulated pyrano[3,2-c] quinoline-2,5(6H)-diones

“…[7][8][9] On the other hand, ortho-dichloro heterocycles are good building blocks for the synthesis of fused heterocyclic compounds. [10][11][12][13] On the basis of the above observation and in continuation to our research work directed on the chemistry of pyrano [3,2-c]quinolinedione derivatives, [14][15][16][17] the present work aimed to synthesize the novel 3,4-dichloro-6-ethyl-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione (2) as a starting material and study its chemical reactivity towards some 1,4-bifunctional nucleophiles, hoping to get a novel heteroannulated pyrano [3,2- The dichloro derivative 2, as 1,2-bifunctional electrophiles, represents a good building block for the synthesis of a series of heteroannulated pyrano[3,2-c]quinolinediones, via its condensation reactions with a variety of 1,4-bifiunctional nucleophiles. Thus, condensation of compound 2 with ethylenediamine and o-phenylenediamine in absolute ethanol produced the heteroannulated pyrano[3,2-c]quinolinediones 3 and 4, respectively (Scheme 2).…”