Synthesis and Reactions of the Novel 6‐ethyl‐4‐hydroxy‐2, 5‐dioxo‐5, 6‐dihydro‐2H‐pyrano[3, 2‐c]quinoline‐3‐carboxaldehyde. (11th December 2018)

• Record Type: Journal Article
• Authors: Ibrahim, Magdy A.; Hassanin, Hany M.
• Is Part Of: Journal of heterocyclic chemistry. Volume 56:Number 2(2019)
• Page Start: 628
• Page End: 635
• Publication Date: 2018-12-11
• Subjects: Heterocyclic compounds -- Periodicals; 547.59
• DOI: 10.1002/jhet.3440
• Languages: English
• ISSNs: 0022-152X

Abstract

Abstract : The novel 6‐ethyl‐4‐hydroxy‐2, 5‐dioxo‐5, 6‐dihydro‐2 H ‐pyrano[3, 2‐ c ]quinoline‐3‐carboxaldehyde (2 ) was efficiently synthesized from Vilsmeier–Haack formylation of 3‐(1‐ethy1‐4‐hydroxy‐2‐oxo‐(1 H )‐quinolin‐3‐yl)‐3‐oxopropanoic acid (1 ). The aldehyde2 was allowed to react with some nitrogen nucleophiles producing a variety of hydrazones3 –7 . Reaction of aldehyde2 with hydrazine hydrate and hydroxylamine hydrochloride afforded pyrazole and isoxazole annulated pyrano[3, 2‐ c ]quinoline‐2, 5(6 H )‐dione, respectively. The reactivity of aldehyde2 was examined toward some active methylene nitrile, namely, malononitrile, ethyl cyanoacetate, and cyanoacetamide leading to 2‐iminopyrano[2′, 3′:4, 5]pyrano[3, 2‐ c ]quinolines10 –12, respectively. Also, some novel pyrazolo[4″, 3″:5′, 6′]pyrano[2′, 3′:4, 5]pyrano[3, 2‐ c ]quinolines (13, 14 ) and thiazolo[5″, 4″:5′, 6′]pyrano[2′, 3′:4, 5]pyrano[3, 2‐ c ]quinolines (15, 16 ) were synthesized. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data. Abstract :