A Convenient and Facile Synthesis of Isoxazolyl‐chromeno[4,3,2‐de]pyrimido[4,5‐h][1,6]napthyridinones

Abstract

The ceric ammonium nitrate‐catalyzed synthesis of (E)‐5‐amino‐N‐(3‐methyl‐5‐styrylisoxazol‐4‐yl)‐2‐arylchromeno[4,3,2‐de][1,6]napthyridin‐4‐carboxamides 5 was simply achieved upon the one‐pot four‐component reaction of isoxazolyl cyanoacetamide 1 with malononitrile 2, 2‐hydroxy acetophenone 3, and aromatic aldehydes 4 in ethanol. Compounds 5 on heating with acetic anhydride underwent tandem N‐acetylation and cyclocondensation involving intramolecular cyclization to afford the title compounds (E)‐11‐methyl‐12‐(3‐methyl‐5‐styrylisoxazol‐4‐yl)‐2‐arylchromeno[4,3,2‐de][1,6]napthyridin‐13(12H)‐ones 6 in good yields. The chemical structures have been confirmed by analytical and spectral analyses.

Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

“…A different approach to tetraazaphenalenoid systems was developed by Shaw et al − By condensing a substituted 1,3,6,9 a 1 -tetraazaphenalene with various bidentate nucleophiles, a range of extended nitrogen-rich frameworks were obtained ( C41.1 – 3 , Chart ). In 2014, a pentacyclic phenalenoid 141.3 was obtained in a uniquely concise synthesis by Rajanarendar et al The initial step involved a CAN-mediated multicomponent condensation of isoxazolyl cyanoacetamide 141.1 with malonodinitrile, benzaldehyde, and 2-hydroxyacetophenone, and was followed by the closure of the pyrimidinone ring with acetic anhydride (Scheme ).…”

Efficient Synthesis of Chromeno[4,3,2‐de] [1,6]naphthyridine Derivatives via Pseudo Four‐Component Reaction

“…[11] In 2014, Rajanarendar et al reported the ceric ammonium nitrate-catalyzed fourcomponent reaction of malononitrile with isoxazolyl cyanoacetamide, 2-hydroxy acetophenone, and aromatic aldehydes for the synthesis of 2-arylchromeno[4,3,2-de][1,6]napthyridin-4carboxamides. [18] Recently, Mohammadi and Shaterian reported a γ-Fe 2 O 3 @SiO 2 -γ-aminobutyric acid-promoted the pseudo four-component of malononitrile with 2,4-dihydroxyacetophe-none, various aromatic aldehydes for the preparation of chromeno [4,3,2-de][1,6]naphthyridine derivatives. [19] Evidently, malononitrile and its derivatives as essential building blocks were used in multicomponent reactions due to the high reactivity of both the methylene and the cyano groups, which played an important role in the efficient construction of complex architectures.…”