One-Pot, Three-Component Synthesis of 1,8-Naphthyridine Derivatives from Heterocyclic Ketene Aminals, Malononitrile Dimer, and Aryl Aldehydes

Abstract

An efficient and versatile method was developed for the access of multisubstituted 1,8-naphthyridine derivatives through a onepot, three-component protocol from heterocyclic ketene animals, malononitrile dimer, and aryl aldehydes in high yields. The 1,8-naphthyridines were formed via Knoevenagel condensation, aza-ene reaction, imine-enamine tautomerization, and intramolecular cyclization.

Efficient Synthesis of Highly Substituted N‐Arylamino quinolone‐based Pyrrolo[3,4‐b]pyridines and Pyrazolone‐based Pyrrolo[3,4‐b]pyridines Through a One‐Pot Three‐Component Reaction

“…Therefore, the reactions of enamines with different biselectrophiles have been investigated extensively for the construction of nitrogen-containing heterocycles. [25] One of the most important and famous enamines for the synthesis of nitrogen-containing heterocycles is nitroketen aminals, [26] cyclic enamino ketones, [27] and αaminomaleimides, [28] which played an important role in this process. According to our knowledge, the three-component reaction of 2-chloroquinoline-3-carbaldehydes, malononitrile derivatives and enamines such as nitroketen aminals, cyclic enamino ketones to synthesize quinoline-based pyrido[1,2a]pyrimidines/imidazo[1,2-a]pyridines [29] and N-arylamino biquinoline derivatives have been previously reported.…”

“…A notable feature of enamines is their highly polarized ethylene system with electron‐donating amino groups and electron‐withdrawing substituents at two ends. Therefore, the reactions of enamines with different biselectrophiles have been investigated extensively for the construction of nitrogen‐containing heterocycles [25] . One of the most important and famous enamines for the synthesis of nitrogen‐containing heterocycles is nitroketen aminals, [26] cyclic enamino ketones, [27] and α‐ aminomaleimides, [28] which played an important role in this process.…”

“…1 H NMR (300 MHz) and 13 C{ 1 H} NMR (75 MHz) spectra were General procedure for the preparation of α-aminomaleimides (3): α-Aminomaleimides 3 were synthesized using the known literature procedure. [25] The mixture of MeOH (3 mL), arylamines (1 mmol), and dimethyl acetylenedicarboxylate (1 mmol) was kept at room temperature with stirring for 10 min. Methylamine or benzylamine (3 mmol) was added to the mixture.…”