An Expeditious One-Pot Three-Component Synthesis of 4-Aryl-3,4-dihydrobenzo[g] quinoline-2,5,10(1H)-triones under Green Conditions

Abstract

: An efficient and facial one-pot synthesis of 4-aryl-3,4-dihydrobenzo[g]quinoline- 2,5,10(1H)-triones was developed for the first time. The process proceeded via the three-component cyclocondensation of 2-amino-1,4-naphthoquinone with Meldrum’s acid and substituted benzaldehydes under green conditions. The fused 3,4-dihydropyridin-2(1H)- one-ring naphthoquinones have been synthesized with good to high yields in refluxing ethanol as a green reaction medium. This protocol is simple and effective as well as does not involve the assistance of the catalyst, additive, or hazardous solvents.

Green Synthesis of Spiro Compounds with Potential Anticancer Activity through Knoevenagel/Michael/Cyclization Multicomponent Domino Reactions Organocatalyzed by Ionic Liquid and Microwave-Assisted

“…However, a mixture of substances that was difficult to purify was obtained when Meldrum's acid 4c was used in place of barbituric acid 4a. This was probably due to the thermal instability of Meldrum's acid, which at temperatures close to 80 °C and long reaction times undergoes a retro-hetero-Diels-Alder reaction, giving rise to the highly reactive ketene 7, acetone 8, and carbon dioxide 9, as shown in Scheme 5 [26,27]. Another possibility is the degradation of Meldrum's acid into its precursor, malonic acid, as reported by Dourado (2018) [28].…”

An efficient synthesis of acridine‐aza‐anthraquinone hybrid compounds under microwave irradiation

“…The 1 H and 13 C assignment of compounds 4a-h were based on the NMR data of naphthoquinones reported in the previous studies. [13][14] Taken compound 4b as example, two doublets of doublets at 8.02 and 7.91 ppm, two triplets of doublets at 7.82 and 7.78 ppm, and one singlet 5.19 ppm were assigned to protons H-10, H-7, H-8, H-9, and H-12 of the aza-anthraquinone ring, respectively. The signals of four aromatic protons in the p-tolyl group appeared as two doublets at 7.12 and 7.00 ppm, three protons of methyl in the p-tolyl group were observed as a singlet at 2.18 ppm.…”

“…[12] Figure 1: Some bioactive aza-anthraquinone and acridine derivatives Although heterocycles having aza-anthraquinone and benzoacridine moieties are a great of interest, the hybridization of these two scaffolds into one single molecules have rarely been studied. [13,14] In that respect, in our ongoing program for the development of novel bioactive agents based on nitrogen-containing heterocycles, herein we reported an efficient synthesis of novel 12-substituted-3,4,4a,5,12,12a-hexahydrobenzo[b]acridine-1,6,11(2H)-triones derivatives 4a-k via microwaveassisted three-component reactions starting from 2amino-naphthoquinone, 1,3-cyclohexanedione and various (hetero)aromatic aldehydes.…”

The Molecular Diversity Scope of Meldrum's Acid in Multicomponent Reactions

“…4‐Aryl‐3,4‐dihydrobenzo[ g ]quinolone‐2,5,10(1 H )‐triones 122 were synthesized via the one‐pot multi‐component condensation of substituted benzaldehydes 13 , 2‐amino‐1,4‐naphthoquinone 121 , and Meldrum's acid 1 in EtOH which was reported by Kamalifar and Kiyani (Scheme 55). [60] …”

“…4-Aryl-3,4-dihydrobenzo[g]quinolone-2,5,10(1H)-triones 122 were synthesized via the one-pot multi-component condensation of substituted benzaldehydes 13, 2-amino-1,4-naphthoquinone 121, and Meldrum's acid 1 in EtOH which was reported by Kamalifar and Kiyani (Scheme 55). [60] The Ir(III) [61] catalyzed treatment of azobenzene 123 and diazotized Meldrum' methanol 126 to produce 3-oxo-2-phenyl-2,3-dihydrocinnoline-4-carboxylic acid 127 or methyl-3-oxo-2-phenyl-2,3dihydrocinnoline-4-carboxylate 128 (Scheme 56). [62] In 2021, Bhardwaj and co-workers reported an expeditious MCR using AgÀ TiO 2 nanocomposites (NPs) as an ecofriendly heterogeneous nanocatalyst (NC) which could be reused four times for the synthesis of pyrido [2,3d]pyrimidines 130 in high yields involving the reaction of Meldrum's acid 1, aromatic aldehydes 13, and 6-amino-1,3dimethyluracil 129 in H 2 O (Scheme 57).…”