Quinoline, quinazoline and acridone alkaloids

Michael, Joseph P.

doi:10.1039/b104971m

Cited by 262 publications

(61 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1-Aza coumarins, also referred to as carbostyrils, are less frequently found in nature than coumarins; although its fused-ring system has been found in the skeleton of many quinoline alkaloids, of which the isolation and structure elucidation has been recently reviewed [39]. The source of these alkaloids encompass plants, sponges and even arthropodes as well.…”

Section: Natural Occurrence Of Coumarins and 1-azacoumarinsmentioning

confidence: 99%

Recent Advances in Coumarins and 1-Azacoumarins as Versatile Biodynamic Agents

Kulkarni¹,

Kulkarni²,

Chao³

et al. 2006

CMC

225

View full text Add to dashboard Cite

Coumarins, also referred as benzopyran-2-ones, and their corresponding nitrogen counterpart, 1-azacoumarins also referred to as carbostyrils, are a family of nature-occurring lactones and lactams respectively. The plant extracts containing coumarin-related heterocycles, which were employed as herbal remedies in early days, have now been extensively studied for their biological activities. These investigations have revealed their potentials as versatile biodynamic agents. For example, coumarins with phenolic hydroxyl groups have the ability to scavenge reactive oxygen species and thus prevent the formation of 5-HETE and HHT in the arachidonic pathway of inflammation suppression. Recent in vivo studies have revealed the role of coumarins in hepatotoxicity and also in depletion of cytochrome P450. Similarly 1-azacoumarins which is part of quinoline alkaloids, are known for their diverse biological activity and recently, a 6-functionalized 1-aza coumarins are undergoing human clinical trials as an orally active anti-tumor drug in view of its farnesyl protein-inhibiting activity in the nanomolar range. Furthermore, several synthetic coumarins with a variety of pharmacophoric groups at C-3, C-4 and C-7 positions have been intensively screened for anti-microbial, anti-HIV, anti-cancer, lipid-lowering, anti-oxidant, and anti-coagulation activities. Specifically, coumarin-3-sulfonamides and carboxamides were reported to exhibit selective cytotoxicity against mammalian cancer cell lines. The C4-substituted aryloxymethyl, arylaminomethyl, and dichloroacetamidomethyl coumarins, along with the corresponding 1-azacoumarins, have been demonstrated to be potential anti-microbial and anti-inflammatory agents. To expand the structural diversity of synthetic courmarins for biological functions, attempts have also been made to attach a chloramphenicol side chain at C-3 position of courmarin. In addition, the bi- and tri-heterocyclic coumarins and 1-azacoumarins with benzofuran, furan and thiazole ring systems along with biocompatible fragments like vanillin have shown remarkable potency as anti-inflammatory agents in animal models. Photobiological studies on pyridine-fused polycyclic coumarins have highlighted their potential as thymine dimer photosensitisers and the structurally related compounds of both coumarin and carbostyrils have also been found to act via the DNA gyrase pathway in their anti-bacterial activity. Apart from the above works, the present review also addresses the potential roles of coumarins and carbostyrils as protease inhibitors, or fluorescent probes in mechanistic investigation of biochemical pathways, and their application for QSAR in theoretical studies. Though 1-Azacoumarins have received less attention as compared to coumarins in the literature, an attempt has been made to compare both the systems at various stages, so that it can spark new thoughts on synthetic methodologies, reactivity pattern and biological activities.

show abstract

Section: Natural Occurrence Of Coumarins and 1-azacoumarinsmentioning

confidence: 99%

Recent Advances in Coumarins and 1-Azacoumarins as Versatile Biodynamic Agents

Kulkarni¹,

Kulkarni²,

Chao³

et al. 2006

CMC

225

View full text Add to dashboard Cite

show abstract

“…

…”

mentioning

confidence: 99%

Novel Basic Mesoporous Catalysts for the Friedländer Reaction from 2‐Aminoaryl Ketones: Quinolin‐2(1H)‐ones versus Quinolines

et al. 2009

View full text Add to dashboard Cite

The quinoline ring [1] is present in a number of natural [2] and synthetic products often exhibiting interesting pharmacological activities or physical properties. [3,4] Different synthetic approaches for the preparation of quinolines have been reported; the Friedländer reaction (FR) being one of the simplest and most efficient methods. [5] FR is a base-or acid-catalyzed condensation of an aromatic 2-amino-substituted carbonyl compound (aldehyde or ketone) with a carbonyl derivative containing a reactive a-methylene group followed by cyclodehydration (Scheme 1). Generally, the annulation takes place by heating aqueous or ethanolic solutions of the reactants at reflux in the presence of bases or acids, or by heating at temperatures of 150-220 8C in the absence of any catalyst. [6] Numerous studies have been undertaken with the aim of developing new catalysts operating under milder conditions. [5] Concerning green chemistry, replacement of homogeneous catalysts with heterogeneous catalysts for the production of fine chemicals in industrial processes, remains a very active research area. FRs have been catalyzed by several heterogeneous catalysts, such as Al 2 O 3 , [7] H 2 SO 4 /SiO 2 , [8] NaHSO 4 /SiO 2 , [9] HClO 4 / SiO 2 , [10] silica gel-supported phosphomolybdic acid, [11] KAIA[12] and sulfonated cellulose. [13] Although the acid or base-promoted FR has been extensively studied with o-aminoaryl aldehydes, [5] the base-catalyzed reactions starting from the corresponding o-aminoaryl ketones are relatively scarce. In 1967, Fehnel [14] described that o-aminobenzophenone (1 a) failed to react with ethyl acetoacetate under basic classical FR conditions, only affording the 3-acetylquinolin-2-(1H)-one 2 a under thermal activation at 160 8C (Scheme 2).Alongside our recent results concerning the synthesis of quinolines in the presence of bases, [15] we are interested in the development of environmentally friendly and potentially reusable heterogeneous catalysts based on modified molecular sieves with different acid/base properties, and also in the comparison of their catalytic activity in the FR. We have prepared and characterized three different MCM-41 materials supporting aminopropyl (AP), methylaminopropyl (MAP), and diethylaminopropyl (DEAP) groups, and modified the acidic properties of Al-SBA-15 by incorporating cesium ions, [16] and tested all of them in the FR (Table 1) The thermal stability of the aminografted MCM-41 was examined by thermogravimetric (TG) experiments in a temperature range from room temperature to 200 8C. Herein, we report the results of the FR of o-aminoacetophenone (1 b) and o-aminobenzophenone (1 a) with ethyl acetoacetate catalyzed by the mesoporous materials.Initially, we screened for a suitable solvent. Unfortunately, the reaction of 1 b in the presence of 20 wt. % DEAP did not proceed in EtOH at 80 8C. However, when we performed the reaction in DMF or toluene at 100 8C, quinolin-2(1H)-one 2 b was isolated with yields of 36 % and 93 % after 7 h and 2 h, respectively (Scheme 2 and T...

show abstract

“…10 For that reason, and in order to test the potential effect that substitution can exert on the chemoselectivity of the process, we decided to prepare a series of methoxysubstituted quinolinones 9a-d from 7a-d. In addition, and trying to get more information about the behavior of these amide precursors under the action of the oxidative I(III) reagent, a further reaction condition was tested on methoxyamides 7a-d.…”

Section: Resultsmentioning

confidence: 99%