Cerium(iv) Ammonium Nitrate Mediated Nitration of Coumarins

Ganguly, Nemai C.; Sukai, Arun K.; De, Sripada

doi:10.1081/scc-100000214

Cited by 35 publications

(24 citation statements)

References 12 publications

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“…These reagents were commercially available, or obtained either by a Knoevenagel condensation or by the cleavage of the pyrone ring of the correspondent coumarin [138]. The synthesis of nitrocoumarins and 3-phenyl-or 6-acylcoumarins has been achieved using this method [139][140][141]. Moreover, esculetin and its derivatives 5-chloroesculetin and 5-bromoesculetin, were obtained by a biomimetic synthesis from a light-induced cyclisation of trans-caffeic acid catalysed by [FeNa(EDTA)] and sulphuric acid [142].…”

Section: Knoevenagel Reactionmentioning

confidence: 99%

Simple Coumarins and Analogues in Medicinal Chemistry: Occurrence, Synthesis and Biological Activity

Borges¹,

Roleira²,

Milhazes³

et al. 2005

CMC

882

458

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Coumarins, also known as benzopyrones, are present in remarkable amounts in plants, although their presence has also been detected in microorganisms and animal sources. The structural diversity found in this family of compounds led to the division into different categories, from simple coumarins to many other kinds of policyclic coumarins, such as furocoumarins and pyranocoumarins. Simple coumarins and analogues are a large class of compounds that have attracted their interest for a long time due to their biological activities: they have shown to be useful as antitumoural, anti-HIV agents and as CNS-active compounds. Furthermore, they have been reported to have multiple biological activities (anticoagulant, anti-inflammatory), although all these properties have not been evaluated systematically. In addition, their enzyme inhibition properties, antimicrobial and antioxidant activities are other foremost topics of this field of research. The present work is to survey the information published or abstracted from 1990 till 2003, which is mainly related to the occurrence, synthesis and biological importance of simple coumarins and some analogues, such as biscoumarins and triscoumarins. Data are also highlighted, concerning the development of new synthetic strategies that could help in drug design and in the work on SAR or QSAR.

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Section: Knoevenagel Reactionmentioning

confidence: 99%

Simple Coumarins and Analogues in Medicinal Chemistry: Occurrence, Synthesis and Biological Activity

Borges¹,

Roleira²,

Milhazes³

et al. 2005

CMC

882

458

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“…Reaction of the hydroxycoumarin with acetylinic halides in the presence of K 2 CO 3 [39][40][41], or alternatively with propargylic alcohols through the Mitsunobu reaction [24], leads to propargylic ethers, which undergo thermal Claisen rearrangement/cyclization reactions under the same conditions as described for allylic ethers. The main problem associated with this approach, as mentioned above, is the formation of pyranocoumarin by-products [29,42], and the extent to which these are formed appears to be dependent on the choice of base used in the reaction.…”

Section: A13mentioning

confidence: 96%

“…More recently, however, coupling of the hydroxycoumarin with allylic alcohols under Mitsunobu conditions has been used with the aim of avoiding allyl rearrangements prior to formation of the ether[24].…”

mentioning

confidence: 99%

Furocoumarins in Medicinal Chemistry. Synthesis, Natural Occurrence and Biological Activity

Santana

Uriarte

Roleira

et al. 2004

CMC

196

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The scope of this review encompasses the importance of furocoumarins and the most important developments in this field that have been made in recent years, with particular emphasis placed on the aspects related to medicinal chemistry. A concise and exhaustive overview is given regarding the methods used for the synthesis of these compounds, new furocoumarins isolated from natural sources, and the most significant biological properties associated with these molecules. The section describing the synthetic methods is organized on the basis of the key step used for the formation of the two different oxygenated rings. In this respect there are three possibilities: (i) formation of the furan ring onto the coumarin, (ii) formation of the pyrone ring onto the benzofuran and (iii) the simultaneous formation of both oxygenated rings onto a benzene unit. The most recent preparative approaches are discussed along with modifications or improvements to methods that, though not particularly new, are still commonly used. The recently discovered natural furocoumarins are focused and presented in tables that provide information about its structure and source. The discussion of the biological importance of furocoumarins mainly focuses on their more relevant applications in photochemotherapy, but also provides examples of their versatility in a range of applications in the fields of biology and pharmacology.

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“…On the other hand, the use of CAN in acetic acid gave both 2a and 8-nitro-6-nitrocoumarin in 68% and 18% yields, respectively. 2 The nitration of 1a using chromium nitrate gave nearly equal amounts of the aforementioned isomers. 3 Recently, Wu et al 4 found that nitration of 1a with NO/O 2 gave 2a in only 63% yield as well as 7-hydroxy-3-nitro-and 7-hydroxy-8-nitrocourmarin in 20% and 5%, respectively.…”

Section: Ortep Compound (2a)mentioning

confidence: 99%

Facile, high-yield, regioselective synthesis of ortho-nitro derivatives of hydroxy heterocycles using cerium (IV) ammonium nitrate

Sathunuru¹,

Biehl²

2004

Arkivoc

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A series of hydroxy heterocycles with two different unsubstituted ortho sites undergo exclusive regioselective nitration with the CAN/NaHCO 3 reagent at the less hindered ortho site. Neither dinitro nor oxidized products were observed. The hydroxy heterocycles studied include: some derivatives of 7-hydroxycoumarins, sesamol, 2,3-dihydrobenzo[b]furan-3-one, 6-hydroxy-1,3-benzoxathiol, 5-hydroxybenzothiazol, 5-hydroxyindole, 7-benzofuranol, and (5-isoxazolyl)phenols. A mechanism is proposed in which an initial oxidation of the phenol to a radical cation by CAN occurs. Another molecule of CAN subsequently reacts with the phenolic radical cation to give an radical adduct from which an NO 2 radical is transferred to the less hindered carbon via a tight ion-radical pair yielding the Wheland complex that furnishes the nitrophenol after proton loss.

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Cerium(iv) Ammonium Nitrate Mediated Nitration of Coumarins

Cited by 35 publications

References 12 publications

Simple Coumarins and Analogues in Medicinal Chemistry: Occurrence, Synthesis and Biological Activity

Simple Coumarins and Analogues in Medicinal Chemistry: Occurrence, Synthesis and Biological Activity

Furocoumarins in Medicinal Chemistry. Synthesis, Natural Occurrence and Biological Activity

Facile, high-yield, regioselective synthesis of ortho-nitro derivatives of hydroxy heterocycles using cerium (IV) ammonium nitrate

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