Journal Article•
Recent studies on 1,3-dipolar cycloadditions of nitrones
05 Jul 2013-Journal of the Indian Institute of Science (Indian Institute of Sciences)-Vol. 81, Iss: 3, pp 313-323
TL;DR: In this article, a new synthesis of 2, 2 - dimethyl - 12 - [ 3 - methylbut - 2 - enyl ] - 2H, 6H - pyrano [ 3, 2- b ] xanthen - 6 - one (7) was described from 1, 3 - dihydroxyxanthone and involved the preparation of a linear dihydropyranoxanthone (26), its conversion into the pyranthone, and its prenylated derivative (31) followed by a Claisen rearragement leading to the target substrate
Abstract: A new synthesis of 2 , 2 - dimethyl - 12 - [ 3 - methylbut - 2 - enyl ] - 2H , 6H - pyrano [ 3 , 2 - b ] xanthen - 6 - one (7) is described from 1 , 3 - dihydroxyxanthone and involved the preparation of a linear dihydropyranoxanthone (26), its conversion into the pyranoxanthone (14) and its prenylated derivative (31) followed by a Claisen rearragement leading to the target substrate (7).
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14 Feb 2013
TL;DR: A green, efficient synthesis of 5-arylidene rhodanine and 2,4-thiazolidinedione derivatives without using any external catalyst in polyethylene glycol (PEG) at 80°C has been described.
Abstract: A green, efficient synthesis of 5-arylidene rhodanine and 2,4-thiazolidinedione derivatives without using any external catalyst in polyethylene glycol (PEG) at 80°C has been described. Reaction procedure is very simple, short, and obtained yields are very high.
6 citations
Cites background from "Recent studies on 1,3-dipolar cyclo..."
...Apart from this major utility their general chemistry is little studied.[27] There are few reports of successful 1,3-additions of nitrones [28, 29]....
[...]
TL;DR: Various 2-[5-(aryl)-1,2,4-oxadiazol-3-yl]quinazolin-$$4(3H)$$4 (3H)-ones have been synthesized from the reaction of diaminoglyoxime-based nitrones with methyl 2-aminobenzoate or 2-amines in the presence of acetic acid.
Abstract: Various 2-[5-(aryl)-1,2,4-oxadiazol-3-yl]quinazolin-
$$4(3H)$$
-ones have been synthesized from the reaction of diaminoglyoxime-based nitrones with methyl 2-aminobenzoate or 2-aminobenzamide in the presence of acetic acid at $$100\,{^\circ }\mathrm{C}$$
. The reaction was extended as a one-pot three-component approach starting from diaminoglyoxime, aldehyde and methyl 2-aminobenzoate.
4 citations
Cites background from "Recent studies on 1,3-dipolar cyclo..."
...cycloaddition reactions that have been studied extensively as concerted [π4s + π2s] cycloaddition reactions [11]....
[...]
TL;DR: In this paper, the authors reported a high-yield method using mild reaction conditions and short reaction times for the synthesis of 3,3′-di-indolylmethane derivatives.
Abstract: 3,3′-Di-indolylmethane derivatives are important biologically active compounds possessing anti-cancer properties. Hence, development of synthetic routes to these are of great interest to organic chemists. In the present communication we report a high-yield method using mild reaction conditions and short reaction times for the synthesis of 3,3′-di-indolylmethane derivatives. The method involved reactions of indole and substituted indoles with C,N-disubstituted nitrones in the presence of acid catalysts, with the utilisation of microwave irradiation techniques. Reactions of indole, 2-methyl indole and 2-phenyl indole were performed with ten different C,N-diaryl- and C-aryl-N-methyl- nitrones in dichloromethane solution in the absence and presence of acid catalysts, viz. ytterbium triflate, p-toluene sulphonic acid and Montmorillonite clay K-10. Reaction times varied between 2 to 18 minutes. In general, yields of the catalysed reactions were above 75%. The products were characterised spectroscopically, including two-dimensional NMR studies. The microwave irradiation technique enhanced reaction rates by a significant amount. Ytterbium triflate proved to be the best catalyst, giving clean reactions, without formation of by-products, in high yields. The structure and conformation of 3,3′-di-indolyl-phenylmethane were computed.
GRAPHICAL ABSTRACT:
We report a high-yield method using mild reaction conditions and short reaction times for the synthesis of 3,3′-di-indolylmethane derivatives, involving reactions of indole and substituted indoles with C, N-disubstituted nitrones in the presence of acid catalysts using microwave irradiation.
1 citations
TL;DR: The ground state interaction of C-(4-chlorophenyl)-N-phenylnitrone (N1) with three different α, β-unsaturated ketones (K1 - K3) in very dilute solution (10-6 mol dm-3) has been noticed through charge transfer band formation in the visible region as discussed by the authors.
Abstract: The ground state interaction of C-(4-chlorophenyl)-N-phenylnitrone (N1) with three different α, β-unsaturated ketones (K1 - K3) in very dilute solution (10-6 mol dm-3) has been noticed through charge transfer band formation in the visible region. The experimentally measured transition dipole, ground state resonance energy and formation constants of the complexes indicate interaction selectivity of the acyclic nitrone (N1) for the ketones. Molar absorptivity of the absorbing complexes were determined for all the three N1/K (1:1) interacting systems in toluene. Experimental findings were well rationalized with the help of electron density based global electrophilicity and nucleophilicity indices as well as with frontier molecular orbital calculations.
1 citations
Cites background from "Recent studies on 1,3-dipolar cyclo..."
...Nitrones, an important category of 1,3-dipolar species [13-17], undergo facile concerted [π4s + π2s]-cycloaddition to different dipolarophiles producing isoxazolidines which serve as a key step in a number of natural product syntheses [13,18-20]....
[...]
...Nitrones are a family of such heterocyclic compounds that have been studied extensively [13-22] due to their stability....
[...]
References
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TL;DR: In this paper, the authors present a review of the literature in the field of acid derivatives and present references to references for references in each chapter including references to the references of the references.
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01 Jan 1988
TL;DR: In this article, the Nitrile Oxides, Nitrones, Nitronates, and Intermediate Isoxazoles, Isoxonolines, and IsoXazolidines in Synthesis are discussed.
Abstract: Preface Introduction and General Considerations The Nitrile Oxides The Nitrones Alkyl and Silyl Nitronates Applications of Nitrile Oxides, Nitrones, Nitronates, and Intermediate Isoxazoles, Isoxazolines, and Isoxazolidines in Synthesis Concluding Remarks Bibliography Author Index Subject Index.
460 citations