An efficient synthesis of benzoxazoles using silica-supported tin exchanged silicotungstic acid catalyst

Srivani, A.; Rao, K.T. Venkateswar; Prasad, P. S. Sai; Lingaiah, N.

doi:10.1016/j.molcata.2010.06.009

Cited by 11 publications

(4 citation statements)

References 15 publications

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“…SiWA is a member of the polyoxometalate (POM, heteropolyacid) family, which shows Keggin-type coordination in aqueous conditions . SiWA is known as a solid-state catalyst (then supported on inert surfaces) for transformation of molecules, − and it was chosen in the present context as a precursor due to its tungsten-rich structure (12 W-atoms per cluster). Melamine–SiWA (10:4 g, 0.08:0.001 mol) was mixed in water overnight and dried afterward.…”

Section: Resultsmentioning

confidence: 99%

In Situ Formation of Arrays of Tungsten Single Atoms within Carbon Nitride Frameworks Fabricated by One-Step Synthesis through Monomer Complexation

et al. 2020

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Deposition of stable single atoms on supports is a hot topic, especially for catalysis, and single atom deposition in nitrogen-framed pores of carbon and carbon nitrides is indeed the most successful. The polymeric semiconductor graphitic carbon nitride (g-CN) is an exciting scaffold due to its nitrogen-rich structure (C 3 N 4 ideally) and the inherent nitrogen-lined pores, which made the whole, structurally diverse g-CN family an attractive choice for heterogeneous catalysis and photocatalysis. Herein, we present the simple thermal treatment of a monomer complex between melamine and silicotungstic acid to yield massive amounts of tungsten single atoms within the carbon nitride framework. The morphology and photophysical properties of the novel semiconductor with a band gap around 2 eV are investigated in dependence of the tungsten content, and the onset of W−W exchange interactions will be described. Due to the ease of W to change the oxidation state and to bind to oxygen atoms, the material turns out to be an effective catalyst for oxidation reactions, which was exemplified with new oxidative photopolymerization of guaiacol to form artificial lignin-like polyphenols.

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Section: Resultsmentioning

confidence: 99%

In Situ Formation of Arrays of Tungsten Single Atoms within Carbon Nitride Frameworks Fabricated by One-Step Synthesis through Monomer Complexation

et al. 2020

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“…The most commonly used synthetic approach of 2substituted benzoxazole moiety to involve condensation of 2aminophenol with carboxylic acids, [28] acid halides, [29] aldehydes. [30] Benzoxazoles moiety can be also synthesized via the condensation of o-aminophenols with ortho-esters, [31] direct coupling 1,1-dihaloalkenes, [32] dehydrogenative coupling reac-tion of primary alcohols with 2-Aminophenol, [33] oxidative Coupling of benzylamines, [34] tandem oxidative process from simple toluene derivatives and 2-aminophenols [35] and carboncarbon triple bonds cleavage. [36] Moreover, aerobic oxidation reactions of the acetals or imines [37][38] and intermolecular oxidative CÀ O Coupling of amides, [39] In addition, domino cross coupling approaches to the synthesis of benzoxazoles via Ortho-haloanilides, [40] and arylation, [41] which applied in the synthesis of benzoxazole derivatives (Scheme 5).…”

Section: Anticancer Activitiesmentioning

confidence: 99%

Nanocatalyzed Synthesis of Benzoxazoles

Patel,

Patil,

Chavan

et al. 2023

ChemistrySelect

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Naturally, occurring as well as synthetic nitrogen and oxygen containing heterocyclic compounds like benzoxazoles and its derivatives have found to be playing a vital role in the Pharmaceutical, agriculture; polymer, material science and they also exhibits series of significant antimicrobial activities. In the last decade, an organic transformation has found abundant application of nanotechnology and nanoscience can aid design catalyst with excellent efficiency, selectivity and stability. Academics and industry have recently shown a lot of interest in the application of nanocatalysts, a field that is expanding significantly, to create sustainable and environmentally friendly processes for the synthesis of benzoxazole derivatives with multi‐component reactions (MCRs). Nanocatalyst reactions have advantages over conventional catalyst reactions because of the interaction of chemical reactants made possible by a high surface area ratio, simple purification, low catalyst loading, high atom economy, inexpensiveness, short reaction time, better yield, and recyclability of the nanocatalysts. In this review article, mainly focus is on the nanocatalysts fabrications, characterizations and their applications for the synthesis of benzoxazoles moiety during the last decennary (2011 to 2022).

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“…To the resulting solution was added triethyl orthopropiolate 54 and catalytic yttrium(III) triflate. After stirring at 55 o C for 1 h, the reaction was worked up to deliver 2,6-bis(trimethylsilylethynyl)benzo [1,2- Beyond this, 1,3-dibromo-5,5-dimethylhydantoin 26 and mildly acidic solvents, such as 1,1,1,3,3,3hexafluoro-2-propanol, 27 were shown to accelerate the formation of benzimidazoles while Brønsted acids, such as silica-supported tin exchanged silicotungstic acid 28 and silica sulfuric acid, 29 were employed to prepare benzoxazoles. Finally, Marko and co-workers 30 reported the use of boron trifluoride etherate (BF 3 •OEt 2 ) in DCM at 23 o C to promote reactions of complex orthoesters which permitted some interesting post-cyclization transformations such as those shown in Scheme 16.…”

Section: Fused Rings: Two Heteroatomsmentioning

confidence: 99%

Orthoesters in heterocycle synthesis

Bunce¹

2020

Arkivoc

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Orthoesters have occupied an important niche in heterocycle synthesis since the mid-20 th century. They have found wide application in the synthesis of five-and six-membered nitrogen-, oxygen-and sulfur-containing rings from precursors having an acyclic 1,3-or 1,4-arrangement of heteroatoms. Since orthoesters incorporate three geminal alkoxy groups on the central carbon, all of which can be lost, the central carbon of the orthoester [RC(OR) 3 ] is a synthetic equivalent for "RC 3+ " and can be introduced between the two heteroatoms by means of neutral or acid-catalyzed condensative processes. The current review surveys the literature on the use of orthoesters in heterocycle synthesis and presents numerous examples with mechanisms.

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An efficient synthesis of benzoxazoles using silica-supported tin exchanged silicotungstic acid catalyst

Cited by 11 publications

References 15 publications

In Situ Formation of Arrays of Tungsten Single Atoms within Carbon Nitride Frameworks Fabricated by One-Step Synthesis through Monomer Complexation

In Situ Formation of Arrays of Tungsten Single Atoms within Carbon Nitride Frameworks Fabricated by One-Step Synthesis through Monomer Complexation

Nanocatalyzed Synthesis of Benzoxazoles

Orthoesters in heterocycle synthesis

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