Syntheses of Benzo[b]furan-6-carbonitrile and 6 …
Categories: Synthesis of O-Heterocycles > benzo-fused O-Heterocycles > Synthesis of Benzofurans
General Synthesis of Polysubstituted Benzo[ b ]furans
In most published literature, the synthesis of benzo[b]furans is via tandem Sonogashira coupling/5-endo-dig cyclization using a palladium catalyst or copper salt and oxidative pathway. Using our protocol, we were able to cyclize o-alkynylphenols (3a-m) to the corresponding benzo[b]furans (4a-m) in moderate to good yields (). It should be noted that many of the same cyclizations, such as 4a, 4c and 4d, have been noted under Pd catalysis. Our results suggest that metal catalysis is not necessary in some of the literature procedures.
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Benzo[b]furan is used in the manufacture of coumarone-indene resin. It has been used to make floor tiles and other products. It is also used as a coating on grapefruit, lemons, lirnes, oranges, tangelos and tangerines and in the production of COITosion-resistant paints and varnishes, in water-resistant coatings on paper products and fabrics and as adhesives in food containers.
Synthesis of benzo[b]furan-2-thioles from 4-(2 …
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Brief review on 2-azetidinones derivatives: Kumat et al 22 synthesized α-Naphthol into 4-methyl-2H-benzo[h]chromen-2-one by reacting with ethyl acetoacetate in the presence of bismuth trichloride.
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Application to benzo[b]furan synthesis
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We next used the Chern procedure to produce the desired 3-hydroxy-4-iodobenzonitrile (4) in moderate-to-low yield (). Before optimizing this reaction, we wanted to unambiguously assign the regiochemistry of the product. The NMR spectrum of 3-hydroxy-4-iodobenzonitrile (5) matched literature precedent;  however, that synthesis also relied upon an iodination reaction that could have provided multiple products. We were, unfortunately, unable to validate the structure using HMBC/HSQC because of overlapping resonances in the 13C spectrum. Upon synthesis of the corresponding mesylate ester (6, ), however, a highly crystalline product was obtained. Determination of the X-ray crystal structure of mesylate 6 proved that the desired material was, in fact, obtained from the de-iodination reaction (see ).
The 3-iodobenzofurans 9 can be further elaborated by using a variety of palladium-mediated processes, such as Suzuki-Miyaura coupling,, carbonylative Suzuki coupling, Sonogashira coupling, Heck coupling, and carboalkoxylation (). The crude products 14 were purified by either column chromatography or preparative HPLC. The results of this parallel library synthesis are summarized in , which indicates that the products 14 can be obtained in moderate to good yields with high purities. The reagents used for substitution of the iodine-containing products 9 were chosen on the basis of their commercial availability (e.g. boronic acids 10, terminal alkynes 6, styrenes 12, and alcohols 13) () and potential drug-like properties, resulting in a virtual library of all theoretically possible products of approximately 5,000 potential compounds. This number was arrived at by determining all possible combinations of the R group variation with available starting materials. However, only a small subset of 121 compounds out of these 5,000 virtual structures was actually made in the laboratory. Most of the selected 121 benzo[b]furan library members were Lipinski, compliant. The molecular weight, clog P, number of hydrogen bond donors and acceptors, and the number of rotatable bonds were either specified or calculated for each of the library members using the SYBYL program.
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Benzo[b]furan dimers and processes for their preparation are provided
New Synthesis of Benzo(b)furan and Indole ..
The Selective Reaction of Aryl Halides with KOH: Synthesis of Phenols, Aromatic Ethers, and Benzofurans
Benzofuran|CAS:271-89-6|JiaXing SiCheng Chemical …
FULL TEXT Abstract: A new base-promoted cyclization for the synthesis of substituted benzo[b]furans is described
Coumarone; 2,3-Benzofuran; Benzo[b]furan : Cas No
The solution phase parallel synthesis of a 121 member library of multi-substituted benzo[b]furans is described
Synthesis and Cytotoxic Distinction of Benzo…
To synthesize the requisite boronic acid ester 10 from the 2-unsubstituted benzo[b]furan 9, we used a modification of Hartwig’s boronylation procedure  to provide the target compound in good yield (). Boronic acid ester 10 is a useful two-point scaffold for the preparation of compounds with a benzofuran core that exhibit biological activity
Benzofuran synthesis - Organic Chemistry Portal
In conclusion, the 3-iodobenzofurans 9 have proven to be very useful templates for further diversification by a variety of C-C, C-N, and C-O bond forming reactions,– and are thus valuable building blocks for combinatorial chemistry., We have demonstrated that 3-iodobenzofurans 9 readily react with various building blocks, e.g. boronic acids 10, terminal alkynes 6, styrenes 12, and carbon monoxide plus alcohols 13, to efficiently construct a 121 member library of highly substituted benzo[b]furans 14. The desired 3-iodobenzofurans 9 are readily prepared by our previously published electrophilic cyclization chemistry. Of the 121 compounds produced, 74 compounds were obtained in >99% purity. The benzo[b]furan library members 14 will be evaluated against various biological screens by the National Institutes of Health Molecular Library Screening Center Network.
2-ETHYNYL-BENZO[B]FURAN(CAS# 39165-03-2) - …
A new base-promoted cyclization for the synthesis of substituted benzo[b]furans is described. This method is simple and inexpensive and gives good yields.
CAS 205-39-0 | UK supplier | Benzo[b]naphtho[1,2-d]furan
We surmised that the corresponding reaction, applied to 3-hydroxy-2,4,6-triiodobenzonitrile (4), would provide compound 5. Indeed, after refluxing the per-iodinated phenol in N-methylmorpholine, we isolated 3-hydroxy-4-iodobenzonitrile (5) in modest yield. Encouraged by these results, we sought to optimize the synthesis such that this sequence could be carried out in high yield on a multi-gram scale.
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