Convenient one-pot method for the preparation of polysubstituted benzo[b]- and naphtho[1,2-b]-furans and -thiophenes

Katritzky, Alan R.; Serdyuk, L.S.; Xie, Linghai

doi:10.1039/a708809d

Cited by 28 publications

(19 citation statements)

References 14 publications

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“…A versatile route to these ketones, based on the reaction of anions of 1-phenoxymethylbenzotriazoles with aldehydes, has been described; the complete sequence leading to the benzofurans can be carried out in one pot. 31 Benzofuran has been isolated in 60% yield from the flash pyrolysis of the cinnamyl ester 25; the reaction probably involves the generation and cyclisation of a phenoxy radical. 32 Two base-induced cyclisation reactions that lead to benzofurans are illustrated in Scheme 10 33 and in Scheme 11.…”

Section: Furans and Benzofuransmentioning

confidence: 99%

“…The route to benzofurans described by Katritzky and co-workers has also been used as a one pot synthesis of benzothiophenes, the thioethers analogous to 24 being intermediates. 31 6-Hydroxybenzothiophenes have been synthesised by a procedure in which the benzene ring is annelated to a 2-substituted thiophene by acid catalysed cyclisation. 44 4-Chloro-1,2,3-dithiazole-5-thione, which is readily prepared from 4,5-dichlorodithiazolium chloride (Appel's salt) and hydrogen sulfide, reacts with diphenyldiazomethane to give the benzothiophene 35 by way of the isolable intermediate 34 In a continuation of their work on benzo[c]thiophenes, Cava and his group have described a synthesis of the bis(2-thienyl)-benzo[c]thiophene 36 from the phthalide 37.…”

Section: Thiophenes and Benzothiophenesmentioning

confidence: 99%

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Synthesis of aromatic heterocycles

Gilchrist¹

1999

J. Chem. Soc., Perkin Trans. 1

200

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Section: Furans and Benzofuransmentioning

confidence: 99%

Section: Thiophenes and Benzothiophenesmentioning

confidence: 99%

Synthesis of aromatic heterocycles

Gilchrist¹

1999

J. Chem. Soc., Perkin Trans. 1

200

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“…Subsequent heating in the presence of ZnBr 2 afforded the corresponding α-aryloxy ketones 97 as a result of a pinacol-type rearrangement. Prolonged heating gave the desired polysubstituted benzo [b]furans 98 in good overall yields [38].…”

Section: T-buok T-buokmentioning

confidence: 99%

Benzotriazole-Mediated Synthesis of Oxygen-Containing Heterocycles

Bol’shakov

2015

Topics in Heterocyclic Chemistry

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This review aims at delivering an overview of the synthetic utility of benzotriazole and its derivatives for the preparation of oxygen-containing heterocycles. This review serves both as a synthetic guide and as a theoretical handbook of benzotriazole-assisted preparations of oxygen heterocycles and offers a complete overview of existing applications for benzotriazole and its derivatives in heterocyclic synthesis. Multiple examples reveal the superiority of benzotriazole-based approaches over conventional ones.

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“…Polysubstituted naphtho[1,2-b]furans were obtained by cyclization of asymmetrically substituted 1-naphthyloxy ketones by heating at high temperature in polyphosphoric acid [17]. Similarly, 2-phenylnaphto[1,2-b]furan and 2-phenylnaphto[2,1-b]furan were prepared by cyclization of naphthyloxyacetophenone with a strong acid [18].…”

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confidence: 99%

Synthesis of regioisomeric naphtho-furans via naphthyloxyalkanals

Kwiecień

Witczak

Kowalewska

et al. 2010

Chem Heterocycl Comp

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A new route to the regioisomeric 2-alkylnaphtho [2,1-b]-and 2-alkylnaphtho[1,2-b]furans via acidcatalyzed cyclization of the corresponding 2-naphthyloxyalkanals under mild conditions over Amberlyst 15 resin has been described. The 2-naphthyloxyalkanals were obtained by palladium-catalyzed reduction of 2-naphthyloxyalkanoyl chlorides. The regioisomeric naphtho[1,2-b]-, naphtho[2,1-b]-, and naphtho[2,3-b]furans are present in many biologically important natural products, mainly belonging to the sesquiterpene class [1]. These products have been isolated from various natural sources such as plants Liguaria przewalskii [2], Trichilia cuneata [3], Gossypium barbadens [4], or fungus Fusarium oxysporum [5]. Several synthetic compounds bearing a naphthofuran skeleton are associated with diverse biological activities such as antibacterial [6], antifungal [7], antifertility [8], and antiprotozoan activity against Trypanosoma cruzi [9]. Some of nitronaphtho[2,1-b]furans have been extensively studied for their mutagenic activities [6, 10] and other naphtho[2,1-b]furan derivatives showed a significant anticancer activity against human colon and liver cancer cell lines in the in vitro assay [11]. Besides, naphthofurans have potential applications as fluorescent dyes and probes as well as phothosensitizers [12, 13].A major route for the synthesis of naphthofurans is the intramolecular formation of a furan ring starting with properly substituted α-naphthyloxycarbonyl compounds and their corresponding acetals [14][15][16]. Polysubstituted naphtho[1,2-b]furans were obtained by cyclization of asymmetrically substituted 1-naphthyloxy ketones by heating at high temperature in polyphosphoric acid [17]. Similarly, 2-phenylnaphto[1,2-b]furan and 2-phenylnaphto[2,1-b]furan were prepared by cyclization of naphthyloxyacetophenone with a strong acid [18]. The regioisomeric naphtho[1,2-b]-and -[2,1-b]furans were obtained by treating 1-and 2-naphthol and methylsulfinylmethyl ethyl ketone with p-toluenesulfonic acid and then desulfurization of 2-alkyl-3-(methylthio)naphtho[1,2-b]-and -[2,1-b]furans with Raney nickel in ethanol [19]. Furthermore, the synthesis of aminonaphtho[1,2-b]furan by cyclodehydratation of naphthyloxyamides with phosphorous oxychloride [20] as well as the synthesis of 2-ethylnaphtho[2,1-b]furan by cyclization of 2-(1-formyl-2-naphthyloxy)butanoic acid [21] have been described. The modern Pd 2+ -catalyzed oxidative cyclization of 1-allyl-2-naphthol using

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Convenient one-pot method for the preparation of polysubstituted benzo[b]- and naphtho[1,2-b]-furans and -thiophenes

Cited by 28 publications

References 14 publications

Synthesis of aromatic heterocycles

Synthesis of aromatic heterocycles

Benzotriazole-Mediated Synthesis of Oxygen-Containing Heterocycles

Synthesis of regioisomeric naphtho-furans via naphthyloxyalkanals

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