A novel three-component reaction of a secondary amine and a 2-hydroxybenzaldehyde derivative with an isocyanide in the presence of silica gel: an efficient one-pot synthesis of benzo[b]furan derivatives

Dialkyl 2-(alkylamino)-4,9-dihydro-9-oxocyclohepta [b]pyran-3,4-dicarboxylates are prepared in a one-pot three-component reaction of alkyl isocyanide, dialkyl acetylenedicarboxylate, and a-tropolone (¼ 2-hydroxycyclohepta-2,4,6-trienone). The reaction proceeds smoothly at room temperature and under neutral conditions to afford tropolone derivatives in high yield.Introduction. -Heterocycle-fused tropolones, an important class of compounds with varied pharmacological and biological properties have attracted great attention since the beginning of tropoid chemistry [1 -4]. The cyclohepta [b]pyran ring system is the backbone of some natural products such as paulitine (Fig.), which displays several biological activities, and some derivatives of this system exhibit platelet anti-aggregating, HIV protease inhibition, anesthetic, histaminic response-reducing, antimalarial, anti-inflammatory, and analgesic activities [5 -8]. . Also the reaction of chloro(phenyl)ketene with 2-(aminomethylidene)cycloheptanones, followed by dehydrochlorination of the primary adducts, yields 4-amino-6,7,8,9-tetrahydro-3-phenylcyclohepta[b]pyran-2(5H)-ones [14].

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“…In continuation of our previous studies on the development of new routes to heterocyclic systems (see [15] and refs. cit.…”

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confidence: 60%

Synthesis of Dialkyl 2‐(Alkylamino)‐4,9‐dihydro‐9‐oxocyclohepta[b]pyran‐3,4‐dicarboxylates

Azizian

Ramazani

Haji

2011

Helvetica Chimica Acta

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“…42 nm) as a catalyst under solvent free conditions at room temperature is developed. The ease of work-up, green chemistry conditions and fairly medium to good yields of the products makes this procedure a useful addition to modern synthetic methods [7,17]. The silica nanoparticles that used in this reaction as a catalyst were prepared by thermal decomposition of rice hulls [31].…”

Section: Resultsmentioning

confidence: 99%

Silica nanoparticles as a highly efficient catalyst for the one-pot synthesis of sterically congested 2-(dibenzylamino)-2-aryl acetamide derivatives from by phthaldehyde isomers, isocyanides and dibenzylamine

Ramazani¹,

Shaghaghi²,

Aghahosseini³

et al. 2017

Bull. Chem. Soc. Eth.

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ABSTRACT.A green and efficient method for the preparation of 2-(dibenzylamino)-2-aryl acetamide derivatives via a three-component reaction of an isocyanide, dibenzylamine and a phthalaldehyde derivative in the presence of silica nanoparticles (silica NPs, ca. 42 nm) as a catalyst under solvent free conditions at room temperature is described. The ease of work-up, green chemistry conditions and high yields of the products make this procedure a useful addition to modern synthetic methods. The silica nanoparticles that used in this reaction as a catalyst were prepared by thermal decomposition of rice hulls. Simple, green and cheap method for the preparation of the nanocatalyst represents a major advantage for this process. The structures of these compounds were confirmed by IR, 1 H and 13 C NMR spectroscopy.

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“…On the basis of the well-established chemistry of isocyanides, [19][20][21][22][23][24]26 it is reasonable to assume that the 2,5-dihydro-5-imino-2-methylfuran-3,4-dicarboxylate derivatives 4 may result from initial addition of the isocyanide to the acetylenic ester and subsequent addition to the electron-poor carbonyl group of acetic anhydride 3 leading to a dipolar specie 6. Cyclization of 6 leads then to the 2,5-dihydro-5-imino-2-methylfuran-3,4-dicarboxylate 4 (Scheme 2).…”

Section: Resultsmentioning

confidence: 99%

Very Efficient and Rapid Catalyst-free One-pot Three Component Synthesis of 2,5-Dihydro-5-imino-2-methylfuran-3,4-dicarboxylate Derivatives Under Ultrasound Irradiation

Rouhani¹,

Ramazani²,

Joo³

et al. 2012

Bulletin of the Korean Chemical Society

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A novel three-component reaction of a secondary amine and a 2-hydroxybenzaldehyde derivative with an isocyanide in the presence of silica gel: an efficient one-pot synthesis of benzo[b]furan derivatives

Cited by 91 publications

References 22 publications

Synthesis of Dialkyl 2‐(Alkylamino)‐4,9‐dihydro‐9‐oxocyclohepta[b]pyran‐3,4‐dicarboxylates

Synthesis of Dialkyl 2‐(Alkylamino)‐4,9‐dihydro‐9‐oxocyclohepta[b]pyran‐3,4‐dicarboxylates

Silica nanoparticles as a highly efficient catalyst for the one-pot synthesis of sterically congested 2-(dibenzylamino)-2-aryl acetamide derivatives from by phthaldehyde isomers, isocyanides and dibenzylamine

Very Efficient and Rapid Catalyst-free One-pot Three Component Synthesis of 2,5-Dihydro-5-imino-2-methylfuran-3,4-dicarboxylate Derivatives Under Ultrasound Irradiation

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