Diels–Alder reaction of fused pyran-2-ones with ethyl vinyl ether

Juranovič, Amadej; Kranjc, Krištof; Polanc, Slovenko; Perdih, Franc; Kočevar, Marijan

doi:10.1007/s00706-012-0734-4

Cited by 7 publications

(4 citation statements)

References 62 publications

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“…1 H NMR spectra were recorded at 29°C with a Bruker (Rheinstein, Germany) Avance DPX 300 spectrometer at 300 MHz or Bruker Avance III spectrometer at 500 MHz instruments using TMS as an internal standard. 13 C NMR spectra were recorded at 29°C with the Bruker Avance DPX 300 spectrometer at 75.5 MHz or Bruker Avance III spectrometer at 125.5 MHz and were referenced against the central line of the solvent signal (CDCl 3 triplet at 77.0 ppm or DMSO-d 6 septet at 39.5 ppm). The coupling constants (J) are given in Hertz.…”

Section: Methodsmentioning

confidence: 99%

“…2 H ‐Pyran‐2‐ones represent an easily accessible and versatile heterocyclic system that is a convenient starting point for the preparation of plethora of important and useful compounds . Previously , we have reported the application of substituted 3‐acylamino‐2 H ‐pyran‐2‐ones as dienes for the Diels–Alder reaction with phenylacetylene, 4‐chlorophenylacetylene, and some other analogues (such as vinyl ethers acting as masked acetylenes) as means for the preparation of various biphenyl systems additionally containing acylamino group. This strategy was applicable also for the preparation of a methyl derivative of boscalid, as well as for some other derivatives.…”

Section: Introductionmentioning

confidence: 99%

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Chloranil as an Efficient Oxidant of the Cyclohexadiene Intermediates Formed by a Cycloaddition of Substituted 2H‐Pyran‐2‐ones and Styrenes En Route to the Boscalid Derivatives

Suljagić

Juranovič

Krivec

et al. 2016

Journal of Heterocyclic Chem

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We describe a three‐step one‐pot metal‐free domino procedure yielding a set of boscalid derivatives, parent compound being a highly important agrochemical agent. The first step of the process consists of the Diels–Alder reaction between a substituted 2H‐pyran‐2‐one and styrene derivatives, followed by the elimination of CO2 and aromatization (oxidation). The last step was found to be efficiently promoted by the application of chloranil as the oxidant. Alternatively, activated carbon Darco KB could also act as the dehydrogenation catalyst necessitating a larger excess of the styrene to act as the hydrogen acceptor.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chloranil as an Efficient Oxidant of the Cyclohexadiene Intermediates Formed by a Cycloaddition of Substituted 2H‐Pyran‐2‐ones and Styrenes En Route to the Boscalid Derivatives

Suljagić

Juranovič

Krivec

et al. 2016

Journal of Heterocyclic Chem

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“…The same synthetic strategy of using ethyl vinyl ether (60, R 4 = Et) as a masked equivalent of acetylene was later extended also to the cases of fused pyran-2-ones, where only final, aromatized products of type 63 were isolated. 42 Application of a vinylated sugar (an appropriately protected D-glucofuranose derivative) as the dienophile for a cycloaddition with 3-methoxycarbonyl-2H-pyran-2-one afforded either the CO 2 -bridged primary adduct (after 6 days at 65 °C) or a cyclohexadiene system (after 2 days at 100 °C) amenable for the further transformation into a carbasugar-sugar pseudodisaccharide. 43 …”

Section: Scheme 17mentioning

confidence: 99%

Regio- and stereoselective syntheses and cycloadditions of substituted 2H-pyran-2-ones and their fused derivatives

Kranjc¹,

Kočevar²

2013

Arkivoc

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Microwave-assisted conditions have been shown to be very efficient for the synthesis of a variety of compounds containing 2H-pyran-2-one skeleton that plays important roles in nature and in synthetic chemistry. Furthermore, such compounds (especially those incorporating a 3-acylamino group) were shown to be efficient partners for the Diels-Alder reactions with a variety of dienophiles including acetylene derivatives, maleic anhydride, substituted maleimides, vinyl-moiety-containing dienophiles, as well as (Z)-1-methoxybut-1-en-3-yne. Reactions were carried out under conventional thermal conditions, microwave irradiation and under high pressure (13-15 kbar) and resulted in a plethora of different product types: anilines, bi-and terphenyls, indoles, isoindoles, 2-oxabicyclo[2.2.2]oct-5-enes and bicyclo[2.2.2]octenes. Many of the transformations showed remarkable regio-and stereoselectivity, depending primarily on the substitution patterns of the reactants and reaction conditions applied.

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“…[16][17][18][19][20][21] Here we applied (Z)-1-methoxybut-1-en-3-yne (4) as the dienophile cycloadding on 2H-pyran-2-one derivative 3 yielding a crucial intermediate 5, a substituted N-{2-[(Z)-2-methoxyethenyl]phenyl}benzamide (Scheme 1). This intermediate 5 has a strategically positioned methoxy group bound to the ethenyl fragment being in an ortho position to the benzamido group, therefore enabling a straightforward cyclization towards the indole ring (i.e.…”

Section: Synthesismentioning

confidence: 99%

Synthesis and Structural Evaluation of 5-Methyl-6-acetyl Substituted Indole and Gramine

Kukuljan

Kranjc

Perdih

2016

ACSi

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The synthesis and crystal structures of 1-(5-methyl-1H-indol-6-yl)ethan-1-one (7), C 11 H 11 NO, and 1-{3-[(dimethylamino)methyl]-5-methyl-1H-indol-6-yl}ethan-1-one (8), C 14 H 18 N 2 O, are reported. The synthesis is based on the Diels-Alder cycloaddition of a substituted 2H-pyran-2-one derivative, followed by an acid-catalyzed cyclization and concomitant deprotection (the last two steps were carried out as a one-pot domino process) yielding substituted indole 7, which was further derivatized via Mannich reaction to the gramine derivative 8. Both structures 7 and 8 were determined on the basis of IR, 1 H NMR and mass spectroscopy, as well as by the elemental analysis and melting point determination. According to the single-crystal X-Ray diffraction analysis, the structure 7 has a single unique molecule in the asymmetric unit whereas the structure 8 contains four unique molecules in the asymmetric unit. Molecules 7 are linked via N-H···O hydrogen bonds between the secondary amine group and carbonyl moiety of the acetyl group of adjacent molecules, whereas molecules 8 are linked via N-H···N hydrogen bonds between the secondary and tertiary amine groups of adjacent molecules. Both structures are further stabilized by weak C-H···O, C-H···π and π···π interactions.

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Diels–Alder reaction of fused pyran-2-ones with ethyl vinyl ether

Cited by 7 publications

References 62 publications

Chloranil as an Efficient Oxidant of the Cyclohexadiene Intermediates Formed by a Cycloaddition of Substituted 2H‐Pyran‐2‐ones and Styrenes En Route to the Boscalid Derivatives

Chloranil as an Efficient Oxidant of the Cyclohexadiene Intermediates Formed by a Cycloaddition of Substituted 2H‐Pyran‐2‐ones and Styrenes En Route to the Boscalid Derivatives

Regio- and stereoselective syntheses and cycloadditions of substituted 2H-pyran-2-ones and their fused derivatives

Synthesis and Structural Evaluation of 5-Methyl-6-acetyl Substituted Indole and Gramine

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