Synthetic study for two 2<i>H</i>‐chromenic acids, 8‐chlorocannabiorcichromenic acid and mycochromenic acid

Yamaguchi, Seiji; Nedachi, Masahiro; Maekawa, Mikiko; Murayama, Yohei; Miyazawa, Masaaki; Hirai, Yoshiro

doi:10.1002/jhet.5570430105

Cited by 11 publications

(8 citation statements)

References 12 publications

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“…Compounds 5 – 10 were identified as 6-(3-carboxybutyl)-7-hydroxy-5-methoxy -4-methylphthalan-1-one [18], 7-hydroxy-6-[2-hydroxy-2-(2-methyl-5-oxotetrahydro-2-furyl) ethyl]-5-methoxy-4-methyl-1-phthalanone [10], 5-hydroxy-7-methoxy-4 –methylphtalide [19], mycochromenic acid [10,20], (−)-brevianamide C [21], and (+)-brevianamide A [22], respectively.…”

Section: Resultsmentioning

confidence: 99%

Brevianamides and Mycophenolic Acid Derivatives from the Deep-Sea-Derived Fungus Penicillium brevicompactum DFFSCS025

Zhang

Nong

et al. 2017

Marine Drugs

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Four new compounds (1–4), including two brevianamides and two mycochromenic acid derivatives along with six known compounds were isolated from the deep-sea-derived fungus Penicillium brevicompactum DFFSCS025. Their structures were elucidated by spectroscopic analysis. Moreover, the absolute configurations of 1 and 2 were determined by quantum chemical calculations of the electronic circular dichroism (ECD) spectra. Compound 9 showed moderate cytotoxicity against human colon cancer HCT116 cell line with IC50 value of 15.6 μM. In addition, 3 and 5 had significant antifouling activity against Bugula neritina larval settlement with EC50 values of 13.7 and 22.6 μM, respectively. The NMR data of 6, 8, and 9 were assigned for the first time.

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Section: Resultsmentioning

confidence: 99%

Brevianamides and Mycophenolic Acid Derivatives from the Deep-Sea-Derived Fungus Penicillium brevicompactum DFFSCS025

Zhang

Nong

et al. 2017

Marine Drugs

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“…Remarkably, this reaction also take place between phenols and , -unsaturated aldehydes under acid conditions. [27,28] Condensation between salicylaldehydes and unsaturated esters followed by a subsequent decarboxylation was also used [29][30][31] as well as oxidative cyclization of 2-allylphenols [32,33]. The present work illustrates the versatility of ytterbium triflate and its usefulness in improving the synthetic method mentioned above [3], which required the use of a pressure reactor and heating, into a room temperature experiment only requiring a stoppered glass tube.…”

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confidence: 94%

“…The present work illustrates the versatility of ytterbium triflate and its usefulness in improving the synthetic method mentioned above [3], which required the use of a pressure reactor and heating, into a room temperature experiment only requiring a stoppered glass tube. We hope that the present procedure, in combination with, for example, an ortho formylation [34] reaction of the corresponding phenols, will sometime provide a useful alternative for the preparation of benzopyran-containing compounds of biological interest [1,31,[35][36][37][38][39][40]. As a conclusion, we could also prepare, in a rather small 10% yield, the 13 C NMR spectra were recorded on a Bruker spectrometer at 400 MHz and 100 MHz, respectively.…”

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confidence: 99%

A simple two steps ytterbium triflate‐catalysed preparation of 2,2‐dimethyl‐2h‐chromenes from salicylaldehydes and 2‐methylpropene

Prado

Janin

Bost

2006

Journal of Heterocyclic Chem

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The preparation of various 2,2-dimethyl-2H-chromenes was achieved in two steps via an ytterbium triflate-catalysed reaction between salicylaldehydes, trimethylorthoformate and 2-methylpropene. From salicylaldehyde, two reaction products were characterised: 4-methoxy-2,2-dimethylchroman and 2-(1,3-dimethoxy-3-methylbutyl)phenol. The former compound probably results from a Lewis acid-catalysed [2+4] cycloaddition between the intermediate quinonemethide and 2-methylpropene whereas the latter may occur via a reaction related to a carbonyl-ene reaction between the quinonemethide and 2-methylpropene. Both compounds were subjected to a catalytic acidic treatment leading to 2,2-dimethyl-2H-chromene. Starting from various salicylaldehydes, the scope of this method was investigated.J. Heterocyclic Chem., 43, 1605Chem., 43, (2006.In the course of synthesis of biologically active chromene derivatives, [1] our attention was drawn [2] to a patent [3] reporting a simple preparation of 2,2-dimethyl-2H-chromene (2) using a reaction between salicylaldehyde (1) and 2-methylpropene catalysed by acidic silicaalumina catalysts at 150 °C or zinc chloride at 75°C. More recently [4], the preparation of furo[2,3-b]benzopyran 5 was achieved in excellent yield using the ytterbium triflate-catalysed reaction between salicylaldehyde (1), trimethylorthoformate and dihydrofuran 4. As illustrated in Scheme 1, this reaction is an example [5][6][7][8][9][10][11] We wish to report here the synthesis of various 2,2-dimethylchromenes via an ytterbium triflate-catalysed reaction between salicylaldehydes, trimethylorthoformate and 2-methylpropene.From the overnight reaction between salicylaldehyde (1), trimethylorthoformate, 2-methylpropene and ytterbium triflate in a sealed flask at room temperature, we could isolate and characterise compounds 6 and 7 in 27 and 14% yield respectively. In a control experiment, compound 6 was subjected to the reaction conditions but no ring opening into 7 took place. Moreover, from salicylaldehyde (1), no reaction was seen if trimethylorthoformate was omitted. From the results of these negative control experiments, we suggest that compound 7 occurs via a reaction related to a carbonylene reaction between the o-quinonemethide intermediate 3 and 2-methylpropene followed by a methanol addition on the resulting double bond. Carbonyl-ene reactions catalysed by lanthanide triflate have been reported [13,14] and an example of a competition between this reaction and a Diels-Alder cycloaddition was also observed [13]. An excellent review describes all the reactions that can be catalysed by lanthanides triflates [15]. As related intramolecular cycloadditions have been reported previously [9], including an iodine-catalysed example [10], we also tried iodine on our substrates but without success. In order to obtain the corresponding chromene, compounds 6 and 7 were heated to reflux in toluene in the presence of a catalytic amount of p-toluenesulfonic acid (PTSA). It is noteworthy that allowing the resulting methanol to distil fr...

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“…In view of the good stability of the long side chain substituted 2 H -chromene under high temperature, we sought to improve synthetic efficiency by building the carbazole ring in the late stage via a nitrene insertion reaction. We envisioned that the early formation of the pyran ring would reduce the number of phenol protecting groups.…”

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confidence: 99%

“…The nitro group introduction is the key of this strategy. It would not only facilitate the final nitrene insertion reaction but also mask the free amine from the very beginning, so as to mitigate complications of the basicity of the nitrogen atom and its susceptibility to oxidation . We also assumed that the nitro group would activate the pyran annulation process (vide infra). ,, …”

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confidence: 99%

Total Synthesis of 7-Hydroxymurrayazolinine, Murrayamine D, and Mahanine via m-Nitro Group Activated Pyran Annulation

et al. 2015

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The facile total synthesis of the natural product (±)-mahanine was obtained in eight steps with an overall 52% yield from readily accessible known nitrophenol derivative 6. After a one-step, acid-catalyzed annulation, two additional natural products were formed including 7-hydroxymurrayazolinine, representing its first reported total synthesis. In the whole process, the introduction of the m-nitro group significantly enhanced the key pyran annulation reaction through inductive effects.

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Synthetic study for two 2H‐chromenic acids, 8‐chlorocannabiorcichromenic acid and mycochromenic acid

Abstract: Two 2H‐chromenes having a fully substituted benzene ring, 8‐chlorocannabiorcichromene (1) and mycochromenic acid (2), were synthesized by a condensation of salicylaldehydes with isopropylidenemalonate or the thermal cyclization of corresponding propargyl ethers.

Cited by 11 publications

References 12 publications

Brevianamides and Mycophenolic Acid Derivatives from the Deep-Sea-Derived Fungus Penicillium brevicompactum DFFSCS025

Brevianamides and Mycophenolic Acid Derivatives from the Deep-Sea-Derived Fungus Penicillium brevicompactum DFFSCS025

A simple two steps ytterbium triflate‐catalysed preparation of 2,2‐dimethyl‐2h‐chromenes from salicylaldehydes and 2‐methylpropene

Total Synthesis of 7-Hydroxymurrayazolinine, Murrayamine D, and Mahanine via m-Nitro Group Activated Pyran Annulation

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