Synthesis of Functionalized Benzopyrans via Intramolecular 1,3-Dipolar Cycloaddition of Nitrile Oxides

Vaidya, Vipraja V.; Wankhede, Karuna S.; Salunkhe, Manikrao M.; Trivedi, Gaurav

doi:10.1080/00397910802138744

Cited by 14 publications

(3 citation statements)

References 9 publications

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“…2-Aryl-3-methylidenechroman-4-ones were obtained by Mannich reaction with 2-arylchroman-4-ones [17,18] and 2-alkyl(aryl)-3-methylidenechroman-4-ones were prepared by palladium-catalyzed tandem carbonylation-allene insertion reaction [19,20]. 3-Methylidenechroman-4-one was prepared by direct α-methylidenation mediated by diisopropylammonium trifluoroacetate [21] or by dehydration of 3-hydroxymethylchromen-4-one in the presence of methanesulfonylchloride [22]. Finally, 2-alkoxycarbonylmethyl-3-methylidenechroman-4-ones were obtained from enol silyl ethers of the corresponding chroman-4-ones [23,24].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Cytotoxic Evaluation of 3-Methylidenechroman-4-ones

et al. 2019

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In the search for new anticancer agents, a library of variously substituted 3-methylidenechroman-4-ones was synthesized using Horner–Wadsworth–Emmons methodology. Acylation of diethyl methylphosphonate with selected ethyl salicylates furnished 3-diethoxyphosphorylchromen-4-ones which were next used as Michael acceptors in the reaction with various Grignard reagents. The adducts were obtained as the mixtures of trans and cis diastereoisomers along with a small amount of enol forms. Their relative configuration and preferred conformation were established by NMR analysis. The adducts turned up to be effective Horner–Wadsworth–Emmons reagents giving 2-substituted 3-methylidenechroman-4-ones, which were then tested for their possible cytotoxic activity against two leukemia cell lines, HL-60 and NALM-6, and against MCF-7 breast cancer cell line. All new compounds (14a–o) were highly cytotoxic for the leukemic cells and showed a moderate or weak effect on MCF-7 cells. Analog 14d exhibited the highest growth inhibitory activity and was more potent than carboplatin against HL-60 (IC50 = 1.46 ± 0.16 µM) and NALM-6 (IC50 = 0.50 ± 0.05 µM) cells. Further tests showed that 14d induced apoptosis in NALM-6 cells, which was mediated mostly through the extrinsic pathway.

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Section: Introductionmentioning

confidence: 99%

Synthesis and Cytotoxic Evaluation of 3-Methylidenechroman-4-ones

et al. 2019

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“…(Esquema 21). Apesar de as duas primeiras etapas desta rota terem sido realizadas com êxito, de acordo com procedimentos descritos na literatura,69 na terceira etapa, utilizando uma metodologia de redução da oxima com NaBH4, ZrCl4 e Al2O3,70 não foi possível obter a amina necessária para as reações de formilação e desidratação subseqüentes. Para a redução da oxima ainda foram testadas as condições experimentais com Pd/C 10%, H2 e HCl;71 e NaOH 72.…”

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“…Para a redução da oxima ainda foram testadas as condições experimentais com Pd/C 10%, H2 e HCl;71 e NaOH 72. Não foi obtido êxito nestas metodologias 69. Vaidya,V.…”

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Síntese de peptóides lineares e cíclicos via reação multicomponente de Ugi e cicloadição Azido/Alcino catalisada por cobre, realizada sob regime de fluxo contínuo

Salvador¹

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In this work, a convergent strategy for the synthesis of linear and cyclic peptoids via the Ugi multicomponent reaction and copper-catalyzed azide/alkyne cycloaddition under continuous flow system was developed. All conditions for the Ugi four component reaction applied to the synthesis of linear peptoids were first established by using the microwave technique, which allowed the preparation of different peptoid structures in excellent yields.The steps of the isonitrile formation and the azido acetic acid preparation were both conducted in situ without any isolation or purification of these compounds. Later, these steps were directly combined in the same continuous flow platform with the Ugi reaction, yielding in three steps, in an efficient manner, a linear peptoid in a total reaction time of 25 min. Thus, the transposition of the experimental conditions established in microwave for continuous flow was accomplished without additional optimizations. The CuAAC cyclization reaction in continuous flow through a copper reactor enabled the preparation of eight ciclopeptoids containing the triazole nucleus in good to excellent yields avoiding the use of any additive.

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PIDA Mediated Synthesis of Benzopyranoisoxazoles via an Intramolecular Nitrile Oxide Cycloaddition (INOC): Application to the Synthesis 4H‐chromeno[4,3‐c]isoxazol‐4‐ones.

Maurya,

Kumar,

Kumar

et al. 2023

Asian J Org Chem

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Presented herein is an approach for the synthesis of highly substituted tricyclic benzopyranoisoxazoles from the corresponding aldoximes via an intramolecular nitrile oxide cycloaddition (INOC) reaction using a hypervalent iodine reagent (Diacetoxyiodo)benzene (PIDA/DIB/(PhI(OAc)2) as the single inexpensive oxidizing agent. The key step involved in this reaction is a sequential intramolecular C‐C and C‐O bond formation. A variety of benzopyranoisoxazoles were constructed in moderate to high yields. In addition, some of the benzopyranoisoxazoles were converted to 4H‐chromeno[4,3‐c]isoxazol‐4‐ones via allylic oxidation using CrO3 as an oxidant.

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Synthesis of Functionalized Benzopyrans via Intramolecular 1,3-Dipolar Cycloaddition of Nitrile Oxides

Cited by 14 publications

References 9 publications

Synthesis and Cytotoxic Evaluation of 3-Methylidenechroman-4-ones

Synthesis and Cytotoxic Evaluation of 3-Methylidenechroman-4-ones

Síntese de peptóides lineares e cíclicos via reação multicomponente de Ugi e cicloadição Azido/Alcino catalisada por cobre, realizada sob regime de fluxo contínuo

PIDA Mediated Synthesis of Benzopyranoisoxazoles via an Intramolecular Nitrile Oxide Cycloaddition (INOC): Application to the Synthesis 4H‐chromeno[4,3‐c]isoxazol‐4‐ones.

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