Browsing by Author "Ladawan Sumunnee"

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    Copper-catalyzed oxidative decarboxylative coupling of α-keto acids and sulfoximines
    (2017-01-01) Chaleena Pimpasri; Ladawan Sumunnee; Sirilata Yotphan; Mahidol University
    © 2017 The Royal Society of Chemistry. A copper-catalyzed oxidative decarboxylative coupling of α-keto acids with NH-sulfoximines has been developed. With CuBr as the catalyst and K2S2O8as the oxidant, this reaction enables the formation of a C-N bond and gives N-aroylsulfoximine products in moderate to excellent yields. The reaction mechanism is likely to involve the generation of a reactive aroyl radical intermediate.
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    Iodine-catalyzed expeditious synthesis of sulfonamides from sulfonyl hydrazides and amines
    (2015-01-01) Sirilata Yotphan; Ladawan Sumunnee; Danupat Beukeaw; Chonchanok Buathongjan; Vichai Reutrakul; Mahidol University
    © 2016 The Royal Society of Chemistry. A new synthesis of sulfonamides has been developed via an iodine-catalyzed sulfonylation of amines with arylsulfonyl hydrazides. This metal-free strategy employs readily accessible and easy to handle starting materials, catalysts and oxidants, and can be easily conducted under mild conditions, providing a convenient access to a wide range of sulfonamides in moderate to excellent yields within a short reaction time.
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    Iodine/TBHP-Promoted One-Pot Deoxygenation and Direct 2-Sulfonylation of Quinoline N-Oxides with Sodium Sulfinates: Facile and Regioselective Synthesis of 2-Sulfonylquinolines
    (2017-01-01) Ladawan Sumunnee; Chonchanok Buathongjan; Chaleena Pimpasri; Sirilata Yotphan; Mahidol University
    © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim A highly efficient iodine/TBHP-mediated one-pot deoxygenative and regioselective 2-sulfonylation of quinoline N-oxides with sodium sulfinate salts has been developed. This metal-, base-, and phosphorus-free protocol employs readily accessible and easy-to-handle reagents and can be conveniently carried out at room temperature under mild conditions, providing an alternative access to a series of 2-sulfonylquinolines and other related heteroaryl sulfone products in moderate-to-excellent yields within a short reaction time.
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    Metal-free direct oxidative C-C bond coupling of pyrazolones and quinoxalinones
    (2018-06-21) Saowanee Toonchue; Ladawan Sumunnee; Khamphee Phomphrai; Sirilata Yotphan; Vidyasirimedhi Institute of Science and Technology; Mahidol University
    © the Partner Organisations 2018. A highly efficient transition metal-free oxidative chemo- and regioselective C-C bond coupling of pyrazolones and quinoxalinones mediated by K2S2O8 is described. This reaction can be conveniently carried out under mild conditions and gives various hydroxy-pyrazolyl quinoxalinone products in moderate to excellent yields in a short reaction time.
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    Persulfate-promoted oxidative C-N bond coupling of quinoxalinones and: NH -sulfoximines
    (2018-01-01) Ladawan Sumunnee; Chaleena Pimpasri; Medena Noikham; Sirilata Yotphan; Mahidol University
    © The Royal Society of Chemistry. The persulfate-meditated oxidative C-N bond coupling of the C-H bond of quinoxalinones and the N-H bond of NH-sulfoximines is reported. The reaction proceeds smoothly under transition metal-free conditions and provides good to excellent yields of sulfoximidoyl-functionalized quinoxalinone products under mild conditions. The optimized conditions were found to be suitable for a range of sulfoximine and quinoxalinone substrates. This reaction offers a new and convenient strategy to directly install the sulfoximine moiety into the C3 position of quinoxalinone.