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Examinando por Autor "Thobokholt, Elida N."

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    ÍtemAcceso Abierto
    Efficient Buchwald–Hartwig and nitrene-mediated five-membered ring closure approaches to the total synthesis of quindoline. Unexpected direct conversion of a nitro group into a phosphazene
    (Royal Society of Chemistry, 2023-05-05) Thobokholt, Elida N.; Simonetti, Sebastián Osvaldo; Kaufman, Teodoro Saúl; Larghi, Enrique Leandro; Bracca, Andrea Beatriz Juana; https://orcid.org/0000-0001-5780-6433; https://orcid.org/0000-0003-4236-7380; https://orcid.org/0000-0003-3173-2178; https://orcid.org/0000-0002-9791-4831; https://orcid.org/0000-0003-2647-475X
    Two total syntheses of quindoline, which take place through the intermediacy of 3-nitroquinoline derivatives, are reported. The general synthetic sequence involves construction of the latter by mechanochemical condensation of benzaldehydes with 2-amino-nitrostyrene, followed either by reduction of the nitro group of the heterocycle and Buchwald–Hartwig cyclization or by a nitrenemediated cyclization under solventless conditions. Use of PPh3 to generate the nitrene resulted in the unprecedented formation of a phosphazene in place of quindoline. This unexpected transformation was explained by means of DFT computations.
  • Miniatura
    ÍtemAcceso Abierto
    Isolation and synthesis of cryptosanguinolentine (isocryptolepine), a naturally-occurring bioactive indoloquinoline alkaloid
    (Royal Society of Chemistry, 2020-05-19) Thobokholt, Elida N.; Larghi, Enrique Leandro; Bracca, Andrea Beatriz Juana ; Kaufman, Teodoro Saúl ; https://orcid.org/0000-0001-5780-6433; https://orcid.org/0000-0002-9791-4831; https://orcid.org/0000-0003-2647-475X; https://orcid.org/0000-0003-3173-2178
    Cryptosanguinolentine (isocryptolepine) is one of the minor naturally-occurring monomeric indoloquinoline alkaloids, isolated from the West African climbing shrub Cryptolepis sanguinolenta. The natural product displays such a simple and unique skeleton, which chemists became interested in well before it was found in Nature. Because of its structure and biological activity, the natural product has been targeted for synthesis on numerous occasions, employing a wide range of different strategies. Hence, discussed here are aspects related to the isolation of isocryptolepine, as well as the various approaches toward its total synthesis.