Please use this identifier to cite or link to this item: https://app.uff.br/riuff/handle/1/18071
Title: NAFTOQUINONAS NATURAIS A PARTIR DO LAPACHOL E SEU EPÓXIDO CICLIZAÇÃO ELETROFÍLICA COM SAIS DE TÁLIO III E ABERTURA DO EPÓXIDO EM MEIO BÁSICO
Other Titles: Natural naphthoquinones from lapachol and its epoxide-electrophilic cyclization with thallium III salts and opening of the epoxide in basic way
Keywords: Naftoquinonas;  Lapachol;  Quinonas;  Naftoquinonas - Derivados;  Lapachol - Derivados;  Quinonas - Derivados;  Ciclização eletrofílica;  Eletrophilic cyclization;  Naphthoquinones;  Lapachol;  Quinones
Issue Date: 14-Feb-2007
Abstract: This work describes cyclization of lapachol 3 using thallium triacetate (TTA) and thallium trinitrate (TTN) in acetic anhydride, acetic anhydride/water (1: 1), acetic acid, acetic acid/water (1: 1), methanol, dimethylsulfoxide, water, tetrahydrofuran, ethyl ether and dichloromethane, as solvent, under magnetic agitation and irradiation for microwaves. In these reactions, α-xiloidone 4 was isolated as main product to a large extent of the reactions, with yields that vary of 20- 75%. On the other hand, dehidro-iso-α-lapachone 6, was gotten as main product in 21% yield, when dichloromethane TTA was used as solvent and as electrophile. The decrease of the reacional time was also observed when irradiation for microwaves was used, however the results had not been satisfactory.This work still describes the study of the opening of the epoxide of lapachol 3 in basic condictions. The reaction of 3 with MCPBA that, followed for KOH/DMSO, led to the formation of 3-hidroxi-β-lapachona (stenocarpoquinona-A) 39 and of avicequinone-C 65, both in 20% yield. Several other reactions conditions of opening of the epoxide in basic condiction had been evaluated, where optimum result was gotten enters a reaction of 3 with MCPBA in dichloromethane as solvent and Na2HPO4 as base. In this in case that it had the formation of 3-hidroxi-β-lapachone 39 and orto-furanic derivative 59 in the ratio of 1: 5.62 respectively.
URI: https://app.uff.br/riuff/handle/1/18071
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