- Oxygen-Free Regioselective Biocatalytic Demethylation of Methyl-phenyl Ethers via Methyltransfer Employing Veratrol- O-demethylase
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The cleavage of aryl methyl ethers is a common reaction in chemistry requiring rather harsh conditions; consequently, it is prone to undesired reactions and lacks regioselectivity. Nevertheless, O-demethylation of aryl methyl ethers is a tool to valorize natural and pharmaceutical compounds by deprotecting reactive hydroxyl moieties. Various oxidative enzymes are known to catalyze this reaction at the expense of molecular oxygen, which may lead in the case of phenols/catechols to undesired side reactions (e.g., oxidation, polymerization). Here an oxygen-independent demethylation via methyl transfer is presented employing a cobalamin-dependent veratrol-O-demethylase (vdmB). The biocatalytic demethylation transforms a variety of aryl methyl ethers with two functional methoxy moieties either in 1,2-position or in 1,3-position. Biocatalytic reactions enabled, for instance, the regioselective monodemethylation of substituted 3,4-dimethoxy phenol as well as the monodemethylation of 1,3,5-trimethoxybenzene. The methyltransferase vdmB was also successfully applied for the regioselective demethylation of natural compounds such as papaverine and rac-yatein. The approach presented here represents an alternative to chemical and enzymatic demethylation concepts and allows performing regioselective demethylation in the absence of oxygen under mild conditions, representing a valuable extension of the synthetic repertoire to modify pharmaceuticals and diversify natural products.
- Grimm, Christopher,Lazzarotto, Mattia,Pompei, Simona,Schichler, Johanna,Richter, Nina,Farnberger, Judith E.,Fuchs, Michael,Kroutil, Wolfgang
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p. 10375 - 10380
(2020/10/02)
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- 3-site piperazinylchalcone derivative, and pharmaceutical composition and applications thereof
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The present invention relates to a 3-site piperazinylchalcone derivative, which has a structure formula represented by a general formula (I) defined in the specification, wherein R is one selected from a substituted or unsubstituted phenyl group, a fused ring group and substituted or a unsubstituted heterocyclic group. The present invention further provides a pharmaceutical composition of the3-site piperazinylchalcone derivative, and applications thereof. According to the present invention, the results of the activity test based on P-gp target show that the 3-site piperazinylchalcone derivative and the pharmaceutical composition have good activity, can provide practical value in the treatment of the multidrug resistance of tumors, can solve the technical problems of difficult synthesis and high cost in the synthesis of the reversing agent used in the prior art, and is meaningful.
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Paragraph 0084-0088
(2019/02/04)
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- Design, synthesis and biological evaluation of chalcones as reversers of P-glycoprotein-mediated multidrug resistance
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Overexpression of P-glycoprotein (P-gp) is one of the major causes for multidrug resistance (MDR), which has become a major obstacle in cancer therapy. One hopeful approach to reverse the MDR is to develop inhibitors of P-gp in expression and/or function. Here, we designed and synthesized a series of chalcone derivatives as P-gp inhibitors and evaluated their potential reversal activities against MDR. Among them, the most active compound MY3 had little intrinsic cytotoxicity and showed the highest activity (RF = 50.19) in reversing DOX resistance in MCF-7/DOX cells. Further studies demonstrated that MY3 could increase intracellular accumulation of DOX and inhibit expression of P-gp at mRNA and protein levels. More importantly, MY3 significantly enhanced the efficacy of DOX against the tumor xenografts bearing MCF-7/DOX cells with the precondition of unchanged body weight. Therefore, MY3 might represent a promising lead to develop MDR reversal agents for cancer chemotherapy.
- Yin, Huanhuan,Dong, Jingjing,Cai, Yingchun,Shi, Ximeng,Wang, Hao,Liu, Guixia,Tang, Yun,Liu, Jianwen,Ma, Lei
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p. 350 - 366
(2019/07/19)
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- INTRODUCTION OF ALKYL SUBSTITUENTS TO AROMATIC COMPOUNDS
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Novel selective synthesis route to introduce primary alkyl groups on aromatic compounds is disclosed. The synthesis route is based on electrophilic aromatic substitutions of thionium ion species that are generated in-situ from aldehydes and thiols, affording benzyl sulfide that can be reduced with triethylsilane.
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Page/Page column 56
(2016/09/15)
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- Reductive Alkylation of Arenes by a Thiol-Based Multicomponent Reaction
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A simple and highly chemo- and regioselective method for introducing primary alkyl substituents into aromatic compounds was developed. The method is based on an electrophilic aromatic substitution of an aldehyde, promoted by a thiol, to afford 1-(alkylthio)alkylarenes, which can either be reduced in situ with triethylsilane or reacted further. This multicomponent reaction enables the direct introduction of both aromatic and linear and branched aliphatic alkyl groups into arenes. The above one-pot protocol may be performed in air and in the presence of water and is compatible with various functional groups.
- Parnes, Regev,Pappo, Doron
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p. 2924 - 2927
(2015/06/30)
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- Synthetic Flavonoids and Pharmaceutical Compositions and Therapeutic Methods of Treatment of HIV infection and other pathologies
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A compound, pharmaceutical composition and method for the treatment of mammals wherein the active therapeutic agent is a compound having the structure: wherein: R1 is an electronegative substituent, R2 is R1 or alkyl,R3 is H or O-alkyl,R4 and R5 are the same or different and are alkyl andR6 is H or OH.
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Page/Page column 4
(2012/10/23)
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- Synthesis of novel flavonoid derivatives as potential HIV-integrase inhibitors
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Eighteen novel flavonoid derivatives - substituted chalcones and flavones were synthesized and characterized by using NMR, IR, UV/Vis spectroscopy and elemental analysis. The target compounds were achieved by using a sequence of simple and effective reactions starting from phloroglucinol. The initial hydroxyl groups were protected by methylation and in the final flavones the 5-OH group was selectively demethylated by means of AlBr3. 5-methoxy flavones exhibit a strong fluorescence, which was quenched after the removal of the methyl group.
- Mateeva, Nelly N.,Kode, Rao N.,Redda, Kinfe K.
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p. 1251 - 1258
(2007/10/03)
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- Natural Benzofurans. Synthesis of Moracin A and B
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2-(3,5-Dihydroxyphenyl)-4,6-dimethoxybenzofuran (Moracin A) and 2-(3-hydroxy-5-methoxyphenyl)-5-hydroxy-6-methoxybenzofuran (Moracin B), phytoalexins isolated from diseased mulberry have been synthesized by short routes in which the benzofuran heterocyclic system is formed by an intramolecular Wittig reaction.
- Burke, John M.,Stevenson, Robert
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p. 451 - 466
(2007/10/02)
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