- Catalyst-Controlled Regioselective Chlorination of Phenols and Anilines through a Lewis Basic Selenoether Catalyst
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We report a highly efficient ortho-selective electrophilic chlorination of phenols utilizing a Lewis basic selenoether catalyst. The selenoether catalyst resulted in comparable selectivities to our previously reported bis-thiourea ortho-selective catalyst, with a catalyst loading as low as 1%. The new catalytic system also allowed us to extend this chemistry to obtain excellent ortho-selectivities for unprotected anilines. The selectivities of this reaction are up to >20:1 ortho/para, while the innate selectivities for phenols and anilines are approximately 1:4 ortho/para. A series of preliminary studies revealed that the substrates require a hydrogen-bonding moiety for selectivity.
- Dinh, Andrew N.,Maddox, Sean M.,Vaidya, Sagar D.,Saputra, Mirza A.,Nalbandian, Christopher J.,Gustafson, Jeffrey L.
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p. 13895 - 13905
(2020/11/03)
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- A shan tiefen derivative and its synthetic method and application in pesticide
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The invention relates to a shan tiefen derivative and its synthetic method and in pesticide application, especially in the application of the pesticide in the fungicide, which belongs to the technical field of agricultural chemicals. The invention solves the technical problem is to provide a new shan tiefen derivative and its synthetic method and in pesticide application, the structure of this compound is shown as formula I. This compound the structure is simple, novel, easy to synthesize, at the same time having fungicidal activity, the tomato alteso, zones all of tomato, cucumber wilt disease, magnaporthe grisea, galenical such important plant pathogenic fungi, have better bacteriostatic or bactericidal effect.
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Paragraph 0036-0039
(2019/07/08)
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- Semisynthetic Phenol Derivatives Obtained from Natural Phenols: Antimicrobial Activity and Molecular Properties
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Semisynthetic phenol derivatives were obtained from the natural phenols: thymol, carvacrol, eugenol, and guaiacol through catalytic oxychlorination, Williamson synthesis, and aromatic Claisen rearrangement. The compounds characterization was carried out by 1H NMR, 13C NMR, and mass spectrometry. The natural phenols and their semisynthetic derivatives were tested for their antimicrobial activity against the bacteria: Staphylococcus aureus, Escherichia coli, Listeria innocua, Pseudomonas aeruginosa, Salmonella enterica Typhimurium, Salmonella enterica ssp. enterica, and Bacillus cereus. Minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values were determined using concentrations from 220 to 3.44 μg mL-1. Most of the tested compounds presented MIC values ≤220 μg mL-1 for all the bacteria used in the assays. The molecular properties of the compounds were computed with the PM6 method. Through principle components analysis, the natural phenols and their semisynthetic derivatives with higher antimicrobial potential were grouped.
- Pinheiro, Patrícia Fontes,Menini, Luciana Alves Parreira,Bernardes, Patrícia Campos,Saraiva, Sérgio Henriques,Carneiro, José Walkimar Mesquita,Costa, Adilson Vidal,Arruda, Társila Rodrigues,Lage, Mateus Ribeiro,Gon?alves, Patrícia Martins,Bernardes, Carolina De Oliveira,Alvarenga, Elson Santiago,Menini, Luciano
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p. 323 - 330
(2018/01/17)
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- Highly Selective Synthesis of Chlorophenols under Microwave Irradiation
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Oxychlorination of various phenols is finished in 60 minutes with high efficiency and perfect selectivity under microwave irradiation. These reactions adopt copper(II) chloride (CuCl2) as the catalyst and hydrochloric acid as chlorine source instead of expensive and toxic ones. Oxychlorination of phenols substituted with electron donating groups (methyl, methoxyl, isopropyl, etc.) at ortho- and meta-positions is accomplished with higher conversion rates, lower reaction time, and excellent selectivity. A proposed reaction mechanism is deduced; one electron transfers from CuCl2 to phenol followed by the formation of tautomeric radical that can be rapidly captured by chlorine atom and converts into para-substituted product.
- Xiong, Yawen,Duan, Hongdong,Meng, Xia,Ding, Zhaoyun,Feng, Weichun
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- Enzymatic halogenation of the phenolic monoterpenes thymol and carvacrol with chloroperoxidase
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The conversion of the phenolic monoterpenes thymol and carvacrol into antimicrobials by (electro)-chemoenzymatic halogenation was investigated using a chloroperoxidase (CPO) catalyzed process. The CPO catalysed process enables for the first time the biotechnological production of chlorothymol, chlorocarvacrol and bromothymol as well as a dichlorothymol with high conversion rates, total turnover numbers and space time yields of up to 90%, 164000 and 4.6 mM h -1, respectively.
- Getrey, Laura,Krieg, Thomas,Hollmann, Frank,Schrader, Jens,Holtmann, Dirk
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p. 1104 - 1108
(2014/03/21)
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- Identification and structure-activity relationship study of carvacrol derivatives as Mycobacterium tuberculosis chorismate mutase inhibitors
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In the present study, we identified carvacrol, a major phenolic component of oregano oil as a novel small molecule inhibitor of Mycobacterium tuberculosis (MTB) chorismate mutase (CM) enzyme with IC50 of 1.06±0.4μM. Virtual screening of the BITS-Pilani in-house database using the crystal structure of the MTB CM bound transition state intermediate (PDB: 2FP2) as framework identified carvacrol as a potential lead. Further various carvacrol derivatives were evaluated in vitro for their ability to inhibit MTB CM enzyme, whole cell MTB and cytotoxicity as steps toward the derivation of structure-activity relationships (SAR) and lead optimization.
- Alokam, Reshma,Jeankumar, Variam Ullas,Sridevi, Jonnalagadda Padma,Matikonda, Siddharth Sai,Peddi, Santosh,Alvala, Mallika,Yogeeswari, Perumal,Sriram, Dharmarajan
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p. 547 - 554
(2014/08/05)
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- Synthesis of halogenated derivatives of thymol and their antimicrobial activities
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In order to test the antibacterial and antifungal activities of different halogenated thymol derivatives, thymol has been converted into chlorothymol, dichlorothymol with N-chlorosuccinimide; monobromothymol, dibromothymol with N-bromosuccinimide; O-methylated iodothymol with ceric ammonium nitrate and iodine from methylated thymol. Among the different derivatives tested, 4-chlorothymol was found to be most active against Staphylococcus aureus and Staphylococcus epidermis at a concentration of 12.5 and 25 ppm, respectively. Also it was tested to be active against Candida albicans (AI). Springer Science+Business Media 2013.
- Kaur, Ranjeet,Darokar, Mahendra P.,Chattopadhyay, Sunil Kumar,Krishna, Vinay,Ahmad, Ateeque
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p. 2212 - 2217
(2014/05/06)
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- High-yielding cleavage of (aryloxy)acetates
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A reliable and high-yielding one-pot sequence for the removal of O-carboxymethyl moieties from phenols is presented. When diethylphosphoryl azide is employed as the azide transfer reagent in the Curtius rearrangement and glycerol in the subsequent hydrolytic workup, the protocol can be reliably applied to a very broad scope of substrates. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Spurg, Anke,Waldvogel, Siegfried R.
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p. 337 - 342
(2008/09/18)
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- Reliable and general method for the cleavage of α-arylheteroatom- substituted carboxylic acids
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Bonds between arylheteroatom moieties and α-carbons of carboxylic acids are efficiently cleft by azide transfer and subsequent Curtius rearrangement. The scope of the one-pot protocol covers differently substituted carboxylic acids and heteroatoms like O, S, Se, and N. Georg Thieme Verlag Stuttgart.
- Spurg, Anke,Waldvogel, Siegfried R.
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p. 3042 - 3044
(2008/03/12)
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- Novel highly selective catalytic oxychlorination of phenols
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The highly selective oxychlorination of various phenols catalyzed by CuCl2 under mild conditions, in which chloride ions are used as chlorinating agents and dioxygen as a final oxidant, has been developed. The Royal Society of Chemistry 2006.
- Menini, Luciano,Gusevskaya, Elena V.
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p. 209 - 211
(2008/02/07)
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