533-73-3Relevant articles and documents
Titanosilicate molecular sieve for size-screening photocatalytic conversion
Shiraishi, Yasuhiro,Saito, Naoya,Hirai, Takayuki
, p. 8304 - 8306 (2005)
Titanosilicate molecular sieves, when activated by ultraviolet light irradiation in water in the presence of molecular oxygen, catalyze a conversion of molecules having a size close to the pore of the catalysts but are inactive for molecules having much larger or smaller size. This unprecedented size-screening photocatalytic activity is triggered by a combination of H2O-induced shortened lifetime of active species (charge-transfer excited state of tetrahedrally coordinated titanium oxide) and restricted diffusion of a molecule inside the pore. This catalytic property demonstrates a potential utility of the catalyst for selective transformation of molecules that is associated with a size reduction of molecules, so-labeled molecular shave transformation. Copyright
Metabolism of halohydroquinones in Rhodococcus chlorophenolicus PCP-1
Uotila, J. S.,Kitunen, V. H.,Coote, T.,Saastamoinen, T.,Salkinoja-Salonen, M.,Apajalahti, J. H. A.
, p. 119 - 126 (1995)
The actinomycete Rhodococcus chlorophenolicus PCP-1 metabolises pentachlorophenol into ultimate inorganic end products via tetrachloro-p-hydroquinone. This intermediate was further dehalogenated in the cytoplasm requiring reductant in the cell free system. Tetrafluoro-p-hydroquinone and tetrabromo-p-hydroquinone were also dehalogenated. Chlorophenol analogs, thiol blocking agents and molecular oxygen inhibited the activity. The dehalogenating reactions led to 1,2,4-trihydroxybenzene, which was further metabolized into maleic acid.
Preparation method of sesamol
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, (2021/11/21)
The invention belongs to the technical field of compound synthesis, and particularly relates to a preparation method of sesamol, which firstly prepares 2 -chloro -1, 4 -diphenol, and then 2 - chlorine -1, 4 -biphenol and sodium hydroxide in an aqueous solution to obtain the sesamol, namely 1 2, 1 2 4 - 4 -triphenol and dichloromethane. The invention provides a new method for preparing the sesame phenol, and the yield of the sesamol is remarkably improved.
Enhanced nonradical catalytic oxidation by encapsulating cobalt into nitrogen doped graphene: highlight on interfacial interactions
Yu, Xiaoyong,Wang, Lijing,Wang, Xin,Liu, Hongzhi,Wang, Ziyuan,Huang, Yixuan,Shan, Guoqiang,Wang, Weichao,Zhu, Lingyan
supporting information, p. 7198 - 7207 (2021/03/29)
Supported metal catalysts are widely used for heterogeneous catalytic processes (e.g., Fenton-like reaction), but the mechanisms of interfacial processes are still ambiguous. Herein, unique nanocarbon based catalysts with Co nanoparticles encapsulated in
Antagonistic activity of hydroxycoumarin-based antioxidants as possible singlet oxygen precursor photosensitizers
Guerrero, Tomás,Vázquez-Ortega, Fernanda,Lagunes, Irene,Ortiz-Blanco, Erik,Sosa-Ortiz, Gabriela,Tovar-Miranda, Ricardo,Medina, Manuel E.,Trigos, ángel
, (2021/05/10)
Coumarins are phenolic-type compounds with efficient antioxidant activity due to their ability to scavenge reactive oxygen species. Nevertheless, their ability to behave as photosensitizers capable of generating reactive oxygen species, such as singlet oxygen, has been less studied. In this work, the photosensitizing ability of seven hydroxycoumarins was evaluated through the photooxidation of ergosterol by quantifying the conversion of ergosterol into ergosterol peroxide. In our experimental conditions, we found that almost every tested antioxidant coumarin promotes the peroxidation of ergosterol. The results suggest that the hydroxycoumarins exhibit potential photosensitizing activity by promoting singlet oxygen generation by a Type II photochemical mechanism. Density functional theory (DFT) calculations were also performed to obtain further insight into the chemical reactivity of tested compounds; the observed tendency in the group of antioxidant coumarins to promote the reaction was their hardness due to the principle of maximum hardness. To evaluate our conclusion, we performed the reaction using a highly polarizable coumarin as a photosensitizer, which resulted in an increased photosensitizing capacity supported with DFT calculations, which reinforces our analysis. Finally, we found that hydroxycoumarins can be potentially pro-oxidants since some of them can act as photosensitizers and generate singlet oxygen in the presence of UV–Vis light, a characteristic that must be considered when these compounds are used as antioxidants.
Mannich bases of hydroxycoumarins: Synthesis, DFT/QTAIM computational study and assessment of biological activity
Castro, María Eugenia,Durand-Niconoff, J. Sergio,Fernández-Pomares, Cynthia,Guerrero, Tomás,Juárez-Aguilar, Enrique,Melendez, Francisco J.,Montoya-Hernández, Eva Luz,Olivares-Romero, José L.,Ortiz-Blanco, Erik,Sosa-Ortiz, Gabriela,Tovar-Miranda, Ricardo
, p. 31260 - 31271 (2021/11/30)
The synthesis of six Mannich bases derived from hydroxycoumarins was carried out in moderate yields, two of these derivatives were described for the first time. Conformational analysis was performed through DFT theoretical calculations explaining the formation of stable six membered rings based on intramolecular hydrogen bonds within the structure. These findings were correlated with the antiproliferative activity. The biological activity of the Mannich bases through their antiproliferative activity in the HeLa cancer cell line is described for the first time, showing that the compounds were able to inhibit proliferation in cervical cancer by more than 60%. Likewise, the theoretical modeling of the photophysical properties was realized with promising results, showing that the HOMO-LUMO energies of the new compounds present the lowest electronic gap values for those with donor groups in their structure, which makes them potential fluorophores. This journal is
Synthesis of renewable C-C cyclic compounds and high-density biofuels using 5-hydromethylfurfural as a reactant
Cai, Taimei,Deng, Qiang,Deng, Shuguang,Gao, Rui,Peng, Hailong,Wang, Jun,Zeng, Zheling,Zhong, Jin,Zou, Ji-Jun
, p. 2468 - 2473 (2020/05/14)
The major challenge in the synthesis of high-density biofuels is to identify the bio-based source for C-C cyclic compounds and C-C coupling reactions with a suitable selectivity. Herein, we selectively synthesize 1,2,4-benzenetriol (BTO) with a yield of 51.4% from cellulose-derived 5-hydromethylfurfural via a ring-rearrangement reaction. The cellulose-derived route is a more meaningful route for the C-C cyclic compounds compared to the traditional hemicellulose- and lignin-derived routes. Furthermore, BTO is very easily dimerized via a C-C oxidative coupling reaction, showing a yield of 94.4% and selectivity of nearly 100% under environmentally friendly reaction conditions. After hydrodeoxygenation, bicyclohexane is obtained with a yield of 87.4%. This work not only provides a promising route to produce C-C cyclic fine compounds based on a cellulose-derived route, but also shows a highly efficient synthesis route for high-density biofuels via the C-C oxidative coupling reaction.
Br?nsted Acid Catalyzed Tandem Defunctionalization of Biorenewable Ferulic acid and Derivates into Bio-Catechol
Bal, Mathias,Bomon, Jeroen,Liao, Yuhe,Maes, Bert U. W.,Sels, Bert F.,Sergeyev, Sergey,Van Den Broeck, Elias,Van Speybroeck, Veronique
supporting information, p. 3063 - 3068 (2020/02/05)
An efficient conversion of biorenewable ferulic acid into bio-catechol has been developed. The transformation comprises two consecutive defunctionalizations of the substrate, that is, C?O (demethylation) and C?C (de-2-carboxyvinylation) bond cleavage, occurring in one step. The process only requires heating of ferulic acid with HCl (or H2SO4) as catalyst in pressurized hot water (250 °C, 50 bar N2). The versatility is shown on a variety of other (biorenewable) substrates yielding up to 84 % di- (catechol, resorcinol, hydroquinone) and trihydroxybenzenes (pyrogallol, hydroxyquinol), in most cases just requiring simple extraction as work-up.
CONCERTED PROCESSES FOR FORMING 1,2,4-TRIHYDROXYBENZENE FROM HYDROQUINONE
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, (2018/04/26)
Flow batteries incorporating an active material with one or more catecholate ligands can have a number of desirable operating features. Commercial syntheses of catechol produce significant quantities of hydroquinone as a byproduct, which presently has limited value in the battery industry and can represent a significant waste disposal issue at industrial production scales. Using a concerted, high-yield process, low-value hydroquinone can be transformed into high-value 1,2,4-trihydroxybenzene, which can be a desirable ligand for active materials of relevance in the flow battery industry. Methods for forming 1,2,4-trihydroxybenzene can include: oxidizing hydroquinone in a first reaction to form p-benzoquinone, converting the p-benzoquinone in a second reaction to form 1,2,4-triacetoxybenzene, deacetylating the 1,2,4-triacetoxybenzene in a third reaction to form 1,2,4-trihydroxybenzene, and isolating the 1,2,4-trihydroxybenzene after performing the first reaction, the second reaction and the third reaction consecutively.
Insight into sulfamethoxazole degradation, mechanism, and pathways by AgBr-BaMoO4 composite photocatalyst
Ray, Schindra Kumar,Dhakal, Dipesh,Lee, Soo Wohn
, p. 686 - 695 (2018/07/14)
A composite photocatalyst, AgBr-BaMoO4 was fabricated by two step method; microwave hydrothermal and precipitation-deposition. The as prepared photocatalyst samples were characterized by various techniques. The facet coupling was seen between the (204) plane of BaMoO4 and (200)/(222) planes of AgBr on the basis of XRD/HRTEM analysis. The pharmaceutical pollutant, sulfamethoxazole was adopted to investigate the photocatalytic performances of samples under UV–vis irradiation. The AgBr-BaMoO4 composite degraded the aqueous sulfamethoxazole drug in UV–vis light about 64% within 75 min, which was attributed to efficient separation of photogenerated electron–hole pairs across the interface between Ag/AgBr and BaMoO4. The multi-electron induced oxygen reduced reaction (ORR) was observed. The radical trapping experiment indicates that OH? has major role for sulfamethoxazole degradation. The four successive photodegradation of sulfamethoxazole in UV–vis light indicates the stability of composite photocatalyst. Furthermore, the three different degradation pathways were designed on the basis of retention time and molecular masses of 18 degraded organic fragments that was confirmed by high-performance liquid chromatography photodiode array (HPLC-PDA) and high resolution-quadruple time of flight electrospray ionization mass spectroscopy (HR-QTOF ESI/MS) techniques. The total organic carbon (TOC) analysis suggested the mineralization of SMZ by composite photocatalyst. This study not only demonstrates the enhancement of photocatalytic performance of wide band gap semiconductor by making composite with narrow band gap semiconductor but also detail degradation pathways and mechanisms of sulfamethoxazole.
