- METHOD FOR PREPARING CRISABOROLE
-
The invention relates to a method for preparing Crisaborole of Formula I, comprising using m-methylphenol as the starting material to obtain a target product through a five-step reaction. The starting materials and the raw materials used in each step of the method according to the present invention are cheap and easy to obtain, and the process is simple. The reaction of introducing boron atoms into the benzene ring to form an oxygen boron heterocycle is novel, with high yield and mild conditions, and is suitable for industrial production.
- -
-
Paragraph 0086-0093
(2021/02/26)
-
- Regioselective monobromination of phenols with KBr and ZnAl–BrO3?–layered double hydroxides
-
The regioselective mono-bromination of phenols has been successfully developed with KBr and ZnAl–BrO3?–layered double hydroxides (abbreviated as ZnAl–BrO3?–LDHs) as brominating reagents. The para site is much favorable and the ortho site takes the priority if para site is occupied. This reaction featured with excellent regioselectivity, cheap brominating reagents, mild reaction condition, high atom economy, broad substrate scope, and provided an efficient method to synthesize bromophenols.
- Wang, Ligeng,Feng, Chun,Zhang, Yan,Hu, Jun
-
supporting information
(2020/02/22)
-
- SELECTIVE BTK IRREVERSIBLE INHIBITORS
-
The invention provides a series of conformationally stable and selective, irreversible kinase inhibitors, and methods of using the kinase inhibitors. The effect of atropisomerism on kinase selectivity was assessed, finding improved selectivity compared to rapidly interconverting parent compounds. The compounds herein are atropisomers having increased kinase selectivity and are for use in treating conditions that benefit from selective BTK kinase inhibition.
- -
-
Page/Page column 30-31
(2021/01/23)
-
- Synthesis of natural product inulavosin via Ga(OTf)3-Catalyzed Hetero Diels–Alder Dimerization of salicyl alcohol derivative
-
Inulavosin, a natural melanogenesis inhibitor, has been synthesized smoothly from readily available and inexpensive starting materials by using a Ga(OTf)3-catalyzed room temperature hetero Diels–Alder dimerization of salicyl alcohol derivative and a regioselective phenol monobromination as the key steps.
- Gong, Pi-Xian,Li, Hui-Jing,Wang, Meirong,Cheng, Yun-Fei,Wu, Yan-Chao
-
supporting information
p. 2911 - 2916
(2018/10/15)
-
- Mild and Regioselective Bromination of Phenols with TMSBr
-
In this work, an unexpected promoting effect of by-product thioether was observed, leading to a mild and regioselective bromination of phenols with TMSBr. This method can tolerate a series of functional groups such as the reactive methoxyl, amide, fluoro, chloro, bromo, aldehyde, ketone and ester groups, and has the potential to recycle the by-product thioether and isolate the desired product under column chromatography-free conditions. Mechanism studies revealed that O–H···S hydrogen bond may be formed between phenol and by-product thioether. Possibly owing to the steric hindrance effect from by-product thioether, the electrophilic bromination at para-position of phenols is much favorable.
- Ma, Xiantao,Yu, Jing,Jiang, Mengyuan,Wang, Mengyu,Tang, Lin,Wei, Mengmeng,Zhou, Qiuju
-
supporting information
p. 4593 - 4596
(2019/07/05)
-
- A phenol compound high regioselective bromination method
-
The invention discloses a phenol compound high regioselective bromination of the method, the method to trimethyl silane as brominating agent, in order to aryl sulfoxide as activator, with the phenol compound in the 0 - 50 °C lower, in a solvent, the reaction is stirred under an atmosphere of nitrogen at 1 - 12 hours, to realize the phenol compound high regioselective bromination, filtered, extraction columns chromatography separation to obtain the bromo phenol compound. This invention adopts the aryl sulfoxide as activator, sulfoxide substituted Kiev, on the one hand so that the phenol compound bromo the higher selectivity of the reaction region, and when the phenol compound hydroxy alignment not substituted basetime, regional selective para - bromo product, when the phenol compound hydroxy position there is substituted basetime, selective ortho - bromo product obtained; on the other hand if it through the filter, the extraction can be realized at the same time the isolation and purification of the recycling of the by-product, compared with column chromatography, reduces the separation and purification cost.
- -
-
Paragraph 0025; 0026; 0027
(2019/06/05)
-
- o-xylylene bis(triethyl ammonium tribromide) as a mild and recyclable reagent for rapid and regioselective bromination of anilines and phenols
-
Background: o-Xylylene bis(triethyl ammonium tribromide) (OXBTEATB) as a recyclable and high bromine containing di-(tribromide) reagent has been employed for the bromination of various organic substrates such as phenol and aniline or its derivatives. This catalyst can be recovered and reused several times. Methods: Aryl bromides shown in Table 1, were easily produced from bromination of aromatic compounds by OXBTEATB. This high-yield process lets the reagents to be recycled and reused. Results: As shown in Table 1, substituted anilines, phenols and β-naphthol were found to be the most reactive and immediately converted to the corresponding mono-brominated products by OXBTEATB. Conclusion: OXBTEATB can be considered a solidified bromine. This novel reagent has variable solubility in different polar protic and aprotic solvents but insoluble in non-polar aprotic solvent. Subsequently, OXBTEATB can be recognized as a more useful brominating and regioselective catalyst than the liquid bromine.
- Hemati, Roya,Shahvelayati, Ashraf S.,Yadollahzadeh, Khadijeh
-
p. 682 - 687
(2018/07/14)
-
- 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane: An efficient and high oxygen content oxidant in various oxidative reactions
-
Several oxidative approaches namely thiocyanation of aromatic compounds, epoxidation of alkenes, amidation of aromatic aldehydes, epoxidation of α β-unsaturated ketones, oxidation of sulfides to sulfoxides and sulfones, bayer-villeger reaction, bromination and iodation of aniline and phenol derivatives oxidative esterification, oxidation of pyridines and oxidation of secondary, allylic and benzyllic alcohols were carried out using 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane as the potential solid oxidant which can be stored for several months without any loss in its activity. All of the procedures were accomplished via mild reaction conditions and the products were afforded in high yields and short reaction times.
- Khosravi, Kaveh,Naserifar, Shirin
-
supporting information
p. 6584 - 6592
(2018/10/05)
-
- Ultrasonically assisted halogenation of aromatic compounds using isoquinolinium bound hypervalent chromium and tetrabutylammonium halides in PEG-600 solutions under acid free and solvent-free conditions
-
Isoquinolinium bound Cr(VI) reagents like isoquinolinium dichromate (IQDC) and isoquinolinium chlorochromate (IQCC) have been successfully accomplished as efficient reagents for oxidative halogenation of aromatic compounds using tetrabutylammonium halide (TBAX) as halogenating agents in aqueous polyethylene glycol (PEG-600) under acid free conditions. Tetrabutylammonium bromide (TBAB) has been used for bromination and tetrabutylammonium iodide (TBAI) for iodination. The halogenation reactions that occurred smoothly in 2 to 7 h under conventional conditions are accelerated magnificently under sonication with few minutes (25 to 70 min) of reaction time and fairly good yields. The reactions occurred at moderate temperature under mild and environmentally safe conditions with simple work up.
- Sambashiva Rao,Ramesh, Kola,Rajanna,Chakrvarthi
-
p. 1892 - 1896
(2018/07/10)
-
- Regioselective Halogenation of Arenes and Heterocycles in Hexafluoroisopropanol
-
Regioselective halogenation of arenes and heterocycles with N-halosuccinimides in fluorinated alcohols is disclosed. Under mild condition reactions, a wide diversity of halogenated arenes are obtained in good yields with high regioselectivity. Additionally, the versatility of the method is demonstrated by the development of one-pot sequential halogenation and halogenation-Suzuki cross-coupling reactions.
- Tang, Ren-Jin,Milcent, Thierry,Crousse, Benoit
-
p. 930 - 938
(2018/01/28)
-
- Examination of Selectivity in the Oxidation of ortho- and meta-Disubstituted Benzenes by CYP102A1 (P450 Bm3) Variants
-
Cytochrome P450 CYP102A1 (P450 Bm3) variants were used to investigate the products arising from the P450 catalysed oxidation of a range of disubstituted benzenes. The variants used all generated increased levels of metabolites compared to the wild-type enzyme. With ortho-halotoluenes up to six different metabolites could be identified whereas the oxidation of 2-methoxytoluene generated only two aromatic oxidation products. Addition of an ethyl group markedly shifted the selectivity for oxidation to the more reactive benzylic position. Epoxidation of an alkene was also preferred to aromatic oxidation in 2-methylstyrene. Significant minor products arising from the migration of one substituent to a different position on the benzene ring were formed during certain P450-catalysed substrate turnovers. For example, 2-bromo-6-methylphenol was formed from the turnover of 2-bromotoluene and the dearomatisation product 6-ethyl-6-methylcyclohex-2,4-dienone was generated from the oxidation of 2-ethyltoluene. The RLYF/A330P variant altered the product distribution enabling the generation of certain metabolites in higher quantities. Using this variant produced 4-methyl-2-ethylphenol from 3-ethyltoluene with ≥90 % selectivity and with a biocatalytic activity suitable for scale-up of the reaction.
- Munday, Samuel D.,Dezvarei, Shaghayegh,Lau, Ian C.-K.,Bell, Stephen G.
-
p. 2512 - 2522
(2017/07/12)
-
- Accelerated Discovery in Photocatalysis using a Mechanism-Based Screening Method
-
Herein, we report a conceptually novel mechanism-based screening approach to accelerate discovery in photocatalysis. In contrast to most screening methods, which consider reactions as discrete entities, this approach instead focuses on a single constituent mechanistic step of a catalytic reaction. Using luminescence spectroscopy to investigate the key quenching step in photocatalytic reactions, an initial screen of 100 compounds led to the discovery of two promising substrate classes. Moreover, a second, more focused screen provided mechanistic insights useful in developing proof-of-concept reactions. Overall, this fast and straightforward approach both facilitated the discovery and aided the development of new light-promoted reactions and suggests that mechanism-based screening strategies could become useful tools in the hunt for new reactivity. Enlightened! A mechanism-based screening approach can accelerate discovery in photocatalysis. It focuses on a single mechanistic step of a reaction class: the quenching step central to photocatalytic transformations. Luminescence spectroscopy was used to screen 100 compounds, identifying two promising substrate classes. A second, more-focused screen provided mechanistic insights for developing proof-of-concept reactions.
- Hopkinson, Matthew N.,Gómez-Suárez, Adrián,Teders, Michael,Sahoo, Basudev,Glorius, Frank
-
supporting information
p. 4361 - 4366
(2016/04/05)
-
- Isoquinolinium Dichromate and Chlorochromate as Efficient Catalysts for Oxidative Halogenation of Aromatic Compounds under Acid-Free Conditions
-
Isoquinolinium dichromate and isoquinolinium chlorochromate were found as efficient catalysts to trigger oxidative bromination and iodination of aromatic hydrocarbons with KBr/KI and KHSO4 under acid-free conditions. Reaction times reduced highly significantly under sonication, followed by corresponding mono bromo derivatives in very good yield with high regioselectivity.
- Rao, A. Sambashiva,Rajanna,Reddy, K. Rajendar,Kulkarni, Subhash
-
p. 832 - 837
(2016/02/12)
-
- Efficient and Practical Oxidative Bromination and Iodination of Arenes and Heteroarenes with DMSO and Hydrogen Halide: A Mild Protocol for Late-Stage Functionalization
-
An efficient and practical system for inexpensive bromination and iodination of arenes as well as heteroarenes by using readily available dimethyl sulfoxide (DMSO) and HX (X = Br, I) reagents is reported. This mild oxidative system demonstrates a versatile protocol for the synthesis of aryl halides. HX (X = Br, I) are employed as halogenating reagents when combined with DMSO which participates in the present chemistry as a mild and inexpensive oxidant. This oxidative system is amenable to late-stage bromination of natural products. The kilogram-scale experiment (>95% yield) shows great potential for industrial application.
- Song, Song,Sun, Xiang,Li, Xinwei,Yuan, Yizhi,Jiao, Ning
-
supporting information
p. 2886 - 2889
(2015/06/30)
-
- A Metal-Free and Ionic Liquid-Catalyzed Aerobic Oxidative Bromination in Water
-
A metal-free aerobic oxidative bromination of aromatic compounds in water has been developed. Hydrobromic acid is used as a bromine source and 2-methylpyridinium nitrate ionic liquid is used as a recyclable catalyst. Water is used as the reaction mediate. This is the first report of aerobic oxidative bromination using only catalytic amount of metal-free catalyst. This system shows not only high bromine atom economy, but also high bromination selectivity. The possible mechanism and the role of the catalyst in this system have also been discussed.
- Wang, Jian,Chen, Shu-Bin,Wang, Shu-Guang,Li, Jing-Hua
-
p. 513 - 517
(2015/03/30)
-
- Copper(II)-catalyzed aromatization followed by bromination of cyclohexenones leading to phenols and bromophenols
-
Conversion of substituted cyclohexenones into the corresponding phenols can be achieved using copper acetate as the catalyst in the presence of LiBr and CF3COOH under oxygen. With the use of excess LiBr, electrophilic aromatic bromination afforded the corresponding bromophenol under similar catalytic conditions. Copyright
- Tong, Hung-Chun,Reddy, K. Rajender,Liu, Shiuh-Tzung
-
p. 3256 - 3261
(2014/06/09)
-
- Poly(4-vinylpyridinium bromochromate): An efficient reagent for bromination of aromatic compounds
-
A simple and efficient method for the bromination of various aromatic compounds by using poly(4-vinylpyridinium bromochromate) is reported. This method has several advantages such as good selectivity between ortho and para positions of aromatic compounds, simple workup, short reaction times, and high yields of the products.
- Albadi, Jalal,Tajik, Hassan,Keshavarz, Mosadegh,Abedini, Masoumeh
-
p. 179 - 181
(2013/07/27)
-
- Enthalpy-entropy compensation combined with cohesive free-energy densities for tuning the melting temperatures of cyanobiphenyl derivatives
-
This work illustrates how minor structural perturbations produced by methylation of 4′-(dodecyloxy)-4-cyanobiphenyl leads to enthalpy-entropy compensation for their melting processes, a trend which can be analyzed within the frame of a simple intermolecular cohesive model. The transformation of the melting thermodynamic parameters collected at variable temperatures into cohesive free-energy densities expressed at a common reference temperature results in a novel linear correlation, from which melting temperatures can be simply predicted from molecular volumes. In tune with temperature! The transformation of the melting thermodynamic parameters into cohesive free-energy densities (CFED) for 4′-(n-oxy)-i′-methyl-j-methyl-4-cyanobiphenyl (CnLi′,j) provides a novel linear correlation for predicting melting temperatures in a simple way. Copyright
- Dutronc, Thibault,Terazzi, Emmanuel,Guenee, Laure,Buchwalder, Kerry-Lee,Spoerri, Aurore,Emery, Daniel,Mareda, Jiri,Floquet, Sebastien,Piguet, Claude
-
supporting information
p. 8447 - 8456
(2013/07/19)
-
- Fast and efficient bromination of aromatic compounds with ammonium bromide and Oxone
-
A highly efficient, rapid and regioselective protocol was developed for the ring bromination of aromatic compounds under mild conditions with ammonium bromide as a source of bromine source and Oxone (potassium peroxysulfate) as an oxidant. No metal catalyst or acidic additive is required. A variety of aromatic compounds, including methoxy, hydroxy, amino, and alkyl arenes, reacted smoothly to give the corresponding monobrominated products in good to excellent yields in very short reaction times. Moreover, dibromination of deactivated anilines to give the corresponding dibromides proceeded in high yields. Interestingly, 1-(2-naphthyl)ethanone provided a ring-brominated product. Georg Thieme Verlag Stuttgart . New York.
- Naresh, Mameda,Arun Kumar, Macharla,Mahender Reddy, Marri,Swamy, Peraka,Nanubolu, Jagadeesh Babu,Narender, Nama
-
p. 1497 - 1504
(2013/06/27)
-
- Selectivity enhancement of aromatic halogenation reactions at the micellar interface: Effect of highly ionic media
-
Halogenation (iodination and bromination) of various aromatic compounds has been studied in micellar media in order to observe the effect on regioselectivity and conversion of the reaction. The addition of surfactant causes a change in the chemical shifts of the aromatic proton resonance of phenol which proves the orientation of the aromatic compound on the micellar surface. However, increase in ionic strength of the reaction media affects the selectivity of reaction by disturbing this spatial orientation of the aromatic compound in the micelle. Selectivity towards particular isomers is dependent on the concentration of the surfactant. In bromination of chlorobenzene (deactivated aromatic compound) enhancement in selectivity and conversion towards the para isomer has been observed.
- Samant, Bhupesh S.,Bhagwat, Sunil S.
-
scheme or table
p. 1039 - 1044
(2012/10/18)
-
- Green, mild and efficient bromination of aromatic compounds by HBr promoted by trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane in water as a solvent
-
A combination of HBr and trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as a new and powerful oxidant was found effective for facile bromination of different aromatic compounds at room temperature in water as a green solvent. Mild reaction conditions, high selectivity and yield, high reaction rate and non-toxicity are some of the major advantages of this synthetic protocol.
- Khosravi, Kaveh,Kazemi, Samira
-
experimental part
p. 387 - 390
(2012/05/20)
-
- Regioselective bromination and iodination of aromatic substrates promoted by trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane
-
Selective and efficient bromination and iodination of aromatic compounds by ammonium bromide and ammonium iodide, respectively, under promotion of trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane have been explored. Mild reaction conditions, high selectivity and yield, and high reaction rate are some of the major advantages of this synthetic method.
- Azarifar, Davood,Khosravi, Kaveh,Najminejad, Zohreh,Soleimani, Khadijeh
-
experimental part
p. 321 - 326
(2012/08/14)
-
- Aerobic oxybromination of phenols catalyzed by sodium nitrite under mild conditions
-
An efficient catalytic system for oxybromination of phenols under mild conditions has been developed, which utilizes sodium nitrite as the catalyst, dioxygen or air as the terminal oxidant, aqueous hydrobromic acid or molecular bromine as the bromine resource. From both the atom-economic and environmental points of view, the developed protocol is expected to provide a valuable synthetic method for practical applications in laboratory or industry. Georg Thieme Verlag Stuttgart - New York.
- Xu, Li,Wang, Yong,Wen, Xin,Ding, Chengrong,Zhang, Guofu,Liang, Xinmiao
-
supporting information; experimental part
p. 2265 - 2269
(2011/10/31)
-
- Regioselective and high-yielding bromination of phenols and anilins using N-bromosaccharin and amberlyst-15
-
A regioselective and facile conversion method for bromination of anilines and phenols using N-bromosaccharine in the presence of a catalytic amount of Amberlyst-15 lead to enhancement of the reaction rate and yielded brominated products in good to excellent yields and short reaction times.
- Baharfar,Alinezhad,Azimi,Salehian
-
experimental part
p. 863 - 865
(2012/04/23)
-
- Chemo-and regioselective bromination of aromatic compounds in the presence of γ-picolinium bromochromate (γ-PBC)/CH3CN
-
Regioselective oxidative bromination of activated aromatic compounds has been studied using γ-Picolinium bromochromate in either CH3COOH or CH3CN is reported. The results obtained revealed excellent yields of monobromo compounds at para-position under thermal condition especially in methyl cyanide.
- Mahmoodi,Yazdanbakhsh,Hassanzadeh
-
experimental part
p. 429 - 434
(2012/04/04)
-
- Synthesis and reactivity studies of a new reagent, ethyltriphenylphosphonium tribromide
-
A new reagent, ethyltriphenyl phosphonium tribromide (ETPPTB), has been synthesized and studied. Results show that the reagent is quite efficient for various reactions such as organic bominations, acylations, and isothiocyanate preparation. Copyright
- Jamir, Latonglila,Alimenla,Kumar, Anil,Sinha, Dipak,Sinha, Upasana B.
-
experimental part
p. 147 - 155
(2011/03/17)
-
- An efficient copper-catalysed aerobic oxybromination of arenes in water
-
An aerobic oxybromination of arenes catalysed by Cu(NO3) 2 was achieved using HBr as a bromine source, molecular oxygen as the oxidant and water as solvent with high selectivity. The catalyst shows not only high chemoselectivity for monobromination, but also a remarkable regioselectivity for para-isomers.
- Wang, Jian,Wang, Wei,Li, Jing-Hua
-
supporting information; experimental part
p. 2124 - 2126
(2011/02/24)
-
- Efficient and regioselective bromination of aromatic compounds with ethylenebis(N-methylimidazolium) ditribromide (EBMIDTB)
-
A regioselective and highly efficient method for bromination of phenol and aniline derivatives using ethylenebis(N-methylimidazolium) ditribromide (EBMIDTB) as an efficient reagent in dichloromethane at ambient temperature is reported. The reagent can be recovered and reused several times.
- Hosseinzadeh, Rahman,Tajbakhsh, Mahmood,Mohadjerani, Maryam,Lasemi, Zahra
-
experimental part
p. 868 - 876
(2010/05/18)
-
- Synthesis and application of poly(diallyldimethylammonium tribromide) as a novel polymeric brominating agent
-
In this study, the synthesis and applications of a new supported tribromide reagent based on poly(diallyldimethylammonium chloride) is reported. This supported tribromide is used in α-bromoacetalization of ketones, bromination of alkenes and regioselective bromination of activated aromatic compounds. This method is mild and no Br2 and HBr were used. Other advantages of this reagent are stability, high efficiency, simple filtera- bility and reusability. In this study, the synthesis and applications of a new supported tribromide reagent based on poly(diallyldimethylammonium chloride) is reported. This supported tribromide is used in α-bromoacetalization of ketones, bromination of alkenes and regioselective bromination of activated aromatic compounds. This method is mild and no Br2 and HBr were used. Other advantages of this reagent are stability, high efficiency, simple filterability and reusability. Copyright
- Hossein, Mahdavi,Zahra, Kachoei
-
experimental part
p. 2221 - 2225
(2011/10/12)
-
- Facile p-toluenesulfonic acid-promoted para-selective monobromination and chlorination of phenol and analogues
-
para-Regioselective bromination of phenol and analogues, promoted by p-toluenesulfonic acid, is achieved in high to excellent yields at room temperature with N-bromosuccinimide. Chlorination with N-chlorosuccinimide and catalysed by p-toluenesulfonic acid also gives para-chlorinated phenol analogues in good yields at room temperature. para-Bromination of phenol, promoted by p-toluenesulfonic acid, is achieved in excellent yields at room temperature with N-bromosuccinimide. p-Toluenesulfonic acid is also effective as a promoter of para-chlorination with N-chlorosuccinimide.
- Bovonsombat, Pakorn,Ali, Rameez,Khan, Chiraphorn,Leykajarakul, Juthamard,Pla-On, Kawin,Aphimanchindakul, Suraj,Pungcharoenpong, Natchapon,Timsuea, Nisit,Arunrat, Anchalee,Punpongjareorn, Napat
-
experimental part
p. 6928 - 6935
(2010/10/01)
-
- Efficient, rapid, and regioselective bromination of phenols and anilines with N-bromosaccharin using tungstophosphoric acid as a heterogeneous recyclable catalyst
-
A simple, efficient, and rapid method for high-yielding regioselective mono bromination of phenols and anilines has been achieved by treatment with N-bromasaccharin in the presence of a catalytic amount of tungstophosphoric acid. Copyright Taylor & Francis Group, LLC.
- Alinezhad, Heshmatollah,Tavakkoli, Sahar Mohseni,Salehian, Fatemeh
-
experimental part
p. 3226 - 3232
(2010/12/24)
-
- Regioselective, photochemical bromination of aromatic compounds using N-bromosuccinimide
-
Regioselective nuclear bromination of aromatic compounds is investigated with N-bromosuccinimide as the brominating agent under UV irradiation to afford the corresponding brominated compounds. The reaction proceeds at ambient temperature (30 ± 2 °C) without any catalyst. In most of the reactions, regioselectively mono-brominated products are obtained in good to high yields. The conversion and selectivity for bromination depend on the nature of the substituent on the aromatic ring.
- Chhattise, Prakash K.,Ramaswamy,Waghmode, Suresh B.
-
p. 189 - 194
(2008/03/30)
-
- Regioselective bromination of activated aromatic substrates with a ZrBr4/diazene mixture
-
A regioselective method for the bromination of phenols, ethers and anilines using a ZrBr4/diazene mixture is described. The reaction takes place under mild reaction conditions and the bromine atom adds first at the para unsubstituted position with respect to the OH, OR or NR2 group of the activated aromatic substrate. Less reactive compounds such as toluene, phenyl acetate, benzonitrile and trifluoromethylbenzene remain intact under the same conditions.
- Stropnik, Tadej,Bombek, Sergeja,Ko?evar, Marijan,Polanc, Slovenko
-
p. 1729 - 1733
(2008/09/18)
-
- A practical highly selective oxybromination of phenols with dioxygen
-
A simple, low cost and highly selective method for the synthesis of mono-bromophenols from phenol and electron-rich phenolic compounds has been developed. Bromide ions are used as halogenating agents, dioxygen as a final oxidant, and Cu(OAc)2 as a catalyst.
- Menini, Luciano,Parreira, Luciana A.,Gusevskaya, Elena V.
-
p. 6401 - 6404
(2008/02/12)
-
- An efficient, rapid and regioselective nuclear bromination of aromatics and heteroaromatics with NBS using sulfonic-acid-functionalized silica as a heterogeneous recyclable catalyst
-
A simple, efficient and rapid method has been developed for high-yielding regioselective nuclear monobromination of aromatic and heteroaromatic compounds using NBS in the presence of sulfonic-acid-functionalized silica at room temperature. The catalyst works under heterogeneous conditions and can be recycled.
- Das, Biswanath,Venkateswarlu, Katta,Krishnaiah, Maddeboina,Holla, Harish
-
p. 8693 - 8697
(2007/10/03)
-
- A new recyclable ditribromide reagent for efficient bromination under solvent free condition
-
1,2-Dipyridiniumditribromide-ethane (DPTBE) has been synthesized and explored as a new efficient brominating agent. The crystalline ditribromide reagent is stable for months and acts as a safe source of bromine requiring just 0.5 equiv for complete bromination. It has high active bromine content per molecule and shows a remarkable reactivity compared to other tribromide reagents toward various substrates by just grinding the reagent and substrates in a porcelain mortar at room temperature. No organic solvent has been used during any stage of the reaction for substrates giving product as solid. Product can easily be isolated by just washing the highly water soluble 1,2- dipyridiniumdibromide-ethane (DPDBE) from the brominated product. The spent reagent can be recovered, regenerated, and reused without any significant loss.
- Kavala, Veerababurao,Naik, Sarala,Patel, Bhisma K.
-
p. 4267 - 4271
(2007/10/03)
-
- Mild regioselective monobromination of activated aromatics and heteroaromatics with N-bromosuccinimide in tetrabutylammonium bromide
-
Highly regioselective nuclear bromination of activated aromatic and heteroaromatic compounds has been accomplished using N-bromosuccinimide in tetrabutylammonium bromide. Pre-dominant para-selective monobromination of activated aromatics such as phenols and anilines, rate acceleration of bromination for moderately activated and less reactive substrates on addition of acidic montmorillonite K-10 clay, with or without microwave assistance, are the notable features of this protocol.
- Ganguly, Nemai C.,De, Prithwiraj,Dutta, Sanjoy
-
p. 1103 - 1108
(2007/10/03)
-
- Method of preparing mixtures of bromophenols and benzoquinones
-
A method is described for the simultaneous preparation of 4-bromophenols and p-benzoquinones, intermediates useful in the preparation of hydroquinones and 4,4′-dihydroxybiphenyls respectively. Hydroquinones and 4,4′-dihydroxybiphenyls are useful monomers for the preparation of a variety of polymers. In one example phenol is reacted with in the presence of HBr, a catalytic amount of cupric bromide and a stoichiometric excess of oxygen under relatively mild conditions to provide a mixture of the phenol, 4-bromophenol, and 1,4-benzoquinone. Phenol conversion was 54 percent and selectivities for bromophenol and benzoquinone were 23% and 37% respectively. Limiting the amount of HBr present in the reaction mixture was shown to control the amount of benzoquinone produced.
- -
-
Page column 7-8
(2008/06/13)
-
- Mild and regioselective oxidative bromination of aromatic compounds using ammonium bromide and oxone
-
The selective mono-bromination of various activated aromatic compounds is reported using in situ generated bromine from NH4Br as a bromine source and oxone as an oxidant for the first time.
- Narender,Mohan, K.V.V. Krishna,Kulkarni,Raghavan
-
p. 597 - 598
(2007/10/03)
-
- Bicyclic aromatic compounds and pharmaceutical/cosmetic compositions comprised thereof
-
Novel pharmaceutically/cosmetically-active bicyclic aromatic compounds have the structural formula (I): in which Ar1 is a radical having one of the structural formulae (a)-(c): Ar2 is a radical having one of the following formulae (d)-(h): and X is a radical having one of the following formulae (i)-(l): and are useful for the treatment of a wide variety of disease states, whether human or veterinary, for example dermatological, rheumatic, respiratory, cardiovascular and ophthalmological disorders, as well as for the treatment of mammalian skin and hair conditions/disorders.
- -
-
Page/Page column 20
(2010/01/31)
-
- Indazole compounds and pharmaceutical compositions for inhibiting protein kinases, and methods for their use
-
Indazole compounds that modulate and/or inhibit the activity of certain protein kinases are described. These compounds and pharmaceutical compositions containing them are capable of mediating tyrosine kinase signal transduction and thereby modulate and/or inhibit unwanted cell proliferation. The invention is also directed to the therapeutic or prophylactic use of pharmaceutical compositions containing such compounds, and to methods of treating cancer and other disease states associated with unwanted angiogenesis and/or cellular proliferation, such as diabetic retinopathy, neovascular glaucoma, rheumatoid arthritis, and psoriasis, by administering effective amounts of such compounds.
- -
-
-
- Transition metal-catalyzed oxidations. 11 : Para-selective chlorination and bromination of phenols with tert-butyl hydroperoxide and TiX(OiPr)3
-
Mononuclear phenols 1-4 are chlorinated or brominated with high para-selectivity and in good yields to the halides 5-11 with the TiXn(OiPr)m/TBHP system (X = Cl or Br). WILEY-VCH Verlag GmbH, 1999.
- Krohn, Karsten,Rieger, Hagen,Steingroever, Klaus,Vinke, Ingeborg
-
-
- N-Bromosuccinimide as a Regioselective Nuclear Monobrominating Reagent for Phenols and Naphthols
-
A wide range of substituted phenols and naphthols were regioselectively monobrominated with N-bromosuccinimide, at para position in acetonitrile and at ortho position in carbon disulfide, under mild conditions in good yields. Methylphenols afforded only nuclear bromination products.
- Carre?o, M. Carmen,García Ruano, José L.,Sanz, Gema,Toledo, Miguel A.,Urbano, Antonio
-
p. 1241 - 1242
(2007/10/03)
-
- 4,4-Dibromo-3-methylpyrazol-5-one: New applications for selective monobromination of phenols and oxidation of sulfides to sulfoxides
-
Dibromopyrazolone 1, a stable, crystalline solid effects para selective monobromination of phenols and aniline substrates under mild conditions. Selective oxidation of sulfides to sulfoxides can also be accomplished by using 1 in high yields.
- Mashraqui, Sabir H.,Mudaliar, Chandrashekar D.,Hariharasubrahmanian, Harini
-
p. 4865 - 4868
(2007/10/03)
-
- SELECTIVE MONOBROMINATION OF PHENOLS
-
A method is proposed for the selective monobromination of the hydroxy derivatives of benzene with bis(dimethylacetamide)hydrogen tribromide in aprotic media as brominating agent.
- Mikhailov, V. A.,Savelova, V. A.,Rodygin, M. Yu.
-
p. 1868 - 1870
(2007/10/02)
-
- A new mild and selective reagent for nuclear bromination
-
Hexamethylene tetramine tribromide HMTAHBr3 - a new, mild and regioselective brominant is reported for bromination of aromatic hydrocarbons, substituted ethers, phenols and anilides in high yields.
- Bisarya,Rao
-
p. 779 - 788
(2007/10/02)
-
- Selective para-Bromination of Phenols via a Regenerable Polymer-bound Tetraalkylammonium Tribromide
-
Amberlyst-A26 resin in its tribromide form effects para-bromination of phenols with high yields and selectivity; the resin is easily recovered by filtration and can be reconverted into the tribromide form by addition of bromine.
- Smith, Keith,James, D. Martin,Matthews, Ian,Bye, Martin R.
-
p. 1877 - 1878
(2007/10/02)
-
- The rearrangement of some cyclopentanone-aryloximes: Synthesis of (±)-aplysin, (±)-filiformin and of their debromo analogues
-
Upon acid catalyzed rearrangement after Sheradsky, the aryloximes A gave the tricyclic aminals C, which suffered hydrolysis to lactols E. The unique alcohol 29 was then prepared through a highly stereoselective equilibration-reductive alkylation of the epimeric mixture of lactols 22a,b. Two routes, one of which was stereospecific, allowed cyclization of 29 to (±)-aplysin 34. The yield was 2.5 % from oximes 2a,b. The isomeric epi-aplysin 35 and filiformin 36 were also obtained from 29. The debromo analogues 37,38 and 39 and their trideutero derivatives 41,42 and 43 were synthesized along similar line and allowed unequivocal structure elucidation by NMR spectroscopy.
- Laronze, J. Yves,El Boukili, Rachida,Patigny, Dominique,Dridi, Seloua,Cartier, Dominique,Levy, Lean
-
p. 10003 - 10014
(2007/10/02)
-