- A convenient and efficient H2SO4-promoted regioselective monobromination of phenol derivatives using N-bromosuccinimide
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A convenient, rapid H2SO4-promoted regioselective monobromination reaction with N-bromosuccinimide was developed. The desired para-monobrominated or ortho-monobrominated products of phenol derivatives were obtained in good to excellent yields with high selectivity. Regioselective chlorination and iodination were also achieved in the presence of H2SO4 using N-chlorosuccinimide and N-iodosuccinimide, respectively.
- Wu, Yong-Qi,Lu, Hai-Jia,Zhao, Wen-Ting,Zhao, Hong-Yi,Lin, Zi-Yun,Zhang, Dong-Feng,Huang, Hai-Hong
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supporting information
p. 813 - 822
(2020/02/15)
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- Aromatic Halogenation Using N-Halosuccinimide and PhSSiMe3 or PhSSPh
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We developed a mild aromatic halogenation reaction using a combination of N-halosuccinimide and PhSSiMe3 or PhSSPh. Less reactive aromatic compounds, such as methyl 4-methoxybenzoate, were brominated with PhSSiMe3 or PhSSPh and N-bromosuccinimide in high yields. No reaction was observed in the absence of PhSSiMe3 or PhSSPh. This method is also applicable to chlorination reactions using N-chlorosuccinimide and PhSSPh.
- Hirose, Yuuka,Yamazaki, Mirai,Nogata, Misa,Nakamura, Akira,Maegawa, Tomohiro
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p. 7405 - 7410
(2019/06/14)
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- Mechanistic study on iodine-catalyzed aromatic bromination of aryl ethers by N-Bromosuccinimide
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Although iodine-catalyzed reaction has rapid advances in recent years, examples on iodine-catalyzed bromination are rare and the mechanism of these reactions remains unclear. Herein, we reported an I2-catalyzed aromatic bromination of aryl ethers by NBS and presented the details of the mechanistic study including kinetic study and the study of kinetic isotope effects. The study revealed that the reaction was actually catalyzed by IBr formed in the induction period, and the rate-determining step was the HBr-elimination of the Wheland intermediate assisted by IBr.
- Pramanick, Pranab Kumar,Hou, Zhen-Lin,Yao, Bo
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p. 7105 - 7114
(2017/11/27)
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- Intermolecular Aryl C?H Amination through Sequential Iron and Copper Catalysis
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A mild, efficient and regioselective method for para-amination of activated arenes has been developed through a combination of iron and copper catalysis. A diverse range of products were obtained from an operationally simple one-pot, two-step procedure involving bromination of the aryl substrate with the powerful Lewis acid iron(III) triflimide, followed by a copper(I)-catalysed N-arylation reaction. This two-step dehydrogenative process for the regioselective coupling of aromatic C?H bonds with non-activated amines was applicable to anisole-, phenol-, aniline- and acetanilide-type aryl compounds. Importantly, the arene substrates were used as the limiting reagent and required no protecting-group manipulations during the transformation.
- Mostafa, Mohamed A. B.,Calder, Ewen D. D.,Racys, Daugirdas T.,Sutherland, Andrew
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supporting information
p. 1044 - 1047
(2017/02/05)
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- Promising hydrogen peroxide stabilizers for large-scale application: unprecedented effect of aryl alkyl ketones
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Aryl alkyl ketones with substituents in the aromatic ring taken in an amount from 0.005 to 0.5% efficiently stabilize hydrogen peroxide in an aqueous solution during storage at 22–25°C for 16–24 months.
- Terent'ev, Alexander O.,Pastukhova, Zhanna Yu.,Yaremenko, Ivan A.,Bruk, Lev G.,Nikishin, Gennady I.
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p. 329 - 331
(2016/08/09)
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- A Metal-Free Approach to Carboxylic Acids by Oxidation of Alkyl, Aryl, or Heteroaryl Alkyl Ketones or Arylalkynes
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The metal-free oxidation of dialkyl, alkyl aryl, or alkyl heteroaryl ketones or arylalkynes to the corresponding carboxylic acids is achieved using an oxidative mixture of Oxone and trifluoroacetic acid. This green method is a simple and mild protocol to obtain carboxylic derivatives in excellent yields.
- Aravinda Kumar,Venkateswarlu, Vunnam,Vishwakarma, Ram A.,Sawant, Sanghapal D.
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p. 3161 - 3168
(2015/10/19)
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- DMSO/I2 mediated C-C bond cleavage of α-ketoaldehydes followed by C-O bond formation: A metal-free approach for one-pot esterification
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A novel and efficient I2/DMSO mediated metal-free strategy is presented for the direct C-C bond cleavage of aryl-/heteroaryl- or aliphatic α-ketoaldehydes by C2-decarbonylation and C1-carbonyl oxidation to give the corresponding carboxylic acids followed by esterification in one pot, offering excellent yields in both the steps. Here, DMSO acts as the oxygen source/oxidant and this reaction works very well under both conventional heating and microwave irradiation. This is a very simple and convenient protocol.
- Venkateswarlu, Vunnam,Aravinda Kumar,Gupta, Sorav,Singh, Deepika,Vishwakarma, Ram A.,Sawant, Sanghapal D.
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p. 7973 - 7978
(2015/07/27)
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- A mild oxidation of deactivated naphthalenes and anthracenes to corresponding para-quinones by N-bromosuccinimide
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A new method to synthesize 1,4-naphthoquinone and 9,10-anthraquinone from naphthalene and anthracene functionalized with either -CHO or -COOH groups, using N-bromosuccinimide (NBS) in aqueous N,N-dimethylformamide at 75-80 °C, has been developed. Further, -CN and -CONH2 functionalized naphthalenes and anthracenes can also be transformed into respective para-quinones in a one pot reaction, after successive acid hydrolysis and subsequent reaction with NBS. We believe that the present finding may serve as a valuable alternative to the classical approaches for the synthesis of polycyclic quinones from polyaromatic carbaldehydes through Dakin oxidation followed by further oxidation of the resulting hydroquinone by heavy metal oxides.
- Natarajan, Palani,Vagicherla, Vinuta Devi,Vijayan, Muthana Thevar
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p. 3511 - 3515
(2014/06/10)
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- Bromination of arenes using I2O5-KBr in water
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An efficient and environmentally benign bromination of various aromatic compounds using aN aqueous I2O5-KBr system at room temperature has been developed in this work. A series of aromatic compounds such as acetophenones, benzaldehydes, benzoic acids, anilines, amides, and aminopyridine have been successfully brominated in excellent regioselectivities and good yields under the typical reaction conditions. The features of KBr as brominating reagent, water as solvent, and mild conditions make this system an attractive synthetic procedure. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Hou, Jieping,Li, Zejiang,Jia, Xiao-Dong,Liu, Zhong-Quan
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supporting information
p. 181 - 187
(2013/12/04)
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- Synthesis and biological activities of new halophenols
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A series of new halophenols were synthesized, and their structures were established on the basis of 1H, 13C NMR and mass spectral data. All of the prepared compounds were screened for their in vitro protein tyrosine kinase (PTK) and vascular smooth muscle cell (VSMC) proliferation inhibitory activity. Twelve halophenols showed significant PTK inhibitory activity, most of them exhibited stronger activities than that of genistein, a positive reference compound. Several halophenols also displayed moderate VSMC proliferation inhibitory activity, compound 8c showed higher activity than that of tetrandrine, a positive reference compound. The preliminary structure-activity relationships of these compounds were investigated and discussed. The results provided a foundation for the action mechanism study and further structure optimization of the halophenols.
- Zheng, Fei Lang,Ban, Shu Rong,Feng, Xiu E.,Zhao, Cheng Xiao,Du, Guan Hua,Li, Qing Shan
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p. 303 - 311
(2013/07/28)
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- Hypervalent iodine(III)-LiX combination in fluoroalcohol solvent for aromatic halogenation of electron-rich arenecarboxylic acids
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The novel reagent system, PhI(OAc)2-LiX combination in fluoroalcohol solvents, was found to be effective for halodecarboxylation of electron-rich arenecarboxylic acids. The method provided an efficient route to halogenated phenol ether derivatives. Georg Thieme Verlag Stuttgart ? New York.
- Hamamoto, Hiromi,Hattori, Sho,Takemaru, Kaori,Miki, Yasuyoshi
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scheme or table
p. 1563 - 1566
(2011/08/03)
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- Synthesis and in vitro protein tyrosine kinase inhibitory activity of furan-2-yl(phenyl)methanone derivatives
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A series of novel furan-2-yl(phenyl)methanone derivatives were synthesized, and their structures were established on the basis of 1H-NMR, 13C-NMR and mass spectral data. All the prepared compounds were screened for their in vitro protein tyrosine kinase inhibitory activity and several new derivatives exhibited promising activity, which, in some cases, was identical to, or even better than that of genistein, a positive reference compound. The preliminary structure-activity relationships of these compounds were investigated and are discussed.
- Zheng, Fei Lang,Ban, Shu Rong,Feng, Xiu E,Zhao, Cheng Xiao,Lin, Wenhan,Li, Qing Shan
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experimental part
p. 4897 - 4911
(2011/08/10)
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- TETRAHYDROCYCLOPENTA[B]INDOL-3-YL CARBOXYLIC ACID DERIVATIVES USEFUL IN THE TREATMENT OF AUTOIMMUNE AND INFLAMMATORY DISORDERS
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The present invention relates to certain (1,2,4-oxadiazol-3-yl)-1,2,3,4-tetrahydrocyclo-penta[b]indol-3-yl carboxylic acid derivatives of Formula (Ia) and pharmaceutically acceptable salts thereof, which exhibit useful pharmacological properties, for example, as agonists of the S1P1 receptor. Also provided by the present invention are pharmaceutical compositions containing compounds of the invention, and methods of using the compounds and compositions of the invention in the treatment of S1P1 associated disorders, for example, psoriasis, rheumatoid arthritis, Crohn's disease, transplant rejection, multiple sclerosis, systemic lupus erythematosus, ulcerative colitis, type I diabetes, acne, microbial infections or diseases and viral infections or diseases.
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Page/Page column 86
(2009/07/18)
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- First general, direct, and regioselective synthesis of substituted methoxybenzoic acids by ortho metalation
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(Chemical Equation Presented) New general methodology of value in aromatic chemistry based on ortho-metalation sites in o-, m-, and p-anisic acids (1-3) (Scheme 1) is described. The metalation can be selectively directed to either of the ortho positions by varying the base, metalation temperature, and exposure times. Metalation of o-anisic acid (1) with s-BuLi/TMEDA in THF at -78°C occurs exclusively in the position adjacente to the carboxylate. On the other hand, a reversal of regioselectivity is observed with n-BuLi/t-BuOK. With LTMP at 0°C, the two directors of m-anisic acid (2) function in concert to direct introduction of the metal between them while n-BuLi/t-BuOK removes preferentially the proton located ortho to the methoxy and para to the carboxylate (H-4). s-BuLi/TMEDA reacts with p-anisic acid (3) exclusively in the vicinity of the carboxylate. According to these methodologies, routes to very simple methoxybenzoic acids with a variety of functionalities that are not easily accessible by other means have been developed (Table 1).
- Nguyen, Thi-Huu,Chau, Nguyet Trang Thanh,Castanet, Anne-Sophie,Nguyen, Kim Phi Phung,Mortier, Jacques
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p. 3419 - 3429
(2008/02/03)
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- Cis-imidazolines
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The present invention provides compounds according to formula I and formula II and pharmaceutically acceptable salts and esters thereof, having the designations provided herein and which inhibit the interaction of MDM2 protein with a p53-like peptide and have antiproliferative activity
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- Bromodecarbonylation and bromodecarboxylation of electron-rich benzaldehydes and benzoic acids with oxone and sodium bromide
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Benzaldehydes and benzoic acids bearing ortho- and paraelectron donating substituents having unshared electron-pair have undergone bromodecarbonylation or bromodecarboxylation on treatment with sodium bromide in the presence of Oxone in aqueous methanol.
- Koo, Bon-Suk,Kim, Eun-Hoo,Lee, Kee-Jung
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p. 2275 - 2286
(2007/10/03)
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- Compounds and pharmaceutical use thereof
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PCT No. PCT/JP97/00291 Sec. 371 Date Aug. 6, 1998 Sec. 102(e) Date Aug. 6, 1998 PCT Filed Feb. 6, 1997 PCT Pub. No. WO97/29079 PCT Pub. Date Aug. 14, 1997The compounds of the formula (I) wherein each symbol is as defined in the specification, pharmaceutically acceptable salts thereof and pharmaceutical use thereof. The Compound (I) and pharmaceutically acceptable salts thereof of the present invention selectively act on cannabinoid receptors, particularly peripheral receptors, cause less side effects on the central system, and have superior immunoregulating action, antiinflammatory action, antiallergic action and therapeutic effect on nephritis. Therefore, they are useful as cannabinoid receptor, particularly peripheral cannabinoid receptor activators and antagonists, immunoregulators, therapeutic agents for autoimmune diseases, antiinflammatory agents, antiallergic agents and therapeutic agents for nephritis.
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- An extended β-strand mimic for a larger artificial β-sheet
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This paper reports the development of β-strand mimic B, which duplicates the hydrogen-bonding functionality of one edge of a tetrapeptide β-strand. When attached to a tripeptide by a suitable linking group, β- strand mimic B forms a hydrogen-bonded antiparallel β-sheet structure, artificial β-sheet 2. β-Strand mimic B is based upon a 5-hydrazino-2- metboxybenzoic acid building block. The first half of the paper describes synthetic, IR and 1H NMR spectroscopic, X-ray crystallographic, and molecular modeling studies of 5-hydrazino-2-methoxybenzoic acid derivatives and related molecules. These studies establish that hydrazide derivatives of 5-hydrazino-2-methoxybenzoic acid adopt a conformation similar to that of a peptide β-strand and are suitable for use as β-strand mimics. The second half of the paper describes synthetic and 1H NMR spectroscopic studies of artificial β-sheet 2 and of controls 20 and 21, which resemble the peptidomimetic and peptide strands of 2. These experiments indicate that 2 adopts a conformation and hydrogen-bonding pattern similar to that of an antiparallel β-sheet and establish that β-strand mimic B can induce β- sheet formation in an attached peptide strand.
- Nowick, James S.,Pairish, Mason,Lee, In Quen,Holmes, Darren L.,Ziller, Joseph W.
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p. 5413 - 5424
(2007/10/03)
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- Marine Bacteria, I. - Synthesis of Pentabromopseudiline, a Cytotoxic Phenylpyrrole from Alteromonas luteo-violaceus
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A new synthesis of 2,3,4-tribromo-5-(3,5-dibromo-2-hydroxyphenyl)pyrrole (1a, pentabromopseudiline), an antibiotic, enzymeinhibitory and cytotoxic active constituent of the marine bacterium Alteromonas luteo-violaceus, is described.For investigation of structure-activity relationships further 2-phenylpyrroles are investigated.Key step in their synthesis is the Grignard reaction of 2-(1,3-dioxan-2-yl)ethylmagnesium bromide (9d) with benzoyl chlorides yielding γ-phenyl-γ-ketoaldehydes 24, and the Paal-Knorr cyclisation of the latter. - Key Words: Alteromonas luteo-violaceus / Bromopyrrole / Marine bacteria / Pentabromopseudiline
- Laatsch, Hartmut,Pudleiner, Heinz
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p. 863 - 882
(2007/10/02)
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- Steric Enhancement of Resonance-Evidence from Kinetic Study on some Acetophenones
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The kinetics of oxidation of some mono-, di- and tri-substituted acetophenones by alkaline hexacyanoferrate(III) in 50percent (v/v) methanol-water mixture at constant ionic strength and at 20, 30 and 40 deg have been studied spectrophotometrically and the rate constants determined by least-squares analysis.Electron-withdrawing groups in the ring facilitate the oxidation of the acetyl function while electron-releasing groups retard the rate.The rate constant values for the oxidation of 3-substituted-4-alkoxy-acetophenones are computed based on the principle of additivity of group effects.The observed rate constants are significantly lower than the calculated values.This is attributed to the phenomenon of steric enhancement of resonance (SER). 3,5-Disubstituted-4-methoxyacetophenones have higher observed rate constant values than the calculated ones.The steric inhibition of resonance (SIR) operates in these systems.In the case of 3-halogeno-4-methoxyacetophenones, the importance of SER increases with increase in the bulkiness of the 3-substituents.The difference between the calculated and observed multiple substituent constants of 3-substituted-4-methoxyacetophenones also lends support for SER.
- Pillay, M. Krishna,Palanivelu, S.
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p. 1055 - 1059
(2007/10/02)
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- N-Bromosuccinimide (NBS) Bromination of Anisole and p-Substituted Anisoles in 50percent Aqueous Acetic Acid
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The kinetics of bromination of anisole and p-substituted anisoles by NBS was investigated in the presence of HClO4/NaOAc and Hg(OAc)2 in 50percent aq.HOAc.Pure NBS bromination can be followed by initial addition of Hg(OAc)2, which prevents accumulation of bromine in the system.The reaction is catalysed by AgClO4.Based on Hammett plot, the reaction constant is -7.85 for Ag+-catalysed bromination.As the water content in aq.HOAc is increased from 0-60percent (v/v), the rate constant is found to increase 20 fold for PNA-NBS reaction.The product analysis of the PNA-NBS reaction catalysed by Ag+ was done by glc which gave 2-bromo-4-nitroanisole as the only product.
- Srinivasan, S. P.,Gnanapragasam, N. S.
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p. 953 - 957
(2007/10/02)
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