14500-40-4Relevant academic research and scientific papers
Reactivity of substrates with multiple competitive reactive sites toward NBS under neat reaction conditions promoted by visible light
Grjol, Bla?,Jereb, Marjan
, p. 5235 - 5248 (2021/06/07)
Regioselectivity of visible-light-induced transformations of a range of (hetero)aryl alkyl-substituted ketones bearing several competitive reactive sites (α-carbonyl, benzyl and aromatic ring) with N-bromosuccinimide (NBS) was studied under solvent-free reaction conditions (SFRC) and in the absence of inert-gas atmosphere, radical initiators and catalysts. An 8-W energy-saving household lamp was used for irradiation. Heterogeneous reaction conditions were dealt with throughout the study. All substrates were mono- or dibrominated at the α-carbonyl position, and additionally, some benzylic or aromatic bromination was observed in substrates with benzylic carbon atoms or electron-donating methoxy groups, respectively. Surprisingly, ipso-substitution of the acyl group with a bromine atom took place with (4-methoxynaphthyl) alkyl ketones. While the addition of the radical scavenger TEMPO (2,2,6,6-tetramethylpiperidin-1-yloxy) decreased the extent of α- and ring bromination, it completely suppressed the benzylic bromination and α,α-dibromination with NBS under SFRC.
Copper nitrate-catalyzed α -bromination of aryl ketones with hydrobromic acid
Wang, Jianqiang,Wang, Xiaolei,Niu, Zong-Qiang,Wang, Jian,Zhang, Man,Li, Jing-Hua
, p. 165 - 168 (2016/02/23)
An efficient method for α-bromination of aryl ketones, using the combination of molecular oxygen and aqueous hydrobromic acid as a brominating agent in the presence of the copper nitrate, has been developed. This catalytic system, which uses cheap and readily available reactants, shows good atom economy with water as the only by-product.
Synthesis, spectral studies and biological evaluation of a novel series of 2-substituted-5,6-diarylsubstituted imidazo(2,1-b)-1,3, 4-thiadiazole derivatives as possible anti-tubercular agents
Palkar, Mahesh B.,Noolvi, Malleshappa N.,Maddi, Veeresh S.,Ghatole, Mangala,Nargund, Laxmivenkat G.
, p. 1313 - 1321 (2012/08/07)
A novel series of 18 analogs of 2-substituted-5,6- diarylsubstituted imidazo(2,1-b)-1,3,4-thiadiazole 6a-r have been synthesized by the reaction of 2-amino-5-substituted- 1,3,4-thiadiazoles 5a-d and an appropriately substituted a-bromo-1,2-(p-substituted)diaryl-1-ethanones 4a-e. Structures of these compounds were established by physiochemical, elemental analysis and spectral data. All the title compounds were tested for their in-vitro anti-tubercular activity against Mycobacterium tuberculosis H37Rv using Alamar Blue susceptibility test and the activity expressed as the minimum inhibitory concentration (MIC) in lg/ml. Among synthesized compounds, compound 6h (MIC = 1.25 μg/ml) exhibited excellent anti-tubercular activity with respect to other synthesized compounds and reference drugs. Compounds 6c, 6f, and6g have also displayed an encouraging anti-tubercular activity profile. Further, some title compounds were also assessed for their cytotoxic activity (IC 50) against in a mammalian Vero cell line using MTT assay. The results reveal that these compounds exhibit anti-tubercular activity at non-cytotoxic concentrations. Springer Science+Business Media, LLC 2011.
Synthesis and biological evaluation of 2-trifluoromethyl/sulfonamido-5,6-diaryl substituted imidazo[2,1-b]-1,3,4-thiadiazoles: A novel class of cyclooxygenase-2 inhibitors
Gadad, Andanappa K.,Palkar, Mahesh B.,Anand,Noolvi, Malleshappa N.,Boreddy, Thippeswamy S.,Wagwade
, p. 276 - 283 (2008/03/28)
A series of 2-trifluoromethyl/sulfonamido-5,6-diarylsubstituted imidazo[2,1-b]-1,3,4-thiadiazole derivatives 15a-j have been synthesized by the reaction of 2-amino-5-trifluoromethyl/sulfonamido-1,3,4-thiadiazoles 14a-b and appropriately substituted α-bromo-1,2-(p-substituted)diaryl-1-ethanones 13a-h. Structures of these compounds were established by IR, 1H NMR, 13C NMR, Mass, and HRMS data. The selected compounds were evaluated for their preliminary in vitro cyclooxygenase inhibitory activity against COX-2 and COX-1enzymes using colorimetric method. The compounds tested showed selective inhibitory activity toward COX-2 (80.6-49.4%) over COX-1 (30.6-8.6), amongst them compounds 15f and 15j showed appreciable COX-2 selective inhibitory activity. These compounds also exhibited significant anti-inflammatory activity (70.09-42.32%), which is comparable to that of celecoxib in the carrageenan-induced rat paw edema method.
A novel synthesis of arylpyrrolo[1,2-a]pyrazinone derivatives
Wang, Fei,Wang, Jiawei,Zhang, Shoufang
, p. 574 - 582 (2007/10/03)
Some aryl-2-methyl-1-pyrrolo[1,2-a]pyrazinones were designed and prepared to study the Structure-Activity Relationships (SAR) of pyrrolo[1,2-a]pyrazinone derivatives. With methyl pyrrole-2-carboxylate as the starting material, the title compounds were prepared through N-alkylation and two novel cyclizations. Eleven aryl-2-methyl-1-pyrrolo[1,2-a]pyrazinone derivatives not previously reported in the literature are presented in this paper. Some of them show potent anti-inflammatory and analgesic activities.
Concerning the reaction mechanism of the hydantoin synthesis according to Biltz, II: Influence of substituents on the direction of the rearrangement
Schwenker,Guo
, p. 45 - 50 (2007/10/02)
From 1-13C-labelled 4-monosubstituted benzils 1a-c and the ureas 3a-d the 5-aryl-5-phenylhydantoines 6a-c and the 3-substituted 5-aryl-5-phenylhydantoines 9a-i were obtaincd as mixtures of isotopomeres. The distribution of 13C-labelling of C-4 and C-5 was determined by mass- and 13C-nmr-spectroscopy. As in the case of benzilic acid rearrangement the a-methylphenyl- and 4-methoxyphenyl-increment, respectively, migrate less easily than does the unsubstituted phenyl group, which in turn migrates less easily than the 4-chlorophenylrest. In the latter case the differences are small and in one example cven slightly reversed. The characteristics of the rearrangement is explained by thermodynamic control of the reaction by preceding equilibria (Schemes 2 and 3).
Concerning the reaction mechanism of the hydantoin synthesis according to Biltz, I: Proof of the intermediates
Schwenker,Guo,Bernhart
, p. 779 - 783 (2007/10/02)
The reaction mechanism of the rearrangement occurring during the hydantoin synthesis according to Biltz, proposed by Butler and Leitch, has been ascertained. The intermediate 3a, already proposed by Biltz, could be isolated out of the reaction mixture. Th
