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Thomas Wurm, Ben W H Turnbull, Brett R Ambler, Michael J Krische
Benzocyclobutenones 1a-1g undergo cycloreversion at 150 °C in m-xylene solvent to form transient α-oxo-ortho-quinodimethanes or "ortho-quinoid ketene methides", which engage in intermolecular [4+2] cycloadditions with isatins 2a-2f to form 2-oxindole spirolactones 3a-3l. This process tolerates an array of different functional groups and substitution patterns, and is applicable to unprotected isatins 2b-2f bearing free NH-functionalities. The superior performance of isatins compared to other carbonyl based dienophiles was demonstrated and rationalized with the aid of quantum chemical calculations...
November 22, 2017: Journal of Organic Chemistry
Giulia Rainoldi, Matteo Faltracco, Claudia Spatti, Alessandra Silvani, Giordano Lesma
This work describes the synthesis of enantioenriched spiro compounds, incorporating the azetidine and the oxindole motifs. The preparation relies on a formal [2 + 2] annulation reaction of isatin-derived N-tert-butylsulfonyl ketimines with allenoates. The asymmetric induction is secured by an organocatalytic strategy, exploiting a bifunctional cinchona-type β-isocupridine-based catalyst. Some post-transformation products, including unexpected spiropyrroline and 3,3-disubstituted oxindole derivatives, are also presented...
November 21, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Sivakumar Prasanth Kumar, Chirag N Patel, Prakash C Jha, Himanshu A Pandya
The identification of isatin sulfonamide as a potent small molecule inhibitor of caspase-3 had fuelled the synthesis and characterization of the numerous sulfonamide class of inhibitors to optimize for potency. Recent works that relied on the ligand-based approaches have successfully shown the regions of optimizations for sulfonamide scaffold. We present here molecular dynamics-based pharmacophore modeling of caspase-3-isatin sulfonamide crystal structure, to elucidate the essential non-covalent contacts and its associated pharmacophore features necessary to ensure caspase-3 optimal binding...
August 9, 2017: Computational Biology and Chemistry
Michael Kisiela, Annette Faust, Bettina Ebert, Edmund Maser, Axel J Scheidig
The human dehydrogenase/reductase SDR family member 4 (DHRS4) is a tetrameric protein that is involved in the metabolism of several aromatic carbonyl compounds, steroids and bile acids. The only invertebrate DHRS4 that has been characterized to date is that from the model organism Caenorhabditis elegans. We have previously cloned and initially characterized this protein that was recently annotated as DHRS4_CAEEL in the UniProtKB database. Crystallization and X-ray diffraction studies of the full-length DHRS4_CAEEL protein in complex with diacetyl revealed its tetrameric structure and showed that two subunits are connected via an intermolecular disulfide bridge that is formed by N-terminal cysteine residues (Cys5) of each protein chain, which increases the enzymatic activity...
November 19, 2017: FEBS Journal
Dieter Enders, Xiang-Yu Chen, Jia-Wen Xiong, Qiang Liu, Sun Li, He Sheng, Carolina von Essen, Kari Rissanen
A strategy to control the switchable linear and cycloaddition reactions of enals through NHC catalyisis has been developed. The new scalable protocol leads to γ-amino acid esters bearing a tetrasubstituted stereocenter in good yields and high stereoselectivities via homo-Mannich reactions of enals and isatin-derived ketimines. By simply changing the N-ketimine substituent to an ortho-hydroxy phenyl group, the corresponding spirocyclic oxindolo-γ-lactams are obtained.
November 17, 2017: Angewandte Chemie
Rameshwar S Cheke, Sandip D Firke, Ravindra R Patil, Sanjay B Bari
Epilepsy is one of the most significant chronic neurological disorders with high occurrence worldwide. Many epileptic patients are not completely treated with currently available marketed drugs as well as so many drugs have shown unfavorable side effect and drug interaction. Therefore, there are continuing interests to find new anticonvulsant drugs. Recently, there has been wide interest in compounds containing the isatin moiety with diverse biological effects. In view of the previous continuation of an ongoing program aiming at finding new structure leads to potential anticonvulsant activities, we are trying to compile recent efforts which have been made in the design and development of isatin derived anticonvulsant agents...
November 13, 2017: Central Nervous System Agents in Medicinal Chemistry
Reem I Al-Wabli, Azza S Zakaria, Mohamed I Attia
Molecular hybridization has a wide application in medicinal chemistry to obtain new biologically active compounds. New isatin-indole molecular hybrids 5a-n have been synthesized and characterized by various spectroscopic tools. The in vitro antimicrobial potential of the prepared compounds 5a-n was assessed using diameter of the inhibition zone (DIZ) and minimum inhibitory concentration (MIC) assays against a panel of Gram-negative bacteria, Gram-positive bacteria and fungi. Most of the synthesized compounds 5a-n showed weak activities against Gram-negative bacteria while compounds 5b and 5c exhibited good activities against Gram-positive bacteria...
November 15, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Pavol Tisovský, Róbert Šandrik, Miroslav Horváth, Jana Donovalová, Juraj Filo, Martin Gáplovský, Klaudia Jakusová, Marek Cigáň, Róbert Sokolík, Anton Gáplovský
Five isatin anions were prepared by deprotonation of initial isatins in aprotic solvents using basic fluoride and acetate anions (F(-) and CH₃COO(-)). The F(-) basicity is sufficient to deprotonate isatin NH hydrogen from all the studied compounds. This process is reversible. In the presence of proton donor solvents, the anions form the corresponding isatins. The isatin hydrogen acidity depends on the overall structure of the isatin derivatives. The anions were characterized by ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy...
November 14, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Jisook Park, Alexandre Jean, David Y-K Chen
Herein we report the total syntheses of communesin F and putative members of the communesin family of polycyclic bis-aminal alkaloids. The successful strategy featured a novel organocatalytic reaction between two oxindole subunits to cast, after extensive optimization, the all-carbon vicinal quaternary stereocenters of the target molecule with high enantiocontrol. The resulting bis-oxindole intermediate further underwent a Ti(OiPr)4-mediated dehydrative skeletal rearrangement to furnish the communesin core structure...
November 1, 2017: Journal of Organic Chemistry
M Urban, M Franc, M Hofmanová, I Císařová, J Veselý
An asymmetric organocatalytic addition of fluorinated phenylsulfonylnitromethane to isatin-derived ketimines was developed. The reaction was efficiently catalyzed by a chiral tertiary amine, cinchonine. This methodology provides a new type of optically active compound with two adjacent quaternary carbon stereocenters in good yield (up to 96%), with moderate diastereoselectivity (up to 5.7 : 1 dr) and excellent enantioselectivity (up to 98/96% ee).
November 7, 2017: Organic & Biomolecular Chemistry
Saumen Hajra, Suhas Shivajirao Bhosale, Atanu Hazra
A highly efficient TMSOTf-mediated asymmetric acetate-Mannich reaction of isatin derived tert-butylsulfinyl ketimines and S-phenyl thioacetate was developed to afford the direct synthesis of indole-based β(3,3)-amino acid thioester with excellent selectivity (dr > 98 : 2). Syntheses of (+)-AG-041R and 3-aminopyrroloindoline have been accomplished utilizing the developed method.
November 7, 2017: Organic & Biomolecular Chemistry
Ana Cristina Lima Leite, José Wanderlan Pontes Espíndola, Marcos Veríssimo de Oliveira Cardoso, Gevanio Bezerra de Oliveira Filho
Privileged motifs are recurring in a wide range of biologically active compounds that reach different pharmaceutical targets and pathways and could represent a suitable start point to access potential candidates in the neglected diseases field. The current therapies to treat these diseases are based in drugs that lack of the desired effectiveness, affordable methods of synthesis and allow a way to emergence of resistant strains. Due the lack of financial return, only few pharmaceutical companies have been investing in research for new therapeutics for neglected diseases (ND)...
October 23, 2017: Current Medicinal Chemistry
Kuntal Pal, Rahul K Shukla, Chandra M R Volla
A convenient, Rh(II)-catalyzed, denitrogenative reaction of N-sulfonyl-1,2,3-triazoles and isatins to access (E)-2-(1-amino-2-oxo-2-phenylethylidene)indolin-3-ones, the core structure of indigo dyes, was achieved under operationally simple conditions with high levels of diastereoselectivity. Moreover, photophysical and electrochemical studies were conducted to understand their applicability in optoelectronic applications.
October 23, 2017: Organic Letters
Guo-Li Chai, Jian-Wei Han, Henry N C Wong
An efficient catalytic asymmetric Darzens reaction of N-protected isatins with diazoacetamides using a chiral BINOL/Ti(O(i)Pr)4 complex as the catalyst has been developed. This reaction is a straightforward method for the synthesis of spiro-epoxyoxindoles in 40-95% yields, up to >20:1 dr and up to >99% ee. A gram-scale reaction was also achieved in 95% yield with excellent stereoselectivity and enantioselectivity (>20:1 dr, >99% ee).
October 31, 2017: Journal of Organic Chemistry
Hidenobu Tsutsui, Takaomi Shimokawa, Takeshi Miura, Masashi Takama, Toru Nishinaka, Tomoyuki Terada, Masayo Yamagata, Tokihito Yukimura
Increases in renal sympathetic nerve activity during ischaemia and renal venous norepinephrine levels after reperfusion play important roles in the development of ischaemia/reperfusion-induced acute kidney injury. In the present study, we examined the effect of isatin, an endogenous monoamine oxidase inhibitor, on renal venous norepinephrine levels, superoxide production after reperfusion, and ischaemia/reperfusion-induced acute kidney injury. Ischaemia/reperfusion-induced acute kidney injury was accomplished by clamping the left renal artery and vein for 45min, followed by reperfusion, 2 weeks after contralateral nephrectomy...
October 12, 2017: European Journal of Pharmacology
Yu-Lun Qian, Peng-Ju Xia, Jun Li, Qing-Lan Zhao, Jun-An Xiao, Hao-Yue Xiang, Hua Yang
A diversity-driven three-component 1,3-dipolar cycloaddition of isatins, amino acids and isatin-derived ketimines was developed to facilely assemble dispirooxindole-imidazolidine skeletons bearing vicinal quaternary carbon centers. This protocol features additive-free, minimal solvent usage (0.1 mL DMSO/0.2 mmol scale), wide substrate scope (34 examples), mild reaction conditions (room temperature) and high chemical yield (up to 99%).
October 25, 2017: Organic & Biomolecular Chemistry
Konda Swathi, Cidda Manasa, Manda Sarangapani
In the present work, some new 5-[2(3)-dialkylamino alkoxy] Indole 2,3-diones were prepared from 5-hydroxy isatin. A mixture of 5-hydroxy isatin, dialkylamino alkylhalide in alcoholic potassium hydroxide was stirred at room temperature for 6 h to get the 5-[2(3)-dialkylamino alkoxy] Indole 2,3-diones. The structures of the products were characterized by IR, NMR, MASS Spectral studies. All the compounds were evaluated for anti-inflammatory activity. Some of these compounds showed good anti-inflammatory activity compared with standard compound Indomethacin...
2017: Advances in Experimental Medicine and Biology
Qiong Tang, Lili Lin, Jie Ji, Haipeng Hu, Xiaohua Liu, Xiaoming Feng
A direct asymmetric vinylogous aldol reaction of nonactivated natural α-angelica lactone to isatins has been developed. With a N,N'-dioxide-Sc(OTf)3 complex as catalyst, a variety of δ-hydroxy butenolides bearing congested adjacent tetrasubstituted stereocenters were obtained in good yields with high diastereoselectivities and excellent enantioselectivities. Besides, a possible transition state was proposed to explain the origin of the asymmetric induction.
September 28, 2017: Chemistry: a European Journal
Yiyi Liu, Hengyu Li, Xun Zhou, Zhengjie He
The reductive (1 + 4) annulation reaction of isatins and substituted nitroalkenes mediated by a trivalent phosphorus reagent has been realized for the first time, providing easy access to spirooxindolyl isoxazoline N-oxides in moderate to excellent yields with a flexible substrate scope. This reaction presumably proceeds through a Michael addition-intramolecular substitution sequence via active in situ generated Kukhtin-Ramirez zwitterions from isatins and P(NMe2)3. It is also demonstrated that the spirooxindolyl isoxazoline N-oxides can be readily converted into the corresponding isoxazolines in good yields...
October 6, 2017: Journal of Organic Chemistry
Dhanarajan Arunprasath, Balasubramanian Devi Bala, Govindasamy Sekar
An efficient diastereoselective synthesis of α-tetralone-fused spirooxindoles is reported. The Pd-catalyzed domino reaction proceeds through a carbene migratory insertion followed by a 6-endo-trig mode of conjugate addition sequence from easily accessible isatin-derived N-tosylhydrazones and 2'-iodochalcones. The versatility of the protocol has been showcased by high functional group tolerance, broad substrate scope, and extension to an expedient synthesis of spiroacenaphthylenes. NMR reaction profiling and deuterium-labeling investigations provide insight into the mechanistic pathway...
October 6, 2017: Organic Letters
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