- Synthesis of indole-fused scaffolds via [3+3] cyclization reaction of 2-indolylmethanols with quinone imines
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A formal [3 + 3] cyclization reaction of 2-indolylmethanols with quinones was realized to furnish indole-fused scaffolds in moderate to excellent yields. This protocol was proceeded smoothly under acid condition, with high high yields and broad substrate scope.
- Qin, Lu-Zhe,Cheng, Ya-Long,Wen, Xiaoan,Xu, Qing-Long,Zhen, Le
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- Cobalt-Catalyzed Selective Unsymmetrical Dioxidation of gem-Difluoroalkenes
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gem-Difluoroalkenes represent valuable synthetic handles for organofluorine chemistry; however, most reactions of this substructure proceed through reactive intermediates prone to eliminate a fluorine atom and generate monofluorinated products. Taking advantage of the distinct reactivity of gem-difluoroalkenes, we present a cobalt-catalyzed regioselective unsymmetrical dioxygenation of gem-difluoroalkenes using phenols and molecular oxygen, which retains both fluorine atoms and provides β-phenoxy-β,β-difluorobenzyl alcohols. Mechanistic studies suggest that the reaction operates through a radical chain process initiated by Co(II)/O2/phenol and quenched by the Co-based catalyst. This mechanism enables the retention of both fluorine atoms, which contrasts most transition-metal-catalyzed reactions of gem-difluoroalkenes that typically involve defluorination.
- Altman, Ryan A.,Douglas, Justin T.,Orsi, Douglas L.,Sorrentino, Jacob P.
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- Synthesis of Novel Pterocarpen Analogues via [3?+?2] Coupling-Elimination Cascade of α,α-Dicyanoolefins with Quinone Monoimines
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By employing triethylamine as a catalyst, [3?+?2] coupling-elimination cascade of α,α-dicyanoolefins with quinone monoimines was realized. The reactions afforded various novel pterocarpen analogues with generally moderate yields (up to 75%). In addition, a plausible reaction mechanism was proposed.
- Chen, Hui,Zhao, Sihan,Cheng, Shaobing,Dai, Xingjie,Xu, Xiaoying,Yuan, Weicheng,Zhang, Xiaomei
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p. 1672 - 1683
(2019/04/08)
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- Synthesis of: N -arylsulfonamides via Fe-promoted reaction of sulfonyl halides with nitroarenes in an aqueous medium
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A fascinating Fe-promoted protocol for the synthesis of N-arylsulfonamides has been developed. Starting from commercially available nitroarenes and sulfonyl chlorides, moderate to excellent yields of the corresponding N-arylsulfonamides can be obtained. In particular, Fe dust serves as the sole reductant in the transformation and it can be easily performed on a large scale.
- Jiang, Jun,Zeng, Sheng,Chen, De,Cheng, Chaozhihui,Deng, Wei,Xiang, Jiannan
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supporting information
p. 5016 - 5020
(2018/07/25)
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- Silver/Scandium-Cocatalyzed Bicyclization of β-Alkynyl Ketones Leading to Benzo[c]xanthenes and Naphtho[1,2-b]benzofurans
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The combination of AgTFA and Sc(OTf)3 enables the bimetallic synergistic catalysis of β-alkynyl ketones and para-quinone methides (p-QMs), allowing direct synthesis of 17 examples of benzo[c]xanthenes with generally good yields through a benzannulation/1,6-addition/cyclization sequence. Exchanging p-QMs for quinone imine ketal resulted in 10 examples of tetracyclic naphtho[1,2-b]benzofurans via a similar benzannulation/1,4-addition/cyclization cascade. During these reaction processes, AgTFA and Sc(OTf)3 could be perfectly compatible, together with the realization of C(sp3)-H functionalization adjacent to carbonyl group on the β-alkynyl ketone unit.
- Chen, Ke,Liu, Shuai,Wang, Dan,Hao, Wen-Juan,Zhou, Peng,Tu, Shu-Jiang,Jiang, Bo
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supporting information
p. 11524 - 11530
(2017/11/10)
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- An efficient practical tosylation of phenols, amines, and alcohols employing mild reagent [DMAPTs]+Cl?
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Efficient exploration of [DMAPTs]+Cl?for base free and chromatography free preparation of sulfonate esters from phenols and alcohols and sulfonamides from amines was achieved in excellent yields. Majority of the phenols irrespective of their substituents electronic nature underwent tosylation nearly at same reaction rate with an average yield of 95%. For amines, ring activating substituents favors rapid sulfonylation while the ring deactivating substituents relatively lowers the rate of tosylation. Furthermore the reagent was employed for Chemoselective sulfonylation as well as solvent free tosylation of phenols and amines.
- Dhonthulachitty, Chiranjeevi,Kothakapu, Sridhar Reddy,Neella, Chandra Kiran
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supporting information
p. 4620 - 4623
(2016/09/23)
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- Synthesis and biological evaluation of novel gigantol derivatives as potential agents in prevention of diabetic cataract
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As a continuation of our efforts directed towards the development of natural anti-diabetic cataract agents, gigantol was isolated from Herba dendrobii and was found to inhibit both aldose reductase (AR) and inducible nitric oxide synthase (iNOS) activity, which play a significant role in the development and progression of diabetic cataracts. To improve its bioefficacy and facilitate use as a therapeutic agent, gigantol (compound 14f) and a series of novel analogs were designed and synthesized. Analogs were formulated to have different substituents on the phenyl ring (compounds 4, 5, 8, 14a-e), substitute the phenyl ring with a larger steric hindrance ring (compounds 10, 17c) or modify the carbon chain (compounds 17a, 17b, 21, 23, 25). All of the analogs were tested for their effect on AR and iNOS activities and on D-galactose-induced apoptosis in cultured human lens epithelial cells. Compounds 5, 10, 14a, 14b, 14d, 14e, 14f, 17b, 17c, 23, and 25 inhibited AR activity, with IC50 values ranging from 5.02 to 288.8 μM. Compounds 5, 10, 14b, and 14f inhibited iNOS activity with IC50 ranging from 432.6 to 1188.7 μM. Compounds 5, 8, 10, 14b, 14f, and 17c protected the cells from D-galactose induced apoptosis with viability ranging from 55.2 to 76.26%. Of gigantol and its analogs, compound 10 showed the greatest bioefficacy and is warranted to be developed as a therapeutic agent for diabetic cataracts.
- Wu, Jie,Lu, Chuanjun,Li, Xue,Fang, Hua,Wan, Wencheng,Yang, Qiaohong,Sun, Xiaosheng,Wang, Meiling,Hu, Xiaohong,Chen, C.-Y. Oliver,Wei, Xiaoyong
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- The Diels-Alder reactions of para-benzoquinone nitrogen-derivatives: An experimental and theoretical study
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An experimental and theoretical study of the comparative reactivity and selectivity of the Diels-Alder reactions of para-benzoquinones and three nitrogen derivatives have been performed. The mono-oximes derivatives do not react under the tested reaction conditions, whereas the tosylated mono-oximes react slowly. However, the mono N-tosyl imines show excellent reactivity, and superior to the parent parabenzoquinones. DFT calculations support these experimental results.
- Uliana, Marciana P.,Servilha, Bruno M.,Alexopoulos, Olga,De Oliveira, Kleber T.,Tormena, Cláudio F.,Ferreira, Marco A.B.,Brocksom, Timothy J.
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p. 6963 - 6973
(2015/11/09)
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- Methylprenyl and prenyl protection for sulfonamides
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2-Methylprenyl (MePre) is an efficient protection for sulfonamides. The acidic cleavage of this group leads to volatile by-products and the product can be obtained in high purity without additional purification. MePre group is resistant to Pd/C-catalysed hydrogenolysis at 1 atm, Suzuki-Miyaura reaction, Ni(0) catalysis conditions and oxidising reagents such as NIS and DDQ. The prenyl (Pre) group can also be used to protect sulfonamides in certain cases; however, the substrate scope is limited due to the side product formation.
- Nikitjuka, Anna,Nekrasova, Aleksandra,Jirgensons, Aigars
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- Development of a novel class of mitochondrial ubiquinol-cytochrome c reductase binding protein (UQCRB) modulators as promising antiangiogenic leads
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Recently, we identified a novel therapeutic target and a small molecule for regulating angiogenesis. Our study showed that ubiquinol-cytochrome c reductase binding protein (UQCRB) of the mitochondrial complex III plays a crucial role in hypoxia-induced angiogenesis via mitochondrial reactive oxygen species (ROS) mediated signaling. Herein, we developed new synthetic small molecules that specifically bind to UQCRB and regulate its function. To improve the pharmacological properties of 6-((1-hydroxynaphthalen-4-ylamino)dioxysulfone)-2H-naphtho[1,8-bc]thiophen-2-one (HDNT), a small molecule that targets UQCRB, a series of HDNT derivatives were designed and synthesized. Several derivatives showed a significant increase in hypoxia inducible factor 1 (HIF-1) inhibitory potency compared to HDNT. The compounds bound to UQCRB and suppressed mitochondrial ROS-mediated hypoxic signaling, resulting in potent inhibition of angiogenesis without inducing cytotoxicity. Notably, one of these new derivatives significantly suppressed tumor growth in a mouse xenograft model. Therefore, these mitochondrial UQCRB modulators could be potential leads for the development of novel antiangiogenic agents.
- Jung, Hye Jin,Cho, Misun,Kim, Yonghyo,Han, Gyoonhee,Kwon, Ho Jeong
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p. 7990 - 7998
(2014/12/10)
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- Discovery of 4-amino-2-(thio)phenol derivatives as novel protein kinase and angiogenesis inhibitors for the treatment of cancer: Synthesis and biological evaluation. Part II
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A novel series of 4-amino-2-(thio)phenol derivatives were well synthesized. The preliminary biological test revealed that several compounds displayed high specific protein kinase and angiogenesis inhibitory activities compared with previous work mainly because of the substitution of sulfonamide structure for amide fragment. Among which, compound 5i was identified to inhibit protein kinase B/AKT (IC50 = 1.26 μM) and ABL tyrosine kinase (IC 50 = 1.50 μM) effectively. Meanwhile, compound 5i demonstrated competitive in vitro antiangiogenic activities to Pazopanib in both human umbilical vein endothelial cell (HUVEC) tube formation assay and the rat thoracic aorta rings test.
- Xu, Fuming,Zhang, Lei,Jia, Yuping,Wang, Xuejian,Li, Xiaoguang,Wen, Qingli,Zhang, Yingjie,Xu, Wenfang
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p. 191 - 200
(2013/10/01)
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- Chemoselective nitration of aromatic sulfonamides with tert-butyl nitrite
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A methodology for the efficient conversion of aromatic sulfonamides into their mono-nitro derivatives using tert-butyl nitrite is reported. The reaction exhibits a high degree of chemoselectivity for sulfonamide functionalized aryl systems, even in the presence of other sensitive or potentially reactive functionalities.
- Kilpatrick, Brenden,Heller, Markus,Arns, Steve
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supporting information
p. 514 - 516
(2013/02/25)
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- Design, synthesis, and biological evaluation of sulfonic acid ester and benzenesulfonamide derivatives as potential CETP inhibitors
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Epidemiological studies have established an inverse relationship between plasma high-density lipoprotein (HDL) cholesterol concentration, and incidence of coronary artery disease (CAD); thus, the development of novel therapies that attempt to exploit the atheroprotective functions of HDL is a major goal. Inhibition of cholesteryl ester transfer protein (CETP) is one of the approaches targeted to increase HDL cholesterol concentration. CETP is a glycoprotein involved in transporting lipoprotein particles and neutral lipids between HDL and low-density lipoproteins (LDL), and therefore CETP inhibitors could be useful agents in the future for treating dyslipidemia and related disorders. Guided by our previously reported pharmacophore and QSAR models for CETP inhibition, we synthesized and bioassayed a series of sulfonic acid ester and benzenesulfonamide derivatives that can serve as a promising lead compounds for the development of potential and selective CETP inhibitors. The most potent compound 6k illustrated an IC50 of 3.4 lM. Springer Science+Business Media, LLC 2011.
- Khalaf, Reema Abu,Sheikha, Ghassan Abu,Al-Sha'er, Mahmoud,Albadawi, Ghadeer,Taha, Mutasem
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p. 3669 - 3680
(2013/02/23)
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- SUBSTITUTED 8 - AMINO - IMIDAZO [1, 2-A] PYRAZ1NES AS ANTIBACTERIAL AGENTS
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The present invention relates to substituted imidazo[1,2-a]pyrazines of Formula (I) and their use as antibacterial agents.
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Page/Page column 99
(2013/02/27)
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- Total synthesis of (±)-decursivine
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The first preparation of the antimalarial natural product decursivine is described. A Diels-Alder/Plieninger indolization protocol allows convenient preparation of the indole 15 which, in turn is a suitable substrate for a boron-enolate aldol reaction with piperonal (16). The resulting adduct 14 is transformed efficiently to the natural product. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Leduc, Andrew B.,Kerr, Michael A.
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p. 237 - 240
(2007/10/03)
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- Total synthesis of (±)-herbindole B and (±)-cis-trikentrin B
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(Chemical Equation Presented) Herbindole B and cis-trikentrin B are naturally occurring indoles having the unusual and synthetically challenging pattern of carbon substitution at the 4-7 and 5-7 positions, respectively, with no substitution at the 1-3 positions. The total syntheses of these polyalkylated indoles have been achieved in 19 and 12 steps, respectively. The synthesis of herbindole B relies on two iterations of a quinine monoimine Diels-Alder reaction, while cis-trikentrin B uses a single cycloaddition of a suitable quinone monoimine. Indolization of the adducts provides suitably substituted benzopyrrole nuclei for elaboration to the natural products.
- Jackson, Stephen K.,Banfield, Scott C.,Kerr, Michael A.
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p. 1215 - 1218
(2007/10/03)
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- Novel one-pot preparation of 5-methoxylated indoline and indole derivatives using a hypervalent iodine(III) reagent
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A novel and efficient one-pot preparation of 1-tosylindoline and indole derivatives from N-tosylaniline derivatives (1) and activated olefin derivatives (2) using a hypervalent iodine(III) reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA), is described.
- Tohma, Hirofumi,Watanabe, Hiroaki,Takizawa, Shinobu,Maegawa, Tomohiro,Kita, Yasuyuki
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p. 1785 - 1788
(2007/10/03)
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- REACTION OF HYDROGEN BROMIDE WITH N-(p-TOLYL)- AND N-(p-TOLYLSULFONYL)-1,4-BENZOQUINONE MONOIMINES
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In the reaction of hydrogen bromide with N-(p-tolyl)-1,4-benzoquinone monoimines bromination of the p-tolyl fragment takes place as well as nucleophilic addition.Bromination is fully suppressed by the addition of resorcinol to the reaction mass.In the case of N-(p-tolylsulfonyl)-1,4-benzoquinone monoimine the products from the entry of two bromine atoms at the ortho position to the oxygen atom are formed sucessively.
- Toropin, N. V.,Burmistrov, K. S.,Burmistrov, S. I.,Zaichenko, N. L.
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p. 894 - 899
(2007/10/02)
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