- Total Synthesis of (±)-Impatien A via Aza-Heck Cyclization
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The first total synthesis of the natural product impatien A is described. This concise synthesis features an aza-Heck cyclization to construct the complex spirocyclic ring system and provides a rare example of the use of aza-Heck cyclizations in complex molecule synthesis. To enable this key cyclization of an electrophilic nitrogen atom with a tetrasubstituted alkene, we utilized high-throughput experimentation to identify a new ligand and ultimately deliver impatien A in seven steps from known compounds.
- Korch, Katerina M.,Watson, Donald A.
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supporting information
p. 7285 - 7289
(2021/09/14)
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- Metal- and Hydride-Free Pentannulative Reductive Aldol Reaction
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Traditionally, the reductive aldol reaction is a metal-catalyzed and hydride-promoted coupling between enones and aldehydes. We present a phosphine-mediated diastereoselective intramolecular reductive aldol reaction of α-substituted dienones and aldehydes, which is metal-free and hydride-free. The synthetic utility of the reductive aldol adducts is demonstrated by elaborating them in one step to indeno[1,2-b]furanones, indeno[1,2-b]pyrans, and dibenzo[a,h]azulen-8-ones.
- Satpathi, Bishnupada,Dutta, Lona,Ramasastry
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supporting information
p. 170 - 174
(2019/01/04)
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- Copper-Catalyzed Aerobic Oxidative Cyclization Cascade to Construct Bridged Skeletons: Total Synthesis of (?)-Suaveoline
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Based on the discovery of copper-catalyzed cyclopropanol ring-opening addition to iminium ions, an unprecedented catalytic aerobic C?H oxidation/cyclopropanol cyclization cascade using CuCl2 as the multifunctional catalyst and air as the oxidant was developed to construct the azabicyclo[3.3.1]nonane skeleton, which is widespread in natural products and medicines. Using this method, concise asymmetric total synthesis of the indole alkaloid (?)-suaveoline was achieved. This study not only provides an efficient, low-cost, and environmentally benign method for constructing such bridged frameworks, but also enriches the realm of cyclopropanol chemistry and C?H functionalization.
- Tan, Qiuyuan,Yang, Zhao,Jiang, Dan,Cheng, Yuegang,Yang, Jiao,Xi, Song,Zhang, Min
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supporting information
p. 6420 - 6424
(2019/04/13)
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- Dehydroxymethyl Bromination of Alkoxybenzyl Alcohols by Using a Hypervalent Iodine Reagent and Lithium Bromide
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We describe the dehydroxymethylbromination of alkoxybenzyl alcohol by using a hypervalent iodine reagent and lithium bromide in F 3 CCH 2 OH at room temperature. Selective monobromination or dibromination was possible by adjusting the molar ratios of hypervalent iodine reagent and lithium bromide.
- Shibata, Ayako,Kitamoto, Sara,Fujimura, Kazuma,Hirose, Yuuka,Hamamoto, Hiromi,Nakamura, Akira,Miki, Yasuyoshi,Maegawa, Tomohiro
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supporting information
p. 2275 - 2278
(2018/10/20)
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- Deconjugative alkylation/Heck reaction as a simple platform for dihydronaphthalene synthesis
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A simple platform for carbocycle synthesis by Knoevenagel adduct deconjugative alkylation/Heck reaction is described. Deconjugative alkylation of Knoevenagels adducts is two-fold synthetically enabling because C-C bond formation is (1) operationally simple due to the ease of Knoevenagel adduct carbanion generation and (2) results in alkene migration, which poises the substrate for cyclization. Furthermore, the gem-dinitrile moiety serves as a functional group for synthetic manipulation.
- Navaratne, Primali V.,Grenning, Alexander J.
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supporting information
p. 69 - 75
(2016/12/27)
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- An enantioselective organocatalytic intramolecular Morita-Baylis-Hillman (IMBH) reaction of dienones, and elaboration of the IMBH adducts to fluorenones
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An enantioselective organocatalytic intramolecular Morita-Baylis-Hillman (IMBH) reaction of dienones is reported for the first time. This has been achieved by incorporating entropy and synergy considerations during the substrate design. The reaction conditions are thoroughly verified for an efficient synthesis of highly functionalised cyclopenta-fused arenes and heteroarenes in excellent yields and enantioselectivities. The synthetic utility of the IMBH-adducts has been demonstrated by transforming them into 3,4-disubstituted fluorenones in a serendipitous manner.
- Satpathi, Bishnupada,Wagulde, Siddhant V.,Ramasastry
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supporting information
p. 8042 - 8045
(2017/07/22)
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- Synthesis of polymethoxy-substituted triazolobenzoxazepines
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A new approach has been proposed for the synthesis of polymethoxy-substituted [1,2,3]triazolo-[1,5-a][4,1]benzoxazepines starting from 2-bromo-4,5-dimethoxy- and 2-bromo-3,4,5-dimethoxybenzyl alcohols with thermal [3 + 2]-dipolar cycloaddition as the key stage.
- Bukhvalova, S. Yu.,Ivanov,Malysheva, Yu. B.,Fedorov, A. Yu.
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p. 1481 - 1489
(2016/11/29)
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- Water-soluble isoindolo[2,1-a]quinoxalin-6-imines: In vitro antiproliferative activity and molecular mechanism(s) of action
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Water-soluble isoindoloquinoxalin (IIQ) imines and the corresponding acetates were conveniently prepared from the key intermediates 2-(2′-aminophenyl)-2H-isoindole-1-carbonitriles obtained by a Strecker reaction between substituted 1,2-dicarbaldehydes and 1,2-phenylenediamines. Both series were screened by the National Cancer Institute (Bethesda, MD) and showed potent antiproliferative activity against a panel of 60 human tumor cell lines. Several of the novel compounds showed GI50 values at a nanomolar level on the majority of the tested cell lines. Among IIQ derivatives, methoxy substituents at positions 3 and 8 or/and 9 were especially effective in impairing cell cycle progression and inducing apoptosis in cancer cells. These effects were associated to IIQ-mediated impairment of tubulin polymerization at pharmacologically significant concentrations of tested compounds. In addition, impaired DNA topoisomerase I functions and perturbation in telomere architecture were observed in cells exposed to micromolar concentrations of IIQ derivatives. The above results suggest that IIQ derivatives exhibit multi-target cytotoxic activities.
- Parrino, Barbara,Carbone, Anna,Ciancimino, Cristina,Spanò, Virginia,Montalbano, Alessandra,Barraja, Paola,Cirrincione, Girolamo,Diana, Patrizia,Sissi, Claudia,Palumbo, Manlio,Pinato, Odra,Pennati, Marzia,Beretta, Giovanni,Folini, Marco,Matyus, Peter,Balogh, Balázs,Zaffaroni, Nadia
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p. 149 - 162
(2015/03/18)
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- Hydrazone-palladium catalyzed annulation of 1-allyl-2-bromobenzene derivatives with internal alkynes
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Annulation of 1-allyl-2-bromobenzene derivatives with internal alkynes using a hydrazone-palladium catalyst system proceeded smoothly and gave the corresponding polysubstituted naphthalene derivatives in good to high yields.
- Watanabe, Kohei,Mino, Takashi,Hatta, Chikako,Ito, Shisei,Sakamoto, Masami
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supporting information
p. 11645 - 11650
(2015/12/08)
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- PYRIDINE- AND PYRIMIDINECARBOXAMIDES AS CXCR2 MODULATORS
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There is disclosed pyridine-and pyrimidinecarboxamide compounds useful as pharmaceutical agents, synthesis processes, and pharmaceutical compositions which include pyridine-and pyrimidinecarboxamides compounds. More specifically, there is disclosed a genus of CXCR2 inhibitor compounds that are useful for treating a variety of inflammatory and neoplastic disorders.
- -
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Paragraph 0154
(2015/11/27)
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- An efficient synthesis of 4-isochromanones via Parham-type cyclization with Weinreb amide
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The synthesis of 4-isochromanones via Parham-type cyclization with Weinreb amide as the internal electrophilic group, t-BuLi as the lithium reagent was described. The reaction was efficient and could be completed in one minute. The application scope of this new protocol was investigated and the desired products could be obtained in good to excellent yields. Besides, the synthetic potential of this method was further demonstrated by the synthesis of natural product (±)-XJP, which was obtained in six steps with overall yield up to 54%.
- Wang, Chaolei,Wu, Zheng,Wang, Jia,Liu, Jie,Yao, Hequan,Lin, Aijun,Xu, Jinyi
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p. 8172 - 8177
(2015/12/30)
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- CuI-catalyzed coupling of gem-dibromovinylanilides and sulfonamides: An efficient method for the synthesis of 2-amidoindoles and indolo[1,2-a] quinazolines
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A Cu(I)-catalyzed, intermolecular protocol for the synthesis of 2-amidoindoles and tetrahydroindolo[1,2-a]quinazolines in shorter time and high yields is reported. The key highlight of this disclosure is the formation of 2-amidoindole and tetrahydroindolo[1,2-a]quinazoline moieties directly from gem-dibromovinylanilides and sulfonamides in a one-pot fashion through the in situ formation of ynamides followed by a base-promoted intramolecular hydroamidation.
- Kiruthika, Selvarangam E.,Perumal, Paramasivan Thirumalai
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supporting information
p. 484 - 487
(2014/04/03)
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- Novel hybrids of natural isochroman-4-one bearing N-substituted isopropanolamine as potential antihypertensive candidates
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A series of novel hybrids of natural isochroman-4-one bearing isopropanolamine moiety were designed, synthesized and evaluated for their antihypertensive activity. It was found that compound IIId, prepared by hybridizing N-isopropyl substituted isopropanolamine functionality to a phenolic oxygen of isochroman-4-one, exhibited potent β1-adrenoceptor blocking effect comparable to the well-known antihypertensive drug propranolol. Additionally, IIId significantly reduced the systolic and diastolic blood pressure in SHRs by over 40%, which was obviously stronger than the lead compounds 7,8-dihydroxy-3-methyl-isochroman-4-one (XJP) and its analogue XJP-B. Overall, IIId may be a promising antihypertensive candidate for further investigation.
- Bai, Renren,Huang, Xiaojing,Yang, Xue,Hong, Wen,Tang, Yiqun,Yao, Hequan,Jiang, Jieyun,Liu, Jie,Shen, Mingqin,Wu, Xiaoming,Xu, Jinyi
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p. 2495 - 2502
(2013/06/26)
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- Sequential one-pot method for oxy-Michael addition, Heck coupling, and degradation followed by condensation: Facile synthesis of 2-benzoxepin-3(1H)- ones Dedicated to the memory of my teacher Professor P.V. Subba Rao, Department of Chemistry, Andhra University, Visakhapatnam
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A sequential one-pot intermolecular oxy-Michael addition, intermolecular Heck coupling, and intramolecular degradation (retro-oxy-Michael addition) followed by condensation method has been developed for the synthesis of interesting 2-benzoxepin-3(1H)-ones. Significantly, the 2-benzoxepin-3(1H)-ones form the core quantum of biologically vital natural products. The initial oxy-Michael addition and Heck coupling steps involve a straight forward construction of C-O and C-C bonds, whereas, the final condensation step follows a novel mechanistic path via intramolecular degradation, double bond isomerization, and intramolecular condensation. Notably, a remarkable solvent effect has been observed in-order to promote the final intramolecular condensation.
- Reddy, A. Gopi Krishna,Krishna,Satyanarayana
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supporting information
p. 10098 - 10107
(2013/11/06)
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- An efficient sequential one-pot base mediated C-O and Pd-mediated C-C bond formation: Synthesis of functionalized cinnamates and isochromenes
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An efficient sequential one-pot intermolecular oxy-Michael addition and intermolecular Heck coupling for the synthesis of functionalized cinnamates is presented. Bulky tert-butyl acrylate was identified as a more suitable Michael acceptor for initial oxy-Michael addition, as it precludes the formation of undesired cross condensed ester. Most importantly, the present method was further divergently extended to the successful synthesis of isochromenes via a sequential one-pot O-allylation and subsequent intramolecular Heck cyclization.
- Gopi Krishna Reddy,Krishna,Satyanarayana
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supporting information
p. 5635 - 5640
(2012/10/29)
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- Synthesis and in vitro antibacterial activity of gemifloxacin derivatives containing a substituted benzyloxime moiety
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A series of novel gemifloxacin (GMFX) derivatives containing a substituted benzyloxime moiety with remarkable improvement in lipophilicity were synthesized. The target compounds evaluated for their in vitro antibacterial activity against representative strains. Our results reveal that most of the target compounds have considerable potency against all of the tested Gram-positive strains including MRSA and MRSE (MIC: 90: 1 μg/mL) is 8-fold more active than GMFX, and 2-fold more active than GMFX and moxifloxacin against MRSE clinical isolates (MIC90: 4 μg/mL). Crown Copyright
- Feng, Lianshun,Lv, Kai,Liu, Mingliang,Wang, Shuo,Zhao, Jing,You, Xuefu,Li, Sujie,Cao, Jue,Guo, Huiyuan
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p. 125 - 136
(2012/11/07)
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- Synthesis and biological activity of pyridopyridazin-6-one p38α MAP kinase inhibitors. Part 2
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This manuscript concludes the Structure Activity Relationship (SAR) on the pyridazinone scaffold and identifies a compound with subnanomolar p38α activity and 24 h coverage in the rat arthritis efficacy model.
- Tynebor, Robert M.,Chen, Meng-Hsin,Natarajan, Swaminathan R.,O'Neill, Edward A.,Thompson, James E.,Fitzgerald, Catherine E.,O'Keefe, Stephen J.,Doherty, James B.
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p. 5971 - 5975
(2012/11/07)
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- Palladium-catalyzed intramolecular hydroarylation of 2-bromobenzyl propargyl ethers: A new access to exocyclic isochromans
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An efficient, stereo- and regioselective palladium-catalyzed 6-exo-dig intramolecular hydroarylation of propargyl ethers which provides a concise access to functionalized isochromans in high yields has been developed. A wide range of substrates possessing aromatic, aliphatic and heteroaromatic alkynes can be efficiently transformed into the targeted isochromans. Irrespective of the nature of the substrates, the cyclization follows highly selective -stereo- and regiochemistry.
- Nandakumar, Avanashiappan,Balakrishnan, Krishnamoorthy,Perumal, Paramasivan Thirumalai
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scheme or table
p. 2733 - 2739
(2011/12/04)
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- Pyridine- and Pyrimidinecarboxamides as CXCR2 Modulators
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There is disclosed pyridine- and pyrimidinecarboxamide compounds useful as pharmaceutical agents, synthesis processes, and pharmaceutical compositions which include pyridine- and pyrimidinecarboxamides compounds. More specifically, there is disclosed a genus of CXCR2 inhibitor compounds that are useful for treating a variety of inflammatory and neoplastic disorders.
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Page/Page column 45
(2010/08/22)
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- Stereomanipulation of (η5-1-arylcyclohexadienyl)iron complexes
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A crystallographic investigation comparing five 1-aryl-substituted tricarbonyl[(1-5-η)-cyclohexadienyl]iron(1+) salts demonstrates that introducing additional electron density on the aromatic ring increases π overlap between the arene and the cyclohexadienyl ligand, thus flattening the structures sufficiently to make available a conformation in which nucleophiles can approach the site of substitution, despite the steric blockade of o-benzyl substituents. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Anson, Christopher E.,Malkov, Andrei V.,Roe, Caroline,Sandoe, Elizabeth J.,Stephenson, G. Richard
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p. 196 - 213
(2008/09/18)
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- Diversity oriented microwave-assisted synthesis of (-)-steganacin aza-analogues
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(Chemical Equation Presented) A novel microwave-assisted, highly efficient protocol for the synthesis of hitherto unknown aza-analogues of (-)-Steganacin, a naturally occurring bisbenzocyclooctadiene lignan lactone with potent antileukemic and tubulin polymerization inhibitory activity, has been developed. Focused microwave irradiation is demonstrated to be highly beneficial in promoting the three crucial steps of the sequence to effect the final ring closure: the Suzuki-Miyaura reaction, Cu-mediated A3-coupling, as well as the intramolecular Huisgen 1,3-dipolar cycloaddition.
- Mont, Nuria,Mehta, Vaibhav Pravinchandra,Appukkuttan, Prasad,Beryozkina, Tetyana,Toppet, Suzzane,Van Hecke, Kristof,Van Meervelt, Luc,Voet, Arnout,DeMaeyer, Marc,Van Der Eycken, Erik
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p. 7509 - 7516
(2008/12/22)
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- Cascade synthesis of polyoxygenated 6H,11H-[2]benzopyrano-[4,3-c][1] benzopyran-11-ones
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(Chemical Equation Presented) 2-(Methoxymethoxymethyl)aryllead triacetates, obtained in situ from the corresponding arylboronic acids, reacted with 4-hydroxycoumarins, leading to 3-(2-methoxymethoxymethyl)aryl-4-hydroxycoumarin derivatives in good to high yields. These compounds underwent a cascade sequence of reactions, deprotection-halogenation-annulation, to afford polyoxygenated tetracyclic 6H, 11H-[2]benzopyrano-[4,3-c] [1]benzopyran-11-ones in good yields. Some compounds showed a moderate cytotoxicity against human epithelial mammary HBL100 cells.
- Naumov, Mikael I.,Sutirin, Sergey A.,Shavyrin, Andrey S.,Ganina, Olga G.,Beletskaya, Irina P.,Bourgarel-Rey, Veronique,Combes, Sebastien,Finet, Jean-Pierre,Fedorov, Alexey Yu.
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p. 3293 - 3301
(2008/02/03)
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- Intermolecular silyl migration reactions
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Sodium hydride promoted O-alkylation of 2-[(4-t-butyldimethylsilyloxy) phenyl]ethan-1-ol with 1-bromo-2-(bromomethyl)-4,5-dimethoxybenzene depend on the solvent used in the coupling reaction. Mixtures of 2-[4-(2-bromo-4,5- dimethoxybenzyloxy)phenyl]-1-t-butyldimethylsilyloxyethaneand2-[4-(2-bromo-4, 5-dimethoxybenzyloxy)phenyl] ethan-1-ol (in DMF), or 2-[4-(2-bromo-4,5- dimethoxybenzyloxy)phenyl]-1-t-butyldimethylsilyloxyethane and 4-[2-(2-bromo-4,5-dimethoxybenzyloxy)ethyl]phenol (in THF), were detected. These results can be explained by an unusual intermolecular silyl migration reaction.
- Rodriguez, Carolina,Garcia, Antonio G.,Marco-Contelles, Jose
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p. 698 - 701
(2007/10/03)
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- Microwave-enhanced synthesis of new (-)-steganacin and (-)-steganone aza analogues
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A novel, microwave-enhanced, highly efficient protocol for the synthesis of hitherto unknown (-)-steganacin and (-)-steganone 7-aza analogues containing a 1,2,3-triazole ring has been presented. Microwave irradiation was found to be highly beneficial in promoting the Suzuki reaction and the 1,3-dipolar cycloaddition reaction to generate the highly strained medium-sized ring system of the title molecules.
- Beryozkina, Tetyana,Appukkuttan, Prasad,Mont, Nuria,Van Der Eycken, Erik
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p. 487 - 490
(2007/10/03)
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- NOVEL HETEROCYCLIC COMPOUNDS AS HSP90-INHIBITORS
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Novel heterocyclic compounds are described and demonstrated to have utility as Heat Shock Protein 90 (HSP90) inhibiting agent. Method of synthesis and use of such compounds are also described.
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Page/Page column 331
(2008/06/13)
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- Novel bromination method for anilines and anisoles using NH 4Br/H2O2 in CH3COOH
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A simple, efficient, regioselective, environmentally safe, and economical method for the oxybromination of anilines and anisoles without catalyst is reported. The electrophilic substitution of bromine generated in situ from ammonium bromide as a bromine source and hydrogen peroxide as an oxidant for the first time.
- Krishna Mohan,Narender,Srinivasu,Kulkarni,Raghavan
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p. 2143 - 2152
(2007/10/03)
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- Total syntheses of justicidin B and retrojusticidin B using a tandem Horner-Emmons-Claisen condensation sequence
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Short syntheses of justicidin B 1 and retrojusticidin B 4 are reported. The key feature is a new annulation reaction, involving a base induced union of ketoaldehyde 2 and phosphonate 3, that is used to construct the highly substituted naphthalene core.
- Harrowven, David C,Bradley, Mark,Lois Castro, J,Flanagan, Stuart R
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p. 6973 - 6975
(2007/10/03)
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- A Convenient Strategy for the Synthesis of 4,5-Bis(o-haloaryl)isoxazoles
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A series of new 1,2-bis(o-haloaryl)ethanones is efficiently prepared and applied to the synthesis of 4,5-bis(o-haloaryl)isoxazoles. Isolation of intermediate hydroxyisoxazolines, which are structurally examined, provides a definitive proof for a heterocyclization mechanism based on an amine exchange process. The isolation and X-ray crystallographic studies of significant side products such as benzamides and triarylpropionitriles are also described.
- Olivera, Roberto,SanMartin, Raul,Dominguez, Esther,Solans, Xabier,Urtiaga, Miren Karmele,Arriortua, Maria Isabel
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p. 6398 - 6411
(2007/10/03)
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- Synthesis of the salutaridine and aporphine skeleton via palladium(0) catalyzed cyclization and S(RN)1 reaction of 2'-bromoreticulines
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The intramolecular aryl-aryl-coupling reactions of 2'-bromoreticulines are described. Their regioselectivity depends on the cyclization method. The palladium(0) catalyzed reaction of 22 leads preferentially to the salutaridine derivative 27, whilst via the photochemically induced S(RN)1 reaction of 22 the aporphine skeleton 24 is obtained.
- Wiegand,Schafer
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p. 5341 - 5350
(2007/10/02)
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- Rotenoid Synthesis by Wadsworth-Emmons Coupling and Mukaiyama Cyclisation: Application to 5-Thiorotenoids
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A new synthesis of general applicability to rotenoid structures is described, through its specific objectives were 5-thiorotenoids.The synthons carrying the A/B- and the B/C-ring components are coupled by Wadsworth-Emmons synthesis and the ring B chromene is formed by Mukaiyama directed aldol cylisation: Michael addition completes the formation of the rotenoid at its correct oxidation state and in its stable cis-form.Examples with, and without 2,3-dimethoxylation in ring A are described.
- crombie, Leslie,Josephs, Jonathan L.
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p. 2599 - 2604
(2007/10/02)
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- A New Synthesis of Phthalides by Internal Trapping in Ortho-Lithiated Carbamates Derived from Benzylic Alcohols
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The addition of t-BuLi to a low-temperature THF solution of o-bromocarbamates 2 leads to ortho-lithiated intermediates 3, in which internal trapping by the electrophile on the side chain then takes place.This novel Parham-type anionic cyclization procedure affords the variously substituted phthalides 5 in high yields and can also be used for the preparation of lactones 8, which are useful for the synthesis of aristocularine alkaloids.
- Paleo, M. Rita,Lamas, Carlos,Castedo, Luis,Dominguez, Domingo
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p. 2029 - 2033
(2007/10/02)
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- Preparation of Novel 4-Substituted 6-Methoxy, 6,7-Dimethoxy-, and 6,7-(Methylenedioxy)isochroman-3-ones. 2
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The title compounds 20, 21, and 22 have been prepared in modest yields by a two-step reaction involving first the reaction of bromoarenes 3, 7, and 8 with lithioalkyl- and lithioarylacetonitriles under aryne-forming conditions.The cyano products 10, 14, and 16 so formed were then converted to the corresponding isochroman-3-ones by acidic hydrolysis.
- Khanapure, Subhash P.,Biehl, Edward R.
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p. 1471 - 1475
(2007/10/02)
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