- Copper-catalyzed tri- or tetrafunctionalization of alkenylboronic acids to prepare tetrahydrocarbazol-1-ones and indolo[2,3-a]carbazoles
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We describe a cascade strategy for tri- or tetrafunctionalization of alkenylboronic acids to prepare diverse tetrahydrocarbazol-1-ones and indolo[2,3-a]carbazoles in good yields withN-hydroxybenzotriazin-4-one (HOOBT) and arylhydrazines as oxygen and nitrogen sources, respectively. Mechanistic studies reveal that the domino reaction undergoes the copper-catalyzed Chan-Lam reaction, [2,3]-rearrangement, nucleophilic substitution, oxidation and sequential [3,3]-rearrangement over five steps in a one-pot reaction. The reaction shows a broad substrate scope and tolerates a wide range of functional groups. More importantly, the reaction is easily performed at gram scales and the product is purified by simple extraction, washing, and recrystallization without flash column chromatography. The present protocol features easily available starting materials, high site-marked functionalization, five-step cascade in one pot, multiple C-C/C-O/C-N bond formation, and diversity of indole motifs.
- Bi, Hong-Yan,Li, Cheng-Jing,Liang, Cui,Mo, Dong-Liang,Wei, Cui
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supporting information
p. 5815 - 5821
(2020/09/21)
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- Zinc-promoted cyclization of tosylhydrazones and 2-(dimethylamino)malononitrile: An efficient strategy for the synthesis of substituted 1-tosyl-1: H -pyrazoles
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A Zn(OTf)2-promoted cyclization reaction of tosylhydrazones with 2-(dimethylamino)malononitrile has been successfully developed providing an efficient strategy for the synthesis of substituted 1-tosyl-1H-pyrazoles.
- Zhang, Bang-Hong,Lei, Lin-Sheng,Liu, Si-Zhan,Mou, Xue-Qing,Liu, Wei-Ting,Wang, Shao-Hua,Wang, Jie,Bao, Wen,Zhang, Kun
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supporting information
p. 8545 - 8548
(2017/08/04)
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- One-Pot Synthesis of Spirocyclic or Fused Pyrazoles from Cyclic Ketones: Calcium Carbide as the Carbon Source in Ring Expansion
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N-Tosylhydrazones generated in situ from cyclic ketones smoothly underwent a [3 + 2] cycloaddition to afford saturated spirocyclic pyrazoles and further transformed to the fused analogues via a ring expansion in certain cases. An inexpensive and renewable
- Yu, Yue,Chen, Yang,Huang, Wei,Wu, Wanqing,Jiang, Huanfeng
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p. 9479 - 9486
(2017/09/23)
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- Regioselective preparation of saturated spirocyclic and ring-expanded fused pyrazoles
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Saturated bicyclic pyrazoles represent an important class of biologically active molecules, but their preparation can be hampered by labor-intensive synthesis of required starting materials. A convenient one- or two-step procedure for the synthesis of sat
- Merchant, Rohan R.,Allwood, Daniel M.,Blakemore, David C.,Ley, Steven V.
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p. 8800 - 8811
(2015/01/08)
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- Catalytic three-component one-pot reaction of hydrazones, dihaloarenes, and amines
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A new three-component assembly reaction between N-tosylhydrazones, dihalogenated arenes, and various primary and secondary amines was devised, producing nitrogen-containing 1,1'-diarylethylenes in good yields. The two C-C and C-N bonds formed through this
- Roche, Maxime,Hamze, Abdallah,Brion, Jean-Daniel,Alami, Mouad
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supporting information
p. 148 - 151
(2013/05/08)
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- An efficient coupling of N-tosylhydrazones with 2-halopyridines: Synthesis of 2-α-styrylpyridines endowed with antitumor activity
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The synthesis of 2-α-styrylpyridines has been carried out by using the coupling of polyoxygenated N-tosylhydrazones with various 2-halopyridines. We demonstrated that the use of a catalytic amount of PdCl2(MeCN) 2 in combination with a bidentate ferrocene DPPF or a monodentate alkyl phosphine tBu2MeP-HBF4 constitutes an efficient protocol for this coupling, providing 2-α-styrylpyridines 2 in satisfactory to good yields. Among several polyoxygenated derivatives 2 evaluated, compound 2aa was found to exhibit excellent antiproliferative and antimitotic activities comparable to that of the reference compound isoCA-4. The Royal Society of Chemistry 2013.
- Lawson, Marie,Hamze, Abdallah,Peyrat, Jean-Fran?ois,Bignon, Jér?me,Dubois, Joelle,Brion, Jean-Daniel,Alami, Mouad
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p. 3664 - 3673
(2013/06/26)
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- N-Tosylhydrazine-mediated deoxygenative hydrogenation of aldehydes and ketones catalyzed by Pd/C
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A mild and efficient method for the deoxygenative hydrogenation of aldehydes and ketones has been developed. The reaction is mediated by N-tosylhydrazine with H2 (1 atm) as the reductant and 10% Pd/C as the catalyst.
- Zhou, Lei,Liu, Zhenxing,Liu, Yizhou,Zhang, Yan,Wang, Jianbo
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p. 6083 - 6087
(2013/07/25)
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- Transition-metal-free synthesis of pinacol alkylboronates from tosylhydrazones
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Highly efficient: Pinacol alkylboronates were synthesized by the reaction of tosylhydrazones with bis(pinacolato)diboron or pinacolborane under transition-metal-free conditions. This reaction represents an expeditious conversion of carbonyl functionality into a boronate group. Copyright
- Li, Huan,Wang, Long,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 2943 - 2946
(2012/04/18)
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- Exploring a pocket for polycycloaliphatic groups in the CXCR3 receptor with the aid of a modular synthetic strategy
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A CXCR3 pocket capable of accommodating polycycloaliphatics was explored using a modular synthetic strategy. The systematic studies reveal that the tricyclic 2-adamantane and bicyclic (iso)bornyl group are efficiently recognized by CXCR3.
- Wijtmans, Maikel,Verzijl, Dennis,van Dam, Cindy M.E.,Bosch, Leontien,Smit, Martine J.,Leurs, Rob,de Esch, Iwan J.P.
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supporting information; scheme or table
p. 2252 - 2257
(2009/12/03)
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- Synthesis and biological activity of enantiomeric pairs of 5-(alk-2-enyl)thiolactomycin and 5-[(E)-cycloalk-2-enylidenemethyl] thiolactomycin congeners
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The title compounds were synthesized by the efficient route previously explored for the synthesis of enantiomeric pairs of thiolactomycin and its 3-demethyl derivative. These studies were carried out to prove the flexibility of the previously explored synthetic route to natural thiolactomycin (TLM) 1 and to examine the structure-activity relationship on the 5-position of 1. While all of the synthesized congeners lacked in vitro antibacterial activity, these studies led us to find 5-(alk-2-enyl)-TLM (ent-4d) which exhibits mammalian type I fatty acid synthase (FAS) inhibitory activity equal to that of C75, a potent inhibitor reported previously. It was also found that 5-[(E)-cycloalk-2- enylidenemethyl]-TLM (ent-5c) exhibited slightly less potent mammalian type I FAS inhibitory activity than C75.
- Ohata, Kohei,Terashima, Shiro
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experimental part
p. 920 - 936
(2010/03/23)
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- Catalytic enantioselective allyl- and crotylboration of aldehydes using chiral diol·SnCl4 complexes. Optimization, substrate scope and mechanistic investigations
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We report a novel class of C2-symmetric chiral diols derived from the hydrobenzoin skeleton. The combination of these diols with SnCl 4 under Yamamoto's concept of Lewis acid assisted Bronsted acidity (LBA catalysis) leads to high levels of asymmetric induction in the allylboration of aldehydes by commercially available allylboronic acid pinacol ester 1a. The corresponding homoallylic alcohol products of synthetically useful aliphatic aldehydes are obtained in excellent yields with up to 98:2 er. This combined acid manifold is also efficient in catalyzing the diastereo- and enantioselective crotylboration of aldehydes, thus providing the propionate units in >95:5 dr and up to 98:2 er. The X-ray crystal structure of the optimal diol·SnCl4 complex, Vivol (4m)·SnCl 4, unambiguously shows the Bronsted acidic character of this LBA catalyst and its highly dissymmetrical environment. Further controls have ruled out a possible boron transesterification mechanism with the chiral diol and point to LBA catalyst-derived activation of the pinacol allylic boronates 1. Due to slow dissociation of the diol·SnCl4 complex, a small excess of diol is required in order to suppress a competing racemic cycle catalyzed by free SnCl4.
- Rauniyar, Vivek,Zhai, Huimin,Hall, Dennis G.
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supporting information; experimental part
p. 8481 - 8490
(2009/02/02)
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- Convenient preparation of cycloalkenyl boronic acid pinacol esters
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A practical method for the preparation of cycloalkenyl boronic acid pinacol esters is described. These important synthetic intermediates are typically made using more expensive methods like transition metal-catalyzed borylation of alkenyl halides or trifl
- Rauniyar, Vivek,Zhai, Huimin,Hall, Dennis G.
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experimental part
p. 3984 - 3995
(2009/04/11)
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- Cyclic compounds and uses thereof
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Compounds of general formula (1) R1—X1—W—X2—Z1—Z2—R2 or salts thereof, exhibiting preventive and therapeutic effects against HIV infectious diseases wherein R1is an optionally substituted five- or six-membered ring group; X1is a free valency or the like; W is a divalent group represented by, e. g., general formula (2) (wherein A and B are each an optionally substituted five- to seven-membered ring; E1and E4are each optionally substituted carbon or the like; E2and E3are each oxygen or the like; and a and b are each a single bond or a double bond); X2is a divalent group constituting a straight chain moiety; Z1is a divalent cyclic group or the like; Z2is a free valency or the like; and R2is optionally substituted amino or the like.
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- CYCLIC COMPOUNDS AND USES THEREOF
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Compounds of general formula (1) or salts thereof, exhibiting preventive and therapeutic effects against HIV infectious diseases wherein R1 is an optionally substituted five- or six-membered ring group; X1 is a free valency or the like; W is a divalent group represented by, e. g., general formula (2) (wherein A and B are each an optionally substituted five-to seven-membered ring; E1 and E4 are each optionally substituted carbon or the like; E2 and E3 are each oxygen or the like; and a and b are each a single bond or a double bond); X2 is a divalent group constituting a straight chain moiety; Z1 is a divalent cyclic group or the like; Z2 is a free valency or the like; and R2 is optionally substituted amino or the like.
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- Generation and Solution-phase Behaviour of Some 2-Halogeno-1,3-ring-fused Cyclopropenes
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The title cyclopropenes 2b are readily formed by reaction of ring-fused β-silylated-gem-dihalogenocyclopropanes of the general type 1b with tetrabutylammonium fluoride in tetrahydrofuran solution.Those halogenocyclopropenes 2b which are fused to a seven-
- Banwell, Martin G.,Corbett, Madelaine,Gulbis, Jacqueline,Mackay, Maureen F.,Reum, Monica E.
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p. 945 - 964
(2007/10/02)
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- Reaction of Substituted Hydrazones with Thionyl Chloride and Sulfuryl Chloride
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Treatment of acetylhydrazones 2, ethoxycarbonylhydrazones 3, p-tolylsulfonylhydrazones 4 or semicarbazones 5 with thionyl chloride leads to the 1,2,3-thiadiazoles 6a-o.Sulfuryl chloride on the other hand accomplishes the transfer of chlorine without incorporating a sulfur atom.The new synthesized 1,2,3-thiadiazoles 6g-o are characterized in detail by spectroscopic methods.
- Meier, Herbert,Trickes, Georg,Laping, Elisabeth,Merkle, Ursula
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p. 183 - 192
(2007/10/02)
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