- Preparation of anthranilsviachemoselective oxidative radical cyclization of 3-(2-azidoaryl) substituted propargyl alcohols
-
In the presence of K2S2O8and HOAc, 3-(2-azidoaryl) substituted propargyl alcohols can go through chemoselective oxidative radical cyclizations to give a pool of anthranils based on Meyer-Schuster rearrangement. It's proposed that the cyclizations were triggered exclusively by the direct attack of oxygen radicals on the azides. The weak N-O bonds in anthranils could be easily cleaved in the presence of transition metal catalysts and went through aminations with 2-oxo-2-phenylacetic acid and iodobenzene.
- Gao, Chao,Xu, Jian,Zhu, Shuxian,Jian, Kaixia,Xuan, Qingqing,Song, Qiuling
-
supporting information
p. 2037 - 2040
(2021/03/01)
-
- Synthesis of Azidoanilines by the Buchwald-Hartwig Amination
-
We report a Buchwald-Hartwig amination compatible with azido functionality. Treatment of azidoaryl iodides and amines with fourth-generation Buchwald precatalyst coordinated by CPhos and sodium tert-butoxide in 1,4-dioxane at 50 °C afforded the corresponding azidoanilines while leaving the azido groups intact. The method showed a broad substrate scope and was applicable to the synthesis of diazido compounds as photoaffinity probe candidates of pharmaceutical amines and multiazido platform molecules.
- Hosoya, Takamitsu,Sakata, Yuki,Yoshida, Suguru
-
p. 15674 - 15688
(2021/11/16)
-
- Discovery of a Series of Theophylline Derivatives Containing 1,2,3-Triazole for Treatment of Non-Small Cell Lung Cancer
-
Chemotherapy is the most common clinical treatment for non-small cell lung cancer (NSCLC), but low efficiency and high toxicity of current chemotherapy drugs limit their clinical application. Therefore, it is urgent to develop hypotoxic and efficient chemotherapy drugs. Theophylline, a natural compound, is safe and easy to get, and it can be used as a modified scaffold structure and hold huge potential for developing safe and efficient antitumor drugs. Herein, we linked theophylline with different azide compounds to synthesize a new type of 1,2,3-triazole ring-containing theophylline derivatives. We found that some theophylline1,2,3-triazole compounds showed a good tumor-suppressive efficacy. Especially, derivative d17 showed strong antiproliferative activity against a variety of cancer cells in vitro, including H460, A549, A2780, LOVO, MB-231, MCF-7, OVCAR3, SW480, and PC-9. It is worth noting that the two NSCLC cell lines H460 H and A549 are sensitive to compound d17 particularly, with IC50 of 5.929 ± 0.97?μM and 6.76 ± 0.25?μM, respectively. Compound d17 can significantly induce cell apoptosis by increasing the ratio of apoptotic protein Bax/Bcl-2 by downregulating the expression of phosphorylated Akt protein, and it has little toxicity to normal hepatocyte cells LO2 at therapeutic concentrations. These data indicate that these theophylline acetic acid-1,2,3-triazole derivatives may be potential drug candidates for anti-NSCLC and are worthy of further study.
- Li, Qingjiao,Liu, Yulin,Mao, Longfei,Peng, Lizeng,Xie, Luoyijun,Yang, Jianxue,Ye, Jiahui,Yuan, Miaomiao,Zhang, Rongjun
-
-
- Implementation of the CYP Index for the Design of Selective Tryptophan-2,3-dioxygenase Inhibitors
-
A class of imidazoisoindole (III) heme-binding indoleamine-2,3-dioxygenase (IDO1) inhibitors were optimized via structure-based drug design into a series of tryptophan-2,3-dioxygenase (TDO)-selective inhibitors. Kynurenine pathway modulation was demonstrated in vivo, which enabled evaluation of TDO as a potential cancer immunotherapy target. As means of mitigating the risk of drug-drug interactions arising from cytochrome P450 inhibition, a novel property-based drug design parameter, herein referred to as the CYP Index, was implemented for the design of inhibitors with appreciable selectivity for TDO over CYP3A4. We anticipate the CYP Index will be a valuable design parameter for optimizing CYP inhibition of any small molecule inhibitor containing a Lewis basic motif capable of binding heme.
- Castanedo, Georgette M.,Dement, Kevin,Dipasquale, Antonio,Gazzard, Lewis,Goon, Leanne,Gustafson, Amy,Harris, Seth F.,Jaipuri, Firoz A.,Kumar, Sanjeev,La, Hank,Li, Xiaokai,Liu, Wen,Liu, Yichin,Mautino, Mario R.,Mendonca, Rohan,Oh, Angela J.,Parr, Brendan T.,Pastor, Richard,Pavana, Roheeth K.,Pei, Zhonghua,Potturi, Hima,Sellers, Benjamin D.,Shao, Cheng,Vanderporten, Erica C.,Velvadapu, Venkata,Waldo, Jesse P.,Wu, Guosheng,Yuen, Po-Wai,Zhang, Yamin,Zhang, Zuhui
-
supporting information
p. 541 - 549
(2020/04/30)
-
- Self-Assembled Multilayer Iron(0) Nanoparticle Catalyst for Ligand-Free Carbon-Carbon/Carbon-Nitrogen Bond-Forming Reactions
-
Self-assembled multilayer iron(0) nanoparticles (NPs, 6-10 nm), namely, sulfur-modified Au-supported Fe(0) [SAFe(0)], were developed for ligand-free one-pot carbon-carbon/carbon-nitrogen bond-forming reactions. SAFe(0) was successfully prepared using a well-established metal-nanoparticle catalyst preparative protocol by simultaneous in situ metal NP and nanospace organization (PSSO) with 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine (Si-DHP) as a strong reducing agent. SAFe(0) was easy to handle in air and could be recycled with a low iron-leaching rate in reaction cycles.
- Akiyama, Toshiki,Arisawa, Mitsuhiro,Haneoka, Hitoshi,Harada, Kazuo,Hasegawa, Jun-Ya,Honma, Tetsuo,Mashima, Kazushi,Sato, Yoshihiro,Shimoda, Shuhei,Shio, Yasunori,Suzuki, Takeyuki,Tamenori, Yusuke,Tsurugi, Hayato,Tsuruta, Kazuki,Wada, Yuki,Yamada, Makito
-
supporting information
p. 7244 - 7249
(2020/10/12)
-
- Pd/C-Catalyzed Carbonylative Synthesis of 2-Aminobenzoxazinones from 2-Iodoaryl Azides and Amines
-
A palladium-catalyzed carbonylative procedure for the synthesis of 2-aminobenzoxazinones from 1-azido-2-iodobenzenes and amines has been developed. A broad range of 2-aminobenzoxazinone derivatives were prepared in moderate to excellent yields by using Pd
- Zhang, Youcan,Yin, Zhiping,Wang, Hai,Wu, Xiao-Feng
-
supporting information
p. 3242 - 3246
(2019/05/10)
-
- Multifunctional Mono-Triazole Derivatives Inhibit Aβ42 Aggregation and Cu2+-Mediated Aβ42 Aggregation and Protect against Aβ42-Induced Cytotoxicity
-
Amyloid beta (Aβ) peptide aggregation is considered as one of the key hallmarks of Alzheimer's disease (AD). Moreover, Aβ peptide aggregation increases considerably in the presence of metal ions and triggers the generation of reactive oxygen species (ROS)
- Kaur, Amandeep,Narang, Simranjeet Singh,Kaur, Anupamjeet,Mann, Sukhmani,Priyadarshi, Nitesh,Goyal, Bhupesh,Singhal, Nitin Kumar,Goyal, Deepti
-
p. 1824 - 1839
(2019/09/30)
-
- Aryl Azides as Forgotten Electrophiles in the Van Leusen Reaction: A Multicomponent Transformation Affording 4-Tosyl-1-arylimidazoles
-
Considering aryl azides as electrophilic partners for the TosMIC mediated Van Leusen reaction, a novel multicomponent synthesis of 4-tosyl-1-arylimidazoles is reported. In this transformation, two molecules of TosMIC participate in the reaction mechanism
- Necardo, Cristiana,Alfano, Antonella Ilenia,Del Grosso, Erika,Pelliccia, Sveva,Galli, Ubaldina,Novellino, Ettore,Meneghetti, Fiorella,Giustiniano, Mariateresa,Tron, Gian Cesare
-
p. 16299 - 16307
(2019/12/27)
-
- Synthesis of indole-fused heteroacenes by cascade cyclisation involving rhodium(ii)-catalysed intramolecular C-H amination
-
Heteroacenes are potentially important materials for organic electronics and their syntheses are of topical interest. Herein we report the development of a catalytic, redox-neutral reaction for the synthesis of the 5,10-dihydroindolo[3,2-b]indole class of
- Matsuda, Takanori,Ito, Hirotaka
-
supporting information
p. 6703 - 6707
(2018/09/29)
-
- Use of an efficient polystyrene-supported cerium catalyst for one-pot multicomponent synthesis of spiro-piperidine derivatives and click reactions in green solvent
-
One-pot multicomponent reactions are very demanding in synthetic organic chemistry. Here we report a new polystyrene-supported cerium catalyst (PS-Ce-amtp) obtained via an easy two-step procedure, which was thoroughly characterized using various techniques. PS-Ce-amtp catalyses the environmentally benign one-pot multicomponent synthesis of spiro-piperidine derivatives through the reaction of substituted aniline, cyclic active methylene compound and formaldehyde at room temperature. The catalyst also exhibits excellent catalytic activity in one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles via click reaction between in situ generated azides (derived from anilines and amines) and terminal alkynes. The catalyst can be recovered easily after reaction and reused five times without significant loss in its catalytic activity. The advantageous features of this catalyst are atom economy, operational simplicity, short reaction times, easy handling and high recycling efficiency.
- Mondal, Paramita,Ghosh, Swarbhanu,Das, Sabuj kanti,Bhaumik, Asim,Das, Debashis,Islam, Sk. Manirul
-
-
- Unprecedented synthesis of 1,2,3-triazolo-cinnolinone via Sonogashira coupling and intramolecular cyclization
-
An unprecedented copper mediated one-pot sequential synthesis of 1,2,3-triazolo cinnolinone derivatives from 2-halo-phenyl triazoles and terminal alkynes has been reported. Under the optimized reaction conditions, a broad range of substituted triazoles and alkynes were found to participate in this transformation, thus affording unknown 1,2,3-triazolo cinnolinone derivatives in moderate to excellent yields. This method proceeds through sequential C-C coupling followed by an annulation cascade sequence in the same vessel under atmospheric air as the sole oxidant, thus representing a simple, efficient and atom economical approach for the synthesis of aza-cinnolinones.
- Kumar, Avnish,Tiwari, Dharmendra Kumar,Sridhar, Balasubramanian,Likhar, Pravin R.
-
supporting information
p. 4840 - 4848
(2018/07/15)
-
- Design and synthesis of novel dehydroepiandrosterone analogues as potent antiproliferative agents
-
The aim of the present study was to determine the cytotoxic effects of a series of novel dehydroepiandrosterone derivatives containing triazole at the C16 position on human cancer cells. The cancer cells used in the present study were A549, Hel
- Huang, Xing,Shen, Qing-Kun,Zhang, Hong-Jian,Li, Jia-Li,Tian, Yu-Shun,Quan, Zhe-Shan
-
-
- N-Heterocycle-Stabilized Iodanes: From Structure to Reactivity
-
Pseudocyclic aryl-λ3-iodanes are superior reagents for a variety of oxidative transformations due to a well-balanced relation between stability, solubility and reactivity. Their properties are substantially influenced by a dative interaction between a Lewis base, in general the oxygen atom of a carboxylic acid or an amide, and the central hypervalent iodine atom. This work presents the first systematic investigation of pseudocyclic N-heterocycle-stabilized iodanes (NHIs). The synthesis of these throughout shelf-stable solids is robust and can be achieved on a large scale. Their reactivity is highly tunable, depending on the stabilizing heterocycle. Solid state structures of selected derivatives are reported and their reactivity in a model oxygen transfer reaction is compared. Further derivatization reactions to N-heterocycle-stabilized pseudocyclic diaryliodonium salts and cyclic iodoso species are presented as well.
- Boelke, Andreas,Lork, Enno,Nachtsheim, Boris J.
-
supporting information
p. 18653 - 18657
(2018/11/23)
-
- Cu(I)-catalyzed cascade intramolecular cyclization of 2-propynol phenyl azides and diarylphosphine oxides for the synthesis of bisphosphorylated indole derivatives
-
The [Cu(OTf)]2·C6H6 catalyzed cascade intermolecular addition–intramolecular cyclization reaction of easily prepared 2-propynol phenyl azides and diarylphosphine oxides was developed. This novel reaction leads to simultane
- Song, Xian-Rong,Li, Ren,Yang, Tao,Bai, Jiang,Yang, Ruchun,Chen, Xi,Ding, Haixin,Xiao, Qiang,Liang, Yong-Min
-
supporting information
p. 3763 - 3766
(2018/09/12)
-
- A novel triazole derivative of betulinic acid induces extrinsic and intrinsic apoptosis in human leukemia HL-60 cells
-
In an attempt to arrive at more potent cytotoxic agent than the bioactive natural product betulinic acid, influence of small structural modifications of its 1, 2, 3 triazole derivatives tethered at C-28 and both C3, C-28 using click chemistry approach has been studied. The chemically characterized triazoles have been screened for in vitro cytotoxicity against four human cancer cell lines HL-60, MiaPaCa-2, PC-3 and A549 which has allowed to identify triazole derivative 28{1N (4-fluoro phenyl)-1H-1, 2, 3-triazol-4-yl} methyloxy betulinic ester having better potency profile than the parent compound with IC50 values in the range of 5-7 μM. It caused disruption of mitochondrial membrane potential, rendered Bcl-2 cleavage, Bax translocation and decrease Bcl-2/Bax ratio. These events are accompanied by activation of caspases -9, -3, which cleave the PARP-1. It also induces caspase-8, which is involved in extrinsic apoptotic pathway. Therefore, it induces apoptosis through both intrinsic and extrinsic pathways in human leukemia HL-60 cells.
- Khan, Imran,Guru, Santosh K.,Rath, Santosh K.,Chinthakindi, Praveen K.,Singh, Buddh,Koul, Surrinder,Bhushan, Shashi,Sangwan, Payare L.
-
p. 104 - 116
(2015/12/04)
-
- Cyclization of Alkyne-Azide with Isonitrile/CO via Self-Relay Rhodium Catalysis
-
A self-relay rhodium(I)-catalyzed cyclization of alkyne-azides with two σ-donor/π-acceptor ligands (isonitriles and CO) to form sequentially multiple-fused heterocycle systems via tandem nitrene transformation and aza-Pauson-Khand cyclization has been dev
- Zhang, Zhen,Xiao, Fan,Huang, Baoliang,Hu, Jincheng,Fu, Bin,Zhang, Zhenhua
-
supporting information
p. 908 - 911
(2016/03/15)
-
- Facile and efficient synthesis of [1,4]oxazino[3,2-b]indoles and 1H-pyrazino[2,3-b]indoles through gold-catalyzed cascade cyclization of (azido)ynamides
-
[1,4]Oxazino[3,2-b]indoles as well as 1H-pyrazino[2,3-b]indoles are constructed in good to excellent yields via gold-catalyzed cascade cyclization of (azido)ynamides. The use of readily available starting materials, a simple procedure and mild reaction co
- Shen, Cang-Hai,Pan, Yuan,Yu, Yong-Fei,Wang, Ze-Shu,He, Weimin,Li, Ting,Ye, Long-Wu
-
supporting information
p. 63 - 67
(2015/03/30)
-
- Synthesis of silver-graphene nanocomposite and its catalytic application for the one-pot three-component coupling reaction and one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles in water
-
A graphene based composite with silver nanoparticles has been synthesized via a simple chemical route and its catalytic activity has been tested for multi-component reactions and click reaction in a one-pot approach. This silver-graphene nanocomposite sho
- Salam, Noor,Sinha, Arjyabaran,Roy, Anupam Singha,Mondal, Paramita,Jana, Nikhil R.,Islam, Sk Manirul
-
p. 10001 - 10012
(2014/03/21)
-
- A convergent synthesis of alkyne-azide cycloaddition derivatives of 4-α,β-2-propyne podophyllotoxin depicting potent cytotoxic activity
-
A facile synthetic approach to construct the O-propargyl derivatives of 4α and 4β-(1,2,3-triazol-4-yl)-podophyllotoxin (9a-k & 10a-k) and 4′-Demethyl-4′-4β-(1,2,3-triazol-4-yl)-epipodophyllotoxin (12a-d) were synthesized by means of click chemistry. The c
- Zilla, Mahesh K.,Nayak, Debasis,Vishwakarma, Ram A.,Sharma, Parduman Raj,Goswami, Anindya,Ali, Asif
-
-
- Cu(II)-anchored functionalized mesoporous SBA-15: An efficient and recyclable catalyst for the one-pot Click reaction in water
-
A new pyridine-imine functionalized mesoporus silica (SBA-15) has been synthesized through the Schiff-base condensation of 3-aminopropyl functionalized SBA-15 with 2-pyridinecarboxaldehyde followed by the grafting of Cu(II) onto it resulting a new Cu@PyIm-SBA-15 material. 2D-hexagonally ordered mesophases of the material are analyzed by small-angle powder X-ray diffractions (PXRD) and transmission electron microscopic (TEM) image analyses. The Cu(II)-anchored mesoporous material, Cu@PyIm-SBA-15 showed excellent catalytic activity towards the one pot click reaction between azides formed in situ from the corresponding amines and acetylenes in water at 0 C to room temperature resulting a wide variety of 1,4-disubstituted 1,2,3-triazoles. The catalyst has been recycled for five cycles without any appreciable loss of catalytic activity and also without any appreciable Cu-leaching, suggesting a future potential of this novel mesoporous catalyst for the synthesis of 1,4-disubstituted 1,2,3-triazoles.
- Roy, Susmita,Chatterjee, Tanmay,Pramanik, Malay,Roy, Anupam Singha,Bhaumik, Asim,Islam, Sk. Manirul
-
-
- Click chemistry inspired synthesis and bioevaluation of novel triazolyl derivatives of osthol as potent cytotoxic agents
-
A new series of diverse triazoles linked through the hydroxyl group of lactone ring opened osthol (1) were synthesized using click chemistry approach. All the derivatives were subjected to 3-(4,5-Dimethylthiazol-yl)-diphenyl tetrazoliumbromide (MTT) cytot
- Farooq, Saleem,Shakeel-U-Rehman,Hussain, Aashiq,Hamid, Abid,Qurishi, Mushtaq A.,Koul, Surrinder
-
p. 545 - 554
(2015/03/14)
-
- Polymer anchored Cu(ii) complex: An efficient and recyclable catalytic system for the one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles starting from anilines in water
-
An efficient procedure for the one-pot synthesis of 1,4-disubstituted 1,2,3-triazole derivatives has been developed by the 'click' reaction of azides generated in situ from anilines or amines and terminal acetylenes catalyzed by the polymer anchored Cu(ii) catalyst in water without using any additives. The polymer anchored Cu(ii) catalyst was synthesized and its catalytic activity was evaluated in the Huisgen [3 + 2] cycloaddition reaction for the first time. This protocol offers several advantages like low catalyst loading, high yields, clean reaction, recyclability of the catalyst, reaction in water, no use of hazardous organic solvents for the purification of product, and one-pot synthesis of triazoles from anilines or amines.
- Roy, Susmita,Chatterjee, Tanmay,Islam, Sk. Manirul
-
p. 2532 - 2539
(2013/09/12)
-
- Tandem synthesis of benzo[b]carbazoles and their photoluminescent properties
-
5 H-Benzo[b]carbazoles were prepared through a tandem reaction between 2-ethynyl-N-triphenylphosphoranylidene anilines and α-diazoketones through ketenimine intermediates in moderate-to-good yields. By using this approach, benzo[b]benzo[5,6]indolo[3,2-h]carbazoles, fluoreno[9,1-ab]carbazoles, and fluoreno[9,1-ab]fluoreno[1′,9′:5,6,7]indolo[3,2-h]carbazoles were constructed in one pot. Moreover, the resulting products emitted light within the range 410-521a nm, with quantum yields of up to 62 %. Lord of the rings: A series of benzo[b]carbazoles was synthesized through a tandem Wolff-rearrangement/aza-Wittig-reaction/biradical-ketenimine-cyclization/1, 5-H-shift process. The products emitted intense light with high emission quantum yields (see scheme). Copyright
- Xing, Yanpeng,Hu, Binbin,Yao, Qijun,Lu, Ping,Wang, Yanguang
-
supporting information
p. 12788 - 12793
(2013/10/01)
-
- Nickel- or Palladium-Catalyzed Stereoselective Synthesis of Tetrasubstituted olefinic indolines-fused triazoles: Extension to the spiroindoline core
-
A nickel- or palladium-catalyzed cascade approach to afford indolines-fused triazoles with tetrasubstituted olefins in good yields with excellent control of regio- and stereoselectivity is described. We have also discussed the synthesis of unsaturated carbonyl species when the alkyne was appended to an alkyl chain. The synthetic methodology has been extended to construct the biologically active spiroindoline core via a vinylcylopropane (VCP) intermediate. The synthesized tetrasubstituted scaffolds were investigated for their photophysical properties and all of the them exhibited good absorption and fluorescence emission in the UV-visible region. Copyright
- Senadi, Gopal Chandru,Hu, Wan-Ping,Boominathan, Siva Senthil Kumar,Wang, Jeh-Jeng
-
supporting information
p. 3679 - 3693
(2014/01/06)
-
- Copper-catalyzed C-H azidation of anilines under mild conditions
-
A novel and efficient copper-catalyzed azidation reaction of anilines via C-H activation has been developed. This method, in which the primary amine acts as a directing group by coordinating to the metal center, provides ortho azidation products regioselectively under mild conditions. This effective route for the synthesis of aryl azides is of great significance in view of the versatile reactivity of the azide products.
- Tang, Conghui,Jiao, Ning
-
supporting information
p. 18924 - 18927
(2013/01/15)
-
- CARBONIC ANHYDRASE INHIBITORS WITH ANTIMETASTATIC ACTIVITY
-
Compositions for the treatment of cancer comprising coumarin and thiocoumarin derivatives of Formulas I- XII are disclosed. Said derivatives preferentially inhibit carbonic anhydrase IX and XII (which are associated with hypoxic and metastatic tumours) over inhibiting carbonic anhydrase I and II activity. The compositions therefore are suited for treatment of hypoxic or metastatic cancers due to this selective mechanism of action.
- -
-
Page/Page column 34-65
(2012/06/15)
-
- Cellulose sulphuric acid as a biodegradable catalyst for conversion of aryl amines into azides at room temperature under mild conditions
-
This article describes simple and efficient method for the diazotization and azidation of different aromatic amines over cellulose sulphuric acid, sodium nitrite and sodium azide under mild conditions at room temperature. Various aryl amines possessing electron-withdrawing groups or electron-donating groups have been converted into the corresponding aryl azides with 71-99% yields. The use of mild reaction conditions, avoids the use of harmful acids and toxic solvents and short reaction times are advantages of this methodology. The selected catalyst is found to be highly efficient and recyclable.
- Nemati, Firouzeh,Elhampour, Ali
-
p. 889 - 892,4
(2020/09/09)
-
- Flow synthesis of organic azides and the multistep synthesis of imines and amines using a new monolithic triphenylphosphine reagent
-
Here we describe general flow processes for the synthesis of alkyl and aryl azides, and the development of a new monolithic triphenylphosphine reagent, which provides a convenient format for the use of this versatile reagent in flow. The utility of these new tools was demonstrated by their application to a flow Staudinger aza-Wittig reaction sequence. Finally, a multistep aza-Wittig, reduction and purification flow process was designed, allowing access to amine products in an automated fashion.
- Smith, Catherine J.,Smith, Christopher D.,Nikbin, Nikzad,Ley, Steven V.,Baxendale, Ian R.
-
supporting information; experimental part
p. 1927 - 1937
(2011/04/21)
-
- A fully automated, multistep flow synthesis of 5-amino-4-cyano-1,2,3- triazoles
-
Having demonstrated in the preceding publication the flow synthesis of aryl azides, we describe here a general protocol for the in-line purification of these versatile intermediates. As part of this investigation, we evaluated the use of ReactIR 45m as a
- Smith, Catherine J.,Nikbin, Nikzad,Ley, Steven V.,Lange, Heiko,Baxendale, Ian R.
-
supporting information; experimental part
p. 1938 - 1947
(2011/04/24)
-
- Preparation of polyfunctional aryl azides from aryl triazenes. A new synthesis of ellipticine, 9-methoxyellipticine, isoellipticine, and 7-carbethoxyisoellipticine
-
(Chemical Equation Presented) The preparation of polyfunctional aryl azides by the reaction of aryl triazenes with NaN3 in the presence of KHSO4 or BF3·OEt2/TFA (trifluoroacetic acid) has been described. A variety of functional groups (halides, esters, ketones, nitriles, aldehydes, and boronic esters) are tolerated under the Lewis acidic conditions. By using this methodology, the potent antitumor agents, ellipticine and 9-methoxyellipticine, have been synthesized. In addition, isoellipticine and a related derivative, 7-carbethoxyisoellipticine, were also prepared.
- Liu, Ching-Yuan,Knochel, Paul
-
p. 7106 - 7115
(2008/02/11)
-
- A novel heterocumulenic Pauson-Khand reaction of alkynylcarbodiimides: A facile and efficient synthesis of heterocyclic ring-fused pyrrolinones
-
The first examples of the heterocumulenic Pauson-Khand reaction are described. Alkynylcarbodiimides undergo an intramolecular Pauson-Khand cycloaddition upon heating in the presence of Mo(CO)6 and DMSO to afford 4,5-dihydro-1H-pyrrolo[2,3-b]pyrrolin-2-ones and 1H-pyrrolo[2,3-b]indol-2-ones.
- Saito, Takao,Shiotani, Masahiro,Otani, Takashi,Hasaba, Satoshi
-
p. 1045 - 1048
(2007/10/03)
-
- Photolysis of regioisomeric diazides of 1,2-diphenylacetylenes studies by matrix-isolation spectroscopy and DFT calculations.
-
A series of diazides of 1,2-diphenylacetylenes was photolyzed in matrices at low temperature and transient photoproducts were characterized by using IR, UV/vis methods combined with ESR studies. Theoretical calculations were also used to understand the experimental findings. The introduction of phenylethynyl groups on phenyl azides has little effect on the photochemical pathway. Thus, upon photoexcitation, (phenylethynyl)phenyl azides afforded the corresponding triplet nitrene, which is in photoequilibrium with the corresponding azacycloheptatetraene. In marked contrast, azidophenylethynyl groups exhibited a dramatic effect not only on the photochemical pathway of phenyl azides but also on the electronic and molecular structure of the photoproducts. The patterns of the effect depended upon the relative position of azide groups in the diphenylacetylene unit. Whenever two azide groups were situated in a conjugating position with respect to each other, as in p,p'-, o,o'-, and p,o'-bis(azides), the azides always resulted in the formation of a quinoidal diimine diradical in which unpaired electrons were extensively delocalizedin the pi-conjugation. The situation changed rather dramatically when azide groups were introduced in the meta position. Thus, the formation of azacycloheptatetraene was noted in the photolysis of the m.m'-isomer. ESR studies indicated the generation of a quintet state that was shown to be a thermally populated state with a very small energy gap of ca. 100 cal mol(-1). The m,p'-isomer was shown to be an excellent precursor for the high-spin quintet dinitrene.The IR spectra of the photoproduct showed no bands ascribable to azacycloheptatetraene. The observed spectra were in good agreement with that calculated for the quintet state. Strong EPR signals assignable to the quintet state were observed, along with rather weak signals due to mononitrenes. Moreover, the quintet bis(nitrene) was rather photostable under these conditions.
- Tomioka, Hideo,Sawai, Shinji
-
p. 4441 - 4450
(2007/10/03)
-
- Highly chemoselective hydrogenolysis of iodoarenes
-
The catalytic hydrodehalogenation reaction using molecular hydrogen and Pd/C has been revisited. It is shown that the speed of removal of halogen increases with increasing electronegativity I Br Cl. Nevertheless, selective dehydrohalogenation in compounds containing other reducible functions can be achieved only with iodine and not with bromine or chlorine. Selective deiodination of iodobenzophenone could be accomplished without reducing the carbonyl group. Hydrogenolysis of azidoiodoaromatic compounds to the corresponding azido compounds is high yielding. This selectivity was exploited for the labeling of benzophenone- and azido-containing compounds by deuterium and tritium.
- Faucher, Nicolas,Ambroise, Yves,Cintrat, Jean-Christophe,Doris, Eric,Pillon, Florence,Rousseau, Bernard
-
p. 932 - 934
(2007/10/03)
-