bluuebunny/crossref_metadata_2025_split huggingface dataset:
ChemInform Abstract: An Unusual Cationic Ru(II) Indenylidene Complex and Its Ru(III) Derivatives—Efficient Catalysts for High Temperature Olefin Metathesis Reactions.
Authors: Songis Olivier , Slawin Alexandra M. Z. , Cazin Catherine S. J. 
Published: May 2012

AbstractThe use of a mixed phosphite/N‐heterocyclic carbene bearing ruthenium precursor permits the synthesis of unprecedented four‐coordinate Ru(II) and Ru(III) cationic complexes adopting an unusual sawhorse structure.
ChemInform Abstract: Efficient Hydrogenation of Biomass‐Derived Cyclic Di‐Esters to 1,2‐Diols.
Authors: Balaraman Ekambaram , Fogler Eran , Milstein David 
Published: May 2012

AbstractAn unprecedented mild and neutral homogeneous hydrogenation of dioxolediones (I) and (III) is presented.
ChemInform Abstract: Rh(I)‐Catalyzed [5 + 1] Cycloaddition of Vinylcyclopropanes and CO for the Synthesis of α,β‐ and β,γ‐Cyclohexenones.
Authors: Jiang Guo‐Jie , Fu Xu‐Fei , Li Qian , Yu Zhi‐Xiang 
Published: May 2012

AbstractThe method is highly efficient in the presence of 0.2 atm CO to give an access to the assembly of six‐membered carbocycles.
ChemInform Abstract: Sulfated Tungstate: A Green Catalyst for Strecker Reaction.
Authors: Pathare Sagar P. , Akamanchi Krishnacharya G. 
Published: May 2012

AbstractThe process can be applied to the reaction of various aldehydes and ketones with amines under solvent‐free conditions at room temperature to form a broad spectrum of functionalized α‐aminonitriles.
ChemInform Abstract: Highly Enantioselective Nitro‐Mannich Reaction Catalyzed by Cinchona Alkaloids and N‐Benzotriazole Derived Ammonium Salts.
Authors: Wei Yu , He Wei , Liu Yulong , Liu Peng , Zhang Shengyong 
Published: May 2012

AbstractThe ammonium salt CIA efficiently promotes the reaction to give a wide range of β‐nitroamines with good to high diastereo‐ and excellent enantioselectivity.
ChemInform Abstract: Palladacycle‐Catalyzed Tandem Allylic Amination/Allylation Protocol for One‐Pot Synthesis of 2‐Allylanilines from Allylic Alcohols.
Authors: Chen Ke , Li Yongxin , Pullarkat Sumod A. , Leung Pak‐Hing 
Published: May 2012

AbstractWith aryl amines bearing electron‐donating and strong electron‐withdrawing groups, hitherto unaccessible C‐allylated anilines are obtained.
ChemInform Abstract: Copper(II)‐Catalyzed O‐Arylation of Tertiary Alcohols with Arylbismuth(III) Reagents: A Convenient System for Aryl Transfer.
Authors: Harada Syuji , Hayashi Daisuke , Sato Itaru , Hirama Masahiro 
Published: May 2012

AbstractReaction of alcohols (I) and (VI) with generally unstable triarylbismuth diacetates under conditions A) provides the corresponding phenol ethers.
ChemInform Abstract: Selective Oxoammonium Salt Oxidations of Alcohols to Aldehydes and Aldehydes to Carboxylic Acids.
Authors: Qiu Joseph C. , Pradhan Priya P. , Blanck Nyle B. , Bobbitt James M. , Bailey William F. 
Published: May 2012

AbstractThe reaction of primary aliphatic alcohols with the oxidant PAB leads directly to the corresponding carboxylic acids.
ChemInform Abstract: Electrochemical Cleavage of Sulfonamides: An Efficient and Tunable Strategy to Prevent β‐Fragmentation and Epimerization.
Authors: Viaud Pierre , Coeffard Vincent , Thobie‐Gautier Christine , Beaudet Isabelle , Galland Nicolas , Quintard Jean‐Paul , Le Grognec Erwan 
Published: May 2012

AbstractThe presence of an N‐benzoyl group is necessary to facilitate the sulfonamide cleavage and prevent β‐fragmentation and epimerization.
ChemInform Abstract: Iron‐Catalyzed Regio‐ and Stereoselective Chlorosulfonylation of Terminal Alkynes with Aromatic Sulfonyl Chlorides.
Authors: Zeng Xiaoming , Illies Laurean , Nakamura Eiichi 
Published: May 2012

AbstractThe title reaction allows a new and selective access to (E)‐β‐chlorovinylsulfones.
ChemInform Abstract: (Tosylimino)phenyl‐λ3‐iodane as a Reagent for the Synthesis of Methyl Carbamates via Hofmann Rearrangement of Aromatic and Aliphatic Carboxamides.
Authors: Yoshimura Akira , Luedtke Matthew W. , Zhdankin Viktor V. 
Published: May 2012

AbstractA new, mild, and efficient method to prepare various methyl carbamates as well as other alkyl carbamates is reported.
ChemInform Abstract: Isolation of Chloro‐Bridged Arylpalladium Complexes, [Pd2Ar2(μ‐Cl)2 (PR3)2], in Palladium Catalyzed C—C Cross Coupling Reaction of Triarylbismuth with Arylhalides.
Authors: Chaudhari Kamal R. , Wadawale Amey P. , Jain Vimal K. 
Published: May 2012

AbstractThe activity of palladium complexes (I) is studied in the reactions of aryl bromides and iodides with triphenyl‐ and tris(p‐tolyl)bismuth in the presence of a base.
ChemInform Abstract: Isosteviol—Proline Conjugates as Highly Efficient Amphiphilic Organocatalysts for Asymmetric Three‐Component Mannich Reactions in the Presence of Water.
Authors: An Ya‐Jie , Wang Chuan‐Chuan , Liu Zi‐Ping , Tao Jing‐Chao 
Published: May 2012

AbstractAmong the conjugates tested, IPC is found to show good activity and stereoselectivity for the reaction of anilines, aromatic aldehydes and cyclohexanone.
ChemInform Abstract: Synthesis of 2‐Aminobenzophenone Derivatives and Their Anticancer Activity.
Authors: Cortez‐Maya S. , Cortes‐Cortes E. , Hernandez‐Ortega S. , Ramirez Apan T. , Martinez‐Garcia M. 
Published: May 2012

Abstract2‐Aminobenzophenone derivatives (IIIa)—(IIIc) show potential anticancer activities, with compound (IIIb), bearing a chlorine atom in the second ring of the benzophenone, being the most potent one.
ChemInform Abstract: Regiospecific and Diastereoselective Aldol Reaction of Chiral N‐Sulfinyl Metalloenamines with α,β‐Unsaturated Trifluoromethyl Ketones: Asymmetric Synthesis of Tertiary Trifluoromethyl Allylic Carbinols.
Authors: Liu Zhen‐Jiang , Zhang Fan , Liu Jin‐Tao 
Published: May 2012

AbstractThe condensation reaction of N‐(tert‐butanesulfinyl) ketimines (I) with α,β‐unsaturated trifluoromethylketones (II) takes place in an 1,2‐addition mode to afford the corresponding tertiary trifluoromethyl allylic carbinols in high yields with good diastereoselectivities.
ChemInform Abstract: Iron‐Catalyzed Ene‐Type Propargylation of Diarylethylenes with Propargyl Alcohols.
Authors: Peng Shiyong , Wang Lei , Wang Jian 
Published: May 2012

AbstractTitle reaction provides access towards propargylic diarylalkenes (III), (V), (VII) and (IX)/(X) as potentially bioactive products in moderate to high yields.
ChemInform Abstract: Halonium‐Initiated C—O Bond Formation via Umpolung of α‐Carbon to the Carbonyl: Efficient Access to 5‐Amino‐3(2H)‐furanones.
Authors: Wei Ying , Lin Shaoxia , Xue Hongxun , Liang Fushun , Zhao Baozhong 
Published: May 2012

AbstractThe monosubstituted oxobutanamide (XIIa) is converted in analogy to the cyclopropane substrates.
ChemInform Abstract: A New Synthesis of γ‐Butyrolactones via AuCl3‐ or Hg(II)‐Catalyzed Intramolecular Hydroalkoxylation of 4‐Bromo‐3‐yn‐1‐ols.
Authors: Reddy Maddi Sridhar , Kumar Yalla Kiran , Thirupathi Nuligonda 
Published: May 2012

AbstractDifferent catalysts are tested for the procedure and the best choice is found with AuCl3 in wet toluene.
ChemInform Abstract: A Ridge Walk Between Reaction Modes: An Unprecedented Pd‐Catalyzed Domino Sequence of Diynyl‐Substituted Bromoarenes.
Authors: Leibeling Markus , Pawliczek Martin , Kratzert Daniel , Stalke Dietmar , Werz Daniel B. 
Published: May 2012

AbstractTwofold carbopalladation/C—H activation is used to construct various heterocyclic polycycles.
ChemInform Abstract: Pd‐Catalyzed Olefination of Furans and Thiophenes with Allyl Esters.
Authors: Zhang Yuexia , Li Zejiang , Liu Zhong‐Quan 
Published: May 2012

AbstractThe reaction proceeds with predominant formation of γ‐substituted allylic esters and ethers with moderate to high (E)‐selectivity.
ChemInform Abstract: An Expedient Diastereoselective Synthesis of Pyrrolidinyl Spirooxindoles Fused to Sugar Lactone via [3 + 2] Cycloaddition of Azomethine Ylides.
Authors: Rao J. Naga Siva , Raghunathan R. 
Published: May 2012

AbstractAzomethine ylides, generated in situ from isatins and amino acids, undergo 1,3‐dipolar cycloaddition with sugar lactones to give the pharmaceutically interesting heterocyclic scaffold with high regio‐ and diastereoselectivity.
ChemInform Abstract: Facile Synthesis of Azaarene‐Substituted 3‐Hydroxy‐2‐oxindoles via Broensted Acid Catalyzed sp3 C—H Functionalization.
Authors: Niu Rui , Xiao Jian , Liang Tao , Li Xingwei 
Published: May 2012

AbstractIn contrast to substrate (XV), other acyclic 1,2‐dicarbonyls such as glyoxylates and pyruvates fail to react.
ChemInform Abstract: Asymmetric Hydroxyamination of Oxindoles Catalyzed by Chiral Bifunctional Tertiary Amine Thiourea: Construction of 3‐Amino‐2‐oxindoles with Quaternary Stereocenters.
Authors: Jia Li‐Na , Huang Jun , Peng Lin , Wang Liang‐Liang , Bai Jian‐Fei , Tian Fang , He Guang‐Yun , Xu Xiao‐Ying , Wang Li‐Xin 
Published: May 2012

AbstractA bifunctional piperidine—thiourea organocatalyst efficiently catalyzes the asymmetric hydroxyamination of oxindoles (I) with nitrosobenzene (II).
ChemInform Abstract: Enantioselective Organocatalytic Oxyamination of Unprotected 3‐Substituted Oxindoles.
Authors: Companyo Xavier , Valero Guillem , Pineda Oriol , Calvet Teresa , Font‐Bardia Merce , Moyano Albert , Rios Ramon 
Published: May 2012

AbstractThe asymmetric α‐oxyamination of 3‐substituted oxindoles (I) and (IV) with nitrosobenzene (II) is readily catalyzed by a bifunctional tertiary amine—thiourea organocatalyst to give the corresponding 3‐aminooxindoles (III) and (V) in moderate enantioselectivities (23—72% e.e.).
ChemInform Abstract: Proline‐Catalyzed Synthesis of 5‐Aryl‐2‐oxazolidinones from Carbon Dioxide and Aziridines under Solvent‐Free Conditions.
Authors: Dou Xiao‐Yong , He Liang‐Nian , Yang Zhen‐Zhen 
Published: May 2012

AbstractL‐proline can be easily recycled and reused more than five times without appreciable loss of catalytic activity.
ChemInform Abstract: A Facile Preparation of 2‐Bromodifluoromethyl Benzo‐1,3‐diazoles and Its Application in the Synthesis of gem‐Difluoromethylene‐Linked Aryl Ether Compounds.
Authors: Jiang Haizhen , Yuan Shijie , Cai Yeshan , Wan Wen , Zhu Shizheng , Hao Jian 
Published: May 2012

AbstractTitle compounds (III) can be easily prepared under the conditions shown.
ChemInform Abstract: High‐Temperature Continuous Flow Synthesis of 1,3,4‐Oxadiazoles via N‐Acylation of 5‐Substituted Tetrazoles.
Authors: Reichart Benedikt , Kappe C. Oliver 
Published: May 2012

AbstractIt is demonstrated that tetrazoles can be readily converted to various biologically interesting 1,3,4‐oxadiazoles using anhydrides or acid chlorides under microwaves or continuous flow.
ChemInform Abstract: New Type of Azacyclization: Thermal Preparation of 4,6‐Disubstituted 2‐Piperidinone from N‐Sulfonyldienamide and Its Substituent Effect.
Authors: Maekawa Yuya , Sakaguchi Taku , Tsuchikawa Hiroshi , Katsumura Shigeo 
Published: May 2012

AbstractA new thermal cyclization of sulfonamides (I) or (III) proceeds through a 6π‐azaelectrocyclization to yield 4,6‐disubstituted 2‐piperidinones as core structures of alkaloid skeletons.
ChemInform Abstract: Catalytic Enantioselective Synthesis of Azacycloalkenes via Intermolecular Rhodium Carbenoid C—H Insertion/Ring‐Closing Metathesis Sequence.
Authors: McMills Mark C. , Humes Ross J. , Pavlyuk Oksana M. 
Published: May 2012

AbstractTreatment of amines (I) with diazoester (II) in the presence of a chiral catalyst affords cyclopropanes (III) and C—H insertion products (IV) as single diastereomers and with good to excellent enantioselectivity.
ChemInform Abstract: Au(III)‐Catalyzed Tandem Amination—Hydration of Alkynes: Synthesis of α‐(N‐2‐Pyridonyl)ketones.
Authors: Romero Nathan A. , Klepser Benjamin M. , Anderson Carolyn E. 
Published: May 2012

AbstractThe silyl ether (IIb) decomposes and only 2‐pyridone is formed.
ChemInform Abstract: Iodine Catalyzed One‐Pot Multi‐Component Reaction to CF3‐Containing Spiro[indene‐2,3′‐piperidine] Derivatives.
Authors: Dai Baifan , Duan Yijun , Liu Xiaoqing , Song Liping , Zhang Min , Cao Weiguo , Zhu Shizheng , Deng Hongmei , Shao Min 
Published: May 2012

AbstractA series of novel trifluoromethyl‐substituted spiro[indene‐2,3′‐piperidine] scaffolds are obtained in one‐pot multicomponent reactions of trifluoroacetoacetate (II), indandione (I), various aromatic aldehydes (III), and ammonium acetate.
ChemInform Abstract: Two‐Directional Approach for the Rapid Synthesis of 2,4‐Bis‐aminoaryl Pyridine Derivatives.
Authors: Morgentin Remy , Barlaam Bernard , Foote Kevin , Hassall Lorraine , Hawkins Janet , Jones Clifford D. , Le Griffon Antoine , Peru Aurelien , Ple Patrick 
Published: May 2012

AbstractTwo different approaches to synthesize 2,4‐bis‐aminoaryl pyridine derivatives are introduced.
ChemInform Abstract: Copper‐Catalyzed [5 + 1] Annulation of 2‐Ethynylanilines with an N,O‐Acetal Leading to Construction of Quinoline Derivatives.
Authors: Sakai Norio , Tamura Kosuke , Shimamura Kazuyori , Ikeda Reiko , Konakahara Takeo 
Published: May 2012

AbstractConditions A) or B) are found to be suitable for the construction of quinoline or naphthyridine skeletons as basic structures of natural products.
ChemInform Abstract: Solvent‐Free Synthesis and Antibacterial Studies of Some Quinolinones.
Authors: Subashini Radhakrishnan , Khan Fazlur‐Rahman Nawaz 
Published: May 2012

AbstractThe strongly acidic cation exchange resin Amberlite SR1L in Na+ form catalyzes the microwave‐promoted condensation to quinolones (III) as well as a subsequent microwave‐assisted N‐alkylation reaction.
ChemInform Abstract: 1,4‐Dipolar Cycloaddition Reactions in Ionic Liquids: A Facile Synthesis of 9aH,15H‐[1]Benzopyrano[3′2′:3,4]pyrido[2,1‐a]isoquinolines (= 9aH,15H‐Benzo[a][1]benzopyrano[2,3‐h]quinolizines).
Authors: Reddy Basi V. Subba , Yadav Nagendra Nath , Srivastava Nikhil , Yadav Jhillu S. , Sridhar Balasubramanian 
Published: May 2012

AbstractThe three‐component reaction is investigated in ionic liquid as a recyclable medium.
ChemInform Abstract: Pyridinium‐Based Broensted Acidic Ionic Liquid as a Highly Efficient Catalyst for One‐Pot Synthesis of Dihydropyrimidinones.
Authors: Hajipour Abdol R. , Seddighi Mohadeseh 
Published: May 2012

AbstractThe inexpensive reusable catalyst allows an efficient preparation of various pyrimidine structures within a short time.
ChemInform Abstract: Amberlyst‐15 Mediated Synthesis of 2‐Substituted 2,3‐Dihydroquinazolin‐4(1H)‐ones and Their Crystal Structure Analysis.
Authors: Murthy P. VNS , Rambabu D. , Krishna G. Rama , Reddy C. Malla , Prasad K. R. S. , Rao M. V. Basaveswara , Pal Manojit 
Published: May 2012

AbstractThe methodology may be of interest for the synthesis of libraries for drug discovery and for the study of the solid state properties of the heterocyclic system.
ChemInform Abstract: Multicomponent Transformation of Isoindoline‐1,3‐diimine (= 1H‐Isoindole‐1,3(2H)‐diimine), Acetylenic Esters, and Triphenylphosphine to Novel Dihydropyrimido[2,1‐a]isoindole Derivatives.
Authors: Baharfar Robabeh , Mohajer Saadieh 
Published: May 2012

AbstractThe reaction of zwitterions generated from diesters (II) and PPh3 with the 1,3‐diimine (I) is investigated.
ChemInform Abstract: Synthesis of Functionalized Pyrazines and Quinoxalines from Nef‐Isocyanide Adducts and 1,2‐Diamines.
Authors: Yavari Issa , Pashazadeh Ramin , Hosseinpour Reza 
Published: May 2012

AbstractCoupling of oxalic ester chlorides (I) with isocyanides followed by reaction of the resulting adducts with 1,2‐diamines constitutes a convenient entry to the title compounds (IV).
ChemInform Abstract: Efficient Domino Approaches to Multifunctionalized Fused Pyrroles and Dibenzo[b,e][1,4]diazepin‐1‐ones.
Authors: Jiang Bo , Li Qiu‐Yun , Zhang Hao , Tu Shu‐Jiang , Pindi Suresh , Li Guigen 
Published: May 2012

AbstractA broad spectrum of the important heterocyclic scaffolds is prepared and a complete anti diastereoselectivity is achieved for tricyclic fused pyrroles such as (VIII).
ChemInform Abstract: Facile Synthesis, Single‐Crystal Structure, and Biological Evaluation of Novel Pyrazolo[5,1‐d][1,2,5]triazepin‐4‐ones.
Authors: Zheng Liang‐Wen , Xuan Hong‐Zhuan , Liu Ying‐Rui , Zhao Bao‐Xiang , Liu Jin‐Ting , Miao Jun‐Ying 
Published: May 2012

AbstractAn interesting ring transformation reaction of oxazinones (I) with hydrazine hydrate, generates triazepinones (II) in good yields.
ChemInform Abstract: Palladium‐Catalyzed Ring‐Opening of Aminocyclopropyl Ugi Adducts.
Authors: Dos Santos Aurelie , El Kaim Laurent , Grimaud Laurence , Ramozzi Romain 
Published: May 2012

AbstractThe Ugi four‐component reaction of various o‐iodosubstituted aromatic substrates with aminocyclopropanes (II), aldehydes (III) and isocyanides (IV) provides the corresponding adducts [cf.
ChemInform Abstract: Three‐Component Reaction of Triphenylphosphine, Dialkyl Acetylenedicarboxylates, and Heterocyclic Rings and the Related Iminophosphoranes.
Authors: Anary‐Abbasinejad Mohammad , Hassanabadi Alireza , Khaksari Zahra 
Published: May 2012

AbstractThe title reaction including diester (III) or its diethyl analogue affords phosphorus ylides of type (IV) which exist as mixtures of rotamers.
ChemInform Abstract: Aqueous‐Phase Synthesis of α‐Hydroxyphosphonates Catalyzed by β‐Cyclodextrin.
Authors: Ramesh Katla , Madhav Bandaru , Murthy Sabbavarapu Narayana , Nageswar Yadavalli Venkata Durga 
Published: May 2012

AbstractThe title compounds can be successfully prepared from aromatic or heteroaromatic aldehydes.
ChemInform Abstract: anti‐AIDS Agents. Part 85. Design, Synthesis, and Evaluation of 1R,2R‐Dicamphanoyl‐3,3‐dimethyldihydropyrano‐[2,3‐c]xanthen‐7(1H)‐one (DCX) Derivatives as Novel anti‐HIV Agents.
Authors: Zhou Ting , Shi Qian , Chen Chin‐Ho , Huang Li , Ho Phong , Morris‐Natschke Susan L. , Lee Kuo‐Hsiung 
Published: May 2012

AbstractThree of the twenty‐four title compounds synthesized, i.e.
ChemInform Abstract: A Novel Caryophyllene Type Sesquiterpene Lactone from Asparagus falcatus (Linn.); Structure Elucidation and anti‐Angiogenic Activity on HUVECs.
Authors: Ghalib Raza Murad , et al. et al. 
Published: May 2012

AbstractAspfalcolide (I) is isolated from the leaves of A.falcatus and characterized by spectroscopic methods and X‐ray single crystal diffraction analysis.
ChemInform Abstract: Synthesis, Molecular Modeling and Biological Evaluation of 2‐(Benzylthio)‐5‐aryloxadiazole Derivatives as Antitumor Agents.
Authors: Liu Kai , Lu Xiang , Zhang Hong‐Jia , Sun Juan , Zhu Hai‐Liang 
Published: May 2012

AbstractTwenty title compounds like (I) are prepared via substituted benzoylhydrazines by using published methods.
ChemInform Abstract: Catalytic Asymmetric Carbon—Carbon Bond‐Forming Reactions in Aqueous Media.
Authors: Bhowmick Sudipto , Bhowmick Kartick C. 
Published: May 2012

AbstractReview: complete up to date results concerning organo‐metal‐ and organocatalyzed asymmetric aldol, 1,4‐conjugate addition, Mannich, Diels—Alder, Friedel—Crafts and some other reactions; ca. 200 refs.
ChemInform Abstract: New Functionalized Imidazolium‐Based Room‐Temperature Ionic Liquids and Composite Materials for Gas Separation and Selective Transport Applications
Authors: Gin D. L. , Noble R. D. , Carlisle T. K. , Voss B. A. , Bara J. E. , LaFrate A. L. , Miller, A. L. II , Hudiono Y. C. , Wiesenauer B. R. , Reynolds M. E. 
Published: May 2012

AbstractReview: 39 refs.
Isoperimetric inequality from the poisson equation via curvature
Authors: Jiang Renjin , Koskela Pekka 
Published: May 2012

AbstractIn this paper, we establish an isoperimetric inequality in a metric measure space via the Poisson equation. Let (X,d,μ) be a complete, pathwise connected metric space with locally Ahlfors Q‐regular measure, where Q > 1, that supports a local L2‐Poincaré inequality. We show that, for the Poisson equation Δu = g, if the local L∞‐norm of the gradient Du can be bounded by the Lorentz norm LQ,1 of g, then we obtain an isoperimetric inequality and a Sobolev inequality in (X,d,μ) with optimal exponents. By assuming a suitable curvature lower bound, we establish such optimal bounds on
$\||Du|\|_{L^\infty_{\rm loc}}$. © 2011 Wiley Periodicals, Inc.
Donor/Acceptor‐Substituted Chiral Molecular Clips – Synthesis and Host–Guest Complex Formation
Authors: Klärner Frank‐Gerrit , Madenci Süreyya , Kuchenbrandt Mireia Campañá , Bläser Dieter , Boese Roland , Fukuhara Gaku , Inoue Yoshihisa 
Published: May 2012

AbstractThe synthesis, separation, and characterization of some substituted stereoisomeric dimethylene‐bridged molecular clips bearing donor or acceptor groups at the tips of the naphthalene sidewalls and two acetoxy, hydroxy, or methoxy groups at the central benzene spacer unit are reported. The host–guest complex formation was studied for these substituted molecular clips as host molecules with 1,2,4,5‐tetracyanobenzene (TCNB), N‐methyl‐p‐(methoxycarbonyl)pyridinium iodide (Kosower's salt, KS), and N‐methylnicotinamideiodide (NMNA) as guest molecules. The binding constants, Ka, and the complexation‐induced 1H NMR shifts of the guest signals, Δδmax, obtained by NMR titration experiments, are compared with those reported for the parent diacetoxybenzene, hydroquinone, or dimethoxybenzene clips. The diacetoxybenzene clip, bearing donor pyrrolidinyl groups at the tips of both naphthalene sidewalls, forms the most stable complexes with TCNB and KS, overwhelming the corresponding complexes of the parent clip and the clips bearing one nitro or methoxycarbonyl group at the tip of one naphthalene sidewall. The clips bearing two acceptor groups (two nitro or methoxycarbonyl groups) at the tips of both naphthalene sidewalls do not form any complex with TCNB, KS, or NMNA within the limits of NMR detection. The large complexation‐induced 1H NMR shifts of the guest signals provide good evidence that in each complex the guest molecule is clipped between the naphthalene sidewalls of the host molecule by attractive aromatic π–π and CH–π interactions, as suggested by force‐field calculations. This structural assignment of the complexes is further confirmed by a single‐crystal structure of the KS complex of the mono‐nitro‐substituted clip, which resembles the complex structure of the parent clip with KS. The good correlation between the clip's electrostatic potential surface (EPS; calculated by DFT for the donor‐ or acceptor‐substituted molecular clips) and the host–guest complex stability confirms the assumption that in chloroform solution the host–guest binding (resulting from attractive aromatic π–π and CH–π interactions) is largely electrostatic in nature, whereas the EPS values do not correlate with the binding constants found in methanol solution, indicating that additional binding forces (resulting for example from solvophobic effects) contribute to the host–guest binding. The separated optically active diacetoxybenzene clips substituted by one or two methoxycarbonyl groups at the naphthalene sidewalls are a good starting point for future studies of chiral molecular recognition and organic catalysis.
One‐Step Synthesis of 2‐Amino‐5H‐pyrimido[5,4‐b]indoles, Substituted 2‐(1,3,5‐triazin‐2‐yl)‐1H‐indoles, and 1,3,5‐Triazines from Aldehydes
Authors: Biswas Subhasish , Batra Sanjay 
Published: May 2012

AbstractAn efficient one‐step synthesis of 2‐amino‐5H‐pyrimido[5,4‐b]indoles through a copper‐catalyzed cascade reaction between 3‐haloindole‐2‐carbaldehydes and guanidine hydrochloride is described. In contrast, the base‐mediated reactions of either 3‐haloindole‐2‐carbaldehydes or substituted indole‐2‐carbaldehydes with substituted amidine hydrochlorides in DMSO result in the formation of 2‐(1,3,5‐triazin‐2‐yl)‐1H‐indole derivatives in one step in excellent yields. Studies toward exploring the utility of the method demonstrate that even substituted benzaldehydes undergo a similar reaction to efficiently yield 2,4,6‐trisubstituted 1,3,5‐triazines. A plausible mechanism for the formation of substituted 1,3,5‐triazines identifies the role of DMSO as an oxidant during the reaction.