- An efficient synthesis of 1-H indazoles
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The reaction of substituted salicyaldehydes with hydrazine hydrochloride under different conditions gave the corresponding 1-H indazoles. However, the reaction of benzaldehydes with hydrazine hydrate under the same conditions yielded only hydrazones.
- Lokhande,Raheem, Abdul,Sabale,Chabukswar,Jagdale
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- Visible-Light-Mediated N-Desulfonylation of N-Heterocycles Using a Heteroleptic Copper(I) Complex as a Photocatalyst
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A photoredox protocol that uses a heteroleptic Cu (I) complex, [Cu(dq)(BINAP)]BF4, has been developed for the photodeprotection of benzenesulfonyl-protected N-heterocycles. A range of substrates was examined, including indazoles, indoles, pyrazoles, and benzimidazole, featuring both electron-rich and electron-deficient substituents, giving good yields of the N-heterocycle products with broad functional group tolerance. This transformation was also found to be amenable to flow reaction conditions.
- Hunter, Cameron J.,Boyd, Michael J.,May, Gregory D.,Fimognari, Robert
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p. 8732 - 8739
(2020/07/16)
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- Inhibition of the Cysteine Protease Human Cathepsin L by Triazine Nitriles: Amide???Heteroarene π-Stacking Interactions and Chalcogen Bonding in the S3 Pocket
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We report an extensive “heteroarene scan” of triazine nitrile ligands of the cysteine protease human cathepsin L (hCatL) to investigate π-stacking on the peptide amide bond Gly67–Gly68 at the entrance of the S3 pocket. This heteroarene???peptide bond stacking was supported by a co-crystal structure of an imidazopyridine ligand with hCatL. Inhibitory constants (Ki) are strongly influenced by the diverse nature of the heterocycles and specific interactions with the local environment of the S3 pocket. Binding affinities vary by three orders of magnitude. All heteroaromatic ligands feature enhanced binding by comparison with hydrocarbon analogues. Predicted energetic contributions from the orientation of the local dipole moments of heteroarene and peptide bond could not be confirmed. Binding of benzothienyl (Ki=4 nm) and benzothiazolyl (Ki=17 nm) ligands was enhanced by intermolecular C?S???O=C interactions (chalcogen bonding) with the backbone C=O of Asn66 in the S3 pocket. The ligands were also tested for the related enzyme rhodesain.
- Giroud, Maude,Ivkovic, Jakov,Martignoni, Mara,Fleuti, Marianne,Trapp, Nils,Haap, Wolfgang,Kuglstatter, Andreas,Benz, J?rg,Kuhn, Bernd,Schirmeister, Tanja,Diederich, Fran?ois
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p. 257 - 270
(2017/02/15)
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- The Chemistry of a Non-Interacting Vicinal Frustrated Phosphane/Borane Lewis Pair
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The dimesitylphosphinocyclopentene/HB(C6F5)2-derived vicinal trans-1,2-P/B frustrated Lewis pair (FLP) 4 shows no direct phosphane–borane interaction. Toward some reagents it behaves similar to an intermolecular FLP; it cleaves dihydrogen, deprotonates terminal alkynes, and adds to organic carbonyl compounds including CO2. It shows typical intramolecular FLP reaction modes (cooperative 1,1-additions) to mesityl azide, to carbon monoxide, and to NO. The latter reaction yields a persistent P/B FLPNO nitroxide radical, which undergoes H-atom abstraction reactions. The FLP 4 serves as a template for the CO reduction by [HB(C6F5)2] to generate a FLP-η2-formylborane. The formylborane moiety is removed from the FLP template by reaction with pyridine to yield a genuine pyridine stabilized formylborane that undergoes characteristic borane carbaldehyde reactions (Wittig olefination, imine formation). Most new products were characterized by X-ray diffraction.
- Elmer, Lisa-Maria,Kehr, Gerald,Daniliuc, Constantin G.,Siedow, Melanie,Eckert, Hellmut,Tesch, Matthias,Studer, Armido,Williams, Kamille,Warren, Timothy H.,Erker, Gerhard
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supporting information
p. 6056 - 6068
(2017/05/05)
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- MUSCARINIC AGONISTS
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Compounds of formula (I) and methods are provided for the treatment of disease or conditions in which modification of cholinergic, especially muscarinic receptor activity, has a beneficial effect.
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- A Novel Approach to 1H-Indazoles via Arylazosulfides
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Treatment of variously substituted (o-alkylaryl)azosulfides 1a-n with potassium tert-butoxide in DMSO at room temperature smoothly furnishes 1H-indazoles 2a-n.
- Dell'Erba, Carlo,Novi, Marino,Petrillo, Giovanni,Tavani, Cinzia
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p. 3529 - 3536
(2007/10/02)
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- Phase Transfer Catalyzed Synthesis of Indazoles from o-Alkylbenzenediazonium Tetrafluoroborates
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Reaction of o-methyl- and o-ethylbenzenediazonium tetrafluoroborates with two equivalents of potassium acetate and five mole percent of 18-crown-6 in ethanol-free chloroform produce indazoles in good to excellent yields.Indazoles bearing either electron-withdrawing or electron-donating substituents may be prepared.
- Bartsch, Richard A.,Yang, Il-Woo
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p. 1063 - 1064
(2007/10/02)
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- Aromatic Diazonium Salts, X. - A One-Pot Procedure for the Jacobson Synthesis of Indazole
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Procedures are described for a one-pot synthesis of 1H-indazole and substituted indazoles 3 in good yield (Table 1) from o-toluidines 2, alkyl nitrite or nitrous oxides, potassium acetate, and acetic anhydride in benzene.The spectroscopic properties of substituted indazoles (Tables 2-4) are discussed. - 4-Phenylcinnoline (18) is prepared by the same procedure from o-(α-methylenebenzyl)aniline.
- Ruechardt, Christoph,Hassmann, Volker
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p. 908 - 927
(2007/10/02)
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