- N -Chlorinative Ring Contraction of 1,4-Dimethoxyphthalazines via a Bicyclization/Ring-Opening Mechanism
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An unprecedented N -chlorinative ring contraction of 1,2-diazines was discovered and investigated with an electrophilic chlorinating reagent, trichloroisocyanuric acid (TCICA). Through optimization and mechanistic analysis, the assisting role of n -Bu 4NCl as an exogenous nucleophile was identified, and the optimized reaction conditions were applied to a range of 1,4-dimethoxyphthalazine derivatives. Also, an improvement of overall efficiency was demonstrated by the use of a labile O -silyl group. A bicyclization/ring-opening mechanism, inspired by the Favorskii rearrangement, was proposed and supported by the DFT calculations. Furthermore, the efforts on scope expansion as well as the evaluation of other electrophilic promoters revealed that the newly developed ring contraction reactivity is a unique characteristic of 1,4-dimethoxyphthalazine scaffold and TCICA.
- Im, Jeong Kyun,Jeong, Ilju,Yang, Byeongdo,Moon, Hyeon,Choi, Jun-Ho,Chung, Won-Jin
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p. 1760 - 1770
(2020/12/30)
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- One-Pot and Two-Chamber Methodologies for Using Acetylene Surrogates in the Synthesis of Pyridazines and Their D-Labeled Derivatives
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Acetylene surrogates are efficient tools in modern organic chemistry with largely unexplored potential in the construction of heterocyclic cores. Two novel synthetic paths to 3,6-disubstituted pyridazines were proposed using readily available acetylene surrogates through flexible C2 unit installation procedures in a common reaction space mode (one-pot) and distributed reaction space mode (two-chamber): (1) an interaction of 1,2,4,5-tetrazine and its acceptor-functionalized derivatives with a CaC2?H2O mixture performed in a two-chamber reactor led to the corresponding pyridazines in quantitative yields; (2) [4+2] cycloaddition of 1,2,4,5-tetrazines to benzyl vinyl ether can be considered a universal synthetic path to a wide range of pyridazines. Replacing water with D2O and vinyl ether with its trideuterated analog in the developed procedures, a range of 4,5-dideuteropyridazines of 95–99% deuteration degree was synthesized for the first time. Quantum chemical modeling allowed to quantify the substituent effect in both synthetic pathways.
- Ananikov, Valentine P.,Ledovskaya, Maria S.,Polynski, Mikhail V.
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p. 2286 - 2297
(2021/07/20)
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- CINNOLINE COMPOUNDS, THEIR PREPARATION, AND THEIR USE
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The present invention relates to cinnoline compounds, particularly 4-amino-N-cyclopropyl- 7-fluoro-8-(3,6-dimethoxypyridazin-4-yl)cinnoline-3-carboxamide and salts thereof. The claimed invention also relates to compositions comprising such a compound, as
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Page/Page column 23
(2011/04/13)
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- Functionalized heteroarylpyridazines and pyridazin-3(2H)-one derivatives via palladium-catalyzed cross-coupling methodology
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(Chemical Equation Presented) A general method for the synthesis of functionalized pyridazinylboronic acids/esters is described involving a directed ortho metalation (DoM)-boronation protocol (Schemes 1 and 2). A comprehensive study of the reactivity of t
- Clapham, Kate M.,Batsanov, Andrei S.,Greenwood, Ryan D. R.,Bryce, Martin R.,Smith, Amy E.,Tarbit, Brian
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p. 2176 - 2181
(2008/09/19)
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- Compounds and Uses Thereof - 848
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This invention relates to novel compounds having the structural formula I below: and their pharmaceutically acceptable salts, tautomers or in vivo-hydrolysable precursors, compositions and methods of use thereof, wherein R1, R2, Rsu
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Page/Page column 73
(2009/01/24)
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- First study of syntheses and reactivity of Grignard compounds in the diazine series. Diazines. Part 27
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A preparation of Grignard derivatives of diazines is described using a halogen magnesium exchange reaction. This convenient method allows the functionalization of these rings at 0°C or even room temperature.
- Leprêtre,Turck,Plé,Knochel,Quéguiner
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p. 265 - 273
(2007/10/03)
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- Synthesis of some 3,6-disubstituted pyridazines
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Some novel 3-halo-6-(4-substituted-phenoxy)pyridazines and 3,6-di-(4- substituted-phenoxy)pyridazines were synthesized from 3,6-dichloropyridazine or 3,6-diiodopyridazine. 3,6-Diiodopyridazine was prepared from 3,6- dichloropyridazine using hydriodic acid/iodine monochloride.
- Shin, Mi-Seon,Kang, Young-Jin,Chung, Hyun-A.,Park, Jung-Won,Kweon, Deok-Heon,Lee, Woo Song,Yoon, Yong-Jin,Kim, Sung-Kyu
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p. 1135 - 1142
(2007/10/03)
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- EXHAUSTIVE METHYLATION OF TAUTOMERIC 6-HYDROXY-3(2H)-PYRIDAZINONE AND ITS 2-METHYL- OR 2-PHENYL DERIVATIVES, FOLLOWED BY ISOLATION AND DETERMINATION BY COLUMN CHROMATOGRAPHY AND 1H NMR SPECTRA
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Tautomeric 6-hydroxy-3(2H)-pyridazinone (1,2-dihydro-3,6-pyridazinone or 3,6-dihydroxypyridazine) and its N-methyl- and N-phenyl derivatives had been exhaustively methylated.The resulting N-methylated and O-methylated products were indentified by the 1H N
- Katrusiak, Anna,Baloniak, Sylwester
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p. 403 - 406
(2007/10/02)
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