- Direct Alkynylation of 3H-Imidazo[4,5-b]pyridines Using gem-Dibromoalkenes as Alkynes Source
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C2 direct alkynylation of 3H-imidazo[4,5-b]pyridine derivatives is explored for the first time. Stable and readily available 1,1-dibromo-1-alkenes, electrophilic alkyne precursors, are used as coupling partners. The simple reaction conditions include an inexpensive copper catalyst (CuBr·SMe2 or Cu(OAc)2), a phosphine ligand (DPEphos) and a base (LiOtBu) in 1,4-dioxane at 120 °C. This C-H alkynylation method revealed to be compatible with a variety of substitutions on both coupling partners: heteroarenes and gem-dibromoalkenes. This protocol allows the straightforward synthesis of various 2-alkynyl-3H-imidazo[4,5-b]pyridines, a valuable scaffold in drug design.
- Aziz, Jessy,Baladi, Tom,Piguel, Sandrine
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- Selective Rhodium-Catalyzed Hydroformylation of Terminal Arylalkynes and Conjugated Enynes to (Poly)enals Enabled by a π-Acceptor Biphosphoramidite Ligand
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The hydroformylation of terminal arylalkynes and enynes offers a straightforward synthetic route to the valuable (poly)enals. However, the hydroformylation of terminal alkynes has remained a long-standing challenge. Herein, an efficient and selective Rh-catalyzed hydroformylation of terminal arylalkynes and conjugated enynes has been achieved by using a new stable biphosphoramidite ligand with strong π-acceptor capacity, which affords various important E-(poly)enals in good yields with excellent chemo- and regioselectivity at low temperatures and low syngas pressures.
- Zhao, Jiangui,Zheng, Xueli,Tao, Shaokun,Zhu, Yuxin,Yi, Jiwei,Tang, Songbai,Li, Ruixiang,Chen, Hua,Fu, Haiyan,Yuan, Maolin
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supporting information
p. 6067 - 6072
(2021/08/16)
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- Rh-Catalyzed Asymmetric Hydrogenation of β-Substituted-β-thio-α,β-unsaturated Esters: Expeditious Access to Chiral Organic Sulfides
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Rh/bifunctional bisphosphine-thiourea ligand (ZhaoPhos)-catalyzed asymmetric hydorgenation of both (Z)- and (E)-isomers of β-substituted-β-thio-α,β-unsaturated esters was successfully developed. This new asymmetric catalytic methodology provided highly efficient access to two enantiomers of chiral organic sulfides ethyl β-substituted-β-thio-propanoates with excellent results (up to 99% yield and >99% ee for (Z)-substrates, up to 99% yield and 98% ee for (E)-substrates, TON up to 5000), which are important intermediates in organic synthesis.
- Liu, Gang,Han, Zhengyu,Dong, Xiu-Qin,Zhang, Xumu
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supporting information
p. 5636 - 5639
(2018/09/12)
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- Palladium-catalyzed tandem C-H functionalization/cyclization strategy for the synthesis of 5-hydroxybenzofuran derivatives
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A palladium-catalyzed benzoquinone C-H functionalization/ cyclization strategy with terminal alkynes was employed for the synthesis of some biologically relevant 2, 3-disubstituted 5-hydroxybenzofuran derivatives. The benzoquinone acts as a reactant as well as an oxidant. During the process, an additional alkyne functionality can be introduced at the C3 position of the benzofuran. Base, ligand, and external oxidant are not required in this protocol.
- Ichake, Sachin S.,Konala, Ashok,Kavala, Veerababurao,Kuo, Chun-Wei,Yao, Ching-Fa
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supporting information
p. 54 - 57
(2017/11/28)
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- USE OF CYCLOOXYGENASE-2 INHIBITORS FOR THE TREATMENT OF DEPRESSIVE DISORDERS
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The invention concerns the use of compounds of formula (I), (II) and (III): which are COX-2 (cyclooxygenase-2) inhibitors, and pharmaceutically acceptable salts or solvates thereof, for the treatment of depressive disorders in combination with an effective amount of a second component which is a selective serotonin reuptake inhibitor.
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Page/Page column 36
(2008/06/13)
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- PYRAZOLOPYRIDINE DERIVATIVES AS SELECTIVE COX-2 INHIBITORS
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The invention provides the compounds of formula (I) and pharmaceutically acceptable derivatives thereof wherein: R0 and R1 are independently selected from the group consisting of H, halogen, C1-6alkyl, C1-6alkoxy, and C1-6alkoxy substituted by one or more fluorine atoms; R2 is selected from the group consisting of H, C1-6alkyl, C1-6alkyl substituted by one or more fluorine atoms, C1-6alkoxy, C1-6hydroxyalkyl, SC1-6alkyl, C(O)H, C(O)C1-6alkyl, C1-6alkylsulphonyl, and C1-6alkoxy substituted by one or more fluorine atoms; and R3 is C1-6alkyl or NH2. Compounds of formula (I) are potent and selective inhibitors of COX-2 and are of use in the treatment of the pain, fever, inflammation of a variety of conditions and diseases.
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- 2,3-Diaryl-pyrazolo[1,5-b]pyridazines derivatives, their preparation and their use as cyclooxygenase 2(COX-2) inhibitors
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The invention provides the compounds of formula (I) and pharmaceutically acceptable derivatives thereof in which: R0is halogen, C1-6alkyl, C1-6alkoxy, C1-6alkoxy substituted by one or more fluorine atoms, or O(C
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