- Scalable synthesis of strained cyclooctyne derivatives
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Modifications to the Popik synthesis of aza-dibenzocyclooctyne (DIBAC) derivatives are described, which avoids tedious purifications and dramatically improves the yield. A new and analogous route to biarylazacyclooctynone (BARAC) through an amide disconnection was also attempted. The BARAC derivatives prepared were found to be unstable under the conditions employed, undergoing a known rearrangement. Finally, the synthesis of a difluoro-DIBAC derivative with a second-order rate constant intermediate between DIBAC and BARAC derivatives (0.50 M-1) is described. While more difficult to synthesize, this molecule was found to be considerably more stable than any BARAC derivatives that were prepared. Georg Thieme Verlag Stuttgart New York.
- Chadwick, Ryan C.,Van Gyzen, Sabrina,Liogier, Sophie,Adronov, Alex
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- Photochemical C-F Activation Enables Defluorinative Alkylation of Trifluoroacetates and -Acetamides
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The installation of gem-difluoromethylene groups into organic structures remains a daunting synthetic challenge despite their attractive structural, physical, and biochemical properties. A very efficient retrosynthetic approach would be the functionalization of a single C-F bond from a trifluoromethyl group. Recent advances in this line of attack have enabled the C-F activation of trifluoromethylarenes, but limit the accessible motifs to only benzylic gem-difluorinated scaffolds. In contrast, the C-F activation of trifluoroacetates would enable their use as a bifunctional gem-difluoromethylene synthon. Herein, we report a photochemically mediated method for the defluorinative alkylation of a commodity feedstock: ethyl trifluoroacetate. A novel mechanistic approach was identified using our previously developed diaryl ketone HAT catalyst to enable the hydroalkylation of a diverse suite of alkenes. Furthermore, electrochemical studies revealed that more challenging radical precursors, namely trifluoroacetamides, could also be functionalized via synergistic Lewis acid/photochemical activation. Finally, this method enabled a concise synthetic approach to novel gem-difluoro analogs of FDA-approved pharmaceutical compounds.
- Campbell, Mark W.,Polites, Viktor C.,Patel, Shivani,Lipson, Juliette E.,Majhi, Jadab,Molander, Gary A.
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supporting information
p. 19648 - 19654
(2021/12/01)
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- Access to Cyanoimines Enabled by Dual Photoredox/Copper-Catalyzed Cyanation of O-Acyl Oximes
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An efficient strategy for the synthesis of pharmaceutically important and synthetically useful cyanoimines, as well as cyanamides, has been described. This strategy is enabled by dual photoredox/copper-catalyzed cyanation of O-acyl oximes or O-acyl hydroxamides. This state of the art protocol for cyanoimines and cyanamides features readily available starting materials, mild reaction conditions, good functional group tolerance, and operational simplicity. The resultant cyanoimines can be transformed into structurally diverse and functionally important N-containing heterocycles.
- Wei, Ziyan,Yu, Shouyun,Zhang, Ai Hua,Zhang, Hao
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supporting information
p. 7315 - 7320
(2020/10/02)
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- Methods for Treating Cognitive Disorders Using Inhibitors of Histone Deacetylase
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This disclosure relates to compounds for the inhibition of histone deacetylase and treatment of a cognitive disorder or deficit. More particularly, the disclosure provides for compounds of formula (I) wherein Q, J, L and Z are as defined in the specification.
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Paragraph 0604
(2017/01/23)
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- Regioselective synthesis of heterocycles containing nitrogen neighboring an aromatic ring by reductive ring expansion using diisobutylaluminum hydride and studies on the reaction mechanism
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(Chemical Equation Presented) A systematic investigation of the reductive ring-expansion reaction of cyclic ketoximes fused to aromatic ringswith diisobutylaluminum hydride (DIBALH) is described. This reaction regioselectively afforded a variety of five- to eight-membered bicyclic heterocycles or tricyclic heterocycles containing nitrogen neighboring an aromatic ring, including indoline, 1,2,3,4,5,6-hexahydrobenz[b]azocine, 3,4-dihydro-2H-benzo[b] [1,4]oxazine, 2,3,4,5-tetrahydrobenzo[b][1,4]thiazepine, 1,2,3,4,5,6- hexahydroazepino[3,2-b]-indole, 2,3,4,5-tetrahydro-1H-benzothieno[2,3-b]azepine, 2,3,4,5-tetrahydro-1H-benzothieno[3,2-b]-azepine, 5,6-dihydrophenanthridine, and 5,6,11,12-tetrahydrodibenz[b, f]azocine. The reaction mechanism leading to the rearrangement was investigated on the basis of the restricted Becke three-parameter plus Lee-Yang-Parr (B3LYP) density functional theory (DFT) with the 6-31G (d) basis set. It was found that the reaction proceeds through a three-centered transition state via a stepwise mechanism because the potential energy curve along the intrinsic reaction coordinate (IRC) had twomaxima (saddle points; TS1 and TS2) and the partial phenonium cation intermediate C. In addition to cyclic ketoximes fused to aromatic rings, the reactions of various cyclic and acyclic ketoximeswere examined to investigate preference of migrating group. It was found that themore electron-rich group migrated preferentially to give the corresponding secondary amines.
- Cho, Hidetsura,Iwama, Yusuke,Sugimoto, Kenji,Mori, Seiji,Tokuyama, Hidetoshi
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experimental part
p. 627 - 636
(2010/04/29)
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- Regiospecific synthesis of unsubstituted basic skeletons of heterocycles containing nitrogen neighboring an aromatic ring by the reductive ring expansion reaction using diisobutylaluminum hydride
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A systematic investigation of reductive ring expansion reaction of oximes with diisobutylaluminum hydride (DIBAH) was performed. The reaction regiospecifically provided a variety of unsubstituted bicyclic heterocycles 3a-3g or tricyclic heterocycles 3h, 3j-3l that contained nitrogen attached to an aromatic ring.
- Cho, Hidetsura,Iwama, Yusuke,Sugimoto, Kenji,Kwon, Eunsang,Tokuyama, Hidetoshi
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experimental part
p. 1183 - 1190
(2009/11/30)
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- BICYCLIC HETEROCYCLE DERIVATIVES AND USE THEREOF AS GPR119 MODULATORS
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The present invention relates to Bicyclic Heterocycle Derivatives of formula (I), compositions comprising a Bicyclic Heterocycle Derivative, and methods of using the Bicyclic Heterocycle Derivatives for treating or preventing obesity, diabetes, a metabolic disorder, a cardiovascular disease or a disorder related to the activity of GPR1 19 in a patient.
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Page/Page column 160-161
(2009/12/27)
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- Mapping the active site in a chemzyme: Diversity in the N-substituent in the catalytic asymmetric aziridination of imines
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(Chemical Equation Presented) The active site of the aziridination catalyst derived from either the VANOL or VAPOL ligand and B(OPh)3 is larger than expected and can accommodate not only significant substitution on the diarylmethyl unit of the imine but also that alkyl (but not perfluorylalkyl) substituents on the aryl groups lead to enhanced rates and enantioselection. The screen of diarylmethyl N-substituents on the imine revealed that the 3,5-di-tert-butyldianisylmethyl group (BUDAM) gave exceptionally high asymmetric inductions for imines of aryl aldehydes.
- Zhang, Yu,Lu, Zhenjie,Desai, Aman,Wulff, William D.
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supporting information; experimental part
p. 5429 - 5432
(2009/06/20)
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- Nonpeptide bradykinin B2 receptor antagonists: Conversion of rodent-selective bradyzide analogues into potent, orally-active human bradykinin B2 receptor antagonists
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The 1-(2-nitrophenyl)thiosemicarbazide (TSC) derivative, (S)-l-[4-(4-benzhydrylthiosemicarbazido)-3-nitrobenzenesulfonyl] pyrrolidine-2-carboxylic acid {2-[(2-dimethylaminoethyl)methylamino]ethyl} amide (bradyzide; (S)-4), was recently disclosed as a novel, potent, orally active nonpeptide bradykinin (BK) B2 receptor antagonist. The compound inhibited the specific binding of [3H]BK to NG108-15 cell membrane preparations (rodent neuroblastoma-glioma) expressing B2 receptors with a Ki of 0.5 ± 0.2 nM. Compound (S)-4 also demonstrated oral efficacy against Freund's complete adjuvant (FCA)-induced mechanical hyperalgesia in rats with an ED50 value of 0.84 μmol/kg. After we optimized the terminal binding determinants projecting from the TSC framework, we found that it was possible to replace the potentially toxicophoric nitro and divalent sulfur moieties with only a 15-fold loss in binding affinity ((S)-14a). However, bradyzide and its congeners were found to have much lower affinities for cloned human B2 receptors, expressed in Cos-7 cells. The hitherto synthesized TSC series was screened against the human B2 receptor, and the dibenzosuberane (DBS) pharmacophore emerged as the key structural requirement for potency. Incorporation of this group resulted in a series of derivatives ((S)-14d,e and 19b-d) with Ki ranges of 10.7-176 nM in NG108-15 cells (expressing the rodent B2 receptor) and 0.79-253 nM in Cos-7 cells (expressing the human B2 receptor). There was no evidence of agonist activity with any of the nonpeptides in any of the cell lines tested. In vivo, oral administration of compound 19c reversed FCA-induced and turpentine-induced mechanical hyperalgesia in rodents with ED50 values of 0.027 and 0.32 μmol/kg, respectively. The selectivity profiles of compounds (S)-14f and (S)-14g were also assessed to determine the conformational and/or steric preferences of the double-ring arrangement. The affinity of (S)-14g for the human B2 receptor suggested that it may be a hydrophobic interaction with the ethane bridge of the DBS moiety that accounts for the increased potency of compounds (S)-14d,e and 19b,c at this receptor, by favoring a binding mode inaccessible to the unsubstituted diphenylmethyl derivative, (S)-4.
- Dziadulewicz, Edward K.,Ritchie, Timothy J.,Hallett, Allan,Snell, Christopher R.,Davies, John W.,Wrigglesworth, Roger,Dunstan, Andrew R.,Bloomfield, Graham C.,Drake, Gillian S.,McIntyre, Peter,Brown, Michael C.,Burgess, Gillian M.,Lee, Wai,Davis, Clare,Yaqoob, Mohammed,Phagoo, Steve B.,Phillips, Elsa,Perkins, Martin N.,Campbell, Elizabeth A.,Davis, Andrew J.,Rang, Humphrey P.
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p. 2160 - 2172
(2007/10/03)
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