- Copper-Catalyzed Ullmann-Type Coupling and Decarboxylation Cascade of Arylhalides with Malonates to Access α-Aryl Esters
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We have developed a high-efficiency and practical Cu-catalyzed cross-coupling to directly construct versatile α-aryl-esters by utilizing readily available aryl bromides (or chlorides) and malonates. These gram-scale approaches occur with turnovers of up to 1560 and are smoothly conducted by the usage of a low catalyst loading, a new available ligand, and a green solvent. A variety of functional groups are tolerated, and the application occurs with α-aryl-esters to access nonsteroidal anti-inflammatory drugs (NSAIDs) on the gram scale.
- Cheng, Fei,Chen, Tao,Huang, Yin-Qiu,Li, Jia-Wei,Zhou, Chen,Xiao, Xiao,Chen, Fen-Er
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supporting information
p. 115 - 120
(2022/01/04)
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- Regioselective Arene C?H Alkylation Enabled by Organic Photoredox Catalysis
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Expanding the toolbox of C?H functionalization reactions applicable to the late-stage modification of complex molecules is of interest in medicinal chemistry, wherein the preparation of structural variants of known pharmacophores is a key strategy for drug development. One manifold for the functionalization of aromatic molecules utilizes diazo compounds and a transition-metal catalyst to generate a metallocarbene species, which is capable of direct insertion into an aromatic C?H bond. However, these high-energy intermediates can often require directing groups or a large excess of substrate to achieve efficient and selective reactivity. Herein, we report that arene cation radicals generated by organic photoredox catalysis engage in formal C?H functionalization reactions with diazoacetate derivatives, furnishing sp2–sp3 coupled products with moderate-to-good regioselectivity. In contrast to previous methods utilizing metallocarbene intermediates, this transformation does not proceed via a carbene intermediate, nor does it require the presence of a transition-metal catalyst.
- Holmberg-Douglas, Natalie,Onuska, Nicholas P. R.,Nicewicz, David A.
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supporting information
p. 7425 - 7429
(2020/03/23)
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- Thermal Stability and Explosive Hazard Assessment of Diazo Compounds and Diazo Transfer Reagents
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Despite their wide use in academia as metal-carbene precursors, diazo compounds are often avoided in industry owing to concerns over their instability, exothermic decomposition, and potential explosive behavior. The stability of sulfonyl azides and other diazo transfer reagents is relatively well understood, but there is little reliable data available for diazo compounds. This work first collates available sensitivity and thermal analysis data for diazo transfer reagents and diazo compounds to act as an accessible reference resource. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and accelerating rate calorimetry (ARC) data for the model donor/acceptor diazo compound ethyl (phenyl)diazoacetate are presented. We also present a rigorous DSC dataset with 43 other diazo compounds, enabling direct comparison to other energetic materials to provide a clear reference work to the academic and industrial chemistry communities. Interestingly, there is a wide range of onset temperatures (Tonset) for this series of compounds, which varied between 75 and 160 °C. The thermal stability variation depends on the electronic effect of substituents and the amount of charge delocalization. A statistical model is demonstrated to predict the thermal stability of differently substituted phenyl diazoacetates. A maximum recommended process temperature (TD24) to avoid decomposition is estimated for selected diazo compounds. The average enthalpy of decomposition (?"HD) for diazo compounds without other energetic functional groups is-102 kJ mol-1. Several diazo transfer reagents are analyzed using the same DSC protocol and found to have higher thermal stability, which is in general agreement with the reported values. For sulfonyl azide reagents, an average ?"HD of-201 kJ mol-1 is observed. High-quality thermal data from ARC experiments shows the initiation of decomposition for ethyl (phenyl)diazoacetate to be 60 °C, compared to that of 100 °C for the common diazo transfer reagent p-acetamidobenzenesulfonyl azide (p-ABSA). The Yoshida correlation is applied to DSC data for each diazo compound to provide an indication of both their impact sensitivity (IS) and explosivity. As a neat substance, none of the diazo compounds tested are predicted to be explosive, but many (particularly donor/acceptor diazo compounds) are predicted to be impact-sensitive. It is therefore recommended that manipulation, agitation, and other processing of neat diazo compounds are conducted with due care to avoid impacts, particularly in large quantities. The full dataset is presented to inform chemists of the nature and magnitude of hazards when using diazo compounds and diazo transfer reagents. Given the demonstrated potential for rapid heat generation and gas evolution, adequate temperature control and cautious addition of reagents that begin a reaction are strongly recommended when conducting reactions with diazo compounds.
- Green, Sebastian P.,Wheelhouse, Katherine M.,Payne, Andrew D.,Hallett, Jason P.,Miller, Philip W.,Bull, James A.
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supporting information
p. 67 - 84
(2020/01/31)
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- Modular Synthesis of Arylacetic Acid Esters, Thioesters, and Amides from Aryl Ethers via Rh(II)-Catalyzed Diazo Arylation
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One-pot formation of arylacetic acid esters, thioesters, and amides via Rh(II)-catalyzed arylation of a Meldrum's acid-derived diazo reagent with electron-rich arenes is described. The methodology was used to efficiently synthesize an anticancer compound.
- Best, Daniel,Jean, Micka?l,Van De Weghe, Pierre
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p. 7760 - 7770
(2016/09/12)
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- Barbituric acid derivatives with antimetastatic and antitumor activity
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The invention is directed to barbituric acid derivatives having inhibitory activity for matrix maetalloproteases comprised of formula (I): pharmaceutical compositions thereof, processes for preparing the derivatives, and methods for treating diseases associated with elevated or uncontrolled levels of matrix metalloprotease activity, e.g., cancer, specifically tumor progression and tumor metastasis, inflammation, or as a method of contraception.
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Page column 14
(2010/01/21)
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- Barbituric acid derivatives, processes for their production and pharmaceutical agents containing these compounds
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PCT No. PCT/EP96/05766 Sec. 371 Date Aug. 26, 1998 Sec. 102(e) Date Aug. 26, 1998 PCT Filed Dec. 20, 1996 PCT Pub. No. WO97/23465 PCT Pub. Date Jul. 3, 1997Compounds of formula I, useful as matrix metalloprotease inhibitors, wherein X, Y and Z are each oxygen; R1 is selected from the group consisting of (a) n-octyl, (b) n-decyl, (c) biphenyl and (d) (4-phenoxy)phenyl, wherein the terminal monocycle for moieties (c)-(d) is unsubstituted or substituted by a substituent selected from the group consisting of -NH2, -NO2, -SO2NH2, -SO2CH3, acetyl, hydroxy, methoxy, ethoxy, cyano and halogen; R2 and R3 are each hydrogen; and R4 and R5, together with the nitrogen atom to which they are bound, form a piperazinyl or piperidyl ring, wherein the piperazinyl ring is substituted in the 4-position with a substituent selected from the group consisting of (a) a 6-membered aromatic monocycle having 0, 1 or 2 nitrogen atoms and the remainder of the atoms in the monocycle being carbon and (b) hydroxy-C1-C6 alkyl, wherein the monocycle is unsubstituted or substituted by a substituent selected from the group consisting of halogen, -NH2, -NO2, -SO2NH2, -SO2CH3, acetyl and cyano.
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