- Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
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The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
- Dong, Guangbin,Xu, Yan,Zhou, Xukai
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supporting information
p. 20042 - 20048
(2021/12/03)
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- Cobaloxime-catalyzed hydration of terminal alkynes without acidic promoters
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Cobaloxime (Co(dmgBF2)2·2H2O), an inexpensive first-row transition-metal complex, catalyzed hydration of terminal alkynes gave the corresponding methyl ketones in good to excellent yields under neutral conditions (additional protic acids and silver salts are not required). A wide range of functional groups, such as allyl ether, benzyl ethers, carboxylic esters, imides, amides, nitro, and halogens, were tolerated. The mild reaction conditions together with the inexpensive feature and easy availability of the catalyst well address the current challenges in the field of alkyne hydration.
- Hou, Shengtai,Yang, Hongjian,Cheng, Bin,Zhai, Hongbin,Li, Yun
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p. 6926 - 6929
(2017/07/10)
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- Potentiation of cADPR-induced Ca2+-release by methylxanthine analogues
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Caffeine and other methylxanthines are known to induce Ca2+-release from intracellular stores via the ryanodine receptor. In the present work, a range of caffeine analogues, in which methyl groups at the 1 and 7 positions were replaced with alkyl chains containing different functional groups (oxo, hydroxyl, propargyl, ester, and acids), were synthesized. These compounds were then screened for their ability to potentiate Ca2+-release induced by cADPR (an endogenous modulator of ryanodine receptors) in sea urchin egg homogenates. Two of the synthesized methylxanthines, 1,3-dimethyl-7-(7- hydroxyoctyl)xanthine (37) and 3-methyl-7-(7-oxooctyl)-1-propargylxanthine (66), were shown to be more potent than caffeine in potentiating cADPR- induced Ca2+-release, while 1,3-dimethyl-7-(5-ethylcarboxypentyl)xanthine (14) was shown to be more efficacious. The development of new methylxanthine analogues may lead to a better understanding of ryanodine receptor function and could possibly provide novel therapeutic agents.
- Cavallaro, Rosaria A.,Filocamo, Luigi,Galuppi, Annamaria,Galione, Antony,Brufani, Mario,Genazzani, Armando A.
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p. 2527 - 2534
(2007/10/03)
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- Use of antibodies to TNF or fragments derived thereof and xanthine derivatives for combination therapy and compositions therefor
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A combined preparation for simultaneous combined, simultaneous separate, or sequential use in the therapy of prophylaxis of disorders associated with undesirable high levels of TNF, e.g. septic or endotoxic shock and immunoregulatory and inflammatory disorders, which comprises an antibody to TNF or a TNF binding fragment thereof and a xanthine derivative. Particular preferred xanthine derivatives are 3,7-dimethyl-1(5-oxo-hexyl)xanthine (known as Pentoxifylline or TRENTAL) and 1-(5-hydroxy-5-methylhexyl)-3-methylxanthine and similar compounds. The anti-TNF antibody or fragment is preferably monospecific especially a humanized recombinant antibody or fragment.
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