- Photocatalyst-controlled and visible light-enabled selective oxidation of pyridinium salts
-
This study proposes two different methods of photocatalytic-controlled and visible light-induced selective oxidation of pyridiniums with air as the terminal oxidant. The key to these transformations is to choose the appropriate light source and photocatal
- Peng, Xiang-Jun,He, Hai-Ping,Liu, Qian,She, Kun,Zhang, Bao-Qi,Wang, Heng-Shan,Tang, Hai-Tao,Pan, Ying-Ming
-
p. 753 - 760
(2021/03/31)
-
- Half-sandwich ruthenium complex containing phenyl benzoxazole structure as well as preparation method and application of half-sandwich ruthenium complex
-
The invention relates to a half-sandwich ruthenium complex containing a phenyl benzoxazole structure as well as a preparation method and application of the half-sandwich ruthenium complex. The ruthenium complex has the following structure as shown in the specification. The preparation method comprises the steps of dissolving phenyl benzoxazole, [CymRuCl2] 2 and sodium acetate in methanol at room temperature, heating the system, and continuing to react; and after the reaction is finished, standing, filtering, carrying out reduced pressure pumping on the solvent, carrying out column chromatography separation on the obtained crude product to obtain the red half-sandwich ruthenium complex containing the phenyl benzoxazole structure, and applying the red half-sandwich ruthenium complex to catalysis of oxidation of alkyl pyridine compounds to prepare nitrogen heterocyclic ketone compounds. Compared with the prior art, the preparation method provided by the invention is simple and green, the catalytic oxidation reaction can be carried out under mild conditions, and the catalyst has high stability and is not sensitive to air and water.
- -
-
Paragraph 0041-0044
(2021/04/14)
-
- Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen
-
The methylene group of various substituted 2- and 4-benzylpyridines, benzyldiazines and benzyl(iso)quinolines was successfully oxidized to the corresponding benzylic ketones using a copper or iron catalyst and molecular oxygen as the stoichiometric oxidant. Application of the protocol in API synthesis is exemplified by the alternative synthesis of a precursor to the antimalarial drug Mefloquine. The oxidation method can also be used to prepare metabolites of APIs which is illustrated for the natural product papaverine. ICP-MS analysis of the purified reaction products revealed that the base metal impurity was well below the regulatory limit.
- Sterckx, Hans,De Houwer, Johan,Mensch, Carl,Herrebout, Wouter,Tehrani, Kourosch Abbaspour,Maes, Bert U.W.
-
p. 144 - 153
(2016/04/05)
-
- NOVEL CYTOCHROME P450 INHIBITORS AND THEIR METHOD OF USE
-
Embodiments of the present invention relate to novel cytochrome P450 inhibitors and pharmaceutical compositions thereof having a disease-modifying action in the treatment of diseases associated with the overproduction of cortisol that include metabolic sy
- -
-
Paragraph 0203
(2015/08/04)
-
- Replacement of imidazolyl by pyridyl in biphenylmethylenes results in selective CYP17 and dual CYP17/CYP11B1 inhibitors for the treatment of prostate cancer
-
Androgens are well-known to stimulate prostate cancer (PC) growth. Thus, blockade of androgen production in testes and adrenals by CYP17 inhibition is a promising strategy for the treatment of PC. Moreover, many PC patients suffer from glucocorticoid overproduction, and importantly mutated androgen receptors can be stimulated by glucocorticoids. In this study, the first dual inhibitor of CYP17 and CYP11B1 (the enzyme responsible for the last step in glucocorticoid biosynthesis) is described. A series of biphenylmethylene pyridines has been designed, synthesized, and tested as CYP17 and CYP11B1 inhibitors. The most active compounds were also tested for selectivity against CYP11B2 (aldosterone synthase), CYP19 (aromatase), and hepatic CYP3A4. In detail, compound 6 was identified as a dual inhibitor of CYP17/CYP11B1 (IC50 values of 226 and 287 nM) showing little inhibition of the other enzymes as well as compound 9 as a selective, highly potent CYP17 inhibitor (IC50 = 52 nM) exceeding abiraterone in terms of activity and selectivity.
- Hu, Qingzhong,Jagusch, Carsten,Hille, Ulrike E.,Haupenthal, J?rg,Hartmann, Rolf W.
-
body text
p. 5749 - 5758
(2010/10/03)
-
- Tuning the redox chemistry of 4-benzoyl-N-methylpyridinium cations through para substitution. Hammett linear free energy relationships and the relative aptitude of the two-electron reduced forms for H-bonding
-
In anhydrous CH3CN a series of nine 4-(4-substituted-benzoyl)-N-methylpyridinium cations (substituent: -OCH3, -CH3, -H, -SCH3, -Br, -C≡CH, -CHO, -NO2, and -+S(CH3)2) demonstrate two chemically reversible, well-separated one-electron (1-e) reductions in the same potential range as other main stream redox catalysts such as quinones and viologens. Hammett linear free energy plots yield excellent correlation between the E1/2 values of both waves and the substituent constants σp-X. The reaction constants for the two 1-e reductions are ρ1 = 2.60 and ρ2 = 3.31. The lower ρ1 value is associated with neutralization of the pyridinium ring, and the higher ρ2 value with the negative charge developing during the 2nd-e reduction. Structure-function correlations point to a purely inductive role for substitution in both 1-e reductions. The case of the 4-(4-nitrobenzoyl)-N-methylpyridinium cation is particularly noteworthy, because the 4-nitrobenzoyl moiety undergoes reduction before the 2nd reduction of the 4-benzoyl-N-methylpyridinium system. Correlation of the third wave of this compound with the 2nd-e reduction of the others yields σp-NO2- = -0.97 ± 0.02, thus placing the -NO2- group among the strongest electron donors. Solvent deuterium isotope effects and maps of the electrostatic potential (via PM3 calculations) as a function of substitution support that 2-e reduced forms develop H-bonding with proton donors (e.g., CH3-OH) via the O-atom. The average number of CH3OH molecules entering the H-bonding association increases with e-donating substituents. H-bonding shifts the 2nd reduction wave closer to the first one. This has important practical implications, because it increases the equilibrium concentration of the 2-e reduced form from disproportionation of the 1-e reduced form.
- Leventis, Nicholas,Rawaswdeh, Abdel-Monem M.,Zhang, Guohui,Elder, Ian A.,Sotiriou-Leventis, Chariklia
-
p. 7501 - 7510
(2007/10/03)
-
- The redox chemistry of 4-benzoyi-N′-methyipyridinium cations in acetonitrile with and without proton donors: The role of hydrogen bonding
-
In anhydrous CH3CN, 4-benzoyl-W-methyIpyridinium cations undergo two reversible, well-separated (ΔE1/2 ~ 0.6 V) one-electron reductions in analogy to quinones and viologens. If the solvent contains weak protic acids, such as water or alcohols, the first cyclic voltammetric wave remains unaffected while the second wave is shifted closer to the first. Both voltammetric and spectroelectrochemical evidence suggest that the positive shift of the second wave is due to hydrogen bonding between the two-electron reduced form of the ketone and the proton donors. While the one-electron reduction product is stable both in the presence and in the absence of the weak-acid proton donors, the two-electron reduction wave is reversible only in the time scale of cyclic voltammetry. Interestingly, at longer times, the hydrogen bonded adduct reacts further giving nonquaternized 4-benzoylpyridine and 4-(a-hydroxybenzyl)pyridine as the two main terminal products. In the presence of stronger acids, such as acetic acid, the second wave merges quickly with the first, producing an irreversible two-electron reduction wave. The only terminal product in this case is the quatemized 4-(α-hydroxybenzyl)-N-methyIpyridinium cation. Experimental evidence points toward a common mechanism for the formation of the nonquaternized products in the presence of weaker acids and the quaternized product in the presence of CH3CO2H.
- Leventis, Nicholas,Elder, Ian A.,Gao, Xuerong,Bohannan, Eric W.,Sotiriou-Leventis, Chariklia,Rawashdeh, Abdel Monem M.,Overschmidt, Travis J.,Gaston, Kimberly R.
-
p. 3663 - 3674
(2007/10/03)
-