53273-37-3Relevant articles and documents
Probing for the pharmacophore of the cytotoxic neoclerodane salvileucalin B
Heinrich, Nora,Banwell, Martin G.,Willis, Anthony C.,Cade, Ian A.,Capon, Robert J.,Huang, Xiao-Cong
, p. 1679 - 1686 (2012)
The novel [4.3.1]propelladiene 2, which embodies the key structural elements of the pentacyclic core of the cytotoxic neoclerodane salvileucalin B (1), has been prepared using a rhodium-catalysed intramolecular Bchner reaction as the key step. Compound 2 and the readily obtained derivatives 12-17 all proved to be essentially inactive when tested against a panel of four human cancer cell lines. Furthermore, not one of these compounds was a P-gp inhibitor.
Efficient C-H Amination Catalysis Using Nickel-Dipyrrin Complexes
Betley, Theodore A.,Clarke, Ryan M.,Dong, Yuyang,Porter, Gerard J.
supporting information, p. 10996 - 11005 (2020/07/08)
A dipyrrin-supported nickel catalyst (AdFL)Ni(py) (AdFL: 1,9-di(1-adamantyl)-5-perfluorophenyldipyrrin; py: pyridine) displays productive intramolecular C-H bond amination to afford N-heterocyclic products using aliphatic azide substrates. The catalytic amination conditions are mild, requiring 0.1-2 mol% catalyst loading and operational at room temperature. The scope of C-H bond substrates was explored and benzylic, tertiary, secondary, and primary C-H bonds are successfully aminated. The amination chemoselectivity was examined using substrates featuring multiple activatable C-H bonds. Uniformly, the catalyst showcases high chemoselectivity favoring C-H bonds with lower bond dissociation energy as well as a wide range of functional group tolerance (e.g., ethers, halides, thioetheres, esters, etc.). Sequential cyclization of substrates with ester groups could be achieved, providing facile preparation of an indolizidine framework commonly found in a variety of alkaloids. The amination cyclization reaction mechanism was examined employing nuclear magnetic resonance (NMR) spectroscopy to determine the reaction kinetic profile. A large, primary intermolecular kinetic isotope effect (KIE = 31.9 ± 1.0) suggests H-atom abstraction (HAA) is the rate-determining step, indicative of H-atom tunneling being operative. The reaction rate has first order dependence in the catalyst and zeroth order in substrate, consistent with the resting state of the catalyst as the corresponding nickel iminyl radical. The presence of the nickel iminyl was determined by multinuclear NMR spectroscopy observed during catalysis. The activation parameters (ΔH? = 13.4 ± 0.5 kcal/mol; ΔS?= -24.3 ± 1.7 cal/mol·K) were measured using Eyring analysis, implying a highly ordered transition state during the HAA step. The proposed mechanism of rapid iminyl formation, rate-determining HAA, and subsequent radical recombination was corroborated by intramolecular isotope labeling experiments and theoretical calculations.
Reductive C-C Coupling by Desulfurizing Gold-Catalyzed Photoreactions
Zhang, Lumin,Si, Xiaojia,Yang, Yangyang,Witzel, Sina,Sekine, Kohei,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
, p. 6118 - 6123 (2019/07/03)
[Au2(μ-dppm)2]Cl2-mediated photocatalysis reactions are usually initiated by ultraviolet A (UVA) light; herein, an unreported system using blue light-emitting diodes (LEDs) as excitation light source was found. The red shift of the absorption wavelength originates from the combination of [Au2(μ-dppm)2]Cl2 and ligand (Ph3P or mercaptan). On the basis of this finding, a gold-catalyzed reductive desulfurizing C-C coupling of electrophilic radicals and styrenes mediated by blue LEDs is presented, a coupling which cannot be efficiently accessed by previously reported methods. This mild and highly efficient C-C bond formation strategy uses mercaptans both as electron-deficient alkyl radical precursor as well as the hydrogen source. Two examples of amino acids have also been modified by using this strategy. Moreover, this methodology could be applied in polymer synthesis. Gram-scale synthesis and mechanistic insights into this transformation are also presented.
Cooperative iodine and photoredox catalysis for direct oxidative lactonization of carboxylic acids
Duhamel, Thomas,Mu?iz, Kilian
, p. 933 - 936 (2019/01/23)
A new method for the formation of γ- and δ-lactones from carboxylic acids through direct conversion of benzylic C-H to C-O bonds is described. The reaction is conveniently induced by visible light and relies on a mild cooperative catalysis by the combination of molecular iodine and an organic dye.
Multiple Halogenation of Aliphatic C?H Bonds within the Hofmann–L?ffler Manifold
Del Castillo, Estefanía,Martínez, Mario D.,Bosnidou, Alexandra E.,Duhamel, Thomas,O'Broin, Calvin Q.,Zhang, Hongwei,Escudero-Adán, Eduardo C.,Martínez-Belmonte, Marta,Mu?iz, Kilian
, p. 17225 - 17229 (2018/11/10)
An innovative approach to position-selective polyhalogenation of aliphatic hydrocarbon bonds is presented. The reaction proceeded within the Hofmann-L?ffler manifold with amidyl radicals as the sole mediators to induce selective 1,5- and 1,6-hydrogen-atom transfer followed by halogenation. Multiple halogenation events of up to four innate C?H bond functionalizations were accomplished. The broad applicability of this new entry into polyhalogenation and the resulting synthetic possibilities were demonstrated for a total of 27 different examples including mixed halogenations.
NOVEL TRICYCLIC CALCIUM SENSING RECEPTOR ANTAGONISTS
-
Page/Page column 106, (2015/07/07)
Novel tricyclic compounds of Formula (I) and pharmaceutically acceptable salts thereof are disclosed as useful for treating or preventing osteoporosis and similar conditions. The compounds are effective as calcium sensing receptor antagonists. Pharmaceutical compositions and methods of treatment are also included.
NOVEL TRICYCLIC CALCIUM SENSING RECEPTOR ANTAGONISTS FOR THE TREATMENT OF OSTEOPOROSIS
-
Page/Page column 105, (2015/07/07)
Novel tricyclic compounds of the formula (I): and pharmaceutically acceptable salts thereof are disclosed as useful for treating or preventing osteoporosis and similar conditions. The compounds are effective as calcium sensing receptor antagonists. Pharmaceutical compositions and methods of treatment are also included.
PPh3-mediated intramolecular conjugation of alkyl halides with electron-deficient olefins: Facile synthesis of chromans and relevant analogues
Zhu, Jian-Bo,Wang, Peng,Liao, Saihu,Tang, Yong
, p. 4570 - 4572 (2013/06/04)
With the mediation of phosphine, the direct intramolecular coupling of two electrophiles-alkyl halides with electron-deficient olefins-has been successfully realized in an intramolecular conjugate addition manner. The reaction provides a new approach for
Calcilytic compounds
-
Page/Page column 7, (2008/06/13)
Novel phosphate esters compounds and methods of using them as calcilytic compounds are provided.
Calcilytic compounds
-
Page/Page column 6, (2010/02/05)
Novel calcilytic compounds and methods of using them are provided.
