822-66-2Relevant academic research and scientific papers
Tuning acylthiourea ligands in Ru(II) catalysts for altering the reactivity and chemoselectivity of transfer hydrogenation reactions, and synthesis of 3-isopropoxy-1H-indole through a new synthetic approach
Sathishkumar, Pushpanathan N.,Prabha, Padinhattath Sachind,Bhuvanesh, Nattamai S.P.,Karvembu, Ramasamy
, (2020/01/09)
Ru(II)-p-cymene complexes (1–3) containing picolyl based pseudo-acylthiourea ligands (L1-L3) were synthesized and characterized. The crystallographic study confirmed the molecular structures of all the ligands (L1-L3) and complex 3. The catalytic activity of the complexes was tested mainly towards TH of carbonyl compounds and nitroarenes. The influence of steric and electronic effects of the ligands on the chemoselectivity and reactivity were reported. The catalytic activity was enhanced and chemoselectivity was switched after tuning the ligands in the catalysts, compared to their corresponding unmodified Ru(II)-p-cymene complexes. The catalysis was extended to a broad range of substrates including some challenging systems like furfural, benzoylpyridine, benzoquinone, chromanone, etc. The strategy of tuning the bifunctional ligands in the catalysts for effective and selective catalysis worked nicely. Further, the catalysis was extended to one pot synthesis of 3-isopropoxyindole from 2-nitrocinnamaldehyde, the first synthetic route similar to Baeyer Emmerling indole synthesis. All the catalytic experiments exhibited high conversion and selectivity.
Photoredox/Cobalt Dual-Catalyzed Decarboxylative Elimination of Carboxylic Acids: Development and Mechanistic Insight
Cartwright, Kaitie C.,Joseph, Ebbin,Comadoll, Chelsea G.,Tunge, Jon A.
, p. 12454 - 12471 (2020/09/09)
Recently, dual-catalytic strategies towards the decarboxylative elimination of carboxylic acids have gained attention. Our lab previously reported a photoredox/cobaloxime dual catalytic method that allows the synthesis of enamides and enecarbamates directly from N-acyl amino acids and avoids the use of any stoichiometric reagents. Further development, detailed herein, has improved upon this transformation's utility and further experimentation has provided new insights into the reaction mechanism. These new developments and insights are anticipated to aid in the expansion of photoredox/cobalt dual-catalytic systems.
Ru-Photoredox-Catalyzed Decarboxylative Oxygenation of Aliphatic Carboxylic Acids through N-(acyloxy)phthalimide
Zheng, Chao,Wang, Yuting,Xu, Yangrui,Chen, Zhen,Chen, Guangying,Liang, Steven H.
, p. 4824 - 4827 (2018/08/24)
Decarboxylative aminoxylation of aliphatic carboxylic acid derivatives with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) in the presence of ruthenium photoredox catalysis is reported. The key transformation entails a highly efficient photoredox catalytic cycle using Hantzsch ester as a reductant. The ensuing alkoxyamine can be readily converted to the corresponding alcohol in one pot, representing an alternative approach to access aliphatic alcohols under photoredox conditions.
Stereoselective Synthesis of 7-(E)-Arylidene-2-chloro-6-azabicyclo[3.2.1]octanes via Aluminum Chloride-Promoted Cyclization/Chlorination of Six-Membered Ring 3-Enynamides
Yeh, Ming-Chang P.,Chang, Yi-Mei,Lin, Hsin-Hui
supporting information, p. 2196 - 2201 (2017/07/07)
An efficient stereoselective synthesis of 7-(E)-arylidene-2-chloro-6-azabicyclo[3.2.1]octanes is described. The aluminum chloride-promoted cyclization/chlorination of six-membered ring 3-enynamides enables a straightforward approach to the 6-azabicyclo[3.2.1]octane nucleus that is incorporated in many biologically active compounds. Acid treatment of the resultant chlorinated arylideneazabicyclooctanes furnishes 3-alkanoyl-4-chlorocyclohexanamines in excellent yields and high stereoselectivity. (Figure presented.).
Highly Enantioselective Construction of Hajos-Wiechert Ketone Skeletons via an Organocatalytic Vinylogous Michael/Stetter Relay Sequence
Jia, Zhi-Long,Wang, Yao,Zhao, Chuan-Gang,Zhang, Xiao-Hai,Xu, Peng-Fei
supporting information, p. 2130 - 2133 (2017/04/27)
A highly enantioselective supramolecular iminium-catalyzed vinylogous Michael addition/Stetter relay sequence has been developed. This transformation provided a series of Hajos-Wiechert-type fused bicyclic diones with three continuous stereogenic centers in good yields with excellent enantioselectivities. The obtained products can be easily transformed into other structures with potential synthetic value.
Construction of bicyclic systems containing an oxygen bridge by isomerization of cyclic epoxy alcohols
Iwakura, Masaru,Tokura, Hiroshi,Tanino, Keiji
, p. 1223 - 1226 (2017/03/02)
A novel method for constructing a 7-oxabicyclo[2.2.1]heptane skeleton was developed. The substrates, namely cis-3,4-epoxy-1-cyclohexanol derivatives, were prepared from the corresponding 3-cyclohexen-1-ol derivatives via a stereoselective epoxidation reaction using a vanadium catalyst. Upon heating with lithium iodide in propionitrile, the cis-epoxy alcohol was transformed into the 7-oxabicyclo[2.2.1]heptane derivative in high yield. The reaction proceeds through formation of a lithium alkoxide bearing an iodohydrin moiety, followed by an intramolecular SN2 reaction.
SULFIDE ALKYL COMPOUNDS FOR HBV TREATMENT
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Paragraph 0505, (2016/06/28)
The present invention includes a method of inhibiting, suppressing or preventing HBV infection in an individual in need thereof, comprising administering to the individual a therapeutically effective amount of at least one compound of the invention.
Parallel and competitive pathways for substrate desaturation, hydroxylation, and radical rearrangement by the non-heme diiron hydroxylase AlkB
Cooper, Harriet L. R.,Mishra, Girish,Huang, Xiongyi,Pender-Cudlip, Marilla,Austin, Rachel N.,Shanklin, John,Groves, John T.
supporting information, p. 20365 - 20375 (2013/02/25)
A purified and highly active form of the non-heme diiron hydroxylase AlkB was investigated using the diagnostic probe substrate norcarane. The reaction afforded C2 (26%) and C3 (43%) hydroxylation and desaturation products (31%). Initial C-H cleavage at C2 led to 7% C2 hydroxylation and 19% 3-hydroxymethylcyclohexene, a rearrangement product characteristic of a radical rearrangement pathway. A deuterated substrate analogue, 3,3,4,4-norcarane-d 4, afforded drastically reduced amounts of C3 alcohol (8%) and desaturation products (5%), while the radical rearranged alcohol was now the major product (65%). This change in product ratios indicates a large kinetic hydrogen isotope effect of ～20 for both the C-H hydroxylation at C3 and the desaturation pathway, with all of the desaturation originating via hydrogen abstraction at C3 and not C2. The data indicate that AlkB reacts with norcarane via initial C-H hydrogen abstraction from C2 or C3 and that the three pathways, C3 hydroxylation, C3 desaturation, and C2 hydroxylation/radical rearrangement, are parallel and competitive. Thus, the incipient radical at C3 either reacts with the iron-oxo center to form an alcohol or proceeds along the desaturation pathway via a second H-abstraction to afford both 2-norcarene and 3-norcarene. Subsequent reactions of these norcarenes lead to detectable amounts of hydroxylation products and toluene. By contrast, the 2-norcaranyl radical intermediate leads to C2 hydroxylation and the diagnostic radical rearrangement, but this radical apparently does not afford desaturation products. The results indicate that C-H hydroxylation and desaturation follow analogous stepwise reaction channels via carbon radicals that diverge at the product-forming step.
A homogeneous gallium(III) compound selectively catalyzes the epoxidation of alkenes
Jiang, Wenchan,Gorden, John D.,Goldsmith, Christian R.
body text, p. 2725 - 2727 (2012/04/23)
We demonstrate that a simple gallium(III) complex, [Ga(phen) 2Cl2]Cl (phen = 1,10-phenanthroline), can serve as a homogeneous catalyst for the epoxidation of alkenes. The olefin epoxidations proceed relatively quickly at mild temperatures and, under optimum conditions, are highly selective for the epoxide product.
Hydrocarbon chlorination promoted by manganese and iron complexes with methylated derivatives of bis(2-pyridylmethyl)-1,2-ethanediamine
Goldsmith, Christian R.,Coates, Cristina M.,Hagan, Kenton,Mitchell, Casey A.
body text, p. 24 - 30 (2011/04/22)
Non-heme iron halogenases, such as SyrB2 and CytC3, catalyze the regioselective chlorination and bromination of aliphatic C-H bonds. Reported here is the hydrocarbon chlorination promoted by manganese and iron complexes with methylated derivatives of bis(2-pyridylmethyl)-1,2-ethanediamine (bispicen). The reactions between these coordination compounds and meta-chloroperbenzoic acid generate oxidants capable of oxidizing weak C-H bonds to C-Cl bonds. This chemistry is regioselective, with a strong preference for activating C-H bonds on secondary carbons over weaker C-H bonds on tertiary carbons. The reactivity is consistent with the methyl groups on the ligands preventing more sterically encumbered substrates from accessing the reactive portions of a [MIV(LMen)(O)Cl2] oxidant. The iron compounds promote more hydrocarbon chlorination than their manganese analogs.
