1121-55-7Relevant academic research and scientific papers
Copper-Catalyzed Asymmetric Radical 1,2-Carboalkynylation of Alkenes with Alkyl Halides and Terminal Alkynes
Dong, Xiao-Yang,Cheng, Jiang-Tao,Zhang, Yu-Feng,Li, Zhong-Liang,Zhan, Tian-Ya,Chen, Ji-Jun,Wang, Fu-Li,Yang, Ning-Yuan,Ye, Liu,Gu, Qiang-Shuai,Liu, Xin-Yuan
, p. 9501 - 9509 (2020)
A copper-catalyzed intermolecular three-component asymmetric radical 1,2-carboalkynylation of alkenes has been developed, providing straightforward access to diverse chiral alkynes from readily available alkyl halides and terminal alkynes. The utilization of a cinchona alkaloid-derived multidentate N,N,P-ligand is crucial for the efficient radical generation from mildly oxidative precursors by copper and the effective inhibition of the undesired Glaser coupling side reaction. The substrate scope is broad, covering (hetero)aryl-, alkynyl-, and aminocarbonyl-substituted alkenes, (hetero)aryl and alkyl as well as silyl alkynes, and tertiary to primary alkyl radical precursors with excellent functional group compatibility. Facile transformations of the obtained chiral alkynes have also been demonstrated, highlighting the excellent complementarity of this protocol to direct 1,2-dicarbofunctionalization reactions with C(sp2/sp3)-based reagents.
First Total Synthesis of Niphatesines A-D and Assignment of Absolute Configuration
Rao, A. V. Rama,Reddy, Gongiti Ravindra
, p. 8329 - 8332 (1993)
Regio/Enantioselective synthesis of niphatesines A-D is achieved making use of Pd(0) assisted 3-alkylation of pyridine as the key step.Absolute configuration of niphatesines C and D is established.
3-Ethenylpyridine Measured in Urine of Active and Passive Smokers: A Promising Biomarker and Toxicological Implications
Liu, Jia,Benowitz, Neal L.,Hatsukami, Dorothy K.,Havel, Christopher M.,Lazcano-Ponce, Eduardo,Strasser, Andrew A.,Jacob, Peyton
, p. 1630 - 1639 (2021)
In studies of tobacco toxicology, including comparisons of different tobacco products and exposure to secondhand or thirdhand smoke, exposure assessment using biomarkers is often useful. Some studies have indicated that most of the toxicity of tobacco smoke is due to gas-phase compounds. 3-Ethenylpyridine (3-EP) is a major nicotine pyrolysis product occurring in the gas phase of tobacco smoke. It has been used extensively as an environmental tracer for tobacco smoke. 3-EP would be expected to be a useful tobacco smoke biomarker as well, but nothing has been published about its metabolism and excretion in humans. In this Article we describe a solid-phase microextraction (SPME) GC-MS/MS method for determination of 3-EP in human urine and its application to the determination of 3-EP in the urine of smokers and people exposed to secondhand smoke. We conclude that 3-EP is a promising biomarker that could be useful in studies of tobacco smoke exposure and toxicology. We also point out the paucity of data on 3-EP toxicity and suggest that additional studies are needed.
Interconversion of nicotine enantiomers during heating and implications for smoke from combustible cigarettes, heated tobacco products, and electronic cigarettes
Moldoveanu, Serban C.
, p. 667 - 677 (2022/02/02)
Physiological properties of (R)-nicotine have differences compared with (S)-nicotine, and the subject of (S)- and (R)-nicotine ratio in smoking or vaping related items is of considerable interest. A Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC-MS/MS) method for the analysis of (S)- and (R)-nicotine has been developed and applied to samples of nicotine from different sources, nicotine pyrolyzates, several types of tobacco, smoke from combustible cigarettes, smoke from heated tobacco products, e-liquids, and particulate matter obtained from e-cigarettes aerosol. The separation was achieved on a Chiracel OJ-3 column, 250 × 4.6 mm with 3-μm particles using a nonaqueous mobile phase. The detection was performed using atmospheric pressure chemical ionization (APCI) in positive mode. The only transition measured for the analysis of nicotine was 163.1 → 84.0. The method has been summarily validated. For the analysis, the samples of tobacco and smoke from combustible cigarettes were subject to a cleanup procedure using solid phase extraction (SPE). It was demonstrated that nicotine upon heating above 450°C for several minutes starts decomposing, and some formation of (R)-enantiomer from a sample of 99% (S)-nicotine is observed. An analogous process takes place when a 99% (R)-nicotine is heated and forms low levels of (S)-nicotine. This interconversion has the effect of slightly increasing the content of (R)-nicotine in smoke compared with the level in tobacco for combustible cigarettes and for heated tobacco products. The (S)/(R) ratio of nicotine enantiomers in e-liquids was identical with the ratio for the particulate phase of aerosols generated by e-cigarette vaping.
COMPOSITIONS AND METHODS FOR PARASITE CONTROL
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Page/Page column 55; 93; 100, (2022/01/05)
The present invention relates in its broadest aspect to a compound of Formula I as provided herein, formulations comprising such a compound and corresponding uses thereof for the reduction of infestation with ectoparasites, in particular ectoparasites of the insect class, including fleas and mosquitoes and/or ectoparasites of the arachnid class, including ticks and mites, etc. Also provided herein are methods for preparing the formulations of the invention and methods for controlling ectoparasites using the compounds and/or formulations provided herein.
Creation of Redox-Active PdSx Nanoparticles Inside the Defect Pores of MOF UiO-66 with Unique Semihydrogenation Catalytic Properties
Dong, Ming-Jie,Wang, Xuan,Wu, Chuan-De
, (2019/12/27)
Semihydrogenation of alkynes to produce alkenes is very important in the industry; however, over-hydrogenation heavily complicates the postprocesses, which are highly energy consuming and not environmentally friendly. One of the most efficient pathways to solve this challenging issue is to develop highly selective catalysts that could only hydrogenate alkynes and are inactive in hydrogenation of alkenes. This work presents herein an efficient catalyst, consisting of in situ created PdS0.53 nanoparticles as the redox-active sites inside the defect pores of metal–organic framework UiO-66, which demonstrates very high alkene selectivity (up to 99.5%) in semihydrogenation of easily over-hydrogenated terminal alkynes. In contrast to the traditional catalysts, strict control over the reaction time becomes the nonessential condition because the catalyst system is almost inactive in hydrogenation of alkenes. Therefore, this paradigm work provides a practically applicable pathway for the development of efficient catalysts with unique catalytic properties for selective semihydrogenation reactions.
An Annelated Mesoionic Carbene (MIC) Based Ru(II) Catalyst for Chemo- And Stereoselective Semihydrogenation of Internal and Terminal Alkynes
Bera, Jitendra K.,Choudhury, Joyanta,Das, Shubhajit,Dutta, Indranil,Pati, Swapan K.,Saha, Sayantani,Yadav, Suman
, p. 3212 - 3223 (2020/10/02)
The catalytic utility of [RuL1(CO)2I2] (1), containing an annelated π-conjugated imidazo-naphthyridine-based mesoionic carbene (MIC) ligand (L1), is evaluated for E-selective alkyne semihydrogenation. The precatalyst 1, in combination with 2 equiv of AgBArF, semihydrogenates a broad range of internal alkynes with molecular hydrogen (5 bar) in water. (E)-Alkenes are accessed in high yields, and a number of reducible functional groups are tolerated. A chelate MIC ligand and two cis carbonyls provide a well-defined platform at the Ru center for hydrogenation and isomerization. The loss of two iodides and the presence of two carbonyls render the Ru center electron deficient and thus the formation of metal vinylidenes with terminal alkynes is avoided. This is leveraged for the semihydrogenation of terminal alkynes by the same catalytic system in isopropyl alcohol. Reaction profile, isomerization, kinetic, and DFT studies reveal initial alkyne hydrogenation to a (Z)-alkene, which further isomerizes to an (E)-alkene via metal-catalyzed Z → E isomerization.
Iron-Catalyzed Direct Julia-Type Olefination of Alcohols
Landge, Vinod G.,Babu, Reshma,Yadav, Vinita,Subaramanian, Murugan,Gupta, Virendrakumar,Balaraman, Ekambaram
, p. 9876 - 9886 (2020/09/03)
Herein, we report an iron-catalyzed, convenient, and expedient strategy for the synthesis of styrene and naphthalene derivatives with the liberation of dihydrogen. The use of a catalyst derived from an earth-abundant metal provides a sustainable strategy to olefins. This method exhibits wide substrate scope (primary and secondary alcohols) functional group tolerance (amino, nitro, halo, alkoxy, thiomethoxy, and S- A nd N-heterocyclic compounds) that can be scaled up. The unprecedented synthesis of 1-methyl naphthalenes proceeds via tandem methenylation/double dehydrogenation. Mechanistic study shows that the cleavage of the C-H bond of alcohol is the rate-determining step.
INHIBITORS OF FIBROBLAST ACTIVATION PROTEIN
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Paragraph 0195, (2020/07/14)
Compounds and compositions for modulating fibroblast activation protein (FAP) are described. The compounds and compositions may find use as therapeutic agents for the treatment of diseases, including hyperproliferative diseases.
Method for selective synthesis of cis-olefins and trans-olefins by semi-reduction of alcohol hydrogen supply palladium-catalyzed alkynes
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Paragraph 0207-0209, (2019/06/07)
The invention provides a method for selective synthesis of cis-olefins and trans-olefins by semi-reduction of alcohol hydrogen supply palladium-catalyzed alkynes. The method comprises the following steps: performing alkyne reduction reaction with TEOA, NaOAc, a catalyst, alcohol and alkynes in an organic solvent and generating the cis-olefins after reaction; performing alkyne reduction reaction with a ligand, a catalyst, alcohol and alkynes in an organic solvent and generating the trans-olefins after reaction; a reactor for the reduction reaction is a sealed pressure-resistant reactor, the reduction reaction temperature is 120-150 DEG C, and the reduction reaction time is 20-48 hours; the dosage of the catalyst is 5-20 percent of the molar dosage of the alkynes, and the dosage of the alcohol is 10-100 times of the molar dosage of the alkynes; the dosage of R, R-DIPAMP is 0.5-5 times of the molar dosage of the alkynes. According to the method provided by the invention, a catalyst systemhas extremely-high chemical reaction and stereo-selectivity and can synthesize cis-olefin products or trans-olefin products with high yield; the catalyst system is good universality to a substrate, and the alkynes containing various functional groups can be efficiently subjected to the highly-selective reduction reactions.
