- A green and recyclable CuSO4·5H2O/ionic liquid catalytic system for the CO2-promoted hydration of propargyl alcohols: an efficient assembly of α-hydroxy ketones
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α-Hydroxy ketones are important building blocks in biological, pharmaceutical and synthetic chemistry. In this work, diverse α-hydroxy ketones were efficiently constructed through the CO2-promoted hydration process of propargyl alcohols, which was catalyzed by a system consisted of economical CuSO4·5H2O and a green 1-butyl-3-methylimidazolium acetate ionic liquid. Particularly, this catalytic system exhibited excellent activity under atmospheric CO2 or even mimetic flue gas (20 vol% of CO2). Moreover, this system employed the lowest metal loading ever reported (0.004–0.25 mol%) meanwhile reached the highest turnover number (11700) for the target hydration reaction. Additionally, this is the first reported Cu catalytic system with reliable recyclability, which could be easily reused at least 6 times with yields higher than 85%.
- Yuan, Ye,Hu, Jia,Wang, Yu,Huang, Leilei,Zheng, Jiayun,Zhao, Yufeng,Chen, Yiyun,Chen, Cheng,Verpoort, Francis
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p. 561 - 570
(2021/12/03)
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- Synthesis of Imidazo[1,2-a]pyridines and Imidazo[2,1-b]thiazoles Attached to a Cycloalkyl or Saturated Heterocycle Containing a Tertiary Hydroxy Substitution
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A new method has been developed for the synthesis of imidazo[1,2-a]pyridines, imidazo[2,1-b]thiazoles, and benzo[d]imidazo[2,1-b]thiazoles attached to a cycloalkyl or saturated heterocycle containing a tertiary hydroxy substitution. Readily available substituted 2-aminopyridines, 2-aminothiazoles, and 2-aminobenzothiazoles were treated with bromohydroxycycloalkyl ethanones to afford the desired products in good yields.
- Chenna Reddy,Patil, Vineetkumar B.,Nawaz Khan, Fazlur Rahman,Saravanan, Vadivelu
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p. 1486 - 1497
(2019/04/04)
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- Synthesis and Fungicidal Activity of (E)-5-[1-(2-Oxo-1-oxaspiro[4,5]dec/non-3-en-3-yl)ethylidene]-2-aminoimidazolin-4-one Derivatives
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The novel fungicidal agents, (E)-5-[1-(2-oxo-1-oxaspiro[4,5]dec/non-3-en-3-yl)ethylidene]-2-aminoimidazolin- 4-one derivatives, were designed and synthesized in moderate to excellent yields in four steps using α-hydroxyketone and diketene as raw materials and characterized by HR-ESI-MS, 1H NMR and X-ray diffraction. The preliminary bioassay showed that some of these compounds, such as 5e, 6a, 6e, and 7 h exhibit 87.8%, 91.3%, 89.9% and 87.8% inhibition rates against Sclerotinia scleotiorum, 3b, 3c, 4c and 7 h exhibit 96.4%, 92.5%, 90.3% and 76.9% inhibition rates against Phytophthora capsici at the concentration of 50 μg/mL, respectively. These compounds exhibited significant fungicidal activities against S. scleotiorum and P. capsici with EC50 values of 2.56–11.60 μg/mL, and compounds 6e and 7 h exhibited weak inhibition against the spore germination of S. scleotiorum, while the spore germination of P. capsici was strongly inhibited by compound 7 h solution. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation indicated that compound 7 h had a significant impact on the structure and function of the hyphal cell wall of P. capsici mycelium.
- Tang, Bo,Guan, Aiying,Zhao, Yu,Jiang, Jiazhen,Wang, Mingan,Zhou, Ligang
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p. 1133 - 1140
(2017/07/25)
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- Analogues of Acifran: Agonists of the high and low affinity niacin receptors, GPR109a and GPR109b
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Recently identified GPCRs, GPR109a and GPR109b, the high and low affinity receptors for niacin, may represent good targets for the development of HDL elevating drugs for the treatment of atherosclerosis. Acifran, an agonist of both receptors, has been tested in human subjects, yet until recently very few analogs had been reported. We describe a series of acifran analogs prepared using newly developed synthetic pathways and evaluated as agonists for GPR109a and GPR109b, resulting in identification of compounds with improved activity at these receptors.
- Jung, Jae-Kyu,Johnson, Benjamin R.,Duong, Tracy,Decaire, Marc,Uy, Jane,Gharbaoui, Tawfik,Boatman, P. Douglas,Sage, Carleton R.,Chen, Ruoping,Richman, Jeremy G.,Connolly, Daniel T.,Semple, Graeme
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p. 1445 - 1448
(2007/10/03)
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- Electroorganic Chemistry. 140. Electroreductively Intra- and Intermolecular Couplings of Ketones with Nitriles
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Electroreduction of γ- and δ-cyano ketones in i-PrOH with Sn cathode gave α-hydroxy ketones and their dehydroxylated ketones as the intramolecularly coupled products.Guaiazulene, (-)-valeranone, polyquinanes, dihydrojasmone, methyl dihydrojasmonate, and rosaprostol have been synthesized by utilizing this electroreductive intramolecular coupling of γ- and δ-cyano ketones in one of the key steps.Similarly, electroreduction of a mixture of ketone and nitrile gave the corresponding intermolecularly coupled product.The product obtained by the electroreductive intermolecular coupling of (+)-dihydrocarvone with acetonitrile has been found to be the precursor of an effective chiral ligand for the enantioselective addition of diethylzinc to aldehydes.
- Shono, Tatsuya,Kise, Naoki,Fujimoto, Taku,Tominaga, Naoto,Morita, Hiroshi
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p. 7175 - 7187
(2007/10/02)
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- Biomimetic Polyene Cyclizations. Participation of the Methylacetylenic Terminator and Nitroalkanes. A Synthesis of Testosterone
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The aim of this study was to examine nitroalkanes as trapping agents for the presumed intermediary vinyl cation formed in the acid-catalyzed cyclization of allylic alcohols 1, 5, and 8.Treatment of a solution of the allylic alcohols 1, 5, and 8 with excess trifluoroacetic acid in nitroethane resulted in the formation of the isomeric oxime ethers 3, 7, and 10.Confirmation of the trans-fused hydrindan skeleton of 3 was established by oxidative degradation to the known dione 4.The use of nitroethane as the cyclization solvent allows for the formation of syn and anti forms of the oxime ethers, thereby increasing the complexity of the products formed.This problem was eliminated by using 2-nitropropane as the cyclization solvent.Cyclization of 8 in 2-nitropropane with trifluoroacetic acid yielded the oxime ether 12 which was readily converted to diol 13 with lithium aluminuim hydride in refluxing THF.The stereoisomeric mixture of diols was converted, by two different synthetic pathways (see Schemes I and V), into the 17-hydroxypregnan-20-ones 15 and 16 and dl-testosterone benzoate (34).Catalytic reduction of the Δ1 olefinic bond in diol 13, followed by oxidation of the secondary hydroxyl group with N-bromosuccinimide, afforded dl-17α-hydroxy-5β,17β-pregnan-20-one (15) and dl-17β-hydroxy-5β,17α-pregnan-20-one (16).Alternatively, treatment of the diol 13 with periodic acid gave ketone 28 which upon reduction with sodium borohydride and esterification of the resulting hydroxyl group with benzoyl chloride afforded the benzoate 30.Oxidation of 30 with tert-butyl chromate, followed by reduction of the Δ1 olefinic bond, gave ketone 32.Enol acetylation of ketone 32, followed first by bromination, then dehydrobromination, and cleavage of the resulting semicarbazone, resulted in the completion of a facile synthesis of dl-testosterone benzoate (34) in 18percent overall yield from trienynol 8.
- Gravestock, Michael B.,Morton, Douglas R.,Boots, Sharon G.,Johnson, William S.
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p. 800 - 807
(2007/10/02)
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- α-DIALKYLAMINONITRILES: PRACTICAL REAGENTS FOR NUCLEOPHILIC ACYLATION
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An efficient synthesis of α-hydroxyketones from the reaction of carbonyl compounds and lithio α-dialkylaminonitriles is described.
- Reutrakul, Vichai,Ratananukul, Piniti,Nimgirawath, Surachai
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