326496-52-0Relevant academic research and scientific papers
A nonacid degradable linker for solid-phase synthesis
Colombo, Aina,De La Figuera, Natalia,Fernandez, Joan Carles,Fernandez-Forner, Dolors,Albericio, Fernando,Forns, Pilar
, p. 4319 - 4322 (2007)
Synthesis and applications of two new nonacid degradable linkers as an alternative to the Wang linker for solid-phase synthesis are described. Resin from linker 2 looks superior to linker 1 in terms of yields for both anchoring of the first building block and cleavage and in terms of higher purity of the final product. Use of linker 2 avoids side reactions associated with the use of Wang resin due to an undesired cleavage during final acid treatment.
Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
Liu, Xin,Werner, Thomas
supporting information, p. 1096 - 1104 (2020/12/31)
Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).
Catalytic α-Hydroarylation of Acrylates and Acrylamides via an Interrupted Hydrodehalogenation Reaction
Cherney, Emily C.,Engle, Keary M.,Gurak, John A.,Joe, Candice L.,Vasquez, Alena M.
supporting information, p. 10477 - 10484 (2020/08/07)
The palladium-catalyzed, α-selective hydroarylation of acrylates and acrylamides is reported. Under optimized conditions, this method is highly tolerant of a wide range of substrates including those with base sensitive functional groups and/or multiple enolizable carbonyl groups. A detailed mechanistic study was undertaken, and the high selectivity of this transformation was shown to be enabled by the formation of a [PdII(Ar)(H)] intermediate, which performs selective hydride insertion into the β-position of α,β-unsaturated carbonyl compounds.
Bidentate Ru(II)-NC Complexes as Catalysts for α-Alkylation of Unactivated Amides and Esters
Gong, Dawei,Hu, Bowen,Yang, Weiwei,Chen, Dafa
, p. 4841 - 4847 (2019/11/05)
Five Ru(II)-NC complexes were tested as catalysts for α-alkylation of unactivated amides using alcohols as alkylating agents, and complex {(C5H4N)-(C6H4)}RuCl(CO)(PPh3)2 (1) showed the highest activity. With 0.5 mol% catalyst loading, a series of α-alkylated amides were isolated at 80 °C within 6 hours. Furthermore, under similar conditions, complex 1 was also active for α-alkylation of unactivated esters with alcohols, and the reaction time was shortened to 1.5 hours. The catalytic performance of 1 is comparable to the best reported catalyst.
A General and mild catalytic α-alkylation of unactivated esters using Alcohols
Guo, Le,Ma, Xiaochen,Fang, Huaquan,Jia, Xiangqing,Huang, Zheng
supporting information, p. 4023 - 4027 (2015/03/30)
Catalytic α-alkylation of esters with primary alcohols is a desirable process because it uses low-toxicity agents and generates water as the by-product. Reported herein is a NCP pincer/Ir catalyst which is highly efficient for α-alkylation of a broad scope of unactivated esters under mild reaction conditions. For the first time, alcohols alkylate unactivated α-substituted acyclic esters, lactones, and even methyl and ethyl acetates. This method can be applied to the synthesis of carboxylic acid derivatives with diverse structures and functional groups, some of which would be impossible to access by conventional enolate alkylations with alkyl halides. In a pinch: An NCP pincer/iridium catalyst is highly efficient for the α-alkylation of unactivated esters using alcohol under mild reaction conditions. The reaction is simple, clean, and scalable (1-10 mmol), and the scope with respect to the ester is wide.
8-(BIARYL) QUINOLINE PDE4 INHIBITORS
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Page 89, (2010/02/06)
8-(biaryl) quinolines wherein the bi-aryl group at the 8-position is in a meta relationship to the quinoline group, are PDE4 inhibitors useful in the treatment of asthma, chronic bronchitis, chronic obstructive pulmonary disease, eosinophilic granuloma, psoriasis and other benign or malignant proliferative skin diseases, endotoxic shock, laminitis in horses, colic in horses, septic shock, ulcerative colitis, Crohn's disease, reperfusion injury of the myocardium and brain, inflammatory arthritis, chronic glomerulonephritis, atopic dermatitis, urticaria, adult respiratory distress syndrome, chronic obstructive pulmonary disease in animals, diabetes insipidus, allergic rhinitis, allergic conjunctivitis, vernal conjunctivitis, arterial restenosis, ortherosclerosis, atherosclerosis, neurogenic inflammation, pain, cough, rheumatoid arthritis, ankylosing spondylitis, transplant rejection, graft versus host disease, hypersecretion of gastric acid, bacterial, fungal induced sepsis, viral induced sepsis, fungal induced septic shock, viral induced septic shock, inflammation-mediated chronic tissue degeneration, cytokine-mediated chronic tissue degeneration, osteoarthritis, cancer, cachexia, muscle wasting, depression, memory impairment, tumour growth, or cancerous invasion of normal tissues.In another aspect, the present invention is directed to a method of enhancing cognition in a healthy subject comprising administering a safe cognition enhancing amount of phosphodiesterase-4 inhibitor. In particular, this invention is directed to a method of enhancing memory, learning, retention, recall, awareness and judgement in health subjects comprising administering a safe and cognition enhancing amount of a phosphodiesterase-4 inhibitor.
Zinc borates: Functionalized hard nucleophiles for coupling reactions with secondary allylic acetates
Kobayashi, Yuichi,Tokoro, Yuko,Watatani, Kengo
, p. 3825 - 3834 (2007/10/03)
We have succeeded in developing zinc borates of the general structure 3 for coupling reaction with allylic acetates. The advantages of using compounds 3 are their compatibility with carbonyl groups such as aldehyde, ketone, and ester groups, and their high reactivity toward secondary allylic acetates. Zinc borates 3 were prepared from boronate esters 1 [R(T) = p-(CHO)C6H4, p-(Ac)C6H4, p-{Ac(CH2)2}C6H4, p-(Ac-OCH2)C6H4, p-{AcO(CH2)3}C6H4, p-{EtO2C(CH2}2}C6H4, (E)-CH=CH(CH2)4OAc] with MeZnCl; subsequent treatment with allylic acetates 4 [R = n-C5H11, c-C6H11, (CH2)2CH(-O(CH2}2O-)] in the presence of NiCl2(PPh3)2 (10 mol-%) in THF-DMI (1,3-dimethyl-2-imidazolidinone) (10 equiv.) at 40-50 °C overnight furnished the coupling products 5 in good yields. Among the products, 5bb, possessing one free and one protected aldehyde group, is a highlight of this type of reaction. The stereochemical aspects of the reaction were also examined. Thus, the alkenyl groups of (E)- and (Z)-alkenyl borates 3b and c were transformed with retention of the olefinic geometry into acetates 4a and b (R = n-C5H11, c-C6H11), while reaction of cyclic acetate 11 proceeded with inversion at the carbon center involved in the reaction. In addition, we found that the anions generated from (EtO)2P(= O)CH2CO2Et and (MeO)2P(=O)CH2Ac under Masamune's conditions attacked the aldehyde carbon in the boronate 1d to produce - after reduction of the double bond - the boronate esters 1i and 1j, respectively, in good yields.
