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61.
A new synthesis of spirocyclic oxindole analogue spiro[piperidine-4,3’-pyrrolo[2,3-b]pyridin]-2’(1’H)-one 1 is described.The key steps involve dialkylation of arylacetonitrile and cyclization of the azaoxindole ring by an intramolecular Buchwald-Hartwig amidation of carboxylic ami Je and aryl chloride.A small library was obtained by reductive amination of 1 with various aldehydes and was screened against human lung cancer cell A549,human liver cancer cell BEL7402,and human colon cancer cell HCT-8.The results show that most of the 1(?)rary compounds 2 have some inhibitory activities.2-(Trifluoromethoxy) benzylic substituted spirocyclic azaoxindole 2e was identified as a nanomolar inhibitor against human lung cancer cell A-549(IC50=50 nmol/L). 相似文献
62.
JunGU MengZHANG DaLiYIN JiYuGUO XiaoTianLIANG 《中国化学快报》2005,16(4):427-429
Microwave-assisted allylic oxidation at C-13 position of 14-deoxysinenxan A was described. This new method (150℃/10 min/5 bar on microwave synthesizer) led to a better yield of compound 1 and shorter reaction time. 相似文献
63.
The synthesis of a third generation phosphorus-containing dendrimer possessing 24 chiral iminophosphine end groups derived from (2S)-2-amino-1-(diphenylphosphinyl)-3-methylbutane is described. In situ complexation of this dendrimer by [Pd(η3-C3H5)Cl]2 affords a catalyst, which is used in asymmetric allylic alkylations of rac-(E)-diphenyl-2-propenyl acetate and pivalate. The percentage of conversion, the yield of isolated 2-(1,3-diphenylallyl)-malonic acid dimethyl ester, and its enantiomeric excess have been measured in each case, and were found to be good to very good (ee from 90% to 95%). Furthermore, the dendritic catalyst can be recovered and reused at least two times, with almost the same efficiency. 相似文献
64.
The mechanism of the formation of lithiated carbanions derived from (alkenyl) pentamethyl phosphoric triamides has been elucidated. Whereas a few initial ambident allylphosphoramide anion was formed with n-BuLi, both reversible α-reprotonation and not reversible γ-reprotonation simultaneously occurred as a result of the reaction between the ambident carbanion formed and the starting enephosphoramide. A such autocatalytic process led partially to the transposed allylphosphoramide isomer. In the case of α-phenyl substituent the transposed phosphoramide was not a difficulty because it was further γ-deprotonated in situ with the n-BuLi still present, provided finally the expected ambident anion. With α-methyl and α-propyl substituent the transposed enephosphoramide formed in the autocatalytic process was not γ-deprotonated and consequently was prejudicial to the preparation of the target ambident carbanion. In these last cases, adapted experimental conditions avoided the autocatalytic process and allowed the preparation of the corresponding anions. 相似文献
65.
66.
Tiphaine Wong Lorette Brault Eric Gasparotto Romuald Valle Pierre-Yves Morvan Vincent Ferrires Caroline Nugier-Chauvin 《Molecules (Basel, Switzerland)》2021,26(15)
Marine polysaccharides are part of the huge seaweeds resources and present many applications for several industries. In order to widen their potential as additives or bioactive compounds, some structural modifications have been studied. Among them, simple hydrophobization reactions have been developed in order to yield to grafted polysaccharides bearing acyl-, aryl-, alkyl-, and alkenyl-groups or fatty acid chains. The resulting polymers are able to present modified physicochemical and/or biological properties of interest in the current pharmaceutical, cosmetics, or food fields. This review covers the chemical structures of the main marine polysaccharides, and then focuses on their structural modifications, and especially on hydrophobization reactions mainly esterification, acylation, alkylation, amidation, or even cross-linking reaction on native hydroxyl-, amine, or carboxylic acid functions. Finally, the question of the necessary requirement for more sustainable processes around these structural modulations of marine polysaccharides is addressed, considering the development of greener technologies applied to traditional polysaccharides. 相似文献
67.
Chloe C. Ence Whitney K. Walker Ryjul W. Stokes Erin E. Martinez Spencer M. Sarager Stacey J. Smith David J. Michaelis 《Tetrahedron》2019,75(24):3341-3347
The synthesis of six chiral titanium-containing phosphinoamide ligands is discussed. These ligands assemble chiral heterobimetallic Pd–Ti complexes, enable enantioselective intramolecular allylic aminations with hindered amine nucleophiles and achieve selectivity up to 53% ee. Mechanistic studies demonstrate the reversibility of the enantio-determining C–N bond forming step, which leads to a gradual increase in the % ee of the reaction over time. These results represent a rare example of enantioselective heterobimetallic catalysis and suggest that these new ligands could find broad application in enantioselective transition metal catalysis. 相似文献
68.
《Tetrahedron》2019,75(45):130641
Trifluoromethylation of vinylcyclopropanes (VCPs) has been developed under mild reaction conditions to synthesize allylic trifluoromethylated derivatives with high yield and E/Z selectivity using visible light photo-redox catalysis and Langlois reagent (CF3SO2Na) as a trifluoromethylation source. Further, we demonstrate a gram scale synthesis procedure for a trifluoromethylation of vinylcyclopropane. 相似文献
69.
A rhodium-catalyzed direct C–H sulfonamidation and amidation of C-7 position of indolines by simple and commercially available arylsulfonamides and trifluoroacetamide has been developed, affording a series of N-arylsulfonamides and N-aryltrifluoroacetamides in moderate to excellent yields, respectively. Notably, this catalytic system is highly convenient on mmol scale. 相似文献
70.
The reaction of easily available Morita–Baylis–Hillman (MBH) alcohols with AgSCF3 in the presence of n-Bu4NI and KI affords primary allylic SCF3 products in high yields and excellent regioselectivities. This regioselective dehydroxytrifluoromethylthiolation protocol could also be extended to propargylic alcohols for the preparation of the primary propargylic SCF3 products. 相似文献