共查询到17条相似文献,搜索用时 390 毫秒
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发展了一种可见光诱导的1,7-烯炔与全氟烷基卤串联原子转移自由基加成(ATRA)/环化合成含氟2,4-二氢异喹啉-2(1H)-酮的反应。以多氟烷基碘或溴为自由基前体,面式-三( 2-苯基吡啶)合铱(摩尔分数1%)为光敏剂,在5 W蓝光发光二极管(LED)照射下,多种苯桥联1,7-烯炔顺利发生串联(ATRA)/环化反应,以中等到优秀(62%~84%)的产率合成了一系列多氟化异喹啉酮衍生物。 此合成方法反应条件温和、清洁、高效且底物适用范围广,为具有潜在药用价值的多氟化2,4-二氢异喹啉-2(1H)-酮的合成提供新的途径。 相似文献
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发展了一种苯甲酰胺自由基自由基环化制备α-官能化叔烷基取代的异喹啉二酮的新反应。此环化反应以偶氮试剂为α-取代叔烷基自由基源物质,利用碘化亚铜/空气体系催化N-烷基-N-甲基丙烯酰基苯甲酰胺发生环化,经过串联自由基加成/环化/碳-碳键形成过程,一步构建了三重碳-碳键,以41%~71%的产率合成了一系列异喹啉二酮及其衍生物。特别值得提出得是,此研究发展了一种新型α-官能叔烷基自由基源物质,发现了一种同时引入两个α-官能叔烷基片段的串联新反应。反应底物适应范围广,反应高效,催化体系廉价实用,为具有潜在药用价值的含α-取代季碳中心的异喹啉二酮及衍生物的合成提供了一条廉价、简单、快捷的新途径。 相似文献
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异喹啉盐具有两个亲电位点, 用它与双亲核试剂发生去芳构化/环化反应, 是高效构建异喹啉桥环结构的有效策略. 然而, 这一策略主要集中在1,3-桥环结构的合成. 最近利用异喹啉盐与4-羟基香豆素反应, 首次实现了二氢异喹 啉-3-酮-1,4-桥环的合成. 但是, 当用环状1,3-二酮代替4-羟基香豆素反应时, 意外地得到了异喹啉-1,3,4(2H)-三酮. 利用高分辨质谱分析发现, 这一意外转化是由于环状1,3-二酮发生O-亲核取代后, 消除2-溴-1,3-环状二酮, 得到4-溴异喹啉-3(2H)-酮. 该中间体发生两次连续水解/空气氧化后, 得到了异喹啉-1,3,4(2H)-三酮. 基于此机理的认识, 向反应体系中添加催化量的三氟甲烷磺酸后, 成功抑制了环状1,3-二酮的O-亲核取代反应, 顺利得到了二氢异喹啉-3-酮的1,4-桥环结构(33个反应实例). 反应条件温和, 提供了一种构建异喹啉1,4-桥环骨架的高效合成方法. 相似文献
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发展了一种可见光诱导的共轭磺酰胺串联脱砜/环化,合成全氟烷基化吲哚酮或α-芳基酰胺的方法。此反应以多氟烷基碘或溴为氟源,在发光二极管蓝光灯照射下,利用面式-三(2-苯基吡啶)合铱催化N-烷基-N-甲基丙烯酰基苯磺酰胺经过串联自由基加成/β-芳基迁移/脱砜环化过程,一步构筑两重碳-碳键,以41%~78%的产率合成了一系列含氟吲哚酮或α-芳基酰胺。此方法底物适用范围广,反应条件温和(室温),催化体系绿色,为具有潜在生理活性的含氟吲哚酮及α-芳基酰胺的合成提供了一条高效、快捷的新途径。 相似文献
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使用廉价易得的邻烯基甲酰苯胺在可见光的诱导下发生自由基环化反应, 以良好至优秀的产率合成了15种2-喹啉酮衍生物. 该方法简单高效、 条件温和、 产率较高, 具有优异的官能团兼容性, 不仅拓展了邻烯基甲酰苯胺参与的新型有机反应, 也为光催化合成喹啉酮类化合物提供了一条新途径. 相似文献
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Zeng-Zeng Li Jian Yu Liang-Neng Wang Shi-Lu Chen Rui-Long Sheng Shi Tang 《Tetrahedron》2018,74(45):6558-6568
A Cu/Fe-cocatalyzed cyclization of halobenzamides with azo reagents involving regioselective radical/radical cross-coupling toward functionalized isoquinolinediones was developed. Applying azo reagents as the coupling partner, in the presence of cheap, facile and ligand-free catalytic combination of CuI/Fe(NH4)2(SO4)2·6H2O/air, the halobenzamide radicals generated by a prior radical addition/cyclization process underwent radical/radical cross-coupling via the cleavage of C-X (X?=?F, Cl, Br, I, OMe, OBn) bond with excellent site selectivity, leading to a series of isoquinolinediones furnished dual distal α-functional quaternary moieties. In addition, the theoretical calculation on the C-X bond cleavage and the positional selectivity using unrestricted density functional theory (DFT) was also conducted. 相似文献
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《Tetrahedron》2019,75(22):3053-3061
A visible-light induced metal-free thiocyanate radical addition/intramolecular cyclization cascade reaction for the synthesis of thiocyanato-containing isoquinolinediones from N-alkyl-N-methacryloylbenzamides is described. The organic dye 9-mesityl-10-methylacridinium perchlorate (Acr+-Mes ClO4−) is used as a photocatalyst, and cheap and readily available ammonium thiocyanate is used to provide thiocyanate radical by single-electron transfer pathway. The reaction completes the synthesis of CS and CC bonds in one pot with abundant molecular oxygen as the sole sacrificial reagent. The method is easy to implement, and 25 new compounds have been prepared in moderate to good yields under mild conditions. This is the first time that a thiocyanate group has been introduced into isoquinoline-1,3(2H,4H)-diones to construct highly functional drug-like molecules. 相似文献
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Catalytic hydrogenation of some 4-arylidene-1,3-(2H,4H)isoquinolinediones (1) afforded the corresponding 4-arylmethyl-1,3-(2H,4H)isoquinolinediones (2) , but reduction of 1 by sodium borohydride gave 4-arylmethyl-1(2H)isoquinolones (isocarbostyrils, 3). Compounds of type 1 studied had aryl substituents phenyl, 3,4-dimethoxyphenyl, 3,4-methyleneoxyphenyl and 2-furyl. In one example of sodium borohydride reduction of an N-methylisoquinolinedione derivative (1) the heterocylic ring was opened, and 2-(1-hydroxymethyl-2-phenylethenyl)-N-methylbenzamide (4) was obtained from 4-benzylidene-2-methyl-1,3-(2H,4H)isoquinolinedione. 相似文献
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Ishibashi H Kobayashi T Nakashima S Tamura O 《The Journal of organic chemistry》2000,65(26):9022-9027
Bu(3)SnH-mediated aryl radical cyclization onto methylenecycloalkanes having a phenylthio, an ester, or a nitrile group at the terminus of the alkenic bond provides exclusively exo cyclization products. The results are in sharp contrast to those reported for nonsubstituted methylenecycloalkanes, which give exclusively endo cyclization products. Formation of endo cyclization products has been suggested to be a result of a consecutive 5-exo cyclization of an aryl radical and neophyl rearrangement. The exo-selective aryl radical cyclization offers a new method for synthesizing fused aromatic compounds containing a benzylic quaternary carbon atom. 相似文献
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Thermo-chemical reactions and structural evolution of acrylamide-modified polyacrylonitrile 总被引:1,自引:0,他引:1
<正>Thermal properties of acrylonitrile(AN)-acrylamide(AM) copolymers for carbon fibers were studied by DSC and in situ FTIR techniques in nitrogen(N_2) and air flows.The cyclization mechanism and stabilization behavior of polyacrylonitrile(PAN) were discussed.In N_2 flow,it was found that AM had the ability to initiate and accelerate cyclization process,which was confirmed by the fact that the initiation of nitriles shifted to a lower temperature.Compared to AN homopolymer,the initiation temperature of cyclization was ahead 32 K by introducing 3.59 mol%AM into the copolymer.The exothermic reaction was relaxed due to the presence of two separated exothermic peaks.Accompanied by DSC,in situ FTIR and calculation of activation energy,the two peaks were proved to be caused by ionic cyclization and free radical cyclization,respectively,and the corresponding cyclization mechanism was proposed.With increasing in AM content,the ionic cyclization tends to be dominant and the total heat liberated first increases and then decreases.For AN homopolymer,the activation energy of cyclization is 179 kJ/mol.For AN-AM copolymer(containing 3.59 mol%AM),the activation energy of ionic cyclization is 96 kJ/mol and that of free radical cyclization is 338 kJ/mol.In air flow,similar cyclization routes occur and the difference is the contribution of oxidation.The oxygen in environment has no remarkable effect on cyclization of AN homopolymer but retards the cyclization of AN-AM copolymers.For AN-AM copolymer with 3.59 mol%AM,the cyclization temperature is postponed 10℃in air. 相似文献
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The synthesis and "round trip radical cyclization" of 11-iodo-2,7,11-trimethyldodec-6-en-5-one are described. The round trip cyclization is a sequence of 5-exo, 6-endo, and 5-exo cyclizations in which the last radical cyclization occurs at the same carbon atom as the initial radical generation. The key second (6-endo) cyclization produces two stereoisomers, one of which cyclizes efficiently to isogymnomitrene ketone, while the other cyclizes inefficiently to gymnomitrene ketone. Efforts to influence the kinetic or thermodynamic outcome of the second cyclization were not successful, and the results are contrasted with a related cyclization of Jung and Rayle where thermodynamic control was readily established. 相似文献
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A samarium(II)-mediated 4-exo-trig cyclization in which a remote stereocenter serves to control the facial selectivity of the cyclization is described. The apparent coordination of a tert-butyldimethylsilyl ether to the samarium center appears to give rise to the selectivity. The remarkable effect of the cosolvent, 2,2,2-trifluoroethanol, on the cyclization of this substrate, is also discussed. A stereoselective synthesis of the general class of gamma,delta-unsaturated aldehyde cyclization substrate is reported, and the utility of the cyclization is demonstrated in an approach to the fully functionalized core of pestalotiopsin A. 相似文献