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An asymmetric total synthesis of ent‐ancistrocladinium A was developed via chiral phosphoric acid‐catalyzed asymmetric reductive amination of 1‐aryl‐2‐propanone and naphthylamine followed by a Bischler–Napieralski reaction. Direct use of the naphthyl moiety in the amine as a key building block in the natural product allowed us to achieve the total synthesis of ancistrocladinium A in only three steps from the known starting materials.
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Armando Crdova Shuangzheng Lin Abrehet Tseggai 《Advanced Synthesis \u0026amp; Catalysis》2012,354(7):1363-1372
A general strategy for the total asymmetric synthesis of valuable tropane alkaloids by catalytic stereoselective transformations is disclosed. The power of this approach is exemplified by the concise catalytic enantioselective total syntheses of (+)‐methylecgonine, (−)‐cocaine and (+)‐cocaine as well as the first catalytic asymmetric total syntheses of a cocaine C‐1 derivative and (+)‐ferruginine starting from 5‐oxo‐protected‐α,β‐unsaturated enals using only two and three column chromatographic purification steps, respectively. 相似文献
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在氯化亚锡的催化作用下,硫代二甘醇酸与过量的甲醇或乙醇回流反应合成了硫代二甘醇酸二甲酯(Ⅰa)或硫代二甘醇酸二乙酯(Ⅰb),反应的较佳条件是:x(SnCl2)=4.0%,回流3 h,收率分别为93.5%和96.4%。然后在强碱氢氧化钾的作用下,化合物Ⅰa或Ⅰb与二水合三聚乙二醛经缩合和水解反应合成了噻吩-2,5-二甲酸(Ⅱ),反应的较佳条件是:n(硫代二甘醇酸二甲酯或硫代二甘醇酸二乙酯)∶n(二水合三聚乙二醛)∶n(氢氧化钾)=1∶0.4∶4.4,在环己烷中回流5 h,收率为89.3%~90.0%。 相似文献
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Xiaoyu Wu Jianbiao Huang Beibei Guo Long Zhao Yong Liu Jie Chen Weiguo Cao 《Advanced Synthesis \u0026amp; Catalysis》2014,356(16):3377-3382
Kopsinine and related alkaloids are attractive synthetic targets because of their structural complexity and biological activities. An organocatalytic Michael addition/aza‐Michael addition/cyclization cascade sequence has been developed for the enantioselective preparation of tetracyclic spiroindolines from 2,3‐disubstituted indoles and propargyl aldehyde in moderate to good yields and good to excellent enantioselectivities. The synthetic value of these advanced structures has been demonstrated by the synthesis of kopsinine and related alkaloids. Key steps for the concise synthesis of these alkaloids included an efficient enantioselective construction of tetracyclic spiroindolines bearing a dienamino ester moiety and the organocatalyzed nucleophilic addition of a dienamino ester to acrolein.
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以3,5-二羟基苯甲酸为起始原料,由羟基保护,酯基硼氢化钠还原,羟基氯代制备氯苄,制备了膦酸酯;经Wittig-Horner反应,脱甲基反应合成了E-白藜芦醇。合成总收率达47.6%。 相似文献
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Huwei Yuan Wenyi Zhang Hui Qiao Shubo Jin Sufei Jiang Yiwei Xiong Yongsheng Gong Hongtuo Fu 《International journal of molecular sciences》2022,23(20)
HR4, a member of the nuclear receptor family, has been extensively studied in insect molting and development, but reports on crustaceans are still lacking. In the current study, the MnHR4 gene was identified in Macrobrachium nipponense. To further improve the molting molecular mechanism of M. nipponense, this study investigated whether MnHR4 functions during the molting process of M. nipponense. The domain, phylogenetic relationship and 3D structure of MnHR4 were analyzed by bioinformatics. Quantitative real-time PCR (qRT-PCR) analysis showed that MnHR4 was highly expressed in the ovary. In different embryo stages, the highest mRNA expression was observed in the cleavage stage (CS). At different individual stages, the mRNA expression of MnHR4 reached its peak on the fifteenth day after hatching (L15). The in vivo injection of 20-hydroxyecdysone (20E) can effectively promote the expression of the MnHR4 gene, and the silencing of the MnHR4 gene increased the content of 20E in M. nipponense. The regulatory role of MnHR4 in 20E synthesis and 20E signaling was further investigated by RNAi. Finally, the function of the MnHR4 gene in the molting process of M. nipponense was studied by counting the molting frequency. After knocking down MnHR4, the molting frequency of M. nipponense decreased significantly. It was proved that MnHR4 plays a pivotal role in the molting process of M. nipponense. 相似文献
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报道了一种生物聚合物材料的重要单体四乙基-D-葡萄糖酸-1,6-内酯的简便合成方法。室温下以工业原料D-葡萄糖酸-1,5-内酯为起始物,在三苯氯甲烷、吡啶溶液中反应得到三苯甲基保护6-羟基的葡萄糖酸内酯,后者在w(KOH)=30%的甲醇溶液中断裂内酯键,所得葡萄糖酸盐溶于二甲亚砜,0℃时加入氢化钠(12倍摩尔)、溴乙烷(11倍摩尔),25℃搅拌3 h,得6-O-三苯甲基-2,3,4,5-O-四乙基葡萄糖酸乙酯,三步收率40%,后者在V(乙酸)/V(水)=4溶液中70℃反应2 h脱去6-三苯甲基,KOH水溶液中水解除去乙酯键、w(HCl)=5%的盐酸酸化得到重要中间体D-四乙基葡萄糖酸(Ⅵ),最后经双环己基碳化二亚胺(DCC)、4-二甲氨基吡啶(4-DMAP)、4-二甲氨基吡啶盐酸盐(4-DMAP.HCl)脱水成环合成了目标化合物。对上述合成路线进行了优化,羟基的乙基保护反应中,加入过量氢化钠(23倍摩尔),反应结束后加入甲醇和水,所得强碱性溶液断裂乙酯键,产物脱去三苯甲基得到化合物(Ⅵ),实现了羟基保护和羧基脱保护一步法合成,减少了分离提纯步骤。产物结构经核磁共振表征。 相似文献
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以氯化血红素(Ⅰ)为原料,在甲酸-铁粉体系下,通过调节铁粉与氯化血红素的摩尔比,一步合成(2,7,12,18-四甲基-3,8-二乙基-13,17-二羧基乙基)-卟啉(双乙基次卟啉,Ⅱ)。探讨了反应过程中铁粉用量、温度、时间对目标产物(Ⅱ)合成的影响。结果表明,当铁粉和氯化血红素的摩尔比为15∶1、反应温度为120℃、反应时间为2 h时,目标产物(Ⅱ)产率达到97.6%。通过1HNMR、MS、UV-vis和IR测试技术对产物结构进行了表征。 相似文献