Tosylhydrazine mediated conjugate reduction and sequential reductive coupling cyclization: synthesis of 2-arylchromans
摘要:
Tosylhydrazine mediated conjugate reduction of 2-hydroxyl chalcones and sequential reductive coupling cyclization is described. This is an unprecedented protocol and an extremely efficient method for a one-pot domino synthesis of 2-arylchromans in good to excellent yields from commercially available, cheap starting materials. More importantly, the two-step reactions can be easily controlled to afford dihydrochalcones or 2-arylchromans by the mole amounts of tosylhydrazine. Furthermore, the operational simplicity of the process and the high functional group tolerance are remarkable. (C) 2015 Elsevier Ltd. All rights reserved.
Rh-Catalyzed Decarbonylative Addition of Salicylaldehydes with Vinyl Ketones: Synthesis of Taccabulins A-E
作者:Maddali L. N. Rao、Boddu S. Ramakrishna
DOI:10.1002/ejoc.201901314
日期:2019.12.15
A Rh‐catalyzed decarbonylative addition of salicylaldehydes with vinylketones was developed for the synthesis of o‐hydroxydihydrochalcones in good yields. This protocol was applied in the synthesis of taccabulin family of natural products.
deposition may lead to a series of skin disorders. The production of melanin is carried out by melanocytes, in which the enzyme tyrosinase performs a key role. In this work, we identified a series of noveltyrosinaseinhibitorhybrids with a dihydrochalcone skeleton and resorcinol structure, which can inhibittyrosinase activity and reduce the melanin content in the skin. Compound 11c possessed the most
黑色素沉积过多可能会导致一系列的皮肤病。黑色素的产生是由黑色素细胞进行的,其中酪氨酸酶起着关键作用。在这项工作中,我们鉴定了一系列具有二氢查耳酮骨架和间苯二酚结构的新型酪氨酸酶抑制剂杂化物,它们可以抑制酪氨酸酶活性并减少皮肤中的黑色素含量。化合物11c具有最强的抗酪氨酸酶活性,在纳摩尔浓度范围内显示出 IC 50值,同时具有显着的抗氧化活性和低细胞毒性。此外,在 HPLC 分析和 3D OrbiSIMS 成像可视化支持下的体外渗透测试表明11c具有出色的渗透性. 更重要的是,化合物11c在体内的豚鼠模型中减少了紫外线诱导的皮肤色素沉着中的黑色素含量。这些结果表明,化合物11c可以作为一种很有前途的强效酪氨酸酶抑制剂,用于开发治疗皮肤色素沉着过度的潜在疗法。
Brønsted Acid Catalyzed Intramolecular Allylic Substitution Reaction of Allylic Alcohols: A Facile Synthesis of 2-Vinylchromans
作者:Chang-Hua Ding、Bin Xu、Yun-Fan Li、Yu-Ting Xi、Kai-Ji Hu、Qitao Tan
DOI:10.1055/a-2301-9223
日期:——
Brønsted acidcatalyzedintramolecular allylic substitution reaction of secondary and tertiary allylic alcohols has been developed. A variety of 2-vinylchromans were efficiently prepared in moderate to excellent yields. The given method features wide substrate scope, operational simplicity, and mild, metal-free reaction conditions. The practicability of the method was demonstrated by a gram-scale reaction
Iron-Catalyzed Rearrangements and Cycloaddition Reactions of 2<i>H</i>-Chromenes
作者:Yi Luan、Huan Sun、Scott E. Schaus
DOI:10.1021/ol202772k
日期:2011.12.16
Iron(III) salts catalyze the tandem rearrangement/hetero-Diels-Alder reaction of 2H-chromenes to yield tetrahydrochromeno heterocycles. The process can occur as a homodimerization and cycloaddition process using electron-rich dienophiles. Deuterium labeling and mechanistic studies revealed a hydride shift and ortho-quinone methide cycloaddition reaction pathway.
Bird, T. Geoffrey C.; Brown, Ben R.; Stuart, Ian A., Journal of the Chemical Society. Perkin transactions I, 1983, # 8, p. 1831 - 1846
作者:Bird, T. Geoffrey C.、Brown, Ben R.、Stuart, Ian A.、Tyrrell, William R.