Metal-free and benign approach for the synthesis of dihydro-5′<i>H</i>-spiro[benzo[<i>c</i>]chromene-8,4′-oxazole]-5′,6(7<i>H</i>)-dione scaffolds as masked amino acids
作者:Behnaz Shafiee、Joseph Duffield、Rudy Timm、Rohana Liyanage、Jackson O. Lay、Ahmad R. Khosropour、Hadi Amiri Rudbari、M. Hassan Beyzavi
DOI:10.1039/c9gc00428a
日期:——
straightforward, and three-component condensation/cascade reaction of 4-hydroxycoumarins and (Z)-azlactones to construct diversified dihydro-5′H-spiro[benzo[c]chromene-8,4′-oxazole]-5′,6(7H)-diones as new masked amino acid derivatives has been developed with high to excellent yields and regio- and diastereoselectivity. This metal-free reaction proceeds via a one-pot cascade Michael addition/lactoniz
生态友好的,直接的,和4-羟基香豆素三组分缩合/级联反应和(Ž)-azlactones到构建多元化二氢-5' ħ -螺[苯并[ C ^ ]苯并吡喃8,4'-唑] - 5',6(7 H)-二酮作为新的被掩盖的氨基酸衍生物已被开发出来,具有高到极好的产率以及区域和非对映选择性。这种无金属的反应通过使用可重复使用的碳酸亚丙酯作为绿色溶剂的一锅级联迈克尔加成/内酯化/脱羧反应。还进行了放大检查,显示了在反应条件下的高原子经济性。此外,使用同位素标记,LC-MS监测和TLC-MALDI-MS进一步研究了反应机理。
Enantioselective synthesis of optically active cis-β-thio-α-amino acid derivatives through an organocatalytic cascade thio-Michael/ring opening process
作者:Zhi-Cong Geng、Ning Li、Jian Chen、Xiao-Fei Huang、Bin Wu、Guo-Gui Liu、Xing-Wang Wang
DOI:10.1039/c2cc30799e
日期:——
Non-naturally enantioenriched cis-β-thio-α-amino acid derivatives were synthesized through one pot, cascade thio-Michael/ring opening reaction of aromatic thiols with (Z)-olefinic azlactones in good yields with high levels of diastereoselectivities and enantioselectivities, which was catalyzed by a chiral bifunctional thioureaâtertiary amine catalyst.
Two organic-inorganic hybrid polyoxometalates, consist of 1-butyl-3-methylimidazolium salts of (W10O32)(4-) and (RW12O40)(3-) polyanions were prepared and characterized by thermal analysis, X-ray diffraction, FT-IR, diffuse reflectance UV-Vis spectroscopic methods and nitrogen absorption-desorption determination (BET). These heterogeneous catalysts were used for synthesis of azlactones by the reaction of aldehydes with hippuric acid and acetic anhydride under solvent-free conditions. These catalysts were reused several times without loss of their activities. (C) 2011 Elsevier B.V. All rights reserved.
Hirpara; Parikh; Merja, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2003, vol. 42, # 5, p. 1172 - 1175
作者:Hirpara、Parikh、Merja、Parekh
DOI:——
日期:——
A domino approach for the synthesis of naphtho[2,1-b]furan-2(1H)-ones from azlactones
作者:Elmira Salami-Ranjbaran、Ahmad R. Khosropour、Iraj Mohammadpoor-Baltork
DOI:10.1016/j.tet.2014.05.067
日期:2014.12
A domino approach to naphtho[2,1-b]furan-2(1H)-one derivatives from (Z)-4-arylidene-2-phenyl-5(4)-oxazolones (azlactones) and 2-naphthols catalyzed by p-TSA with reasonably moderate to high yields, has been developed. This protocol illustrates attractive features including a unique and convenient process. (C) 2014 Published by Elsevier Ltd.