101999-38-6Relevant articles and documents
Flavinium and Alkali-Metal Assembly on Sulfated Chitin: A Heterogeneous Supramolecular Catalyst for H2O2-Mediated Oxidation
Sakai, Takuya,Watanabe, Mirai,Ohkado, Ryoma,Arakawa, Yukihiro,Imada, Yasushi,Iida, Hiroki
, p. 1640 - 1645 (2019)
Heterogeneous multiple-catalyst assemblies were developed in which the flavinium cation and Na or Li cations were easily immobilized on a chitin-derived anionic polymeric scaffold through noncovalent ionic interactions. The supramolecular flavinium catalysts were successfully employed in the environmentally friendly heterogeneous Baeyer–Villiger oxidation and sulfoxidation by H2O2. Owing to the cooperative catalytic effect of flavinium, alkali metal, and sulfated chitin, the supramolecular flavinium assembly showed higher catalytic activity for the Baeyer–Villiger oxidation of cyclic ketones than the corresponding homogeneous flavinium catalyst. Because the ionic assembly was stable under the reaction conditions, the catalyst could be readily recovered by simple filtration and reused.
Efficient Synthesis of γ-Lactones by Cobalt-Catalyzed Carbonylative Ring Expansion of Oxetanes under Syngas Atmosphere
Tang, Yitian,Shen, Chaoren,Yao, Qiyi,Tian, Xinxin,Wang, Bo,Dong, Kaiwu
, p. 5898 - 5902 (2020/10/02)
A practical route from oxetane or thietane to γ-(thio)butyrolactone via solvated-proton-assisted cobalt-catalyzed carbonylative ring expansion under syngas atmosphere has been established. A wide variety of γ-(thio)butyrolactones can be afforded in good to excellent yields. The versatility of this method has been well demonstrated in the synthesis of intermediates towards the natural product Arctigenin as well as the pharmaceuticals Baclofen and Montelukast. The observed promoting effect of glycol ether solvent has been rationally interpreted.
Total synthesis and stereochemical assignment of nostosin B
Wang, Xiaoji,Feng, Junmin,Xu, Zhengshuang,Ye, Tao,Meng, Yi,Zhang, Zhiyu
, (2017/04/06)
Nostosins A and B were isolated from a hydrophilic extract of Nostoc sp. strain from Iran, which exhibits excellent trypsin inhibitory activity. Nostosin A was the most potent natural tripeptide aldehyde as trypsin inhibitor up to now. Both R- and S-2-hydroxy-4-(4-hydroxy-phenyl)butanoic acid (Hhpba) were prepared and incorporated into the total synthesis of nostosin B, respectively. Careful comparison of the NMR spectra and optical rotation data of synthetic nostosin B (1a and 1b) with the natural product led to the unambiguous identification of the R-configuration of the Hhpba fragment, which was further confirmed by co-injection with the authentic sample on HPLC using both reversed phase column and the chiral AD-RH column.
