Direct biocatalysed synthesis of first sulfur-, selenium- and tellurium- containing <scp>l</scp>-ascorbyl hybrid derivatives with radical trapping and GPx-like properties
作者:Damiano Tanini、Beatrice Lupori、Gianni Malevolti、Moira Ambrosi、Pierandrea Lo Nostro、Antonella Capperucci
DOI:10.1039/c9cc02427a
日期:——
6-O-l-Ascorbyl selenoesters, thioesters and telluroesters can be efficiently and directly prepared from l-ascorbic acid and suitable functionalised chalcogenoesters through lipase-catalysed transesterification reactions.
Isomeric fluorinated α‐bromoenones react with dinucleophilic β‐mercaptoalcohols in CH2Cl2 at room temperature in the presence of Et3N in a multistep process. Depending on the position of the CF3 group, different O,S‐heterocycles or non‐cyclic products were obtained. With 3‐bromo‐1,1,1‐trifluorobut‐3‐en‐2‐ones derivatives of 1,4‐oxathianes were formed, but isomeric2‐bromo‐4,4,4‐trifluorobut‐2‐en‐1‐ones
conversion are sulfur or mercaptan acids. An alternative way to convert H2S is still desirable. Herein, we have developed a green and mild method to convert H2S into mercaptan alcohols by the addition reaction with epoxide mediated in tertiary amine-functionalized protic ionicliquids (PILs). Reaction kinetics, substrate scope, and regeneration experiments have all been explored. Almost quantitative conversion
硫化氢(H 2 S)的资源化利用是能源化工领域的一个重要且具有发展前景的课题。我们集团以前通过 H 2 S 转化开发的产品是硫或硫醇酸。转化H 2 S的替代方法仍然是可取的。在此,我们开发了一种绿色温和的方法来转化 H 2在叔胺官能化的质子离子液体 (PIL) 中,通过与环氧化物的加成反应将 S 转化为硫醇。反应动力学、底物范围和再生实验都已被探索。在 30°C 下通过催化负载 PIL 实现了底物的几乎定量转化。水萃取用于从反应系统中回收催化剂。据信,优异的结果,加上其操作简单性和连续重复使用催化剂的能力,使这种新方法对环境无害且具有成本效益。H 2 S 资源方法的普遍性使其具有在工业规模上应用的潜力。
Catalyst-Free Efficient Regioselective Ring Opening of Oxiranes with Thioacids in Water
Abstract Epoxide ringopening with thioacetic acid and thiobenzoic acid was investigated in the presence of water under catalyst-free conditions. This green and simple process gave an excellent yield. With simple decanting, the products were obtained in high purity and on a large scale. In this process, alkyl halide and ester cleavage were not observed.
TBAF-catalyzed reaction of a range of substituted epoxides with hexamethyldisilathiane smoothly affords a direct and simple access to β-mercaptoalcohols in a highly regio- and stereoselective way.