醛基化合物在银氨溶液中几种反应的探讨

本文对醛和其它含醛基化合物在银氨溶液中可能经过的反应历程做了分析，从中找出银镜反应和其它反应的内在联系，对在此条件下。

N-(4-苯基-噻唑-2-基)芳醛腙类化合物的合成

以芳醛与氨基硫脲进行缩合得到缩氨基硫脲,分别与ω-溴苯乙酮进行成环反应得到了一系列含噻唑环和芳基的腙类化合物,并通过用1H NMR、质谱、红外光谱等对化合物进行了结构表征.

羧基还原法制备4′-(4-甲酰基苯基)-2,2′:6′,2″-三联吡啶化合物研究

以4-对苯甲酸-2,2′:6′,2″-三联吡啶为原料,通过直接还原、先还原后氧化和先酯化后还原再氧化的三种方法将羧基部分还原为醛基,制备了4'-(4-甲酰基苯基)-2,2′:6′,2″-三联吡啶化合物。对所合成的目标产物通过核磁、红外光谱和液相质谱等进行了表征,综合对比了三种羧酸基团还原为醛基合成方法的特点。考察了催化剂用量、溶剂的类型对产品收率的影响,并对合成过程进行了优化。

Ni-mediated Liquid Phase Reduction of Carbonyl Compounds in the Presence of Atmospheric Hydrogen

An efficient reduction system of benzaldehyde with hydrogen under ambient pressure was developed using facile NiO catalyst. The non-aromatic solvents such as cyclohexane, tetrahydrofuran (THF) and n-hexane, and the addi-tive with strong basicity e.g. KOH, were necessary for smooth conversion of the substrate. That the catalyst can be recov-ered and reused for nine times without loss of catalytic activity indicates that this catalyst is a recyclable one for benzal-dehyde reduction.

Scavenging activity and mechanism study of ferulic acid against reactive carbonyl species acrolein

Acrolein,known as one of the most common reactive carbonyl species,is a toxic small molecule affecting human health in daily life.This study is focused on the scavenging abilities and mechanism of ferulic acid and some other phenolic acids against acrolein.Among the 13 phenolic compounds investigated,ferulic acid was found to have the highest efficiency in scavenging acrolein under physiological 8nditions.Ferulic acid remained at(3.04±1.89)%and acrolein remained at(29.51±4.44)%after being incubated with each other for 24 h.The molecular mechanism of the detoxifying process was also studied.Detoxifying products,namely 2-methoxy-4-vinyIphenol(product 21)and 5-(4-hydroxy-3-methoxyphenyl)pent-4-enal(product 22),were identified though nuclear magnetic resonanee(NMR)and gas chromatography-mass spectrometry(GC-MS),after the scavenging process.Ferulic acid showed significant activity in scavenging acrolein under physiological conditions.This study indicates a new method for inhibiting damage from acrolein.

Catalytic transformations of cellulose and its derived carbohydrates into 5-hydroxymethylfurfural, levulinic acid, and lactic acid

The catalytic transformation of cellulose into key building-block or platform chemicals such as 5-hydoxymethylfurfural(HMF),levulinic acid,and lactic acid under mild conditions,has attracted much attention in recent years,as these conversions can be operated without consumption of hydrogen or oxygen and thus are more economical compared to the hydrogenolysis or oxidation of cellulose.This review article highlights recent advances in the development of novel catalysts or catalytic processes for the conversion of cellulose and its derived carbohydrates into HMF,levulinic acid,and lactic acid or their esters under inert atmosphere.We also analyze efficient catalytic systems for HMF production,in particular Lewis acids combined with ionic liquid or biphasic systems.For the formations of levulinic and lactic acids or their esters,we focus on the reactions in aqueous and alcohol media catalyzed by multifunctional catalysts that combine the functions of hydrolysis,isomerization,and dehydration-rehydration or retro-aldol reactions.The reaction mechanism for each process will also be discussed to gain insights into the activation of C–O and C–C bonds in the absence of hydrogen or oxygen.

Regioselective synthesis of α-bromo-α,β-unsaturated carbonyl compounds via photocatalytic α-bromination reactions

A visible light-mediated approach for the preparation of α-bromo-α,β-unsaturated ketones and aldehydes was developed. In comparison to traditional methods that generally take two steps to afford the above compounds, this protocol was highlighted by its operational simplicity, avoiding using hazardous bromine and mild reaction conditions.