The Oxidation of Aldehydes to Methyl Esters using Trichloroisocyanuric Acid

Aldehydes are readily oxidized to methyl esters by a solution of methanol, pyridine, and trichloroisocyanuric acid in acetonitrile, acetone, or methylene chloride.     

Synthesis and Primary Research on Antitumor Activity of Three New Panaxadiol Fatty Acid Esters

For making use of Ginseng resources that exhibit an antitumor activity and for finding new anticancer drugs,three new fatty acid ester compounds: 3β-acetoxy panaxadiol ( Ⅰ ), 3β-palmitic acid aceloxy panaxadiol ( Ⅱ ), and 3β-octadecanoic acid aceloxy panaxadiol( Ⅰ , Ⅱ , and Ⅲ ) were synthesized with panaxadiol, diacetyl oxide, palmityl chloride and stearyl chloride, and their structures were determined via MS, 13C NMR, IR, TLC, and so on. The molar yields of the three compounds are 75.14%, 79. 08%, and 72. 57%, respectively. Meanwhile, the antitumor activity of the three new panaxadiol fatty acid ester derivatives and panaxadiol was compared by using the method of MTT. Tumor cell used was Vero cell line. Positive control was 5-FU, blank was an RPMI1640 culture medium, negative control was an RPMI1640 culture medium and the solvent for drugs to be tested. Compound Ⅰ has the strongest antitumor activity followed by panaxadiol; compounds Ⅱ and Ⅲ have similar and weakest antitumor activities.Furthermore, the antitumor activities of the panaxadiol fatty acid ester derivatives show positive correlation with the concentration of the test group, but show no relationship with the molecular weight of fatty acid. The methods that are used to synthesize the three compounds with high yields and strong antitumor activities are simple and show a great potential for meeting the needs of industrial manufacture of these drugs.     

Oxidation of Primary Alcohols to Carboxylic Acids Using Silica Supported CrO3/H5IO6 Under Microwave Irradiation in a Solvent‐Free System

Chromium trioxide/periodic acid supported onto wet silica gel oxidizes primary alcohols to the corresponding carboxylic acids in very short reaction times in very good yields.     

Highly Selective and Practical Iron-Catalyzed Formal Hydrogenation of Epoxides to Primary Alcohols Using Formic Acid

A highly selective, efficient and practical method for synthesizing primary alcohols was presented. By using cheap Fe(BF₄)₂ ⋅ 6H₂O and /tris[2-(diphenylphosphino)phenyl]phosphine ( L1 ) as catalysts with formic acid as hydrogen source, a variety of primary alcohols bearing versatile functional groups could be obtained from both alkyl- and aryl-substituted epoxides under mild conditions.     

Hydrogenation of Esters to Alcohols Catalyzed by Defined Manganese Pincer Complexes

The first manganese‐catalyzed hydrogenation of esters to alcohols has been developed. The combination of Mn(CO)₅Br with [HN(CH₂CH₂P(Et)₂)₂] leads to a mixture of cationic and neutral Mn PNP pincer complexes, which enable the reduction of various ester substrates, including aromatic and aliphatic esters as well as diesters and lactones. Notably, related pincer complexes with isopropyl or cyclohexyl substituents showed very low activity.     

Efficient Tetrahydropyranylation of Alcohols and Detetrahydropyranylation Reactions in the Presence of Catalytic Amount of Trichloroisocyanuric Acid (TCCA) as a Safe,Cheap Industrial Chemical

Abstract

Preparation and cleavage of THP ethers of different hydroxy functional groups are easily and efficiently performed in the presence of trichloroisocyanuric acid (TCCA) in the absence of solvent with high yields.     

Hydrogenation of Esters to Alcohols with a Well‐Defined Iron Complex

We present the first base‐free Fe‐catalyzed ester reduction applying molecular hydrogen. Without any additives, a variety of carboxylic acid esters and lactones were hydrogenated with high efficiency. Computations reveal an outer‐sphere mechanism involving simultaneous hydrogen transfer from the iron center and the ligand. This assumption is supported by NMR experiments.     

Liquid Chromatographic Analysis of Bile Acid Methyl Esters

Abstract

Methods have been developed for the qualitative and quantitative analysis of hydroxy and keto derivatives of methyl cholanates utilizing a ¼″ by 1′ μPorasil column, various mixtures of hexane and ethyl acetate and a refractive index detector. The system has been calibrated for some of the methyl dihydroxycholanates using 3α;,7α-dihydroxy-12-oxocholanate as an internal standard and applied to the analysis of the mixtures of diols resulting from the reduction of methyl 3,12-dioxocholanate with NaBH₄ and with Raney nickel.     

脱镁叶绿酸a甲酯衍生物的合成

以脱镁叶绿酸a甲酯为起始原料，通过与溴化氢的加成和四氧化饿的氧化反应对2－位乙烃基进行化学修饰，合成了2－位羟烷基或溴烷基取代的脱镁叶绿酸衍生物，再利用邻二醇的碳碳键断裂和羟乙基的氧化生成－2位甲酰基脱镁叶绿酸a甲酯和2位乙酰基焦脱镁叶绿酸a甲酯。     

三氯异氰脲酸-水杨酸光度法测定植物样品中氨氮

提出了三氯异氰脲酸-水杨酸光度法测定植物样品中氨氮含量的方法。在碱性条件下,三氯异氰脲酸、水杨酸与氨氮发生灵敏的显色反应,生成蓝色化合物,该化合物的最大吸收峰位于660 nm波长处,表观摩尔吸光率为9.78×10~4L·mol·cm~(-1),氨氮质量浓度在6.0mg·L~(-1)以内符合比耳定律,该方法用于植物样品中氨氮含量的测定,结果与元素分析法测定值相符。     

Selective Oxidation of Secondary Alcohols in the Presence of Primary Alcohols by an Oxoammonium Salt

Recent reports on the oxidation of alcohols by piperidine oxoammonium salts(1) have aroused much interest in investigation.Semmelhack has found that alcohols can be electrooxidized to aldehydes or ketones at a low potential when the reaction is mediated with 2,2,6,6-tetramethylpiperidinyl-l-oxy radical (2a) and proposed that the oxoammonium ion (la) is the active oxidizing     

Oxidation of primary alcohols to aldehydes with oxygen catalysed by tetra-n-propylammonium perruthenate

The liquid-phase oxidation of a series of saturated and unsaturated non-allylic alcohols to aldehydes with oxygen or air catalysed by tetra-n-propylammonium perruthenate (TPAP, represented as [(n-Pr)₄N]RuO₄) at 80–110 °C is shown to proceed with selectivities of 72–91% at 55–80% alcohol conversion. The unsaturated alcohols, such as 9-decenol, 9-octadecenol and β-citronellol, give the corresponding unsaturated aldehydes without competing double bond attack. The time course of oxidation indicates a complex reaction mechanism. The results on oxidation of a test alcohol, t-Bu(Ph)CHOH, suggest that one-electron processes do not play an important role in the TPAP-catalysed aerobic oxidation of alcohols.     

Formation of Fatty Acid Methyl Esters During Gas Chromatography Using Trimethylanilinium Hydroxide

Abstract

Fatty acid methyl esters may be formed by dissolving the fatty acids in a 0.2 M solution of trimethylanilinium hydroxide in methanol and injecting the solution into a gas chromatograph. The reaction is rapid and quantitative, and the reagent appears to be less hazardous than diazomethane.     

1-Adamantanecarboxylic Acid Esters of Certain Terpenols, Sterols, and Plant Phenols

Esters 1b-15b were prepared from cetyl alcohol 1a, terpenols 2a-6a, sterols 7a-10a, plant phenols 11a-13a, and alcohols 14a-15a by reaction with 1-adamantanecarboxylic acid chloride in the presence of pyridine.     

几种拟除虫菊酸甲酯对映体的毛细管气相色谱手性拆分

4种酰基化环糊精衍生物（2，6－二－O－戊基－3－O－丁酰基－β－CD、2，6－二－O－戊基－3－O－戊酰基－β－CD、2，6－二－O－戊基－3－O－庚酰基-β－CD和2，6－二－O－戊基－3－O－辛酰基－β－CD）用作毛细管气相色谱固定相，对顺式－和反式－3－（2－甲基丙烯基）－2，2－二甲基环丙烷羧酸甲酯（菊酸甲酯）、顺式－和反式－3－（2，2－二氯乙烯基）－2，2－二甲基环丙烷羰酸甲酯（二氯菊酸甲酯）、2－（4－氯苯基）－3－甲基丁酸甲酯（戊菊酸甲酯）和顺式－3－（2－氯－3，3，3－三氟丙烯基）－2，2－二甲基环丙烷羧酸甲酯（功夫菊酸甲酯）等6种拟除虫菊酸甲酯对映体进行了拆分，结果表明：所合成的4种环糊精衍生物可将顺式－和反式－菊酸甲酯、顺式－和反式－二氯菊酸甲酯、戊菊酸甲酯及顺式－功夫菊酸甲酯等6种菊酸甲酯对映体较好分离。发现不同的环糊精衍生物手性分离能力不同，溶质的结构变化对分离结果也有较大影响。     

芳甲酸氰基芳甲酯的合成

芳甲酸氰基芳甲酯是重要的有机合成中间体,其现有合成方法采用剧毒氰化物为氰源来合成。 本研究以K₄[Fe(CN)₆]为绿色氰化试剂,芳酰氯为原料,采用一锅两步反应合成芳甲酸氰基芳甲酯。 通过改变第二步反应温度、反应时间、硼氢化钠和催化剂的用量获得最佳反应条件,以61.7%~80.3%的产率合成了10种芳甲酸氰基芳甲酯(2a~2j),产物结构通过傅里叶变换红外光谱仪(FTIR)、核磁共振波谱仪(NMR)分析确认。 根据实验结果,提出了可能的反应机理。 该法避免了对剧毒氰化剂的使用,具有产率高、操作简单、后处理方便等优点。     

Co-N-Si/AC Catalyst for Aerobic Oxidation of Benzyl Alcohols to Esters under Mild Conditions

A stable, earth-abundant, reusable cobalt-based heterogeneous catalyst is developed for the oxidative esterification of alcohols under ambient conditions, featuring broad substrate scope, providing good to excellent product yields. This protocol enables easy recyclability of the catalyst, measured up to five times without significant loss of efficiency. The active sites of Co-N-Si/AC are proposed to be Co-N species.