Reaction of Reformatsky Reagents with Substituted Alkyl Esters of 2-Oxochromene-3-carboxylic Acid

Reformatsky reagents generated from alkyl esters of bromoacetic, -bromopropionic, -bromobutyric, and -bromoisobutyric acids react with alkyl esters of 6,8-dibromo-2-oxochromene-3-carboxylic acid to form alkyl esters of 6,8-dibromo-4-(1-alkoxycarbonylalkyl)-2-oxochromane-3-carboxylic acid.     

Reaction of 5-Allyl-5-Isobutylbarbituric Acid with Electrophilic Reagents

The reaction of 5-allyl-5-isobutylbarbituric acid with several electrophilic reagents gives products resulting from the addition of the electrophile to the double bond of the allyl group and/or bicyclic products.     

吡啶与7-苯乙酰氨基-3-氯甲基头孢烷烯酸对甲氧基苄酯碘代物亲核取代反应动力学

以7-苯乙酰氨基-3-氯甲基头孢烷烯酸对甲氧基苄酯(GCLE)和吡啶为原料合成头孢他啶中间体7-苯乙酰氨基-3-吡啶甲基头孢-4-羧酸对甲氧苄酯,用高效液相色谱仪监测了吡啶与GCLE碘取代物在二氯甲烷、丙酮、四氢呋喃、乙酸乙酯和DMF混合液中的亲核取代反应,反应动力学行为可用SN2机理解释.在一定的溶剂中不同温度的速率常数可用Arrhenius方程很好的关联,求得了指前因子,初步讨论了反应的溶剂效应,得出在不同溶剂中亲核取代反应活性顺序为:丙酮＞四氢呋喃＞乙酸乙酯-DMF混合液＞二氯甲烷.     

Esters of benzoic, 5-arylisoxazole-3-carboxylic and 4,5-dichloroisothiazole-3-carboxylic acids

The method of synthesis was developed of esters of benzoic, 2-chlorobenzoic, 5-phenylisoxazole-3-carboxylic, 5-tolylisoxazole-3-carboxylic, and 4,5-dichloroisothiazole-3-carboxylic acids with some aliphatic and substituted aromatic alcohols. The latter were obtained by reduction of aldehydes used in perfumery.     

Synthesis of 4,5-Dichloroisothiazole-3-carboxylic Acid Amides and Esters

Previously unknown 4,5-dichloroisothiazole-3-carboxylic acid amides and esters were synthesized by reactions of 4,5-dichloroisothiazole-3-carbonyl chloride with ammonia, heterocyclic and aromatic amines, and functionally substituted alcohols and phenols.     

Action of Nucleophilic Reagents. 5. Interaction of 2-Iminocoumarin-3-carboxamide with Anthranilic Acid and its Derivatives

N-Substituted 2-iminocoumarins are formed on reacting 2-iminocoumarin-3-carboxamide with anthranilic acid, methyl anthranilate, anthranilamide, and anthranilonotrile. Depending on the reaction conditions these recyclize into the corresponding 3-substituted coumarins or are hydrolyzed to coumarin-3-carboxamide. An alternative synthesis of some of the compounds has been effected.     

Reaction of 1-Acetyl-5-hydroxy-2-phenylpyrazolidines with Amino Acid Esters

Reaction of 1-acetyl-2-phenyl-5-hydroxypyrazolidines with amino acid esters occurs to give the corresponding N-pyrazolidinyl amino acids under mild conditions.     

A Practical Synthesis of 1—Oxo—1,2,3,4—tetrahydroisoquinoline—3—carboxylic Acid Esters

A practical synthetic method for methyl 1-oxo-1,2,3,4-tetrahy-droisoquinoline3-3carboxylate was developed by menas of triphosgene,Several analogues were prepared by this new method.     

5-烷氧基-3,4-二卤-2(5H)-呋喃酮与氨基酸酯的串联反应

在三乙胺作用下,亲核试剂氨基酸酯与5-烷氧基-3,4-二卤-2(5H)-呋喃酮在室温下发生串联的迈克尔加成-消除反应,合成了17个新化合物.通过旋光度,UV-Vis,IR,1HNMR,13CNMR,MS,元素分析和X射线单晶衍射等表征方法,确定了目标化合物的化学结构和绝对构型.     

Interaction of Nitromethane with Esters and Amides of 2-Oxo-2H-1-benzopyrane-3-carboxylic Acid

The reaction of esters as well as N,N-disubstituted amides of 2-oxo = 2H-1-benzopyran-3-carboxylic acid with nitromethane in the presence of potassium fluoride leads to the corresponding diesters and ester -amides of 2-carboxy-3-(2-hydroxyphenyl)-4-ni trobutyric acid (2a-m). The configuration and preferable conformation of the ester-amides are discussed.     

3-氨基环己基甲酸和cis-3-氨基环己烯基-5-甲酸立体异构体的合成

通过手性胺拆分方法，从3-环己烯基甲酸出发分别合成得到了3-氨基环己基甲酸（ACHC）的四个立体异构体，以及cis-5-氨基-3-环己烯基甲酸（ACHEC）的二个立体异构体。     

Reactions of Substituted 2,3,7-Triazabicyclo[3.3.0]oct-3-ene-4-carboxylic Acid Esters with Halogens

Substituted 2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acid esters react with chlorine and bromine to give the corresponding 4-halo-2,3,7-triazabicyclo[3.3.0]oct-2-ene-4-carboxylates. Heating of the latter to 120°C under reduced pressure leads to elimination of nitrogen molecule and formation of 6-halo-3-azabicyclo[3.1.0]hexane-6-carboxylates.     

Reactions of 4,5-Dihydro-5-methyl-3H-spiro[benz-2-azepine-3-cyclohexane] N-Oxide with Some Nucleophilic Reagents

4,5-Dihydro-5-methyl-3H-spiro[benz-2-azepine-3-cyclohexane] N-oxide reacted with cyanide ion and isopropyl magnesium bromide to give the corresponding 1-cyano- and 1-isopropyl-4,5-dihydro-5-methyl-3H-spiro[benz-2-azepine-3-cyclohexane], but reaction with phenyl magnesium bromide, benzyl magnesium chloride, and nitromethane gave cyclic hydroxylamines: 1-substituted N-hydroxy-1,2,4,5-tetrahydro-5-methyl-3H-spiro[benz-2-azepine-3-cyclohexanes] which were oxidized to the corresponding nitrones.     

在SN2反应中为什么Nu从背面进攻

饱和碳原子上的亲核取代反应有两类基本的反应机理,即单分子亲核取代反应(SN1)和双分子亲核取代反应(SN2).它们都是由Ingold C K和Hughes E D经过大量研究工作后提出的,有动力学实验、动态立体化学实验、同位素示踪实验的大量实验数据支持,已为广大有机化学家所接受,并广泛用在教科书中.     

Reaction of Stereoisomers of 5-Isopropyl-4-methyl-1,3-dioxane with Esters of Monosubstituted Boric Acid

Gas-liquid chromatography was used to establish that the reactivity of the cis isomer in the reaction of 5-isopropyl-4-methyl-1,3-dioxane with the diisobutyl ester of isobutylboric acid leading to the corresponding 1,3,2-dioxaborinane is greater than for the trans isomer. An AM1 calculation for the energy of the intermediate ions in this reaction with model derivatives of boric acids: dioxyborane and the dimethyl ester of methylboric acid showed that one of the probable reasons for the observed behavior is the lower barrier for conversion of the intermediate bipolar structure of the cis derivative in the step involving formation of the endocyclic B-O bond.     

Synthesis of Halomethyl Derivatives of 3- and 4-(Dialkoxyphosphorylmethyl)-5-tert-butylfuran-2-carboxylic Acid and Their Reactions with Nucleophilic Agents

5-tert-Butyl-4-chloromethyl-, 5-tert-butyl-4-(diethoxyphosphorylmethyl)-3-methylfuran-2-carboxylates are effectively brominated with N-bromosuccinimide by the 3-methyl group. The bis(halomethyl)derivative is phosphorylated under conditions of the Arbuzov reaction to give the corresponding chloromethylphosphonate. The obtained organophosphorus derivatives of bromomethyl- and chloromethylfuran-2-carboxylic acid react with secondary amines and sodium butanethiolate to form the corresponding substitution products. Alkyl 5-tert-butyl-4-chloromethyl-3-(diethoxyphosphorylmethyl)-furan-2-carboxylate reacts with sodium acetate in acetic acid to give a 4-acetoxymethyl derivative. It is the first example of a facile reaction with O-nucleophiles of halomethyl derivatives of phosphonomethylated furans.