A simple and efficient procedure for the synthesis of optically active s-triazolothiadiazole derivatives

A series of novel s-triazolothiadiazoles 3a-h were prepared by condensation reaction of substituted amino triazoles la-b with N-phethaloyl-L-amino acids 2a-d in the presence of the phosphoroxy chloride（POCl₃） as an anhydrous reagent.The structure of all synthesized compounds was confirmed by IR,¹H NMR,and ¹³C NMR spectroscopy.     

The Condensation of Aromatic Aldehydes with Acidic Methylene Compounds in Water

The condensation of aromatic aldehydes with acidic methylene compounds such as malononitrile, methyl cyanoacetate, cyanoacetamide, 5,5-dimethyl-1,3-cyclohexanedione,bartbituric acid and 2-thiobarbituric acid proceeded very efficiently in water in the presence of triethylbenzylammonium chloride (TEBA) and the products were isolated simply by filtration.     

Solid state reaction of aromatic ketones with heteroaromatics

The solid state reactions of p-nitroacetophenone,acetyl-ferrocene with indole were catalyzed by anhydrous zinc chloride or aluminum chloride,and gave exclusively the 1:2 condensation products.The solid state condensation of aromatic ketones with l-phenyl-3-methyl-5-pyrazolone was also investigated,and the 1:1 and 2:1 condensation products were obtained.The structures of eleven new products were determined by IR,MS,1H NMR and elemental analysis.     

First total synthesis of ocimarin

<正>A facile approach for the first synthesis of ocimarin,naturally occurring coumarins,was developed by employing a cerium(Ⅲ) chloride heptahydrate-catalyzed Pechmann condensation of phenols andβ-keto esters in a solvent-free system as key step,by which ocimarin was achieved by three steps starting from acetylacetic ether and resorcinol with total yield 23.2%.All structures of new compounds were confirmed by IR,~1H NMR and MS.     

Syntheses and Biological Activities of Novel 3-Bromo-1-（3-chloropy- ridin-2-yl）-N-hydroxy-N-aryl- 1H-pyrazole-5-carboxamides

A series of novel 3-bromo-1-（3-chloropyridin-2-yl）-N-hydroxy-N-aryl-lH-pyrazole-5-carboxamides was synthesized by the reaction of pyrazole carbonyl chloride with each of substituted phenylhydroxyamines. The latter ones were prepared in good yields by reducing substituted nitrobenzene compounds with Zn/NH4CI reductant system in alcohol. Structures of the title compounds were determined by IR, 1H NMR, and HRMS. Their insecticidal and fungicidal activities were evaluated by larvicidal test against oriental armyworm and the mycelium growth rate method, respectively.     

Environmentally Benign Synthesis of 2-Pyrazolines and Cyclohexenones Incorporating Naphthalene Moiety and Their Antimicrobial Evaluation

We reported the environmental benign synthesis of chalcones,2-pyrazolines and cyclohexanones under microwave irradiation.Chalcones were obtained by the condensation of each of 2-hydroxyacetophenone derivatives with a-naphthaldehyde under microwave irradiation.The condensation reactions of each of synthesized chalcones with phenyl hydrazine under microwave irradiation in the presence of dry acetic acid as a cyclizing agent gave 2-pyrazolines.Also,the new cyclohexenone derivatives,valuable intermediates to synthesize fused heterocycles,have been prepared by the cyclocondensation of each of hydroxychalcones with ethyl acetoacetate.The structures of the synthesized compounds were elucidated by infrared（IR） spectrometry,nuclear magnetic resonance（NMR）,mass spectrometry（MS） and elmental analysis.The results indicate that unlike classical heating,microwave irradiation results in higher yields with shorter and cleaner reactions.The synthesized compounds were screened for antimicrobial activity against Staphylococcus aureus,Escherichia coli,Candida Albicans and Aspergillus niger.We clarified the effects of different substituents in the tested compounds on the obtaind antibacterial activities and antifungal activities.     

Synthesis,Mass Spectrometric Studies,and Biological Evaluation of 3,5-Dimethoxyhomophthalic Acid and Related Compounds

3,5-Dimethoxyhomophthalic acid was synthesized in four steps from 3,5-dimethoxycinnamic acid via a series of reactions including cyclization of 3-(3',5'-dimethoxyphenyl)propionic acid to 5,7-dimethoxy-1-indanone and oxidative decomposition of methyl-2-hydroxy-2-[5,7-dimethyoxy-1-oxo-1H-inden-2(3H)-ylidene]acetate to 3,5-dimethoxyhomophthalic acid.The synthesized compounds were characterized by elemental analysis,IR,1H NMR,and MS.The biological evaluation experiments of 3,5-dimthoxyhomophthalic acid and the related synthesized compounds were also carried out.Naturally occurring biologically active isocoumarins were prepared in a single step by the condensation of the homophthalic acid with appropriate acid chlorides.     

Synthesis and Characterization of Polyesters Based on Diethylketone Moiety

A new class of unsaturated polyesters based on diethylketone have been prepared by interfacial polymerization of 2,4-bis（4-hydroxybenzylidene）-3-pentanone（I） and 2,4-bis（4-hydroxy-3-methoxybenzylidene）-3-pentanone（II） with 4,4’-azodibenzoyl chloride and 3,3’-azodibenzoyl chloride at ambient temperature. The model compounds were synthesized by reaction of（I） and（II） with benzoyl chloride. The new monomers, model compounds and polyesters have been characterized by different spectral analyses. The polyesters have inherent viscosity of 0.55-0.80 d L/g and moderate number average molecular weight（Mn） in the range of 6150-7400 g/mol. Most of the compounds exhibited their solubility in aprotic solvents while partial solubility in various halogenated organic solvents was observed. The temperatures of 10% weight loss were high（225-330 °C） in nitrogen, indicating that these polyesters have excellent thermal stability. Doping with iodine dramatically raised the conductivity and produced brown colored semiconductive polymers with a maximum conductivity of 2.7 × 10-6 --1cm-1. Moreover, the morphological properties of selected example of polyesters were detected by SEM.     

Synthesis of 1-acyl-5-aryl biurets

Fourteen new 1-acyl-5-aryl biurets were synthesized by the reaction of aryl ureas with acylisocynantes. The latter was obtained from acyl chloride and lead cyanate in dichloromethane, using pyridine as catalyst. The structures of compounds 3a-n were confirmed by IR,1H NMR and MS spectra.     

Synthesis of Some Novel Phenyl Substituted Oxothiazolidin- 1’’,3’’,4’’-thiadiazolo-[3’,4’-b]thiazoline of 3β-Substituted Cholestane

Three title compounds 4a—4c have been synthesized by the cyclodehydration of 1’-benzylidine-4’-(3β-substituted-5α-cholestane-6-yl)thiosemicarbazones 2a—2c with thioglycolic acid followed by the treatment with cold conc. H2SO4 in dioxane. The compounds 2a—2c were prepared by condensation of 3β-substituted-5α-cholestan- 6-one-thiosemicarbazones 1a—1c with benzaldehyde. These thiosemicarbazones 1a—1c were obtained by the reaction of corresponding 3β-substituted-5α-cholestan-6-ones with thiosemicarbazide in the presence of few drops of conc. HCl in methanol. The structures of the products have been established on the basis of their elemental, analytical and spectral data.     

Nucleophilic addition reaction of aromatic compounds with α-chloroglycidates in the presence of Lewis acid

The epoxide 1 obtained by the Darzens condensation reaction of aldehydes with methyl dichloroacetate, reacted with aromatic compounds in the presence of aluminium chloride to afford α-aryl-β-chloro-α-hydroxyalkanoate 3. The intra-molecular nucleophilic addition of epoxide 1′ gave cyclisation compound 4. The scope and limitation of these reaction were studied for various aldehydes and aromatic compounds. The reaction was also studied in the presence of aluminium chloride supported on alumina or silica gel, which is thought to be a mild Lewis acid and harmless for environment.     

Synthesis of α,β-epoxy diazomethyl ketones

The preparation of eighteen epoxy diazomethyl ketones 1 is described. Two general methods were developed. Firstly, treatment of the mixed anhydrides of glycidic acids and carbonic acid ester with diazomethane led to the title compounds in yields ranging from 17–74%. Secondly, glycidyl chlorides which were obtained from sodium glycidates and oxalyl chloride, gave the desired products upon treatment with diazomethane (yields 60–74%). The required α,β-epoxy carboxylic esters were prepared by Darzens condensation and epoxidation of α,β-unsaturated esters, but in some cases also by reaction of α-oxo carboxylic esters with diazomethane.     

丹参素衍生物的合成

以取代苯甲醛为原料,经达参缩合、还原、水解反应合成了24个丹参素衍生物,其结构经1H NMR和MS表征。有7个是新化合物。     

无溶剂条件下芳香醛与氯代苯乙酮的Darzens 缩合反应

在无溶剂、氢氧化钠的作用下, 用研磨的方法、通过Darzens缩合反应制备环氧化合物. 它的优点是操作简单、反应条件温和、产率高和环境污染小.     

超声辐射下水溶液中合成2,3-环氧-1,3-二芳基丙酮

在氢氧化钠水溶液中, 通过氯代苯乙酮和芳香醛进行Darzens缩合反应, 在超声辐射下, 合成了系列2,3-环氧- 1,3-二芳基丙酮; 应用超声和相转移催化剂联用的方法进行改进, 取得良好效果. 与传统的合成方法比较, 该方法反应条件温和、溶剂无毒、反应时间短和产率高.     

Reaction of 2,2-dichloroacetophenone and benzaldehydes under conditions of the darzens condensation

The reaction of 2,2-dichloroacetophenone with benzaldehydes was studied under Darzens condensation conditions. Benzaldehyde, p-bromobenzaldehyde, and o,p-dichlorobenzaldehyde condensed with 2,2-dichloroacetophenone to give 1-phenyl-3-aryl-3-chloro-1,2-propanediones. In the case of p-nitrobenzaldehyde, 1-phenyl-2-chloro-3-(p-nitrophenyl)-2,3-epoxy-1-propanone, which is the product of the first step of the Darzens condensation, was isolated.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, 420083 Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 204–206, January, 1992.     

A Novel Diastereoselective Synthesis of 6‐Aryl‐5‐hydroxy‐2,3‐dihydropyrano[2,3‐c]pyrazol‐4(1H)‐ones

A novel one‐pot diastereoselective synthesis of trans‐6‐aryl‐5‐hydroxy‐2,3‐dihydro[2,3‐c]pyrazol‐4(1H)‐ones 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h is described via the Darzens condensation reaction of 2‐chloro‐1‐(5‐hydroxy‐3‐methyl‐1‐phenyl‐1H‐pyrazol‐4‐yl)ethanone ( 2 ) with different aromatic aldehydes in aqueous basic medium. The structures of the compounds prepared were determined by analytical and spectral analyses.     

β-环糊精催化下的不对称Darzens缩合

应用环糊精(CD)作为人工酶模型已经在许多有机反应中显示出特异的结果。CD催化下的合成虽然报道还不多,但已被视为一种有前途的仿生合成。鉴于α,β-环氧酮是一类重要的合成中间体,光学活性的α,β-环氧酮的不对称合成更是人们感兴趣的领域,因而我们研究了如下的在β-CD催化下的Darzens缩合:     

DARZENS REACTION OF 2-CHLOROMETHYLBENZOXALINE

2-chloromethylbenzoxaline reacted with aromatic aldehydes in alkaline solution,giv-ing Darzens condensation product:2-aryl-3-benzoxalinyloxiranes.     

地尔硫卓的合成工艺改进

以对甲氧基苯甲醛和氯乙酸甲酯为原料,经Darzens缩合、环氧开环、酒石酸拆分、环合、N-烃基化、O-乙酰化、成盐等7步反应制得地尔硫卓盐酸盐,其结构经~1H NMR,IR,MS(ESI)和元素分析确证。