Two new compounds from Dendrobium candidum

Two new compounds were isolated from the stems of Dendrobium candidum: (R)-3,4-dihydroxy-5,4',alpha-trimethoxybibenzyl (1), named dendrocandin A; and 4-[2-[(2S,3S)-3-(4-hydroxy-3,5-dimethoxyphenyl)-2-hydroxymethyl-8-methoxy-2,3-dihydrobenzo[1,4]dioxin-6-yl]ethyl]-1-methoxyl benzene (2), dendrocandin B. Five previously known bibenzyls were also identified: 4,4'-dihydroxy-3,5-dimethoxybibenzyl (3), 3,4-dihydroxy-5,4'-dimethoxybibenzyl (4), 3-O-methylgigantol (5), dendrophenol (6), and gigantol (7).     

Comparison of some properties of 2,3- and 3,5-dimethoxybenzoates of light lanthanides

The physico-chemical properties and thermal stability in air of the light lanthanide 2,3- and 3,5-dimethoxybenzoates were studied and compared in order to observe if there is influence of the position of -OCH₃ substituents in benzene ring on their properties, mainly on their thermal stability. The complexes of both of two series are crystalline, hydrated or anhydrous salts with colours typical of Ln³⁺ ions. The carboxylate group shows the different coordination modes. It may coordinate as a bidentate, chelating or tridentate chelating-bridging ligand. The thermal stabilities of 2,3- and 3,5-dimethoxybenzoates of light lanthanides were studied in the temperature range 293-1173 K. The solubilities of 2,3- and 3,5-dimethoxybenzoates of these elements in water at room temperature are in the orders of 10^-3-10^-2 mol dm^-3 and 10^-4 mol dm^-3, respectively. The various positions of -OCH₃ groups in benzene ring influences some physico-chemical properties of these compounds. This revised version was published online in July 2006 with corrections to the Cover Date.     

姜黄素-N-取代吡唑类衍生物合成及抑菌活性

为了寻求杀菌剂的新的先导化合物,用姜黄素与取代酰肼反应得到13个新的姜黄素-N-取代吡唑类衍生物,其结构经IR,1H NMR,13C NMR,MS和元素分析所表征,初步抑菌实验结果表明,在1×10-4mol/L浓度下,所有衍生物与姜黄素对比,对枯草杆菌、金黄色葡萄球菌、大肠杆菌、青霉、黑霉有较好的抑菌效果.其中,3,5-二(4-羟基-3-甲氧基苯基乙烯基)-N-脒基吡唑(3c),3,5-二(4-羟基-3-甲氧基苯基乙烯基)-N-(苯并噻唑-2-硫基乙酰基)吡唑(3k),3,5-二(4-羟基-3-甲氧基苯基乙烯基)-N-(香豆素-3-甲酰基)吡唑(3m)有优异的抑菌效果(抑菌圈16.34～23.81 mm).这些结果表明含有噻唑环、脒基、香豆素环取代基可能有助于提高姜黄素-N-取代吡唑类衍生物的活性.     

含1,2,4,5-四取代苯基的吡唑-4-甲酰胺类化合物的设计、 合成及生物活性

通过活性亚结构拼接的方法, 设计合成了一系列含四取代苯基的吡唑-4-甲酰胺类化合物, 所有化合物的结构均通过高分辨质谱（HRMS）和核磁共振氢谱（¹H NMR）确证. 生物活性测试结果表明, 部分化合物对苹果纹轮病菌、 水稻纹枯病菌、 油菜菌核病菌和黄瓜灰霉病菌表现出较好的杀菌活性. 化合物5c表现出较广的杀菌谱, 在浓度为50 μg/mL时对苹果纹轮病菌的抑制活性高达95.5%. 初步构效关系分析发现, 吡唑环N取代基为甲基或叔丁基时, 化合物表现出较好的活性; 含并环结构的化合物5′杀菌活性低于含单个苯环的化合 物5; 苯环取代基R²为低于4个碳的脂肪链时, 化合物杀菌活性更高.     

2-[4-(5-取代-1,3,4-噁二唑-2-基)苯氧基]丙酸/乙酸酯的合成、结构及其生物活性

以4-氰基苯酚和2-氯丙酸乙酯(或2-氯乙酸甲酯)为起始原料进行反应,得到2-(4-(1H-四唑-5-基)苯氧基)丙酸/乙酸酯,进而发生Huisgen反应合成了一系列新型1,3,4-噁二唑类标题化合物,其结构经~1H NMR,~(13)C NMR,IR,MS及元素分析或高分辨质谱得到表征和确认.用X射线衍射测定了化合物3q的晶体结构.初步生物活性测试结果表明,含有较小体积取代基的噁二唑化合物3c和3d在200μg/mL测试浓度下对水稻KARI酶分别具有94.5%和83.1%的抑制活性.化合物3p在100μg/mL浓度下对双子叶油菜(Brassica campestris)胚根生长抑制率可达82.4%.     

1,3,4-Oxadiazole N-Mannich Bases: Synthesis,Antimicrobial, and Anti-Proliferative Activities

The reaction of 5-(3,4-dimethoxyphenyl)-1,3,4-oxadiazole-2(3H)-thione 3 with formaldehyde solution and primary aromatic amines or 1-substituted piperazines, in ethanol at room temperature yielded the corresponding N-Mannich bases 3-arylaminomethyl-5-(3,4-dimethoxyphenyl)-1,3,4-oxadiazole-2(3H)-thiones 4a–l or 3-[(4-substituted piperazin-1-yl)methyl]-5-(3,4-dimethoxyphenyl)-1,3,4-oxadiazole-2(3H)-thiones 5a–d, respectively. The in vitro inhibitory activity of compounds 4a–l and 5a–d was assessed against pathogenic Gram-positive, Gram-negative bacteria, and the yeast-like pathogenic fungus Candida albicans. The piperazinomethyl derivatives 5c and 5d displayed broad-spectrum antibacterial activities the minimal inhibitory concentration (MIC) 0.5–8 μg/mL) and compounds 4j, 4l, 5a, and 5b showed potent activity against the tested Gram-positive bacteria. In addition, the anti-proliferative activity of the compounds was evaluated against prostate cancer (PC3), human colorectal cancer (HCT-116), human hepatocellular carcinoma (HePG-2), human epithelioid carcinoma (HeLa), and human breast cancer (MCF7) cell lines. The optimum anti-proliferative activity was attained by compounds 4l, 5a, 5c, and 5d.     

大黄酸-缬氨酸加合物的合成及初步抗肿瘤活性

以大黄酸为原料,经酯化、烷基化、水解及缩合等反应步骤合成了12个大黄酸-缬氨酸加合物.目标化合物经1H NMR,~(13)C NMR和HRMS进行了结构确证.以顺铂和阿霉素为阳性对照药,采用四甲基偶氮唑盐(MTT)法考察了目标化合物的体外抗肿瘤(Hela,MCF-7,HepG2,KB和HEK293T等5株细胞)活性.结果表明,化合物5l显示出较好的抗肿瘤活性,其IC50值在1.6~9.4μmol/L之间.作用机制研究结果表明,化合物5l能够与DNA发生较强的结合作用.     

Synthesis and anticancer evaluation of some novel N,O,S heterocyclic compounds pendant to 3-methyl-5-cyano-6-(3,4-dimethoxyphenyl)pyrimidine and other related fused pyrimidines

The key starting compound 5-cyano-6-(3,4-dimethoxyphenyl)-2-thiouracil ( 1 ) was synthesized and allowed to undergo electrophilic substitution with methyl iodide to give the corresponding 6-(3,4-dimethoxyphenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydro-pyrimidine-5-carbonitrile ( 2 ). Nucleophilic substitution on compound 2 with hydrazine hydrate led to the corresponding 2-hyrazinopyrimidone intermediate 3 . Compound 3 underwent several substitution and cyclization reactions with β-ketoester, β-ketone, alkyl halides, arylisothiocyanate, or aromatic aldehydes followed by cyclization reactions to give the corresponding N,O,S heterocyclic compounds incorporated into pyrimidine moiety and/or the related S-triazino[3,4-b]pyrimidine derivatives 4 - 18 . Anticancer evaluation of some representative examples of newly synthesized compounds was carried out against MCF-7, HCT116 cell lines. Some of the newly synthesized compounds showed significant activity.     

Synthesis and Tumor Cytotoxicity of Novel 1, 2, 3-Triazole-substituted 3-Oxo-oleanolic Acid Derivatives

Fifteen novel 3-oxo-oleanolic acid esters bearing aryl substituted 1,2,3-triazolyl methyl moiety were synthesized via the method of Copper(I)-catalyzed Huisgen cycloaddition. The cytotoxicity evaluation results of these compounds against five human tumor cell lines show that most of these compounds presented potent activity and selectivity against A375-S2 and HT1080 cells. Compound 6c, with a p-NO₂ at the bezene ring, possesses the best inhibitory activity against A375-S2(IC₅₀=2.82 μmol/L) and HT1080(IC₅₀=1.69 μmol/L).     

A new cyclobutane lignan from Cinnamomum balansae

A new cyclobutane lignan, named cinbalansan (6), was isolated from the leaves of Cinnamomum balansae, along with five known compounds, 1,2-dimethoxy-4-(1-E-propenyl)benzene (1), 1,2-dimethoxy-4-(1-Z-propenyl)benzene (2), 1,2-dimethoxy-4-(2-propenyl)benzene (3), 3,4-dimethoxybenzaldehyde (4), and E-(3,4-dimethoxyphenyl)-2-propenal (5). The structure of cinbalansan was shown to be 1beta,2beta,3alpha,4alpha-1,2-dimethyl-3,4-bis(3,4-dimethoxyphenyl)cyclobutane by a combination of 1H-, 13C-NMR, and NOE- experiments and by direct analysis of the 1H-NMR spectrum by the method of X-application.     

Photosynthesis-Inhibiting Activity of N-(Disubstituted-phenyl)-3-hydroxynaphthalene-2-carboxamides

A set of twenty-four 3-hydroxynaphthalene-2-carboxanilides, disubstituted on the anilide ring by combinations of methoxy/methyl/fluoro/chloro/bromo and ditrifluoromethyl groups at different positions, was prepared. The compounds were tested for their ability to inhibit photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. N-(3,5-Difluorophenyl)-, N-(3,5-dimethylphenyl)-, N-(2,5-difluorophenyl)- and N-(2,5-dimethylphenyl)-3-hydroxynaphthalene-2-carboxamides showed the highest PET-inhibiting activity (IC₅₀ ~ 10 µM) within the series. These compounds were able to inhibit PET in photosystem II. It has been found that PET-inhibiting activity strongly depends on the position of the individual substituents on the anilide ring and on the lipophilicity of the compounds. The electron-withdrawing properties of the substituents contribute towards the PET activity of these compounds.     

Is the 1,3,5-tridehydrobenzene triradical a cyclopropenyl radical analogue?

The gas-phase heat of formation (DeltaH(f,298)) of the 1,3,5-tridehydrobenzene triradical has been determined by using a negative ion thermochemical cycle. The first three measurements carried out were of the gas-phase acidity of 3,5-dichlorobenzoic acid, the enthalpy for decarboxylation of 3,5-dichlorobenzoate, and the enthalpy for chloride loss from 3,5,-dichlorophenide and constitute the measurement of the heat of formation for 5-chloro-m-benzyne. The last two measurements, the electron affinity of 5-chloro-m-benzyne, and the threshold for chloride loss from 5-chloro-m-benzyne, when combined with DeltaH(f,298) of 5-chloro-m-benzyne, give the heat of formation of the triradical. The 5-chloro-m-benzyne heat of formation is 116.2 +/- 3.7 kcal/mol. The heat of formation of the 1,3,5-tridehydrobenzene triradical measured in this work is 179.1 +/- 4.6 kcal/mol. This heat of formation was used to derive the bond dissociation energy (BDE) at the 5-position of m-benzyne, a third BDE in benzene. The BDE, at 109.2 +/- 5.6 kcal/mol, is ca. 4 kcal/mol lower than the first BDE in benzene (112.9 kcal/mol) and significantly higher than the BDE of phenyl radical at the meta position. The agreement between the first and third BDEs implies that the triradical is best described as a phenyl radical that interacts little with a m-benzyne moiety. The experimentally measured BDE is in good agreement with multireference configuration interaction calculations, which predict a (2)A(1) ground state for the Jahn-Teller distorted triradical. The trends in the first, second, and third BDEs of benzene are similar to those found for cyclopropane, suggesting a cyclopropenyl-like electronic structure within the six-membered ring of the 1,3,5-benzene triradical.     

Design, synthesis and antifungal/insecticidal evaluation of novel cinnamide derivatives

Twenty novel cinnamamide derivatives were designed and synthesized using as lead compound pyrimorph, whose morpholine moiety was replaced by β-phenylethylamine. All the compounds were characterized by their spectroscopic data. The fungicidal and insecticidal activities were also evaluated. The preliminary results showed that all the title compounds had certain fungicidal activities against seven plant pathogens at a concentration of 50 μg/mL, and compounds 11a and 11l showed inhibition ratios of up to 90% against R. solani. Most of the title compounds exhibited moderate nematicidal activities. In general, the morpholine ring may be replaced by other amines and a chlorine atom in the pyridine ring is helpful to fungicidal activity.     

Reactions of [(3,5-Di-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-oxocyclohexa-2,5-dien- 1-ylidene)methyl]phosphonates with Phenols

Dialkyl [(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phosphonates reacted with phenol and benzenediols in the presence of trifluoromethanesulfonic acid to give products of electrophilic substitution in the benzene ring, the corresponding diarylmethylphosphonates or [phenylenebis(arylmethylene)]- diphosphonates. The reaction of diphenyl [(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phosphonate with 2-methylbenzene-1,3-diol at a ratio of 1: 1 afforded 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-6-hydroxy-7-methyl-2-phenoxy-2,3-dihydro-1,2λ⁵-benzoxaphosphol-6-one.     

Synthesis of 4,6-(and 5,7-)dimethoxy-3,3-dimethyl-1-indanones

Grignard reaction of ethyl 3-(3,5-dimethoxyphenyl)-propionate (4) followed by cyclodehydration of the carbinol (5) with conc H₂SO₄ gave 4,6-dimethoxy-3,3-dimethylindane (6). Oxidation of the indane (6) with CrO₃-pyridine complex in methylene chloride gave 4,6-dimethoxy-3,3-dimethylindan-1- one (1) in high yield. Conjugate addition of methyl magnesium iodide to methyl α-cyano-β-methyl-3,5-dimethoxycinnamate (11), prepared from 3,5-dimethoxyacetophenone (10) by Knoevenagel condensation, resulted in methyl 2-cyano-3-(3,5-dimethoxyphenyl)-3,3-dimethylpropionate (12). Refluxing the ester (12) with aq DMSO containing sodium chloride gave the corresponding nitrile (15) which underwent Höesch reaction to yield 5,7-dimethoxy-3,3-dimethylindan-1-one (2).     

两种新型丁二炔衍生物的合成

以3,5-二溴-1-｛3-（十二烷氧基）-2-［（十二烷氧基）甲基］丙氧基｝苯和2-甲基-3-丁炔-2-醇为原料,经选择性Sonogashira偶联反应,Sonogashira偶联反应和去硅保护基反应制得中间体--3-乙炔基-5-（3-甲基-3-羟基)-丁炔基-1-（3-十二烷氧基）-2-｛［（十二烷氧基）甲基］丙氧基｝苯（6）; 6经改良的Glaser偶联反应(CuI为催化剂,Et₃N为溶剂)合成了一个新型的丁二炔衍生物（1）。 6与2,2′-［（2,5-二碘-1,4-亚苯基）双（氧基）］双（四氢-2H-吡喃）经Sonogashira偶联,脱 THP保护基和改良的Glaser偶联反应合成了一个新型的丁二炔衍生物（2）。中间体,1和2的结构经¹H NMR, ¹³C NMR和MALDI-TOF-MS表征。     

硝基呋喃亚甲基哌啶类化合物的合成与抗结核活性

结核是由结核分枝杆菌引起的一种慢性呼吸道传染病,对人类的健康构成严重威胁。 本文利用药效团拼接原理,将片段硝基呋喃和苯基噻唑组合,得到了19个2-(1-((5-硝基呋喃-2-基)甲基)哌啶-4-基)噻唑(5)和2-(1-((5-硝基呋喃-2-基)甲基)哌啶-4-基)-4-苯噻唑(6)系列化合物,测试了所有化合物在1和0.1 μmol/L浓度下对结核分枝杆菌H37Ra的抑制率。 构效关系分析表明,苯环上有取代基有利于活性,且苯环上对位取代普遍优于间位和邻位取代,对位吸电子基团取代活性优于对位供电子基团取代活性。在苯环对位吸电子基团取代中,—CF₃取代的化合物2-(1-((5-硝基呋喃-2-基)甲基)哌啶-4-基)-4-(4-三氟甲基)苯基)噻唑(6f)活性最高,在1和0.1 μmol/L浓度下,抑制率分别为99.6%和93.4%。 鉴于新化合物具有抗结核高活性,化合物6f可作为抗结核候选化合物进一步研究。     

C2 hydroxyl group governs the difference in hydrolysis rates of methyl-α-D-glycero-D-guloseptanoside and methyl-β-D-glycero-D-guloseptanoside

A computational investigation into the hydrolysis of two methyl septanosides, methyl-α-D-glycero-D-guloseptanoside and methyl-β-D-glycero-D-guloseptanoside was undertaken. These septanosides were chosen as model compounds for comparison to methyl pyranosides and allowed direct comparison of α versus β hydrolysis rates for a specific septanoside isomer. Results suggest that hydrolysis takes place without proceeding through a transition state, an observation that was suggested in previous computational studies on exocyclic bond cleavage of carbohydrates. A conformational analysis of α- and β-anomers 1 and 2 and their corresponding oxocarbenium 3, coupled with relaxed potential energy surface (PES) scans (M06-2X/6-311+G**, implicit methanol), indicated that hydrolysis of the α-anomer is favored by 1-2 kcal/mol over the β-anomer, consistent with experiment. Model systems revealed that the lowest energy conformations of the septanoside ring system destabilize the β-anomer by 2-3 kcal/mol relative to the α-anomer, and the addition of a single hydroxyl group at the C2-position on a minimal oxepane acetal can reproduce the PES for the septanoside 1. These results suggest that the C2 hydroxyl plays a unique role in the hydrolysis mechanism, destabilizing the septanoside via its proximity to the anomeric carbon and also through its interaction with the departing methanol from the α-anomer via hydrogen-bonding interactions.     

Syntheses of 2-(3,4-dimethoxyphenyl)ethylamine derivatives and their antiulcer activities.

A series of acyl derivatives of 2-(3,4-dimethoxyphenyl)ethylamine (4) were synthesized and evaluated for their effectiveness to prevent water-immersion stress-induced gastric ulceration when given intraperitoneally to rats. Among them N-[2-(3,4-dimethoxyphenyl)ethyl]-2-phenylaminoacetamide hydrochloride (15) had significant antiulcer activity. Further modification of the four parts of 15 revealed that only the introduction of a carbamoyl group into 2- or 3-position of the phenylamino part gave compounds (49-51, 54 and 55) which retained antiulcer activity comparable to the lead compound. However, the compounds (49-51 and 54) did not exert a prophylactic effect when administered orally except for the 3-substituted bezamide derivative 55. Alkyl substitution on the nitrogen of benzamide gave 3-[[[2-(3,4-dimethoxyphenyl)ethyl]carbamoyl]methyl] amino-N-methylbenzamide (66, DQ-2511) and the related compounds (67, 70, 74 and 77) which all had potent antiulcer activities at oral doses of 50-400 mg/kg.     

Synthesis of cationic beta-cyclodextrin derivatives and their applications as chiral stationary phases for high-performance liquid chromatography and supercritical fluid chromatography

Four cationic beta-cyclodextrin derivatives, namely mono-6-(3-methylimidazolium)-6-deoxy-perphenylcarbamoyl-beta-cyclodextrin chloride (MPCCD), mono-6-(3-methylimidazolium)-6-deoxyper(3,5-dimethylphenylcarbamoyl)-beta-cyclodextrin chloride (MDPCCD), mono-6-(3-octylimidazolium)-6-deoxyperphenylcarbamoyl-beta-cyclodextrin chloride (OPCCD) and mono-6-(3-octylimidazolium)-6-deoxyper(3,5-dimethylphenylcarbamoyl)-beta-cyclodextrin chloride (ODPCCD), have been synthesized and physically coated onto porous spherical silica gel to obtain novel chiral stationary phases (CSPs). The performances of these CSPs are studied on high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) using 18 racemic aryl alcohols as test analytes. Among these four CSPs, OPCCD shows the best separation results for all analytes on both HPLC and SFC analyses. Chromatographic studies reveal that the CSPs consisting of an n-octyl group on the imidazolium moiety and phenylcarbamoyl groups on the cyclodextrin ring provide enhancement of analyte-chiral substrate interactions over CSPs bearing the methyl group on the imidazolium moiety and 3,5-dimethylphenylcarbamoyl groups on the cyclodextrin ring.