Syntheses of Novel Flavones Containing Schiff Base Moiety

Flavones and their derivatives existing in naturae are commonly contained in plants. The members of the flavone class show a wide variety of biological activities, such as anti-inflammatory, antimierobial and antitumor activities. Sehiff bases have been intensively investigated due to their antibacterial activity and antitumor property.     

Reactions of Methyl 1-(Bromoacetyl)azulene-3-carboxylate with Thioamides and Thioureas: Synthesis of 1-(Thiazol-4-yl)-3-methoxycarbonylazulenes

Thiazole derivatives have attracted a great deal of interest owing to their physiological activities. In addition, thiazoles are also useful in dye and photographic industry.[1] In the present paper we report the synthesis of azulenes containing a thiazole moiety.     

Hydrolysis of Phosphorodithioates with a Seven-membered Ring( Ⅰ )——Kinetics and Mechanism of Acidic Hydrolysis

Introduction The phosphorodithioate is an important organophosphate pesticide. The hydrolysis reactions are very important to the metabolism of the pesticides. There have been many papers published in this domain concerning the hydrolysis of organophosphate esters. Studies on the hydrolysis of phosphorodithioate esters with a seven-membered ring, however, have rarely been reported. O, O-biphenyl S-alkyl phosphorothiolothionates with notable biological activities have recently been synthesized. In the present pater, UV spectroscopic method and molecular orbital calculation are used to carry out a research into the kinetics and-mechanisms of their hydrolyses.     

Cobalt(II) Salen Complex with Two Aza-crown Pendants and Its Analogues as Synthetic Oxygen Carriers

Introduction Synthetic oxygen carriers1 are of great interest as models to mimic oxygen carrying metalloenzymes2 for oxygen storage and transport. The cobalt(II) complexes of Schiff bases, such as Salen and its analogues, have been the first and the most extensively investigated due to their structural similarity to those found in biological systems.3,4 However, these complexes are easy to dimerize and lose activities after oxygen molecule ab-sorption.5 Avdeef and coworkers6 demonstrated tha…     

Synthesis and Characterizations of Some New Diacylhydrazones

Acylhydrazine and hydrazine are highly reactive chemicals that have a wide spectrum of uses such as in the chemical and pharmaceutical industries and as a fuel and propellant in aircraft, rockets and satellites. And they can react with microelement in the organism, so they were reported to possess different biological and pharmacological activities, such as antiphthistic, antitumour and so on. But, acylhydrazine and hydrazine have free group of NH2, so they usually have some toxicity to the organism. Hydrazones were investigated in view of the possibility of their being less toxic than the parent hydrazides, because of the blocking of the free NH2 group. In order to reduce the toxicity to the organism, people have been interested in the hydrazones compounds in recent years. In this work, 2,6-dimethylpyridine-3,5-diacylhydrazones were synthesized.     

First Total Synthesis of 7-O-Geranyl-pseudobaptigenin

Isoflavones are a class of compounds mainly occurring in species of the Leguminosae family. These compounds have received much attention recently due to their interesting biological activities1. They have been found to act as the beneficial role in the prevention of hormone based cancers and coronary heart diseases, as well as being potent antioxidant compounds2. 7-O-Geranyl-pseudobaptigenin 1 was first isolated from the root bark of Millettia griffoniana3. The synthesis of 1 has not been re…     

氨基酸水杨醛席夫碱与铜(Ⅱ)配合物的合成及其抗菌活性和稳定性、结构间的关系

n-Salicylideneamino acids and their Cu(Ⅱ) complexes are synthesized. The structures of the compounds are characterized by elementary analysis, molar conductance, magnetic susceptibility, electronic and infrared spectra. The stability constants and the antibacterial activities have been determined. The relativity between antibacterial activities and structures of ligands and stability of complexes has been preliminarily studied.     

Synthesis and Crystal Structure of Ferrocenesulfonyl Benzimidazole Derivatives

Ferrocene derivatives have attracted much attention over the past two decades in many fields due to their diversebiological activities. [1,2] As a part of a continuing investigation into these compounds, we report here six novel com pounds and the crystal structure of 2a. The synthetic routes of the novel compounds are shown in Scheme 1.     

Synthesis and Structure of a New Copper(II) Complex Cu(C_(13)H_9N_3O_2Br)_2.H_2O

1 INTRODUCTION Owing to their biological activities and chemical/industrial versalities, considerable attention has been continually attracted to metal-hydrazine complexes. For instance, Schiff base hydrazine and its analogues have been well studied in order to better understand the action mechanism of Vitamin B6-containing enzymes[1~3]. Six-coordinated copper(Ⅱ) complexes are of considerable interest, mainly due to their coordination geometry and spectroscopic properties[4]. Due to th…     

Organic Semiconducting Materials Based on BDOPV:Structures,Properties,and Applications

What are the major current research activities of your group?To develop high performance organic semiconducting and conducting materials and also to understand their structure-property relationships.We are also interested in the effect of the aggregation states of the con-jugated polymers on their electronic properties,the doping process and mechanism.What is the most important personality for scientific research?Curiosity and the desire to learn.Meanwhile,one should enjoy and be happy in the process of scientific exploration.     

Syntheses and bioactivities of mixed butyl/cyclohexyl tin carboxylates

Eight novel compounds have been synthesized and they are two series of mixed tri(butyl/cyclohexyl) tin carboxylates:Bu_nCy_(3-n) SnO_2CR (n=1,2;R=n-C_3H_7,C_6H_5,4-ClC_6H_4,4-NO_2C_6H_4).Inaddition to the studies of their structures with IR,~(119)Sn and ~(13)C NMR,we tested their fungicidal,insec-ticidal and acaricidal activities.The percentage of inhibition to the aforementioned phytopathogen isabout 80—100% at 50 ppm in glasshouse and 100% for T.Uriticae at 500 ppm.Those findingsindicate that this kindof compounds have both fungicidal and acaricidal activities and mayhave a goodprospect for applications.     

1, 4-Pyrone Effects on O-H Bond Dissociation Energies of Catechols in Flavonoids: A Density Functional Theory Study

In recent years, there has been growing interest in selecting efficient antioxidants with low toxicity to reduce the damage of free radicals. Among these antioxidants, flavonoids have been paid much attention, owing to their excellent antioxidative and pharmacological activities1. Up to now, many efforts have been given to summarize the structure-activity relationships (SAR) for flavonoids. It has been widely accepted that two structural factors are critical for flavonoids to enhance the…     

Synthesis of a Novel Conjugate of Bromoarene and Polyamide Containing N-Methylimidazoles

DNA-photocleavage agents have generated considerable attention in chemistry,biology and medicine1,2,because their DNA-cleavage activities can be easily controlled by photoirradiation.In the past decade,several DNA-cleavage agents have been successfully attached to polyamide3,4,to obtain new conjugates with higher and specific DNA-cleavage activities.Most of them contain only one photocleavage group to induce single-strand breaks,and the conjugates inducing double-strand breaks have been ra…     

Syntheses and Crystal Structures of Bis-[oxo-bis(p-ferrocenylbenzoxy di-n-propyltin)](I) and Bis[oxo-bis(β-ferrocenoylpropionyloxy di-n-propyltin )](II)

1 INTRODUCTION The studies of organotin compounds are of current interest owing to their wide range of applications such as biocides and thermal stabilizers for PVC plastic etc. Besides, the pharmaceutical properties such as the antitumor activities of organotin carboxylates have been investigated[1, 2]. In recent years, reports of synthesis and structural elucidation of various organotin carboxylic esters have appeared, revealing various new structural possibilities[3]. Since Kealy an…     

Isolation and Identification of Prenylflavonoids from Humulus lupulus

The hop plant (Humulus lupulus L. Cannabinaceae ) is cultivated widely through the temperate zones of the world. The female inflorescences of the hop plant (hops) are used in the brewing industry to give bitterness and aroma of beer. In China, hops are used as stomachics, diuretic and tranquilizer. [1] A number of prenylflavonoids have been isolated from hops, [2,3] which caused attention because of their potential anti-cancer properties, [4] endocrine activities, [5] and diacylglycerol acyltransferase inhibition. [6]     

INFLUENCE OF MOLECULAR WEIGHT AND PERIODATE-MODIFICATION OF β-D-GLUCANS FROM PORIA COCOS SCLEROTIUM ON ANTITUMOR ACTIVITIES*

In this work, influence of molecular weight and periodate modification ofβ-D-glucans isolated from Poria cocos sclerotium on the antitumor activities against Sar-coma 180 and Ehrlich ascites carcinoma (EAC) tumor was studied. The results show thattwo glucans PC3 (linear β-(1→3)-D-glucan) and PC4 [β-(1→3)-D-glucan with a fewof branches and glucuronic acid] are devoid of antitumor activity. However, when theglucans were modified by periodate oxidation, borohydride reduction and mild hydrolysisor partially hydrolysis, the derivatives have obvious antitumor activities. The decreasein molecular weight of glucans after periodate modification hardly affects their antitumoractions, but on the other hand, the decrease of molecular weight without periodate modi-fication could lead to an enhancement of the antitumor activities. Moreover, the glucansand these derivatives have much higher enhancement ratios of body weight of mice thanthat of 5-Fluorouracil (5-Fu), suggesting that they are less toxic than 5-Fu.     

POLYMER-SUPPORTED RHODIUM CATALYSTS FOR CARBONYLATION OF METHYL ACETATE TO ACETIC ANHYDRIDE

Two kinds of rhodium catalysts supported on cross-linked styrene-divinylben-zene copolymers containing bipyridine or o-phenylene diamine have been prepared and found to display high activity for methyl acetate carbonylation to form acetic anhydride, the activities are even higher than their homogeneous counterparts. XPS analysis was used to characterize the synthetic catalysts. The apparent activation parameters were determined to be Ea = 73. 3 KJ/mol, △H≠ = 66. 3KJ/mol, △S≠ = - 28.6eu. These parameters are very close to those in methanol carbonylation and imply to have analogous mechanism in both cases.     

Discovery of ferrocene-carborane derivatives as novel chemical antimicrobial agents against multidrug-resistant bacteria

Antimicrobial resistance has now become a very serious global public health problem. New drug discovery and development are urgently needed to combat the growing threat of multidrug-resistant (MDR) bacteria. The aim of this study was to explore the potential application of three ferrocene-carborane derivatives as new promising agents to confront the problem of increasing antibiotic resistance. The results of agar diffusion bioassay, minimal inhibitory concentrations (MIC) testing and time-kill assay illustrate their broad-spectrum antimicrobial activities to both American Type Culture Collection (ATCC) control strains and MDR clinical isolates. It is evident that the relevant antimicrobial properties are all in a dose-dependent manner and gradually transform into a bactericidal effect from a bacteriostatic effect with the increasing of the drug concentration. Furthermore, these ferrocene-carborane derivatives have no/little toxic effect on normal cells like HELF cells and lead to little hemolysis at their MICs. This raises the possibility to develop novel antimicrobial drugs using these new ferrocene carborane derivants.     

POLYMER—SUPPORTED RHODIUM CATALYSTS FOR CARBONYLATION OF METHYL ACETATE TO ACETIC ANHYDRIDE

Two kinds of rhodium catalysts supported on cross-linked styrene-divinylbenzene copolymers containing bipyridine or o-phenylene diamine have been prepared and found to display high activity for methyl acetate carbonylation to form acetic anhydride,the activities are even higher than their homogeneous counterparts. XPS analysis was used to characterize the synthetic catalysts.The apparent activation parameters were determined to be Eα=73.3KJ/mol,ΔH^≠=66.3KJ/mol,ΔS^≠=-28.6eu.These parameters are very close to those in methanol carbonylation and imply to have analogous mechanism in both cases.     

Catalytic Synthesis of Hexyl-naphthalene over H-type Zeolites

H-type zeolites（ HY, Hβ, and HM） were synthesized and characterized by XRD, NH3-TPD, and Py-IR. Selectively catalytic alkylation of naphthalene with n-hexanol to hexyl-naphthalene over the zeolites was carried out. The experimental results show that the catalytic activities of the zeolites are mainly determined by their acid properties and pore structures. The larger the pore diameter is, the higher the catalytic activity is. NH3-TPD profiles show that Hβ and HM have lower acid strengths than HY. HY has both the highest activity and highest selectivity for the hexylnaphthalene. Higher reaction temperatures and longer reaction time are beneficial to the production of β-hexyl-naphthalene over the HY zeolite.