A Novel Plasticizer for the Preparation of Thermoplastic Starch

TPS was a biodegradable material based on starch. Starch was an inexpensive and natural renewable polysaccharide, which was widely investigated as the substitute of petroleum-derived plastics. Native starch commonly existed in granule structure with about…     

STUDY ON 1-HEXENE POLYMERIZATION BASED ON ZIEGLER-NATTA CATALYSTS WITH DOPED SUPPORT

A series of Ti/Mg supported catalysts are prepared by using ball-milled mixtures of MgCl2-ethanol adducts and NaCl as supports, and 1-hexene polymerizations catalyzed by the novel catalysts are studied. It is found that the molecular weight distribution of poly(1-hexene) becomes apparently narrower when catalysts with doped supports are used, indicating that changing the structure of the support is an effective way to regulate the active center distribution of heterogeneous Ziegler-Natta catalyst.     

A New Saponin Transformed from Ginsenoside Rh1 by Bacillus subtilis

A novel saponin was isolated from the transformed products of ginsenoside Rh1 by Bacillus subtilis. It‘s structure was determined to be 3-O-β-D-glucopyranosyl-6-O-β-D-glucopyranosyl-20 (S)-protopanaxatriol on the basis of the spectral data.     

Identification of Cyclic Dipeptides and a New Compound (6-(5-Hydroxy-6-methylheptyl)-5,6-dihydro-2H-pyran-2-one) Produced by Streptomyces fungicidicus against Alternaria solani

As an important microbial resource, Actinomycetes, especially Streptomyces, have important application values in medicine and biotechnology. Streptomyces fungicidicus SYH3 was isolated from soil samples in tomato-growing areas and showed good inhibitory effects on Alternaria solani in tomato. To obtain pure active compounds, SYH3 fermentation broth was subjected to XAD-16 macroporous resin and silica gel column chromatography. Combined with the repeated preparation and separation of preparative high-performance liquid chromatography (HPLC), a total of four monomer compounds were obtained after activity tracking. Compound 4 was identified as a new six-membered lactone ring compound named 6-(5-hydroxy-6-methylheptyl)-5,6-dihydro-2H-pyran-2-one by 1D and 2D nuclear magnetic resonance (NMR) data and mass spectrometry (MS). The other three active compounds belong to the cyclodipeptide, and their half maximal inhibitory concentration (IC₅₀) values against A. solani were 43.4, 42.9, and 30.6 μg/mL, respectively. Compound 4 significantly inhibited the spore germination and induced swollen and deformed local hyphae of A. solani with an IC₅₀ value of 24.9 μg/mL. Compound 4 also had broad-spectrum antifungal activity and had a good antifungal effect on the tested plant-pathogenic fungi. The modes of action of new compound (4) still require further investigation, representing a novel and effective anti-fungal agent for future application.     

Highly efficient heterogeneous procedure for the synthesis of fructone fragrancy

A novel heterogeneous strong acid catalyst was synthesized through the copolymerization of p-toluenesulfonic acid and paraformaldehyde and utilized for the synthesis of fructone. The results showed that the catalyst was very efficient for the reaction with the yield over 95%. The advantages of extremely high density of acidity, high thermal and chemical stability, low cost for the simple synthetic procedure, and reusability made the catalyst one of the best choices for the reaction.     

含有2,4-二卤代联苯基的新型唑类衍生物的合成及其抗真菌活性

以2,4-二卤代联苯为原料,经傅-克酰基化、还原、取代等反应步骤,合成了含有2,4-二卤代联苯基的新型唑类目标化合物3a~3k,其结构用红外光谱(IR)、高分辨质谱(HMRS)、核磁共振氢谱(¹H NMR)、核磁共振碳谱(¹³C NMR)等技术手段进行了表征。 测试了目标化合物的体外抗真菌活性,结果表明,所有目标化合物对所测试的致病真菌均有一定程度的抗真菌活性。 其中化合物3a~3k对红色发癣菌和石膏样毛癣菌的抗真菌活性和两性霉素B相当,化合物3b、3c、3e、3f、3h、3i、3k对白色念珠菌的抗真菌活性优于或等于酮康唑。     

氧化钙和氟化钾负载高岭土固体碱催化制备新型生物柴油

以高岭土为载体,利用浸渍法制备了氧化钙和氟化钾负载高岭土固体碱(GCK);利用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、红外光谱(FT-IR)和哈密特指示剂法等技术手段对催化剂进行表征;考察了KF负载量和反应条件对月桂酸甲酯(ML)与乙二醇单甲醚(EGME)酯交换反应制备新型生物柴油产率的影响。 结果表明,GCK碱强度(H_)在7.2~18.4之间,KCaF₃为主要活性组分,当氟化钾负载量为25%、EGME与ML摩尔比3.0、催化剂用量相对于ML的质量分数为4.5 %、120 ℃下反应2 h,新型生物柴油的收率高达97.1%。 最后对催化剂的重复利用性能进行了考察。     

Synthesis and Crystal Structure of a Novel Manganese Coordination Polymer： 2,5-Bis（4-pyridyl）-3,4-diaza-2,4-hexadiene

A new manganese coordination polymer 1, [Mn(H2O)4(L)]n(ClO4)2n·2nH2O·3nL (L = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene), has been synthesized and structurally characterized. The crystal structure was determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group Pn with a = 13.9176(8), b = 15.4754(9), c = 15.9670(9) , β = 99.5010(10)o, V = 3391.8(3) 3, Z = 2, C56H68Cl2MnN16O14 , Mr = 1315.10, Dc = 1.288 g/cm3, μ = 0.344 mm-1, F(000) = 1374, R = 0.0733 and wR = 0.2035. In the crystal the manganese atom is six-coordinated by two nitrogen atoms from 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene and four oxygen atoms from water molecules, completing an octahedral geometry. The title complex exhibits a novel supramolecular layer architecture sustained by the concurrence of coordination bonds, hydrogen bonds, and π-π stacking interactions.     

New lactoyl glycoside quercetin from <Emphasis Type="Italic">Melia azedarach</Emphasis> leaves

In the course of phytochemical investigations of Melia azedarach leaves, a novel cinnamoyl glycoside, cinnamoyl-1-α-L-rhamnoside (1), and a novel acylated quercetin triglycoside, quercetin-3-O-[rhamnosyl 1→6(4″-lactoyl glucoside)]-4′-O-glucoside (2), have been isolated and characterized on the basis of spectroscopic methods, together with the six known flavonoid compounds kaempferol-3-O-rutinoside, 3-O-rhamnoside, quercetin-3-O-rutinoside, 3-O-rhamnoside, and the aglycones quercetin and kaempferol. All isolated compounds have been evaluated for their structures by chromatographic methods, chemical degradation, and UV and NMR spectroscopy. The antioxidant activity of the extract was studied as well. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 12–14, January–February, 2008.     

Existence of heteroclinic orbits in a novel three-order dynamical system

In this paper,we design a novel three-order autonomous system.Numerical simulations reveal the complex chaotic behaviors of the system.By applying the undetermined coefficient method,we find a heteroclinic orbit in the system.As a result,the Si’lnikov criterion along with some other given conditions guarantees that the system has both Smale horseshoes and chaos of horseshoe type.