Preparation, characterization and antifungal properties of 2-(alpha-arylamino phosphonate)-chitosan

In this paper, 20 kinds of different 2-(alpha-arylamino phosphonate)-chitosan (2-alpha-AAPCS) were prepared by different Schiff bases of chitosan (CS) reacted with di-alkyl phosphite in benzene solution. The structures of the derivatives (2-alpha-AAPCS) were characterized by FT-IR spectroscopy and elemental analysis. In addition, the antifungal activities of the derivatives against four kinds of fungi were evaluated in the experiment. The results indicated that all the prepared 2-alpha-AAPCS had a significant inhibiting effect on the investigated fungi when the derivatives concentration ranged from 50 to 500 mu g mL(-1). Furthermore, the antifungal activities of the derivatives increased with increasing the molecular weight and concentration. And the antifungal activities of the derivatives were affected by their dimensional effect and charge density. Besides, the rule and mechanism of the antifungal activities of them were discussed in this paper. (C) 2009 Elsevier B.V. All rights reserved.

Synthesis and antifungal properties of sulfanilamide derivatives of chitosan

Sulfanilamide derivatives of chitosan (2-(4-acetamido-2-sulfanimide)-chitosan (HSACS, LSACS), 2-(4-acetamido-2-sulfanimide)-6-sulfo-chitosan (HSACSS, LSACSS) and 2-(4-acetamido-2-sulfanimide)-6-carboxymethyl-chitosan (HSACMCS, LSACMCS)) were prepared using different molecular weights of chitosan (CS), carboxymethyl chitosan (CMCS) and chitosan sulfates (CSS) reacted with 4-acetamidobenzene sulfonyl chloride in dimethylsulfoxide solution. The structures of the derivatives were characterized by FT-IR spectroscopy and elemental analysis, which showed that the substitution degree of sulfanilamide group of HSACS, HSACSS, HSACMCS, LSACS, LSACSS and LSACMCS were 0.623, 0.492, 0.515, 0.576, 0.463 and 0.477, respectively. The solubility of the derivatives (pH < 7.5) was higher than that of chitosan (pH < 6.5). The antifungal activities of the derivatives against Aiternaria solani and Phomopsis asparagi were evaluated based on the method of Jasso et al. in the experiment. The results indicated that all the prepared sulfanilamide derivatives had a significant inhibiting effect on the investigated fungi in the polymer concentration range from 50 to 500 mu g mL(-1). The antifungal activities of the derivatives increased with increasing the molecular weight, concentration or the substitution degree. The sulfanilamide derivatives of CS, CMCS and CSS show stronger antifungal activities than CS, CMCS and CSS. (C) 2007 Elsevier Ltd. All rights reserved.

Synthesis of acyl thiourea derivatives of chitosan and their antimicrobial activities in vitro

Three different acyl thiourea derivatives of chitosan (CS) were synthesized and their structures were characterized by FT-IR spectroscopy and elemental analysis. The antimicrobial behaviors of CS and its derivatives against four species of bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Sarcina) and four crop-threatening pathogenic fungi (Alternaria solani, Fusarium oxysporum f. sp. vasinfectum, Colletotrichum gloeosporioides (Penz.) Saec, and Phyllisticta zingiberi) were investigated. The results indicated that the antimicrobial activities of the acyl thiourea derivatives are much better than that of the parent CS. The minimum value of MIC and MBC of the derivatives against E coli was 15.62 and 62.49 mu g/mL, respectively. All of the acyl thiourea derivatives had a significant inhibitory effect on the fungi in concentrations of 50 - 500 mu g/mL; the maximum inhibitory index was 66.67%. The antifungal activities of the chloracetyl thiourea derivatives of CS are noticeably higher than the acetyl and benzoyl thiourea derivatives. The degree of grafting of the acyl thiourea group in the derivatives was related to antifungal activity; higher substitution resulted in stronger antifungal activity. (c) 2007 Elsevier Ltd. All rights reserved.

The preparation and antioxidant activity of 2-[phenylhydrazine (or hydrazine)-thiosemicarbazone]-chitosan

Chitosan (CS) with two different molecular weight were modified by reacting with methyl hydrazine-dithiocarboxylate and methyl phenylhydrazine-dithiocarboxylate to give 2-(hydrazine-thiosemicarbazone)-chitosan (2-HTCHCS, 2-HTCLCS) and 2-(phenylhydrazine-thiosemicarbazone)chitosan (2-PHTCHCS, 2-PHTCLCS). The structure of the derivatives was characterized by FT-IR spectroscopy and elemental analysis. The antioxidant activities of the derivatives were investigated employing various established systems, such as hydroxyl radical (*OH)/superoxide anion (O-2(center dot-)) scavenging/reducing power and chelating activity. All of the derivatives showed strong scavenging activity on hydroxyl radical than chitosan and ascorbic acid (Vc), and IC50 of 2-HTCHCS, 2-HTCLCS, 2-PHTCHCS and 2-PHTCLCS was 0.362, 0.263, 0.531 and 0.336 mg/mL respectively. The inhibitory activities of the derivatives toward superoxide radical by the PMS-NADH system were strong. The results showed that the superoxide radical scavenging effect of 2-[phenylhydrazine (or hydrazine)-thiosemicarbazone]-chitosan were higher than that of chitosan. The derivatives had obviously reducing power and chelating activity. The data obtained from vitro models clearly establish the antioxidant potency of 2-[phenylhydrazine (or hydrazine)-thiosemicarbazone]-chitosan. (C) 2010 Elsevier B.V. All rights reserved.

Synthesis and Bioactivity of Novel Benzisothiazolone Derivatives as Potential Microbiocides

Novel microbiocides 2-(hydroxymethyl)benzo[d)isothiazol-3(2H)-one (7) and (3-oxobenzo[d]isothiazol-2(3H)-yl)methyl benzencarboxylates (11a-c) were synthesized in good yields, and their structures were characterized by means of H-1 NMR, MS, and elemental analysis. The new compounds were tested preliminarily in laboratory assays against the aquicolous bacteria including Escherichia coli, Staphyloccus aurueus, Vibrio alginolyticus, Aeromonas hydrophila, and Bacillus subtilis. The results show all the synthesized compounds have good antimicrobial activity. The antimicrobial activity of all the tested compounds against all test bacteria is >96.6% at the concentration of 10(-2) mg mL(-1). These compounds can be further developed for effective microbiocides in the future.

Synthesis, structure and biological activities of 2-(4-methoxybenzoyl)-N-phenyl-2-(1,2,4-triazol-1-yl)thioacetamide

The title compound, 2-(methoxybenzoyl)-N-phenyt-2-(1,2,4-triazol-1-yl)thioacetamide was synthesized by several reactions from 4-methoxyacetophenone, triazole and phenyl isothiocyanate. The structure was identified by elemental analysis, H-1 NMR, MS and IR. The single crystal structure of 2-(methoxybenzoyl)-N-phenyl-2-(1,2,4-triazol-1-yl)thioacetamide was determined with X-ray diffraction. The preliminary bioassays show that the title compound exhibits weak antifungal activities and plant-growth regulatory activity.

Structure and biological activities of 2-(1,3-dithiolan-2-ylidene)-1-phenyl-2-(1,2,4-triazol-1-yl) ethanone

In order to find leading compounds with an excellent fungicidal activity, the tide compound 2-(1,3-dithiolan-2-yl-idene) -1-phenyl-2-(1,2,4-triazol-1-yl) ethanone was synthesized according to the biological isosterism and its structure was confirmed by means of IR, MS, H-1 NMR and elemental analysis. The single crystal structure of the tide compound was determined by X-ray diffraction. The preliminary biological test shows that the synthesized compound exhibits some biological activities.

Studies on synthesis, structure and biological activities of novel triazole compounds containing thioamide

Four novel triazole compounds containing thioamide group were designed and synthesized by using triazole, phenyl isothiocyanate and aryl ethyl ketone as raw material. Their structures were conformed by elemental analysis, H-1 NMR, IR and MS spectra. The crystal structure of 1-[1-anilinothiocarbonyl-1-(4-fluorobenzoyl)methyl]-1,2,4-trizole has been determined by X-ray diffraction analysis. The preliminary bioassays have shown that the title compounds exhibit certain antifungal activity.

Synthesis, crystal structure and biological activities of N '-(4-methoxybenzylidene)-2-(1H-1,2,4-triazol-1-yl) acetohydrazide

The title compound, N'-(4-methoxybenzylidene)-2-(1H-1,2,4-triazol-1-yl)acetohydrazide, was synthesized and its structure was confirmed by means of IR, MS,H-1 NMR and elemental analysis. The single crystal structure of the title compound was determined by X-ray diffraction. The preliminary biological test shows that the synthesized compound has a low antifungal activity.

Unprecedented 5,5-connected (4(7)center dot 6(3)) (4(8)center dot 6(2)) structural topology: A lead biphosphonate with double layered structure

A new lead(II) phosphonate, Pb[(PO3)(2)C(OH)CH3]center dot H2O (1) was hydrothermally synthesized and characterized by IR, elemental analysis, UV, TGA, SEM, and single crystal X-ray diffraction analysis. X-ray crystallographic study showed that complex 1 has a two-dimensional double layered hybrid structure containing interconnected 4- and 12-membered rings and shows an unusual (5,5)-connected (4(7) . 6(3)) (4(8) .6(2)) topology. (C) 2008 Elsevier B.V. All rights reserved.

Synthesis and. crystal structure of N '-(4-fluorobenzylidene)-2-(1H-1,2,4-triazole-1-yl) acetohydrazide

N'-(4-fluorobenzylidene)-2-(1H-1 2,4-triazole-1-yl) acetohydrazide was synthesized by the reaction of 4-fluorobenzaldehyde with 2-(1H-1 2,4-triazole-1-yl) acetohydrazide. The structure was confirmed via elemental analysis, MS, H-1 NMR, IR, and X-ray diffraction. It crystallized in a monoclinic system with space group P2 (1) a = 0.4905 (1) nm, b = 0.8160 (2) nm, c = 1.4105 (3) nm, beta = 93.33 (3)degrees, Z = 2, V = 0.5636 (2) nm(3), D-c = 1.457 Mg/m(3), mu = 0.112 mm(-1), F(000) = 256, and final R-1 = 0.0685. Several intermolecular hydrogen-bond interactions existed in the crystal structure, facilitating the stabilization of the compound.

Synthesis and QSAR studies of novel triazole compounds containing thioamide as potential antifungal agents

Eighteen novel triazole compounds containing thioamide were designed and synthesized. Their structures were confirmed by elemental analysis, H-1 NMR, IR, and MS. The title compounds exhibited certain antifungal activity. And the geometry structures of the title compounds were optimized by means of the density functional theory (DFT) method at B3LYP/6-31G* level. The quantitative structure-activity relationship (QSAR) of the title compounds was systematically investigated. A correlative equation between FA and DELH, V was well established by using the multiple linear regression (MLR). (c) 2006 Elsevier Ltd. All rights reserved.

Hydrothermal synthesis and crystal structure of cluster compound {[Ni(enMe)(2)][SiW12O40]}[Ni(enMe)(2)(H2O)(2)](2) center dot 3H(2)O

the novel One-dimensional chain structure of the title cluster compound was synthesized and characterized by elemental analysis, IR spectra, TGA and X-ray single-crystal diffraction. The title cluster compound crystallized in a monochnic system with space group C2/c, a = 1.2656 nm, b = 2.20656 (4) nm, c =2.26763 (4) nm, beta = 92.078 degrees, V = 6.32852 (16) nm(3), Z = 4, D-c = 3.801 g/cm(3), A = 2.271 mm(-1), F(000) = 6512, R-1= 0.0549, wR(2) = 0.1087. The structure building block of the structure is the polyanion [SiW12O40](6-) with alpha-Keggin structure. The clusters were linked together with one-dimensional infinite chain through [ Ni ( enMe) (2)] (2+) cations. The [ Ni ( enMe) (2) ( H2O) (2)] (2+) cations and water molecules were filled in the structure. The cluster compound was expanded to three-dimensional framework by hydrogen bond interactions among molecules.

Crystal structure and DFT studies of a triazole derivative: 4-(2-hydrobenzylideneamino)-3-(1,2,4-triazol-4-yl-methyl) 1H-1,2,4-triazole-5 (4H)-thione

A novel triazole derivative 4-(2-hydrobenzylideneamino)-3-(1, 2, 4-triazol-4-ylmethyl)-1H-1, 2, 4-triazole-5 (4H)-thione(1) was synthesized and characterized using elemental analysis, MR, and H-1 NMR, and its crystal structure was determined via X-ray single crystal diffraction analysis. Crystal data: monoclinic, P2 (1)/c, a = 0.83335 (9) nm, b = 1. 49777 (16) run, c = 1. 14724 (12) nm, beta = 107. 990 (2)degrees, D = 1. 470 Mg/m(3), and Z = 4. The geometries and the vibrational frequencies were determined using the density functional theory(DFT) method at the B3LYP/6-31G* level. To demonstrate the accuracy of the reaction route of compound 1, one of the important intermediates was also tested using the same method. The structural parameters of the two compounds calculated using the DFT study are close to those of the crystals, and the harmonic vibrations of the two compounds computed via the DFT method are in good agreement with those in the observed IR spectral data. The thermodynamic properties of the title compound were calculated, and the compound shows a good structural stability at normal temperature. The test results of biological activities show that it has a certain bactericidal ability.

A novel silica-based column packing for reversed-phase HPLC of basic compounds

A novel bonded phase for reversed-phase HPLC was synthesized in two steps. Octylamine was first reacted with beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (beta -ECTS) and then the intermediate product was coupled onto porous silica. The prepared packing was characterized by elemental analysis, solid-state C-13 NMR and Fourier transform infrared (FT-IR). Chromatographic evaluations were carried out by using a mixture of organic compounds including acidic, basic and neutral analytes and methanol-water as binary mobile phase. The results showed that the stationary phase has excellent chromatographic properties and is resistant to hydrolysis between pH = 2 similar to 8. It can be used efficiently for the separation of basic compounds.