Evaluation of Solid Substrates for the Biosynthesis of Cellulase by Trichoderma viride

A series of 4-alkylthio-1,2-dithiolanes were synthesized from S,S′-(2-alkylthiotrimethylene) di(benzenethiosulfonates), and their biological activities were tested on Culex pipience molestus, Laodelphax striatellus and Tetranychus urticae. These compounds showed potent activity against both insect species, the strongest being displayed by 4-ethylthio-1,2-dithiolane and 4-isopropylthio-1,2-dithiolane.     

α-Lipoic Acid,an Organosulfur Biomolecule a Novel Therapeutic Agent for Neurodegenerative Disorders: An Mechanistic Perspective

Neurochemical Research - Lipoic acid (α-LA) (1,2-dithiolane3-pentanoic acid (C8H14O2S2) is also called thioctic acid with an oxidized (disulfide, LA) and a reduced (di-thiol: dihydro-lipoic...     

Control of potato cyst-nematode, Heterodera rostochiensis, in silt and peat loams by ten pesticides applied to the soil at planting time

Incorporated in silt or peat loam top-soil in spring before susceptible potatoes were planted, three carbamoyl oximes, aldicarb, Tirpate (2,4-dimethyl-2-formyl 1-1,3-dithiolane oxime iV-methylcarbamate) and Du Pont 1410 (S-methyl i-(dimethylcarbamoyl)-N-((methylcarbamoyl) oxy) thioformimidate) and one organophosphate, Nemacur (O-ethyl-O-(3-methyl-4-methylthiophenyl)-isopropylamidophosphate) all at n-2 kg a.i./ha greatly increased the yield of tubers and effectively controlled potato cyst-nematode (Heterodera rostochiensis Woll.). At the same dosage thionazin was as effective in the peat loam but was ineffective in the silt loam; phorate and Mocap (O-ethyl S,S-dipropyl phosphorodithioate) were less effective and chlorfenvinphos, diazinon and a coarse granule formulation of fensulphothion were ineffective in controlling potato cyst-nematode.     

Stability and structure of binary and ternary complexes of alpha-lipoate and lipoate derivatives with Mn2+, Cu2+, and Zn2+ in solution.

The stabilities of the 1:1 complexes of Mn²⁺, Cu²⁺, and Zn²⁺ with lipoate and its chainshortened catabolites, viz., bisnorlipoate and tetranorlipoate, were studied by potentiometric titrations in water containing 50% dioxane (I = 0.1, NaClO₄; 25 °C). A comparison of the stabilities of these complexes with those of simple carboxylates reveals that the catabolite complexes formed with Cu²⁺ and Zn²⁺ are more stable than expected from only the basicity of the carboxylate groups. This is evidence that chelates involving the disulfide group are formed. The stability of all Mn²⁺ complexes is determined by the basicity of the carboxylate groups. The same pattern of stability holds for the mixed-ligand complexes formed by Cu²⁺ or Zn²⁺, 2,2′-bipyridyl, and lipoate or one of its derivatives. It is evident that the disulfide group of the 1,2-dithiolane moiety can participate in the formation of binary and ternary complexes. The somewhat less-pronounced coordinating properties of the 1,2-dithiolane moiety compared with the tetrahydrothiophene moiety are discussed. It is apparent that the electron density at S(1) and S(2) in the dithiolane moiety of lipoate is not equivalent: S(1) is favored over S(2) in electrophilic reactions; possible biological implications are indicated.     

Investigation of amino acid containing [FeFe] hydrogenase models concerning pendant base effects

The present investigations deal with the modeling of the peptide surrounding of [FeFe] hydrogenase using amine containing disulphides to simulate possible influences of the amino acid lysine (K237) on the electrochemical and electrocatalytic properties of biomimetic compounds based on [Fe2S2] moieties. Fe₃(CO)₁₂ was reacted with Boc-4-amino-1,2-dithiolane, Boc-Adt-OMe (Adt = 4-amino-1,2-dithiolane-4-carboxylic acid, Boc = tert-butoxycarbonyl) and Boc-Adp tert-butyl ester (Adp = (S)-2-amino-3-(1,2-dithiolan-4-yl)propionic acid) to elongate the FeN distance in comparison to the well known [Fe₂{(SCH₂)₂NR}(CO)₆] model complexes. Efforts to deprotect the complexes containing Boc-4-amino-1,2-dithiolane with trifluoroacetic acid result in the formation of [Fe₃(μ³-O)(μ-O₂C₂F₃)₆(OC₄H₈)₂(H₂O)]. The novel [2Fe2S] complexes are characterized using spectroscopic, electrochemical techniques and X-ray diffraction studies.     

The Structure of Nereistoxin

When treated with Raney nickel, S-bisbenzoyl derivative of dihydronereistoxin gave N,N-dimethylisopropylamine together with dimethylamine. Supported by other evidences, especially on the presence of 1,2-dithiolane ring, this led us to postulate that nereistoxin is 4-N,N-dimethylamino-1,2-dithiolane. The structure was also unequivocally supported by the NMR spectrum. Some additional data on chemical property of nereistoxin and its derivatives were described in succession to the previous paper.     

New manganese complexes with 2-salicyloylhydrazono-1,3-dithiolane ligand and various coordination solvents

The new complexes with 2-salicyloylhydrazono-1,3-dithiolane ligand (H₂L) have been obtained with good yields (≈85%) by reacting manganese (II) acetate tetrahydrate or manganese (II) acetylacetonate with 2-salicyloylhydrazono-1,3-dithiolane ligand in DMF, THF or Py (L′). These compounds have been fully characterized by spectroscopic methods and single crystal X-ray diffraction. In the solid state, supramolecular networks are described and discussed in terms of weak H-bonds and short contacts. The new monomeric complexes will be considered as candidates to obtain polynuclear complexes.     

Mixed SAMs and MALDI-ToF MS: preparation of N-glycosylamine derivative and thioctic acid methyl ester bearing 1,2-dithiolane groups and detection of enzymatic reaction on Au

Herein, we report an enzymatic galactosylation reaction of β-glucopyranosylamide 4 and thioctic acid methyl ester 5 bearing 1,2-dithiolane groups to form a new system of mixed self-assembled monolayers (SAMs) on gold. Characterization of the enzymatic activity was conveniently achieved by mass spectrometry.     

DNA strand scission by the novel antitumor antibiotic leinamycin

Leinamycin is a recently discovered antitumor antibiotic with an unusual 1,3-dioxo-1,2-dithiolane structure. It preferentially inhibits the incorporation of [3H]thymidine into the acid-insoluble fraction of Bacillus subtilis. In vitro, leinamycin causes single-strand cleavage of supercoiled double-helical pBR322 DNA in the presence of thiol cofactors. Scavengers of oxygen radical did not supress the DNA-cleaving activity. Thiol-activated leinamycin binds calf thymus DNA at 4 degrees C and thermal treatment of the leinamycin-DNA adduct released a chemically modified leinamycin from the complex. The lack of cytotoxicity and DNA-cleaving activity for S-deoxyleinamycin indicates that the 1,3-dioxo-1,2-dithiolane moiety is essential for the activity of leinamycin. Thus, the primary cellular target of leinamycin appears to be DNA. It binds DNA and causes single-strand break at low concentrations, which may account for the potent antitumor activity.     

Combined 3D QSAR and molecular docking studies to reveal novel cannabinoid ligands with optimum binding activity

The combination of NMR spectroscopy and molecular modeling studies provided the putative bioactive conformation for the analgesic cannabinoid (CB) ligand (−)-2-(6a,7,10,10a-tetrahydro-6,6,9-trimethylhydroxy-6H-dibenzo[b,d]pyranyl)-2-hexyl 1,3-dithiolane which served as a template in reported three-dimensional quantitative structure–activity relationship (3D QSAR) studies [Durdagi et al., J. Med. Chem. 2007, 50, 2875]. The reported 3D models of the CB1 receptor allowed us to construct a new 3D QSAR model based on theoretical calculations and molecular docking studies. Statistical comparison of the constructed two 3D QSAR studies showed the improvement of the new model. In addition, the new model can explain more effectively the experimental data and thus it can serve more efficiently in the rational drug design of pharmacologically optimized CB analogues.     

Phosphinyliminodithiolane insecticides: Oxidative bioactivation of phosfolan and mephosfolan

2-(Diethoxyphosphinylimino)-1,3-dithiolane (phosfolan) and its 4-methyl analog (mephosfolan) are proinsecticides as determined by microsomal mixed-function oxidase (MFO) activation to potent acetylcholinesterase (AChE) inhibitors. They are similarly activated by peracid oxidation which yields the sulfoxide and sulfone derivatives. The hydrolytically unstable S-oxides are irreversible AChE inhibitors that are 160- to 47,000-fold more potent than phosfolan and mephosfolan. MFO S-oxidation is indicated for both proinsecticides by (a) NADPH-dependent increases in potency as AChE inhibitors to an extent expected of sulfoxides, and (b) formation of the S-oxide hydrolysis product diethyl phosphoramidate.     

Plant peptide hormone phytosulfokine (PSK-alpha): synthesis of new analogues and their biological evaluation.

Phytosulfokine-alpha (PSK-alpha), a sulfated growth factor (H-Tyr(SO3H)-Ile-Tyr(SO3H)-Thr-Gln-OH) universally found in both monocotyledons and dicotyledons, strongly promotes proliferation of plant cells in culture. In our studies on structure/activity relationship in PSK-alpha the synthesis of a series of analogues was performed: [H-D-Tyr(SO3H)1]- (9), [H-Phe(4-SO3H)1]- (10), [H-D-Phe(4-SO3H)1]- (11), [H-Phg(4-SO3H)1]- (12), [H-D-Phg(4-SO3H)1]- (13), H-Phe(4-NHSO2CH3)1]- (14), [H-D-Phe(4-NHSO2CH3)1]- (15), [H-Phe(4-NO2)1]- (16), [H-D-Phe(4-NO2)1]- (17), [H-Phg(4-NO2)1]- (18), [H-D-Phg(4-NO2)1]- (19), [H-Hph(4-NO2)1]- (20), [H-Phg(4-OSO3H)1]- (21), [Phe(4-NO2)3]- (22), [Phg(4-NO2)3]- (23), [Hph(4-NO2)3]- (24), [H-Phe(4-SO3H)1, Phe(4-SO3H)3]- (25) [H-Phe(4-NO2)1, Phe(4-NO2)3]- (26), [H-Phg(4-NO2)1, Phg(4-NO2)3]- (27), [H-Hph(4-NO2)1, Hph(4-NO2)3]- (28) and [Val3]- PSK-alpha (29). For modification of the PSK-alpha peptide chain the novel amino acids and their derivatives were synthesized, such as: H-L-Phg(4-SO3H)-OH (1), H-D-Phg(4-SO3H)-OH (2), Fmoc-Phg(4-SO3H)-OH (3), Fmoc-D-Phg(4-SO3H)-OH (4), Boc-Phg(4-NHSO2CH3)-OH (5), Boc-D-Phg(4-NHSO2CH3)-OH (6) Boc-Phe(4-NHSO2CH3)-OH (7), and Boc-D-Phe(4-NHSO2CH3)-OH (8). Peptides were synthesized by a solid phase method according to the Fmoc procedure on a Wang-resin. Free peptides were released from the resin by 95% TFA in the presence of EDT. All peptides were tested by competitive binding assay to the carrot membrane using 3H-labelled PSK according to the Matsubayashi et al. test.     

The importance of 1,2-dithiolane structure in α-lipoic acid for the downregulation of cell surface β1-integrin expression of human bladder cancer cells

Here, we show that cell surface β1-integrin expression, cell adhesion to fibronectin, migration, and invasion were all significantly inhibited by α-lipoic acid. These effects were not observed when cells were treated with dihydrolipoic acid or caprylic acid. These data reveal that the 1,2-dithiolane structure plays an important role in the action of α-lipoic acid.     

Stability, molecular structures and magnetic properties of dinuclear iron complexes supported by benzoic hydrazide derivative ligands

We report experimental evidences including molecular solid-state structure determinations, magnetic measurements and EPR studies for the formation (in the solid-state) of novel dinuclear (μ-OMe)₂(L)₄ complexes (HL are 2-ylidenhydrazidebenzoic-1,3-dithiolane acid and N′-cyclopentylidene-2-hydroxybenzohydrazide). The two novel dinuclear iron compounds described in the present contribution exhibit antiferromagnetic intra-molecular coupling. Crystal structures of the supporting ligands as well as one mononuclear species have also been determined.     

Phosphinyliminodithiolane insecticides: Novel addition reactions of phosfolan and mephosfolan sulfoxides and sulfones

2-(Diethoxyphosphinylimino)-1,3-dithiolane (phosfolan) and its 4-methyl analog (mephosfolan) are proinsecticides as determined by microsomal mixed-function oxidase (MFO) activation to potent acetylcholinesterase (AChE) inhibitors. They are similarly activated by peracid oxidation which yields the sulfoxide and sulfone derivatives. The hydrolytically unstable S-oxides are irreversible AChE inhibitors that are 160- to 47,000-fold more potent than phosfolan and mephosfolan. MFO S-oxidation is indicated for both proinsecticides by (a) NADPH-dependent increases in potency as AChE inhibitors to an extent expected of sulfoxides, and (b) formation of the S-oxide hydrolysis product diethyl phosphoramidate.     

New antioxidative phenolic glycosides isolated from Kokuto non-centrifuged cane sugar

Nine compounds, 3-hydroxy-4,5-dimethoxyphenyl-beta-D-glucopyranoside (1), beta-D-fructfuranosyl-alpha-D-(6-vanilloyl)-glucopyranoside (2), beta-D-fructfuranosyl-alpha-D-(6-syringyl)-glucopyranoside (3), 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxy-1-(E)-propenyl)-2-methoxyphenoxy]propyl-beta-D-glucopyranoside (4), 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxy-1-(E)-propenyl)-2,6-dimethoxyphenoxy] propyl-beta-D-glucopyranoside (5), dehydrodiconiferyl alcohol-9'-beta-D-glucopyranoside (6), 4-[ethane-2-[3-(4-hydroxy-3-methoxyphenyl)-2-propen]oxy]-2,6-dimethoxyphenyl-beta-D-glucopyranoside (7), 4-[ethane-2-[3-(4-hydroxy-3-methoxyphenyl)-2-propen]oxy]-2-methoxyphenyl-beta-D-glucopyranoside (8), and 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-2-[4-(3-hydroxy-1-(E)-propenyl)-2,6-dimethoxyphenoxy]propyl-beta-D-glucopyranoside (9), were isolated from Kokuto non-centrifuged cane sugar. Their structures were elucidated by spectroscopic evidence, mainly based on the NMR technique. Among them, seven new glycosides were identified. The 2-deoxyribose oxidation method was used to measure their antioxidative activity. All of these compounds showed antioxidative activities.     

Isolation and comparative analysis of multiple isoenzymes of glutathione-S-transferase from the liver of intact rats and rats administered phenobarbital, 3-methylcholanthrene and butylhydroxytoluene

Seven glutathione-S-transferase (GST) isozymes were purified from liver cytosol of intact male Wistar rats: 1-1(A), 1-1(B), 1-2, 2-2, 3-3, 3-4, 4-4. Treatment of rats with butylated hydroxytoluene (BHT) led to the induction of isozymes GST 1-1(A), 1-1(B) (2-fold), 3-3 (3.5-fold) as well as to the appearance of two new isozymes--1-3 and 4-4(A). Phenobarbital (PB) induced isozymes GST 1-1(A), 1-1(B) (2-fold) and 3-3 (1.5-fold). BHT and PB caused an increase in the specific activity of isozymes 1-1(A), 1-1(B), 3-3, 3-4 towards 1-chloro-2.4-dinitrobenzene and 1.2-dichloro-4-nitrobenzene. 3-Methylcholanthrene (MC) induced isozymes 1-2 (1.5-fold), 2-2 (2-fold) and 4-4 (3-fold). A conclusion was drawn that BHT and PB induced the GST subunits 1 and 3, whereas MC--subunits 2 and 4.     

长形肉豆蔻Myristica argentea Warb.化学成分研究(英文)

从长形肉豆蔻Myristica argentea乙醇提取物乙酸乙酯部分分离得到12个化合物,经理化和波谱分析分别鉴定为黄樟醚(1)、甲基丁香酚(2)、异甲基丁香酚(3)、3′-羟基异黄樟醚(4)、7-羟基-3′,4′-亚甲二氧基黄烷(5)、1,4-苯二甲酸二甲酯(6)、内消旋-二氢愈创木脂酸(7)、赤式-1-(4-羟基-3-甲氧基苯基)-4-(3,4-亚甲二氧基苯基)-2,3-二甲基丁烷(8)、赤式-1-(4-羟基-3-甲氧基苯基)-2-(2-甲氧基-4-(1(E)-丙烯基)苯氧基)-丙烷-1-醇(9)、nectandrin B(10)、β-谷甾醇(11)和胡萝卜苷(12)。化合物4~6和8~12为首次自该植物中分离得到,化合物4~6为首次从该属植物中分离得到。     

Synthese von verzweigten zuckern durch 1,4-addition an pyranosid-enone

Methyl (or ethyl) 2,3,6-trideoxy-α-l-glycero-hex-2-enopyranosid-uloses (6 or 7) may react with lithiocopperorganyles under 1,4-addition and introduction of a C-branching at C-2 of the 4-ulose. Similarly, 2-ethoxycarbonyl-2-lithio-1,3-dithiolane (14) reacts under 1,4-addition with 7 to give in high yield 15, which contains a highly functionalized side-chain at C-2. In a series of steps, the branched 2-C-glycoloyl-4-ulose 20 was obtained. All the 1,4-additions proceeded strictly stereoselectively and provided only the product in which the side-chain introduced at C-2 is in the “trans-” position to the anomeric glycosidic group. The addition is controlled by the anomeric group.     

广东土牛膝的化学成分

广东土牛膝为菊科泽兰属植物华泽兰（Eupatorium chinense）的干燥根。从其甲醇提取物中共分离得到11个化合物,其中eupatorinA（1）为一新化合物,经波谱学方法鉴定为（threo）-3-O-acetyl-1-（4-hydroxy-3-methoxyphenyl）-2-[4-（3-hydroxy-1-（E）-propenyl）-2,6-dimethoxyphenoxy]propyl-β-D-glucopy-ranoside。已知化合物分别鉴定为（threo）-3-hydroxy-1-（4-hydroxy-3-methoxyphenyl）-2-[4-（3-hydroxy-1-（E）-propenyl）-2,6-dimethoxyphenox-y]-propyl-β-D-glucopyranoside（2）,ardisiacrispinA（3）,ardisiac-rispinB（4）,euparone（5）,3-（2,3-dihydroxy-isopen-tyl）-4-hydroxyacetophenone（6）,12,13-di-hydroxy-euparin（7）,gymnastone（8）,N-（2′-hydroxy-tetracosanosyl）-2-amino-1,3,4-trihydroxy-octa-dec-8-（E）-ene（9）,stigmasterol（10）和stigmasterol-3-O-β-D-glucopyranoside（11）。化合物2-4为首次从菊科植物,5-8为首次从泽兰属植物中分离得到。