Two new ceramides from <Emphasis Type="Italic">Zephyranthes candida</Emphasis>

Two new ceramides were isolated from the bulbs of Zephyranthes candida. Their structures were established as (2S,3S,4R,13E)-1,3,4-trihydroxy-2-[(2′R)-2′-hydroxytetracosanoylamino]-13-octadecene, named zephyranamide A (1) and (2S,3S,4R)-1,3,4-trihydroxy-2-octacosanoylaminohexadecene, named zephyranamide B (2). The structures of the new compounds were elucidated by spectral techniques including ¹H NMR, ¹³C NMR, as well as HSQC, HMBC, DEPT, and COSY.     

A new kaempferol trioside from <Emphasis Type="Italic">Farsetia aegyptia</Emphasis>

A new kaempferol trioside, kaempferol-3-O-(2″-α-L-arabinopyranosyl)-α-L-rhamnopyranoside-7-O-α-L-rhamnopyranoside, along with eight known flavonoid compounds were isolated from the methanolic extract of Farsetia aegyptia Turra. growing in Egypt. The structures were established on the basis of detailed spectral analysis (UV, ¹H NMR, ¹³C NMR, APT, HMBC, FABMS, and EIMS).     

A new minor diketopiperazine from the sponge-derived fungus Simplicillium sp. YZ-11

Chemical investigation of the cultures of a sponge-derived fungus Simplicillium sp. YZ-11 led to the isolation of a new minor diketopiperazine alkaloid cyclo-(2-hydroxy-Pro-Gly) (1) and a natural lactone (S)-dihydro-5-[(S)- hydroxyphenylmethyl]-2(3H)-furanone (2), together with five known ergostane-type sterols (3–7). Their structures were established based on extensive spectroscopic methods (¹H and ¹³C NMR, ¹H-¹H COSY, HSQC and HMBC) and optical rotation analysis.     

Synthesis and antimicrobial studies of new pyridine derivatives

2-(p-Acetylaminobenzenesulfonylamido)-substituted benzothiazoles were prepared from 2-amino-substituted benzothiazoles and p-acetamidobenzenesulfonyl chloride using a mixture of pyridine and Ac₂O, which formed an electrophilic N-acetyl- pyridinium complex facilitating condensation to give the desired products by removal of HCl. 2-[4-(Substituted benzothiazol-2-yl)aminosulfonylanilino]pyridine-3-carboxylic acids (synthesized from 2-chloropyridine-3-carboxylic acid and the corresponding substituted 2-(p-aminobenzenesulfonylamido)benzothiazole in 2-ethoxyethanol using Cu-powder and K₂CO₃) were then converted to acid chlorides, which on further reaction with piperazine and 4-methoxyphenylpiperazine yielded the corresponding 2-[4-(substituted benzothiazol-2-yl)amino-sulfonyl]anilino-3-(piperazinocarbonyl) pyridine and 2-[4-(substituted benzothiazol-2-yl)amino-sulfonyl]anilino-3-[(4-methoxyphenyl)piperazin-1-yl-carbonyl]pyridine. The structures of the new compounds have been established on the basis of their elemental analyses as well as IR, ¹H NMR, and mass-spectral data. All the compounds have been screened for antimicrobial activity and found to possess considerable antibacterial activity.     

New octahedral Zn<Superscript>II</Superscript> and Cd<Superscript>II</Superscript> complexes based on azo derivatives and azomethines of pyrazole-5-thione

New metal chelates of Zn^II and Cd^II (ML₂) based on (4Z)-3-methyl-1- phenyl-5-thioxo-1,5-dihydro-4-H-pyrazol-4-one quinolin-8-ylhydrazone (HL¹) and (4Z)-5- methyl-2-phenyl-4-[(quinolin-8-ylimino)methyl]-2,4-dihydro-3H-pyrazole-3-thione (HL²) were synthesized. The structures of the metal chelates were studied by EXAFS and NMR (¹H, ¹³C, and ¹¹¹Cd) spectroscopy. The structure of the Cd(L¹)₂ complex was established by X-ray diffraction analysis. The complexes have pseudooctahedral structures with the N₄S₂ ligand environment.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 623–629, March, 2005.     

Two new compounds from Zingiber officinale

A new cyclic diarylheptanoid,1,5-epoxy-3-hydroxy-1-(3-methoxy-4,5-dihydroxyphenyl)-7-(4-hydroxyphenyl)-heptane (1),as well as a new monoterpene,10-O-β-D-glucopyranosyl-hydroxy cineole (2) were isolated from the rhizomes of Zingiber officinale. The structures of compounds 1 and 2 were established based on their spectral data.In addition,the antioxidant activities of these compounds were also measured.     

Syntheses and characterization of new (2S)-2-hydroxy-1,4-oxazin-3-ones derived from β-aminoalcohols

The reactions of methyl glyoxylate hemiacetal 1 with 2-(methylamino)ethanol 2 , (1R,2S)-(–)-ephedrine 3 and (1S,2S)-(+)-pseudoephedrine 4 provide the (2S)-2-hydroxy-1,4-oxazin-3-ones 2a , 3a , 4a in good yield. They were characterized by ¹H, ¹³C, NMR, and infrared and mass spectroscopy. The structures of 2a and 3a were established by X-ray diffraction. The configuration of C₂ (S) is demonstrated by ¹H NMR data and confirmed for compounds 2a and 3a by single-crystal X-ray diffraction studies. © John Wiley & Sons, Inc.     

A new biscoumarin and other constituents from <Emphasis Type="Italic">Guazuma tomentosa</Emphasis> ROOTS

A new dicoumarol, 3,3′-methylenebis(4,6-dihydroxycoumarin) (1), along with the known metabolites, β-sitosteryl stearate (2), n-tetracosanoic acid (3), friedelin (4), friedel-1-en-3-one (5), β-sitosterol (6), 29-norcycloartanol (7), oleanolic acid (8), 3-O-acetyloleanolic acid (9), 6-methoxy-7,8-methylenedioxy coumarin (10), and methyl-3-acetyloleanolate (11), were isolated from the roots of Guazuma tomentosa. The structures of these compounds were established on the basis of spectroscopic (IR, ¹H, ¹³C NMR, and mass) studies.     

A new chromene glycoside from <Emphasis Type="Italic">Tithonia diversifolia</Emphasis>

A new chromene glycoside, 6-acetyl-2,2-dimethylchromene-8-O-β-D-glucoside, together with four known compounds were isolated from the aerial parts of Tithonia diversifolia. Their structures were established by ¹H, ¹³C NMR, and HMQC together with the other physical and chemical investigations.     

Synthesis and stereochemistry of new spiranes containing 2,5-cyclohexadiene and 2,3,3a,6,7,7a-hexahydrobenzofuranone fragments

The reaction of 4-dihalomethyl-4-methyl-2,5-cyclohexadien-1-ones with (Me₃Si)₂NNa yielded spiro[(2,3,3a,6,7, 7a-hexahydro-3, 3-dihalo-3a-methylbenzofuran-6-one)-2, 1′-(4′-dihalomethyl-4′-methyl-2′, 5′-cyclohexadienes)]. The structures of the spiro compounds were established based on the data of¹H and¹³C NMR, UV, and IR spectroscopy and mass spectrometry. The mechanism and stereochemistry of the reaction are discussed.     

A new triterpene glycoside from fruit of <Emphasis Type="Italic">Phytolacca americana</Emphasis>

Glycosides H and I, the structures of which were established by modern physicochemical analytical methods (PMR, ¹³C NMR, COSY, TOCSY, HMBC, MS) and acid-base hydrolysis, were isolated from the purified total saponins from fruit of Phytolacca americana containing at least 10 triterpene glycosides by rechromatography of enriched fractions over a column of silica gel. Glycoside H was a bidesmoside of phytolaccageninic acid, which was isolated earlier from cell culture of Phytolacca acinosa. Glycoside I was 3-O-(β-D-xylopyranosyl-(1 → 3)-β-D-galactopyranosyl-(1 → 3)- β -D-xylopyranosyl)-28-O- β -D-glucopyranosyl phytolaccagenin, which was isolated by us for the first time.     

Synthesis and characterization of biosynthetic polymers based on (2<Emphasis Type="Italic">E</Emphasis>)-3-(4-hydroxy-3-methoxy)-2-phenylpropenoic acid

The polymers obtained by the dehydrogenization enzymatic polymerization of (2E)-3-(4- hydroxy-3-methoxy)-2-phenylpropenoic acid (ferulic acid) in the peroxidase–hydrogen peroxide system were studied by ¹³С NMR and FTIR spectroscopy, elemental analysis, sedimentation diff usion analysis, and viscometry. The amount of the main structure fragments of the macromolecules was established, and comparative analysis of the chemical structures of the polymers was carried out. Differences in the topological structures of macromolecules of the biosynthetic polymers based on ferulic acid were revealed.     

Two new diarylheptanoids isolated from the roots of Juglans mandshurica

Two new diarylheptanoids, ( ? )-threo-3′,4″-epoxy-1-(4-hydroxyphenyl)-7-(3-methoxyphenyl)heptan-2,3-diol (1) and (1α,3β,5α,6α)-1,5-epoxy-3,6-dihydroxy-1,7-bis(3-methoxy-4-hydroxy-phenyl)-heptane (2), along with one known diarylheptanoid, rhoiptelol B (3), were isolated from the roots of Juglans mandshurica. The structures of compounds 1 and 2 were identified based on HR-ESI-MS, 1D and 2D NMR including ¹H–¹H COSY, HMQC, HMBC and NOESY spectroscopic methods.     

One‐pot synthesis of new 3‐substituted coumarins by tandem reactions

The synthesis of new 3‐substituted coumarins appended to imidazolium, pyridinium, 3‐dimethylamino pyridinium, 3‐chloro pyridinium and 3‐bromo pyridinium salts is reported. These salts were prepared by tandem reactions, followed by quantitative anionic metathesis. The structure of these new 3‐substituted coumarins was established by NMR (¹H, ¹³C) and high‐resolution mass spectrometry.     

Two new eudesmanes from <Emphasis Type="Italic">Inula helenium</Emphasis>

Two new eudesmanes, 1α-hydroxy-11,13-dihydroisoalantolactone (1), 3α-hydroxy-11,13dihydroalantolactone (2), and one known compound were isolated from the roots of Inula helenium. Their structures were established on the basis of spectral evidence.     

Bismuth Tri‐ and Tetraarylcarboxylates: Crystal Structures,In Situ X‐ray Diffraction,Intermediates and Luminescence

A systematic investigation of the systems Bi³⁺/carboxylic acid/HNO₃ for the tri‐ and tetracarboxylic acids pyromellitic acid (H₄Pyr), trimellitic acid (H₃Tri) and trimesic acid (H₃BTC) acid led to the discovery of five new bismuth carboxylates. Structural characterisation allowed the influence of the linker geometry and the Bi³⁺:linker molar ratio in the starting solution on the crystal structure to be determined. The crystallisation of three selected compounds was investigated by in situ energy‐dispersive X‐ray diffraction. Three new crystalline intermediates were observed within minutes, and two of them could be isolated by quenching of the reaction mixture. Their crystal structures were determined from laboratory and synchrotron X‐ray powder diffraction data and allowed a possible reaction pathway to be established. In depth characterisation of the luminescence properties of the three bismuth pyromellate compounds was carried out. Fluorescence and phosphorescence could be assigned to (mainly) ligand‐ and metal‐based transitions. The polymorphs of Bi(HPyr) exhibit different luminescence properties, although their structures are very similar. Surprisingly, doping of the three host structures with Eu³⁺ and Tb³⁺ ions was only successful for one of the polymorphs.     

Two new xanthones from the pericarp of Garcinia mangostana

Two new xanthones, designated garcimangosxanthone F (1) and garcimangosxanthone G (2), were isolated from the EtOAc-soluble fraction of ethanolic extract from the pericarp of Garcinia mangostana. Their structures were established as 1,6,7-trihydroxy-5-(3-methylbut-2-enyl)-8-(3-hydroxy-3-methylbutyl)-6′,6′-dimethylpyrano[2′,3′:3,2]xanthone and 1,6,7-trihydroxy-5-(3-methylbut-2-enyl)-8-(3-hydroxy-3-methylbutyl)-6′,6′-dimethyl-4′,5′-dihydropyrano[2′,3′:3,2]xanthone, respectively, on the basis of their 1D, 2D NMR and MS data interpretation.     

Structure elucidation,complete NMR assignment and PM5 theoretical studies of new hydroxy‐aminoalkyl‐α,β‐unsaturated derivatives of the macrolide antibiotic josamycin

Four new hydroxy‐aminoalkyl derivatives of α,β‐unsaturated macrolide‐josamycin (2–5) have been synthesised and their structures have been studied by means of ¹H and ¹³C NMR and FT‐IR methods. Complete assignment of resonances in the ¹H and ¹³C NMR spectra has been made on the basis of ¹H? ¹³C HSQC, ¹H? ¹³C HMBC, ¹H? ¹H COSY, ¹H? ¹H NOESY 2D experiments. Spectroscopic data indicated that for the derivatives 3 and 4 some equilibrium between two different structures exists in contrast to derivatives 2 and 5. The lowest‐energy structures of the new derivatives of josamycin have been calculated and visualised by PM5 method at semi‐empirical level of theory, taking into account the NMR and FT‐IR data. The most significant differences between the structures of josamycin and its newly synthesised derivatives' were found in the conformation of the macrolide aglycone part and in the mutual orientation of the 4‐O‐isovalerylmycarosylmycaminose moiety relative to the aglycone part. PM5 semi‐empirical calculations indicated that the structures of the new macrolide derivatives are stabilised by rather weak intramolecular hydrogen bonds in agreement with spectroscopic data. Antimicrobial properties of the new derivatives 2–5 as well as those having an acetate group at C‐3 (6 and 7) were determined and compared to that of the parent macrolide antibiotic josamycin (1). Copyright © 2010 John Wiley & Sons, Ltd.     

Design,Synthesis, Characterization,and Antimicrobial Evaluation of Novel 2‐(3, 5‐di methoxy‐4‐((1‐aryl‐1H‐1, 2, 3‐triazole‐4‐yl) methoxy) phenyl) benzo[d]thiazoles

A series of 12 new 2‐(3, 5‐dimethoxy‐4‐((1‐Aryl‐4H‐1, 2, 3‐triazol‐4‐yl) methoxy) phenyl) benzo[d]thiazoles have been synthesized from the reaction of 4‐hydroxy‐3, 5‐dimethoxybenzaldehyde, o‐amino thiophenol, propargyl bromide, and different substituted aromatic azides using “click chemistry”. The structures of these compounds were established on the basis of Fourier Transform infrared, ¹H NMR, ¹³C–NMR, and mass spectral analysis. Compounds ( 6a–l ) were screened for in vitro antimicrobial activity.     

Synthesis and characterization of new thiadiazole derivatives bearing a pyrazole moiety

A series of thidiazole derivatives (4, 7) from pyrazole-3-carboxylic acid chloride (2) and pyrazole-3,4-dicarboxylic acid chloride derivatives (6) were synthesized and characterized. The structures of the new compounds were confirmed byelemental analysis, NMR (¹H and ¹³C) and IR spectra. The molecular and crystal structure of 4-benzoyl-N-[5-(methylthio)-1,3,4-thiadiazol-2-yl]-1,5-di-phenyl-1H-pyrazole-3-carboxamide(4d)was determined by single crystal X-ray diffraction method.