The conformers of push–pull 3-[(2,2-dimethylhydrazinyl)methylene]-pentane-2,4-dione (CH3)2NNHCHC(COCH3)2 (DMHMP) have been studied experimentally by NMR and vibrational spectroscopy and theoretically by ab initio calculations at MP2 and DFT B3LYP levels in various basis sets. The NMR spectra were obtained in chloroform and dimethylsulfoxide and the IR and Raman spectra of DMHMP as a solid and as a solute in various less and more polar solvents at room temperature have been recorded.DMHMP was prepared as a pure solid and the data from X-ray analysis revealed that DMHMP exists in solid state as EZa conformer with an intramolecular hydrogen bond. The geometries and relative energies of possible conformers of DMHMP were evaluated at the both levels of theory in several basis sets and compared with the data from X-ray analysis.According to the NMR spectra the studied compound exists as a single entity. On the other hand vibrational spectra revealed that in less polar DMHMP solutions the presence of the second less polar ZZa conformer is possible, whereas in more polar solvent only one EZa conformer is observed. The influence of the environment polarity on this conformational equilibrium is discussed with respect to the SCRF solvent effect calculations using IEFPCM model. The observed IR and Raman bands were compared with calculated MP2/cc-pVTZ harmonic vibrational frequencies and assigned on the basis of potential energy distribution.

The stereoselective synthesis of epi-thieno analogues of the phenanthroquinolizidine bioactive alkaloids (-)-Cryptopleurine and (-)-(15R)-Hydroxycryptopleurine was achieved in five steps starting from easily available enantiopure (S)-2-aminoadipic acid used as chiral pool and nitrogen atom source. During these investigations, both π-cationic cyclization of chiral N-thienylmethyl-6-oxopipecolinic acids into pure (S)-keto-lactams and theirs regioselective and diastereoselective reduction, considered as key steps of this sequence, were studied. Of particular interest, the Friedel-Crafts cyclization using (CF3CO)2O/BF3·Et2O show that near the expected keto-lactams, enamides and enamidones containing trifluoromethyl residue were isolated. A mechanism leading to the latter products with high synthetic potential was discussed.

An NXO building block derived tetrapeptide mimic emulates a natural proline-glycine β-turn/hairpin in polar media, including water at room temperature.

Catalytic hydrogenation of enantiopure furo[3,2-f]indolizin-6(4H)-one 12, furo[3,2-f]-indolizidine 13 and furo[3,2-f]-indolizidin-9-ol 14 accessible in few steps was studied. High diastereoselectivity was obtained with Rh/Al2O3 for 13 and 14 due to haptophilic effect of both OH and CO groups present in these compounds. In addition, the quaternisation of furo-fused compounds and THF-fused derivatives provided ammonium salts in trans- and cis-relationship, respectively.

A new synthetic approach to racemic 3,4-cis- and 3,4-trans-isoxazoldine-4,5-diols and their derivatives is presented. Dihydroxylation reactions of 3-substituted 2,3-dihydroisoxazoles with K(2)OsO(4)2H(2)O in the presence of NMO in acetone-water proceeded from the less hindered side and provided the major 3,4-trans-isoxazolidine-4,5-diols in moderate to good yields. 3,4-cis-5-Methoxyisoxazolidin-4-ol was prepared diastereoselectively from the mixture of 3,4-cis- and 3,4-trans-4-bromo-5-hydroxyisoxazolidines using base-promoted intramolecular cyclization in anhydrous methanol. Representative derivatives of 3,4-cis- and 3,4-trans-5-cyanoisoxazolidin-4-ols are also presented as potentially useful building blocks for the synthesis of various C5-substituted isoxazolidines.

Aroma and flavor profile of MD2 pineapple variety was investigated. Fruits imported from different geographical regions (Costa Rica, Puerto Rico) were labeled as an organic food. Characteristic volatile and non-volatile compounds obtained by hydro-distillation and direct percolation were identified and quantified by gas chromatography-mass spectroscopy (GC/MS). At least 22 components in percolated extract (or 17 in distillate) were detected according to their mass spectra and retention time. Relative concentration of identified substances varied from 547.7 to 1110.0 mu g.kg(-1). Analysis showed dominance of esters and furanone-derived compounds as major aroma constituents. Most abundant volatiles identified in all samples were methyl 2-methylbutanoate and methyl liexatioate. Relationships between volatile and non-volatile compounds were also studied.

Six novel enantiopure epimeric indolizidinediols have been easily prepared in high yields by an effective and well-established regioselective THF ring-opening reaction as a key step. Quarternization of these species was also studied and comparison was made to the quaternizations of other substituted indolizidines. Importantly, a combined theoretical DFT-QTAIM study has cast light on the various factors that explain the observed conformational selectivity. The inhibitory properties of the six synthesized indolizidines were then investigated against the recombinant Golgi a-mannosidase-IIb (dGMIIb) and lysosomal a-mannosidase (dLM408), human homologues of Drosophila melanogaster. Among the tested compounds, two of them, 4a and 4b, exhibited a pH-dependent inhibition of dGMIIb at the milimolar level (IC50 = 3.5 or 1.7 mM at pH 5.8 or 6.5, respectively) without affecting the activity of dLM408.

The present work summarizes results of isolation and identification of polar constituents of the methanolic extract of Ligustrum vulgare L. leaves and of the evaluation of inhibiting activity of selected isolates on rat lung cytosol fraction lipoxygenase. Six different compounds were isolated from the ethylacetate and butanol portions of the methanolic extract (hydroxytyrosol and its glucoside, ligustroflavon, oleuropein, acteoside, echinacoside). The inhibitory activity of oleuropein, echinacoside and the water infusion of Ligustrum vulgare leaves tested on LOX was expressed as IC50. Kinetic parameters (K M, V max) and type of inhibition were determined. As the most effective in competitive inhibition of LOX, oleuropein was proved.

In the course of study of epiphytic microorganisms occurring on the surface of roots of Taxus baccata L. a new strain Streptomyces sp. AC113 was isolated. According to 16S ribosomal DNA‐based identification the new strain is 99% identical with Streptomyces flavidofuscus . This strain cultivated in an arginine glycerol medium produced three major metabolites identified as (–)‐8‐ O ‐methyltetrangomycin ( 1 ), 8‐ O ‐methyltetrangulol ( 2 ) and 8‐ O ‐methyl‐7‐deoxo‐7‐hydroxytetrangomycin ( 3 ). The chemical structures of these angucyclines were elucidated by 1D and 2D NMR as well as by mass spectrometry. Isolated angucycline metabolites showed significant antimicrobial activity against Bacillus cereus and Listeria mocytogenes . Cytotoxic activities of compounds 1 , 2 and 3 against four cell lines (B16, HT‐29 and non – tumor V79, L929) were evaluated. Compound 3 was the most potent anticancer agents with IC 50 0.054 μg/ml against cell line B16. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

New homochiral 6-ethyl-7,8-indolizidinediol derivatives, related to the bioactive dihydroxylated indolizidine alkaloids, are reported to be easily accessible in four or five steps from enantiopure 9-hydroxy-octahydrofuro[3,2-f]indolizin-6(2H)-ones in good overall yields and high diastereomeric purities. The simple procedure used herein involves a regiospecific THF-ring opening as a key step, in addition to the C–Br linkage reduction, and the alcohol deprotection followed by lactam reduction.

Simple and rapid TLC and column chromatographic methods have been established for separation of luteolin-7-rutinoside and luteolin-7-neohesperidoside on polyamide. A flavonoid mixture was isolated from the butanolic fraction of a methanolic extract of leaves of Ligustrum vulgare L. HPLC analysis of the isolated mixture showed the presence of two compounds in a ratio of approximately 1:1. TLC and column separation was achieved on polyamide with CHCl3-MeOH-2-butanone-acetylacetone 9:4:2:1 as mobile phase. After successful separation, the isolated compounds were identified by UV, MS, and NMR spectroscopy and by acid hydrolysis then comparison with authentic samples. Luteolin-7-neohesperidoside was isolated from Ligustrum vulgare L. for the first time.

Enantiopure di- and tetrahydro[1]benzothieno[3,2-f]indolizines 3,4,9 and the benzothieno analogue 5 of the bioactive alkaloid tylophorine 10 were synthesized easily from the readily available benzo[b]thiophene-3-carboxaldehyde 1 and (S)-glutamic acid 2 in good overall yields. Applying a diastereoselective reductive desulfurization of benzo[b]thiophene 3,4 and 5 were readily converted into the enantiopure alcohols 11a–d, alcohols 11c,d and the target 6(R)-phenyl-8a(R)-indolizidine 6 (7 steps, 14%). During these reduction studies, the results obtained including the stereoinduction of the reaction are also discussed.

Chiral tetra- and hexahydro[1]benzothieno[2,3-f]indolizines 3–5, 9, and 11 were synthesized easily from benzo[b]thiophene-2-carboxaldehyde (1) and (S)-glutamic acid (2) in good overall yields and both high enantio- and diastereomeric purities. Applying a diastereoselective reductive desulfurization of benzo[b]thiophene followed by lactam reduction, epimeric alcohols 4a and 4b were readily converted into (7R or S,8aS)-phenylindolizidinols 6a,c. During these studies, the reduction of benzothienoindolizines 3–5, 9, 11, and 12, was investigated and the results obtained are also discussed.

Advanced glycation end products (AGEs) play a key role in the pathogenesis of diabetes and its complications, including the diabetic nephropathy. The renoprotective effects of exercise are well known; however, the mechanisms remain elusive. Here we examined whether a regular moderate exercise in obese Zucker rats (OZR), a model of diabetes- and obesity-associated nephropathy, will affect the development of early renal injury in OZR possibly via alteration of AGEs formation. The OZR were left without exercise (sedentary) or subjected to 10 weeks intermittent treadmill running of moderate intensity. Compared with sedentary OZR, kidneys of running OZR had significantly less glomerular mesangial expansion and tubulointerstitial fibrosis. Running OZR had significantly lower plasma AGEs-associated fluorescence and Nɛ-carboxymethyllysine. Correspondingly, renal AGEs and Nɛ-carboxymethyllysine content were lower in running OZR. Systemically, exercise increased aerobic metabolism, as apparent from urinary metabolite profiling. No differences in plasma glucose, insulin, or lipid profile were found between the 2 groups. Apart from lower advanced oxidation protein products (a marker of myeloperoxidase activity), no other marker of inflammation was altered by exercise, either systemically or locally in kidneys. No indication of changed oxidative status was revealed between the groups. Exercise in OZR decreased advanced glycation. This might represent the early event of exercise-induced renoprotection in diabetic nephropathy in OZR. If confirmed in clinical studies, regular moderate exercise could represent an easy and effective nonpharmacologic approach to reduce advanced glycation.

A concise and very efficient route to enantiopure tetrahydrofuran-fused indolizidinols, which could be considered as protected new indolizidindiols, is described in two-steps sequence starting from the known furoindolizidindiones. The key-step of these transformations was the formation, in one operation, of THF indolizidinols containing a lactam function by simultaneous highly diastereoselective catalytic hydrogenation of the carbonyl function and the furan ring. During these investigations, numerous catalysts in different combinations were tested and the impact of substrates on the reduction profile is discussed.

The behaviour of enaminomalonates and their deprotection to amines under various reductive conditions is described. A new synthetic approach to N-aryl-N-acetyl-β-amino acids using heterogeneous catalytic hydrogenation has been discovered.

Soil phosphorus (P) can exist in various inorganic (Pi) and organic forms (Po). Specific determination of Pi can be obtained by fractionate methods. However, the discrimination between the chemically different forms of Po in soil is not simple. Nowadays, the method of choice for the determination of various soil inorganic and organic P compounds is 31P NMR. In this paper, the determination of various phosphorus forms (available P, total P, Pi and Po fractions) in arable and mountain soils is presented. Besides, the detailed characterisation of P compounds in humic acids (HA) is also shown. The results obtained show that the highest content of the available P can be found in arable soils with a high input of fertilisers, and that the predominant part of Pi is included in hardly soluble fractions, mainly in the soil types with neutral soil reaction. Our data also show the correlation between total P and Po, the dominant form of P in the topsoil of mountain soils. Phosphomonoesters represent the major types of P in HA structure. The correlations between phosphomonoesters of type I and some humification parameters of HA and qualitative parameters of soil organic matter suggest that higher amounts of more recalcitrant monoesters can be found in more mature soil organic matter with a higher humification degree.

The synthesis of three new substituted 4-hetereoaryl-4-oxobut-2-enoic acids with indole ring substitutedin positions 3-, 5- and 7- is described. The addition of these Michael acceptors to 4-(1-phenylsulphonylpyrrol-3-yl)-4-oxobut-2-enoic acid in conjugate addition was explored using both racemic and chiral amines. In tandem with the crystallization-induced asymmetric transformation (CIAT) protocol the effective methodology for the synthesis of enantiomerically highly enriched substituted 2-amino-4-heteroaryl-4-oxobutanoic acids as multifunctional homotryptophan analogues was developed.

ChemInformVolume 35, Issue 24 Heterocyclic Compounds Quinoxalines. Part 3. Synthesis, Properties, and Reactions of 5-Substituted Derivatives of 2,3-Diphenylquinoxaline. Jozef Salon, Jozef Salon Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorViktor Milata, Viktor Milata Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorMiloslav Chudik, Miloslav Chudik Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorNadezda Pronayova, Nadezda Pronayova Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorJan Lesko, Jan Lesko Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorMilan Seman, Milan Seman Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorAnna Belicova, Anna Belicova Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this author Jozef Salon, Jozef Salon Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorViktor Milata, Viktor Milata Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorMiloslav Chudik, Miloslav Chudik Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorNadezda Pronayova, Nadezda Pronayova Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorJan Lesko, Jan Lesko Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorMilan Seman, Milan Seman Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this authorAnna Belicova, Anna Belicova Dep. Org. Chem., Fac. Chem. Technol., Slovak Tech. Univ., SK-812 37 Bratislava, SlovakiaSearch for more papers by this author First published: 19 May 2004 https://doi.org/10.1002/chin.200424145Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume35, Issue24June 15, 2004 RelatedInformation

Catalytic hydrogenation of 5-nitro-2,3-diphenylquinoxaline led to the corresponding amine which, in turn, afforded products of nucleophilic substitution on reaction with alkoxymethylene derivatives. Thermal cyclization of selected alkoxymethylene derivatives yielded substituted pyridoquinoxalines. The conditions for successful hydrolysis of ester, decarboxylation of the acid, following chlorination of pyridone and reductive removal of the chlorine atom from it to produce parental heterocycle 2,3-diphenyl-pyrido[2,3-f]quinoxaline were found. All of the tested products of the nucleophilic substitution showed no antibacterial activity.