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Peatlands store carbon in the form of dead organic residues. Climate change and human impact impose risks on the sustainability of the peatlands carbon balance due to increased peat decomposition. Here, we investigated molecular changes in the upper peat layers (0-40 cm), inferred from high-resolution vertical depth profiles, from a boreal peatland using two-dimensional H-1-C-13 nuclear magnetic resonance (NMR) spectroscopy, and comparison to delta C-13, delta N-15, and carbon and nitrogen content. Effects of hydrological conditions were investigated at respective sites: natural moist, drainage ditch, and natural dry. The molecular characterization revealed preferential degradation of specific side-chain linkages of xylan-type hemicelluloses within 0-14 cm at all sites, indicating organic matter losses up to 25%. In contrast, the xylan backbone, galactomannan-type hemicelluloses, and cellulose were more resistant to degradation and accumulated at the natural moist and drainage site. delta C-13, delta N-15, and carbon and nitrogen content did not correlate with specific hemicellulose structures but reflected changes in total carbohydrates. Our analysis provides novel insights into peat carbohydrate decomposition and indicates substantial organic matter losses in the acrotelm due to the degradation of specific hemicellulose structures. This suggests that variations in hemicellulose content and structure influence peat stability, which may have important implications with respect to climate change.

WOS: 000489544600002, DNA topoisomerase I regulates DNA topological structure in many cellular metabolic processes and is a validated target for the development of antitumor agents. in this work, a series of novel 2-[(5-(4-(5(6)-substituted-1H-benzimidazol-2-yl)phenyl)-1,3,4-oxadiazol-2-yl)thio]-1-(4-substitutedphenyl)ethan-1-ones (4a-4s) derivatives have been synthesized and evaluated for DNA Topo I inhibition and cytotoxicity. the structures of the compounds (4a-4s) were confirmed by IR, H-1-NMR, C-13-NMR, 2D NMR, and mass spectroscopy. Anticancer activity of these compounds was assessed against two different human cancer cell lines A549 (human lung adenocarcinoma) and HepG2 (human liver cancer cell line), as well as normal mouse embryonic fibroblast cells (NIH3T3). IC50 values of compounds 4a, 4c, and 4f were highest than those exhibited for the reference drug cisplatin. Then, the inhibitory effect of 4a, 4c, and 4f compounds on topoisomerase I enzyme with the relaxation assay was investigated on supercoiled DNA using agarose gel electrophoresis. the Annexin V-FITC assay demonstrated that these compounds induce cell death by apoptosis., Anadolu University Scientific Research Projects CommissionAnadolu University [1602S065], This study was financially supported by Anadolu University Scientific Research Projects Commission, Project no. 1602S065.

Innovative processes for converting carbohydrates to materials and fuels form the basis for profitable bio-based economies of the future. For such innovation, approaches that provide detailed structural information would be desirable to detect uncharted chemistries of carbohydrate conversion. Among the most important value-added products accessible though conversion of biomass is 5-hydroxymethylfurfural (HMF), whose market values strongly depends on the quality of the product. Here, we use high-field in situ NMR spectroscopy to shed light on obscure competing reactions of CrCl3-catalyzed carbohydrate conversion to HMF in water. High-field NMR spectroscopy has enormous prowess in distinguishing isomeric and dehydrated products formed from glucose. Previously unidentified compounds were identified with this approach and include anhydrosugars and a variety of branched and linear mono- and disaccharides. Other identified compounds leverage the understanding of the active catalyst species. In addition to providing mechanistic insight, the approaches and findings described herein help to measure and manage carbon balances and product quality in HMF production.

Polyfunctional N,O,O,N-type ligands such as the oxalyl dihydrazide (ODH) may induce formation of mono- , di-, and polynuclear complexes with natural monoterpene ketones, involving ligand bridging and Oxo- bridging. In this context, a novel chiral dihydrazone is designed through hemi-synthesis process by re- acting oxalyldihydrazide (ODH) with ( s )-carvone, the major compound of caraway’s seeds essential oil. The C = N imine bi-condensation is performed without prior isolation of the natural ( s )-carvone and the resulting ( s )-carvone dihydrazone (s-CHD) is structurally characterized by Single-crystal X-ray diffrac- tion, 2D-NMR spectroscopy and chiral LCMS analysis to confirm the formation of a single pure enan- tiomer. In -vitro cell-based assays were conducted on normal fibroblast (L929) using a presBlue (PB) flu- orescence quantification method of cell-viability and by sulforhodamine B calorimetric cytotoxicity as- says to determine the anti-proliferative effect on four human tumoral lines (NCI-H460, Hela, HepG2 and MCF-7) and normal PLP2. Anti-inflammatory assays were determined through NO production by Maurine LPS-stimulated macrophages (RAW 264.7). The ( s )-CHD has no effect on normal cells viability ( > 88%) and PLP2 (GI50 = 326 ug/mL), while a moderate ( ∼55%) to significant ( ∼63%) antigrowth potential was recorded against HepG2, Hela and MCF-7 tumor cell lines, where RAW 264.7 was feebly sensitive. A molecular docking was performed using Autodock vina software on the protein kinase CK2 and Epi- dermal Growth factor Kinase proteins EGFK and the dock scores allowed to identify significant bind- ing affinities (lower G and Ki values) and potential hydrophilic/hydrophobic interactions with ( s )-CHD comparing to the clinical ellipticine as potential ligands. Molecular docking suggests that ( s )-CHD pos- sesses high affinity towards the kinase domain receptors CK2 and EGFR, being able to bind to the ATP region. Thanks are due to the Research Center Scientific and Technical in Analyzes Physico-Chimiques CRAPC Algerian Directorate for research DGRSDT for the financial support. The authors thanks Fundação para a Ciência e a Tecnologia (FC&T, Lisbon) for financial support through projects PTDC/MEC–ONC/29327/2017 and PTDC/EQU-EQU/32473/2017. We are thankful to NOVA University of Lisbon (FCT/UNL) for the financial support from Erasmus + EU international credit mobility 2017–2019. the laboratory for Green Chemistry LAQV-REQUIMTE FCT/MCTES (UID/QUI/50006/2019) is co-financed by the ERDF and the chemistry department for providing the instruments support. info:eu-repo/semantics/publishedVersion

The title compound, 4,4-bis(hydroxymethyl)-2-phenyl-2-oxazoline 2, a well-known substance, was resynthesized in high yields through a conventional method. The structure of compound 2 was characterized for the first time by a single-crystal X-ray structure determination. The compound was further established through NMR spectroscopy (1D and 2D). In the molecular packing, two molecules of 4,4-bis(hydroxymethyl)-2-phenyl-2-oxazoline interact through H-Bonds to define “dimers” in which phenyl groups interact especially using π…π contact.

International audience; Chemical investigation of the methanol extract of the roots of Lecaniodiscus cupanioides led to the isolation and characterisation of three new sesquiterpene glycosides, named cupanioidesosides A (1), B (2) and C (3), together with one new triterpenoid saponin named lecanioside A (4), Their structures were established by extensive analysis of spectroscopic methods including 1D and 2D NMR techniques (COSY, NOESY, TOCSY, HSQC, and HMBC) and HRESIMS. The four new compounds were evaluated for their antiproliferative activity against the Caco-2 cell line (human epithelial cell line). None of the isolated compounds showed positive activity in our assay. Our findings represent a valuable contribution to the chemotaxonomy Lecaniodiscus genus of the subfamily of Sapindoideae of Sapindaceae family, known to be a rich source of farnesol glycosides.

The compound, 4-[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]-4-methyl-2-phenyl-4,5-dihydrooxazole 2 was prepared in high yield, through nucleophilic substitution reaction of the O-tosyl oxazoline derivative 1, by heating in dimethyl sulfoxide (DMSO) and in presence of KOH as base. The structure of the synthesized compound was established on the basis of NMR spectroscopy (1H, 13C), MS data and elemental analysis.

The hemi-synthesis of chiral imine, benzimidazole and benzodiazepine structures is reported by the condensation of (S)-(&minus, )-perillaldehyde, the major phytochemical of Ammodaucus leucotrichus subsp. leucotrichus essential oil, with different amine derivatives of 2,3-diaminomaleonitrile, o-phenylenediamine and 3-[(2-aminoaryl)amino]dimedone. The reaction proceeds in situ at ambient temperature without prior isolation of the natural (S)-(&minus, )-perillaldehyde. Final products precipitate in the ethanolic reaction medium. 2D NMR and single-crystal X-ray diffraction studies were used to unequivocally characterize the structures in solution and in the solid state, respectively. Chiral HPLC analysis confirms the formation of unique enantiomers and diastereomeric mixtures.

The synthesis, chromatographic isolation, and structure elucidation of &beta, &beta, substituted isomers of dinitro-5,10,15,20-tetraphenylporphyrin complexes are described. meso-Tetraphenyl-porphyrin chelates (CuII, NiII, CoII) upon reaction wit e.g., itric acid (yellow HNO3, d = 1.52, diluted to 25&ndash, 50%) in CHCl3 formed a mixture of nitro-derivatives with combined yields of ca 80%. This nitration (under optimized conditions: 25&ndash, 30% HNO3, 30&ndash, 40 min, r.t.) can be carried out selectively to give mainly &beta, dinitro-compounds in yields of up to 73%. From the above mixtures of five possible regioisomers that can be formed, usually two or three of them were isolated, for which the structures were assigned on the basis of 1H NMR spectra including COSY and NOESY measure-ments. These types of products are attractive starting materials for synthesis of potential anticancer PDT agents with unique structures, being practically unavailable by any other alternative method.

10 páginas.-- 5 figuras.-- 4 tablas.-- 41 referencias, The lignin from Cynara cardunculus stalks was isolated by the classical Björkman method and characterized by pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS), two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR), and derivatization followed by reductive cleavage (DFRC). The milled Cynara lignin (MCyL) was constituted mainly by guaiacyl (G) and syringyl-units(S) (S/G molar ratio of 0.7), with the complete absence of p-hydroxyphenyl (H) units. The 2D-NMR analysis indicated a predominance of alkyl-aryl ether linkages (70 % of all inter unit linkages are β–O–4′) and significant amounts of condensed structures such as phenylcoumarans (β-5′, 14 %), resinols (β-β′, 7 %), spirodienones (β-1′, 5 %), and dibenzodioxocins (5-5′, 4 %). Furthermore, the analyses indicated that the lignin is partially acylated at the γ-OH (12 % acylation) by acetate groups and that acetylation occurs preferentially on syringyl-units. As in other plants, acetylation occurs at the monomer stage, and sinapyl acetate behaves as a real lignin monomer participating in lignification in cardoon stalks. The detailed structural characterization of cardoon lignin reported here will foster the industrial use of this biomass for the production of biofuels and other bio-based chemicals under the lignocellulosic biorefinery. © 2015, Springer Science+Business Media New York., We thank Duarte M. Neiva and Solange Araujo for their contribution during the chemical analysis and Alejandro Rico for his technical support during MCyL isolation. We also thank Dr. Manuel Angulo (CITIUS, University of Seville) for performing the NMR analyses.The research was financed by FEDER through the Operational Program for Competitive Factors of COMPETE, and by the Portuguese Science Foundation (FCT), through a R&D project PTDC/AGR-FOR/3872/2012, and the base funding to the Forest Research Center (CEF) under the PEst-OE/AGR/UI0239/2014 and UID/AGR/00239/2013. This study has also been partially funded by the Spanish project AGL2011-25379 (co-financed by FEDER funds), the CSIC project 2014-40E-097, and the EU-project INDOX (KBBE-2013-7-613549). The first author was funded by FCT through a post-doctoral grant (SFRH/BPD/95385/2013). Jorge Rencoret thanks the CSIC for a JAE-DOC contract of the program "Junta para la Ampliación de Estudios" co-financed by Fondo Social Europeo (FSE).

Chemical analysis of the organic extract of Theonella swinhoei yielded two new tridecadepsipeptides of the theonellapeptolide family, namely sulfinyltheonellapeptolide, characterized by a methylsulfinylacetyl group at the N-terminus, and theonellapeptolide If, the first member of this class of compounds to show four valine residues. The structures of the compounds, isolated along with the known theonellapeptolide Id, were determined by extensive 2D NMR and MS/MS analyses followed by application of Marfey’s method. The isolated peptides exhibited moderate antiproliferative activity against HepG2 cells, a hepatic carcinoma cell line.

Site selectivity, regioselectivity and stereoselectivity of [2 + 3] cycloaddition of 4-trifluoromethylbenzonitrile oxide to polyunsaturated medium size rings including 1,5,9-cyclododecatriene, 11-membered sesquiterpenes, 1,3-cyclooctadiene and 5-vinyl-2-norbornene were examined. Site selectivity was correlated with electron charges of alkenyl carbon atoms. Structure of the products has been established by an extensive application of 1D and 2D 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization mass spectrometry. Some of the obtained products showed moderate fungicidal activities.

15 páginas.-- 4 figuras.-- 4 tablas.-- 63 referencias, The structure of lignin and suberin, and ferulic acid (FA) content in cork from Quercus suber L. were studied. Extractive-free cork (Cork), suberin, desuberized cork (Corksap), and milled-cork lignins (MCL) from Cork and Corksap were isolated. Suberin composition was determined by GC-MS/FID, whereas the polymers structure in Cork, Corksap, and MCL was studied by Py-TMAH and 2D-HSQC-NMR. Suberin contained 94.4% of aliphatics and 3.2% of phenolics, with 90% of ω-hydroxyacids and α,ω-diacids. FA represented 2.7% of the suberin monomers, overwhelmingly esterified to the cork matrix. Py-TMAH revealed significant FA amounts in all samples, with about 3% and 6% in cork and cork lignins, respectively. Py-TMAH and 2D-HSQC-NMR demonstrated that cork lignin is a G-lignin (>96% G units), with a structure dominated by β-O-4′ alkyl-aryl ether linkages (80% and 77% of all linkages in MCL and MCLsap, respectively), followed by phenylcoumarans (18% and 20% in MCL and MCLsap, respectively), and smaller amounts of resinols (ca. 2%) and dibenzodioxocins (1%). HSQC also revealed that cork lignin is heavily acylated (ca. 50%) exclusively at the side-chain γ-position. Ferulates possibly have an important function in the chemical assembly of cork cell walls with a cross-linking role between suberin, lignin and carbohydrates., We acknowledge partial financial support from Instituto Politécnico de Lisboa, Portugal (Research Project IPL 19/2003) and base funding from Fundação para a Ciência e Tecnologia, Portugal (FCT research Unit 702) to Centro de Estudos Florestais (PEstOE/AGR/UI0239/2014). This study was also partially funded by the LIGNOCELL project (AGL2011-25379) from the Spanish MICINN (co-financed by FEDER funds). JR acknowledges the CSIC JAE-Doc contract of the program “Junta para la Ampliaciôn de Estudios” co-financed by the European Social Fund (ESF). We also thank Dr. Manuel Angulo (CITIUS, University of Seville) for performing the NMR analyses

Submitted by Bella Nolasco (bellanolasco@ua.pt) on 2017-07-26T17:27:11Z No. of bitstreams: 1 Actions of Bisnucleophiles on (E)-3-[3-(2-Hydroxyaryl)-3-oxoprop-1-en-1-yl]chromones Versatile Transformations into Oxygen- and Nitrogen-Containing Heterocycles_10.1055s-0035-1560829.pdf: 801432 bytes, checksum: 47e808d7770489d6550eaff756a0e612 (MD5) Approved for entry into archive by Bella Nolasco(bellanolasco@ua.pt) on 2017-07-26T17:27:55Z (GMT) No. of bitstreams: 1 Actions of Bisnucleophiles on (E)-3-[3-(2-Hydroxyaryl)-3-oxoprop-1-en-1-yl]chromones Versatile Transformations into Oxygen- and Nitrogen-Containing Heterocycles_10.1055s-0035-1560829.pdf: 801432 bytes, checksum: 47e808d7770489d6550eaff756a0e612 (MD5) Made available in DSpace on 2017-07-26T17:27:55Z (GMT). No. of bitstreams: 1 Actions of Bisnucleophiles on (E)-3-[3-(2-Hydroxyaryl)-3-oxoprop-1-en-1-yl]chromones Versatile Transformations into Oxygen- and Nitrogen-Containing Heterocycles_10.1055s-0035-1560829.pdf: 801432 bytes, checksum: 47e808d7770489d6550eaff756a0e612 (MD5) Previous issue date: 2016

7 páginas, 3 figuras, 3 tablas., The chemical structure of the milled-wood lignin isolated from Paulownia fortunei wood was investigated. The lignins were characterized by analytical pyrolysis and two-dimensional NMR that indicated a predominance of guaiacyl (G) over syringyl (S) units, and only showed small amounts of p-hydroxyphenyl (H) units, with a H:G:S molar ratio of 1:59:40. The heteronuclear single quantum correlation (HSQC) NMR spectrum gave additional information about the relative abundances of the different inter-unit linkages present in the lignin structure. Paulownia lignin showed a predominance of β-O-4' aryl ether linkages (62% of total side-chains), followed by β-β' resinol-type (12%) and β-5' phenylcoumaran-type structures (11%) and with lower amounts of other condensed structures such as spirodienone (3%) and dibenzodioxocin (2%) structures. The high lignin content (ca. 23% Klason lignin), together with the low S/G ratio and the abundance of condensed (carbon-carbon linked) structures (together with the low abundance of the most labile ether-linked structures) could contribute to the low reactivity of paulownia lignin during alkaline pulping., This study has been funded by the Spanish project AGL2005- 01748 and the BIORENEW EU-Project (NMP2-CT-2006-026456). J.R. thanks the CSIC for an I3P fellowship and G.M. thanks the Spanish MEC for a FPI fellowship.

Molecular switches are used as scaffolds for the construction of controlled molecular rotors. The internal position of the switching entity in the molecule controls the dynamic behaviour of the rotor moiety in the molecule. Six new molecular motors with o-xylyl rotor moieties were prepared on the basis of an overcrowded alkene, and their dynamics were systematically studied by 2D EXSY NMR, Variation of the (hetero-)atoms in the upper and lower halves of the overcrowded alkene allows fine tuning of the rate of rotation of the o-xylyl rotor in the lower half of the molecule. For all rotors it was observed that the rotation barrier for the trans-isomer was higher than that of the corresponding cis-isomer. The results are analyzed and discussed in terms of differences in steric interactions in the presented system. (C) 2009 Elsevier Ltd. All rights reserved.

The natural cyclopeptide FR235222 is a potent HDAC inhibitor displaying relevant multiple anticancer effects and is considered an attractive lead compound for the generation of new and more effective antitumor therapeutics. Recently, we have synthesized a small collection of FR235222 simplified analogues which showed interesting biological activities. These results encouraged us to further explore the structural determinants responsible for the activity of this class of HDAC inhibitors in order to gain guidelines for the rational design of new derivatives with putative higher affinity for this target. In the present paper, we report the results obtained, docking these ligands in the binding pocket of HDLP, an HDAC homologue.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:23:31Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:38:22Z : No. of bitstreams: 1 2-s2.0-43049167095.pdf: 133374 bytes, checksum: b8e3b1d2100628bceea6c15aed6a4ad3 (MD5) Made available in DSpace on 2014-05-27T11:23:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-04-01 Item merged in doublecheck by Felipe Arakaki (fe.arakaki@gmail.com) on 2015-11-13T15:11:02Z Item was identical to item(s): 7720, 69856 at handle(s): http://hdl.handle.net/11449/7917, http://hdl.handle.net/11449/70374 We report the synthesis and total NMR characterization of 5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylic acid-3-[[[(4″- nitrophenoxy)carbonyl]oxy]-methyl]-8-oxo-7-[(2-thienyloxoacetyl)amino] -diphenylmethyl ester-5-dioxide (5), a new cephalosporin derivative. This compound can be used as the carrier of a wide range of drugs containing an amino group. The preparation of the intermediate product, 5-thia-1-azabicyclo[4.2.0] oct-2-ene-2-carboxylic acid-3-[methyl 4-(6-methoxyquinolin-8-ylamino) pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (6), as well as the synthesis of the antimalarial primaquine prodrug 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[methyl 4-(6-methoxyquinolin-8-ylamino)pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl) amino]- 5-dioxide (7) are also described, together with their total 1H- and 13C-NMR assignments. © 2008 by MDPI. Departamento de Fármacos e Medicamentos Faculdade de Ciências Farmacêuticas Universidade Estadual Paulista, CP 502, 14801-902, Araraquara, SP Departamento de Farmácia Faculdade de Ciências Farmacêuticas Universidade de São Paulo, CP 66083, 05389-970, São Paulo, SP Departamento de Química Centro de Ciências Exatas e Tecnológicas Universidade Federal de São Carlos, CP 676, 13565-905, São Carlos, SP Núcleo de Pesquisas em Ciências Exatas e Tecnológicas Universidade de Franca, CP 82, 14404-600, Franca, SP Departamento de Fármacos e Medicamentos Faculdade de Ciências Farmacêuticas Universidade Estadual Paulista, CP 502, 14801-902, Araraquara, SP

The synthesis, extraction and chromogenic properties of calix[4]arenes, carrying phenylazo and amido groups on their upper and lower rims, respectively, are described. Novel azocalix[4]arene amides (1a–d, 2a–d, 3a–d) and some of their telomers (T1a–T1d) have been synthesised and characterised by spectroscopic methods as well as elemental analysis techniques. Compounds 1c and 2b were additionally characterised by two-dimensional nuclear magnetic resonance spectroscopic methods. Some of the compounds were examined by absorption spectra using different solvents. The colour changes of the resulting solutions can be observed by the ‘naked eye’. Metal extraction abilities of compounds have been investigated comparatively. Telomer structures of azocalix[n]arenes exhibited higher extraction rates compared to those of their monomers. Products obtained under this study, especially telomers, can be used in the field of ion-selective electrodes.

Two coordination compounds of palladium(II) with N -allylimidazole ( l ) of the general formula [PdL 4 ]Cl 2 · 3H 2 O ( 1 ) and trans -[PdL 2 Cl 2 ] ( 2 ) have been synthesized. The crystal and molecular structure of complexes 1 and 2 was established by single-crystal X-ray diffraction analysis. The X-ray structural data were supplemented by solid-state 13 C NMR measurements (CP MAS and PASS 2D). The 1D and 2D NMR studies in solution reveal that complex 1 is unstable at room temperature and undergoes reversible decomposition to 2 . The method for how to preserve a complex with four allyl-imidazole ligands in solution is shown.

Leucanthoside A, a new allose-containing triterpenoid saponin (1), was isolated from the aerial parts of Cephalaria leucantha L. Its structure was determined by electrospray ionization mass spectrometry and NMR spectroscopy. Complete assignments of the H-1 and 1 C NMR chemical shifts were achieved by two-dimensional NMR experiments: DQF-COSY, NOESY, TOCSY, HSQC, DINE-HSQC, HMBC, C-13-H-1 2D-J-resolved spectroscopy, and 1,1-ADEQUATE. Copyright (c) 2006 John Wiley & Sons, Ltd.

Controlled intramolecular movement and coupling of motor and rotor functions is exerted by this new molecular device. The rate of rotation of the rotor part of the molecule can be adjusted by alteration of the conformation of the motor part of the molecule. For all states of the motor part, different rates of rotation were measured for the rotor part. Conversion between the four propeller orientations was achieved by irradiation and heating.

1H and 13C NMR spectral data for diethyl 2- and 8-quinolylmethylphosphonates (L) and their palladium(II) dihalide complexes, trans-[PdL2X2] (L = 2-dqmp, 8-dqmp; X = Cl, Br), are presented. The NMR analysis was performed on the basis of one- and two-dimensional homo- and heteronuclear experiments including 1H, 13C, APT, 1H–1H COSY, 1H–13C COSY, HMQC and HMBC techniques. Copyright © 2003 John Wiley & Sons, Ltd.

8 páginas.-- 4 figuras.-- 1 tabla.-- 37 referencias.-- Un archivo en pdf. de datos suplementarios (3 páginas.-- 1 figura.-- 1 tabla), Treatment of high-kappa sisal pulp with Trametes villosa laccase and ferulic acid resulted in strong increases of kappa-number and acid-group content due to biografting of this phenolic acid, as shown by pyrolysis in the presence of tetramethylammonium hydroxide. The coupling linkages were investigated by 2D NMR of the lignin isolated from pulps. The aromatic region of the spectra showed incorporation of the cinnamic molecule, representing ∼4% of the lignin content, that according to the displacement of its olefinic 13Cβ–1Hβ signal to 117.0/6.40 ppm would be C4-etherified. The aliphatic region of the spectra showed that ferulic acid also incorporates as the corresponding β–β′ dilactone (another ∼4% of the total lignin) with characteristic 13Cα–1Hα and 13Cβ–1Hβ correlations at 81.8/5.69 and 47.9/4.19 ppm, respectively. The sisal lignin in the treated pulps was only slightly modified (including a small increase of Cα-oxidized units) revealing that the main effect of the treatment was ferulic acid biografting., This study was supported by the EU projects LIGNODECO (KBBE-2009-3-244362) and PEROXICATS (KBBE-2010-4-265397) and the Spanish projectsAGL2011-25379, CTQ2010-20238-CO3-01, CTQ2012-34109 and BIO2011.26694. J.R. thanks the CSIC for a JAE-DOC contract, cofinanced by Fondo Social Europeo.

12 páginas.-- 6 figuras.-- 5 tablas.-- 27 referencias, Xylan–lignin (XL), glucomannan–lignin (GML) and glucan–lignin (GL) complexes were isolated from spruce wood, hydrolyzed with xylanase or endoglucanase/β-glucosidase, and analyzed by analytical pyrolysis and 2D-NMR. The enzymatic hydrolysis removed most of the polysaccharide moieties in the complexes, and the lignin content and relative abundance of lignin–carbohydrate linkages increased. Analytical pyrolysis confirmed the action of the enzymatic hydrolysis, with strong decreases of levoglucosane and other carbohydrate-derived products. Unexpectedly it also revealed that the hydrolase treatment alters the pattern of lignin breakdown products, resulting in higher amounts of coniferyl alcohol. From the anomeric carbohydrate signals in the 2D-NMR spectra, phenyl glycoside linkages (undetectable in the original complexes) could be identified in the hydrolyzed GML complex. Lower amounts of glucuronosyl and benzyl ether linkages were also observed after the hydrolysis. From the 2D-NMR spectra of the hydrolyzed complexes, it was concluded that the lignin in GML is less condensed than in XL due to its higher content in β-O-4′ ether substructures (62 % of side chains in GML vs 53 % in XL) accompanied by more coniferyl alcohol end units (16 vs 13 %). In contrast, the XL lignin has more pinoresinols (11 vs 6 %) and dibenzodioxocins (9 vs 2 %) than the GML (and both have ~13 % phenylcoumarans and 1 % spirodienones). Direct 2D-NMR analysis of the hydrolyzed GL complex was not possible due to its low solubility. However, after sample acetylation, an even less condensed lignin than in the GML complex was found (with up to 72 % β-O-4′ substructures and only 1 % pinoresinols). The study provides evidence for the existence of structurally different lignins associated to hemicelluloses (xylan and glucomannan) and cellulose in spruce wood and, at the same time, offers information on some of the chemical linkages between the above polymers., This study was supported by the EU projects LIGNODECO (KBBE-2009-3-244362), the ProLignin project of the WoodWisdom-Bioenergy ERA-Net, and the Spanish project AGL 2011-25379. J.R. thanks the CSIC for a JAE-DOC contract, cofinanced by Fondo Social Europeo.

Los investigadores del IRNAS Ana Gutiérrez Suárez, Jorge Rencoret Pazo y José Carlos del Río Andrade han sido galardonados con el premio “Universidad de Sevilla-Bruker 2015″ al mejor artículo científico publicado sobre Resonancia Magnética Nuclear aplicada. El acto de entrega del premio, presidido por el Vicerrector de Investigación, Profesor Julián Martínez Fernández, y el Director General de Bruker Española, empresa patrocinadora de estos premios, Víctor García Pidal, se realizó el día 27 de Octubre de 2015 en el Edificio Celestino Mutis de la Universidad., [Background] Biofuel production from lignocellulosic material is hampered by biomass recalcitrance towards enzymatic hydrolysis due to the compact architecture of the plant cell wall and the presence of lignin. The purpose of this work is to study the ability of an industrially available laccase-mediator system to modify and remove lignin during pretreatment of wood (Eucalyptus globulus) feedstock, thus improving saccharification, and to analyze the chemical modifications produced in the whole material and especially in the recalcitrant lignin moiety., [Results] Up to 50% lignin removal from ground eucalypt wood was attained by pretreatment with recombinant Myceliophthora thermophila laccase and methyl syringate as mediator, followed by alkaline peroxide extraction in a multistage sequence. The lignin removal directly correlated with increases (approximately 40%) in glucose and xylose yields after enzymatic hydrolysis. The pretreatment using laccase alone (without mediator) removed up to 20% of lignin from eucalypt wood. Pyrolysis-gas chromatography/mass spectrometry of the pretreated wood revealed modifications of the lignin polymer, as shown by lignin markers with shortened side chains and increased syringyl-to-guaiacyl ratio. Additional information on the chemical modifications produced was obtained by two-dimensional nuclear magnetic resonance of the whole wood swollen in dimethylsulfoxide-d 6. The spectra obtained revealed the removal of guaiacyl and syringyl lignin units, although with a preferential removal of the former, and the lower number of aliphatic side-chains per phenylpropane unit (involved in main β-O-4ʹ and β-βʹ inter-unit linkages), in agreement with the pyrolysis-gas chromatography/mass spectrometry results, without a substantial change in the wood polysaccharide signals. However, the most noticeable modification observed in the spectra was the formation of Cα-oxidized syringyl lignin units during the enzymatic treatment. Further insight into the modifications of lignin structure, affecting other inter-unit linkages and oxidized structures, was attained by nuclear magnetic resonance of the lignins isolated from the eucalypt feedstock after the enzymatic pretreatments., [Conclusions] This work shows the potential of an oxidative enzymatic pretreatment to delignify and improve cellulase saccharification of a hardwood feedstock (eucalypt wood) when applied directly on the ground lignocellulosic material, and reveals the main chemical changes in the pretreated material, and its recalcitrant lignin moiety, behind the above results., This study was funded by the LIGNODECO EU-project on ‘Optimised pre-treatment of fast growing woody and nonwoody Brazilian crops by detailed characterization of chemical changes produced in the lignin-carbohydrate matrix’ (KBBE-3-244362) and the LIGNOCELL Spanish MICINN (co-financed by FEDER funds) project (AGL2011-25379). JR acknowledges the CSIC JAE-Doc contract of the program ‘Junta para la Ampliación de Estudios’ co-financed by the European Social Fund (ESF). H. Lund from Novozymes (Bagsvaerd, Denmark) is acknowledged for the M. thermophila laccase and J. Romero (ENCE, Spain) for the eucalypt wood samples. G. Marques and A. Pereira are acknowledged for their help in carbohydrates analyses, and Manuel Angulo (CITIUS, University of Seville) for providing technical assistance in the NMR analyses. The authors acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

20 páginas.-- 7 figuras.-- 6 tablas.-- 37 referencias.-- Artículo en Prensa, Eucalypt feedstock was pretreated with Myceliophthora thermophila laccase and methyl syringate, as mediator, in a multistage sequence consisting of successive enzymatic and alkaline peroxide stages, directly on the ground wood. Lignin modification was studied by two-dimensional (2D) nuclear magnetic resonance (NMR) of wood (at the gel state) after each stage of the sequence. Decrease of guaiacyl and syringyl lignin units (with preferential removal of the former) and aliphatic (mainly β-O-4′-linked) side chains was observed along the sequence, without a substantial change in polysaccharide cross-signals along the sequence, was observed. However, the most noticeable modification was the formation of Cα-oxidized syringyl units in the enzymatic stages, which were partially removed in the alkaline extractions. Further insight was attained by 2D NMR of the cellulolytic-enzyme lignins, isolated from the pretreated samples, and the filtrates from the different stages. Additionally, a comparison of eucalypt delignification with the high redox potential laccase from Pycnoporus cinnabarinus in the presence of the synthetic mediator 1-hydroxybenzotriazole was carried out. Wood delignification already occurred at the first cycle of the pretreatment with P. cinnabarinus laccase and 1-hydroxybenzotriazole, which directly correlated with increases in glucose (~10 %) yields after enzymatic hydrolysis. In contrast, the first cycle of pretreatment with M. thermophila laccase and methyl syringate did not produce any delignification or saccharification improvement. However, at the end of the sequence, similar delignification (~50 %) of eucalypt feedstock and increases (~30 %) in glucose yields were attained in both laccase-mediator pretreatments. Finally, the influence of lignin content and the ratio of its syringyl and guaiacyl units on recalcitrance of eucalypt feedstock to enzymatic saccharification is discussed., This study was funded by the INDOX (KBBE-2013-7-613549) EU-project and the LIGNOCELL (AGL2011-25379) and HIPOP (BIO2011-2669) Spanish MICINN projects (co-financed by FEDER funds). J. Rencoret acknowledges the CSIC JAE-Doc contract of the program “Junta para la Ampliación de Estudios” co-financed by the European Social Fund (ESF). H. Lund and L. Kalum from Novozymes (Bagsvaerd, Denmark) are acknowledged for the cellulases (Celluclast and Novozym 188) and the M. thermophila laccase, Beldem (Andenne, Belgium) for the P. cinnabarinus laccase and J. Romero (ENCE, Spain) for the eucalypt wood samples. Manuel Angulo (CITIUS, University of Seville) is acknowledged for providing technical assistance in the NMR analyses.

International audience; High Resolution Magic Angle Spinning (HR-MAS) NMR spectroscopy is a versatile technique that provides high resolution NMR data on samples containing solutions, gels and swellable solids. In addition to providing structural information HR-MAS can also be used to investigate interfaces (for example organic structures at the solid-aqueous soil interface), processes such as swelling/flocculation, kinetic transfer between gel/liquid phases, as well as conformation and molecular interactions in situ. As such, HRMAS has potential in a diversity of fields including organic, biological, environmental, and medical research. This manuscript focuses on the application of HR-MAS to intact natural samples. A range of 1D and 2D NMR experiments are reviewed and compared in terms of general performance on a range of samples. Therefore, this practical guide and review should be a useful reference and starting point for those wishing to apply HR-MAS NMR. While this article focuses on natural samples, common key 1D and 2D experiments are considered which may be of interest to readers with diverse research interests.

The 1,3-dipolar cycloaddition reaction of nitrile oxides to norbornenes substituted with an acrylate-derived moiety was examined. Only adducts to norbornene system were formed with a good exo selectivity and complete site-selectivity. Structures of the products were elucidated by an extensive application of electrospray ionization-mass spectrometry (ESI-MS) and 2D ¹H and 13C nuclear magnetic resonance (NMR). A reação de cicloadição 1,3-dipolar de óxidos de nitrila a norbornanos substituídos com um grupo derivado de acrilato foi examinada. Somente adutos para o sistema norbornano foram formados com boa exo seletividade e completa seletividade ao sítio. As estruturas dos produtos foram elucidadas através das técnicas de espectrometria de massas com ionização por electrospray (ESI-MS) e de ressonância magnética nuclear (RMN) 2D de ¹H e 13C.

International audience; The discrimination and analysis of the NMR spectra of optically active molecules dissolvedin chiral liquid crystal solvents through 2D correlation experiments is studied. The techniqueallows the identification of the line positions of each enantiomer, thus providing a notablesimpliûcation of the spectral analysis. The 2D HOHAHA and multiple-quantum experimentsare investigated and discussed. The potential of the method is illustrated using a sample of( + ) 3,3,3-trichloroepoxypropane dissolved in a thermotropic cholesteric solvent. The case ofchiral molecules bearing a fluorine or deuterium nucleus has also been studied. In addition,it is shown that 2D heteronuclear correlation experiments are powerful methods for correlatingcarbon and proton spectral data of two enantiomers. A specific example is given through( * ) 2-bromopropanoic acid dissolved in a lyotropic polypeptide liquid crystal. Spectralparameters of each enantiomer are calculated for the different examples

13C-labeled amorphous cellulose and 13C NMR chemical shifts by 2D 13C–13C correlation spectroscopy were obtained in the regenerated solid-state from ionic liquids. On the basis of the assigned chemical shifts, combined with information from molecular dynamics and quantum chemistry computer simulations a twisted structure for amorphous cellulose is proposed exposing more hydrophilic surface than that of extended crystalline cellulose.

The occurrence and nature of acetate groups in the milled wood lignin (MWL) isolated from birch (Betula pendula Roth) has been addressed by spectroscopic (2D-NMR) and chemical degradative (derivatization followed by reductive cleavage, DFRC) methods. Considerable amounts of acetate groups were present in the MWL preparation. However, 2D-NMR analysis indicated that the lignin polymer is not extensively acetylated and that the major part of the acetate groups is attached to the xylan moieties present in the MWL preparation. Nevertheless, evidence of the presence of minor acetylation of the gamma-carbon of the lignin side chain (

International audience; NMR of weakly polar analytes in an apolar ultraviscous solvent has recently been proposed for mixture analysis as a pertinent alternative to the DOSY experiment. The present article reports the first use of glycerol and glycerol carbonate as polar solvents for the NMR analysis of a model mixture of dipeptides. This work demonstrates the high potentiality of these solvents for the analysis of mixtures made of polar and potentially bioactive compounds. Medium-sized molecules slowly reorient in glycerol and glycerol carbonate under particular temperature conditions, so that solute resonances may show spin diffusion in NOESY spectra, thus opening the way to mixture analysis. Glycerol and glycerol carbonate have turned out to be ultraviscous solvents of choice for the individualization of four structurally close mixed dipeptides: Leu-Val, Leu-Tyr, Gly-Tyr and Ala-Tyr by means of 1D and 2D NOESY experiments. Selective sample excitation and signal detection were implemented to eliminate the intense proton signals of the non-deuterated solvents. Moreover, the recording of a multiplet selective 2D NOESY-TOCSY has shown that the analytical power of NMR in highly viscous solvents is not limited to the extraction of mixture component 1D subspectra but may also yield some supplementary information about atom connectivity within components.

Identification of individual components of essential oils by comparative techniques (GC-MS and/or13C NMR) can be carried out exclusively for compounds whose spectroscopic data are compiled in computerized libraries. Otherwise, the compound should be isolated and submitted to a full set of spectroscopic analyses. In this paper we report on the direct identification of the two major components of Chamaemelum fuscatum (Brot.) Vasconcellos essential oil using “Extraction NMR”. Indeed, 2-methylallyl isobutyrate and ( E)-2-methyl-2-butenyl methacrylate have been identified, without previous isolation, by combination of the data from one and two-dimensional NMR spectra of the essential oil.

From the seeds of white currant (Ribes rubrum, cv. White Champagne), a new sesquiterpenoid glycoside 1 was isolated, along with two known compounds: dihydrophaseic acid 3'-O-beta-D-glucopyranoside (2), and 3-carboxymethyl-indole-1-N-beta-D-glucopyranoside (3). The structure of the new compound was identified as dihydrophaseic acid 3'-O-beta-gentiobioside, based on extensive NMR and MS spectral studies. Iz semena bele ribizle (Ribes rubrum, cv. bela šampanjska) izolovan je novi seskviterpenski glukozid (1), zajedno sa dva poznata jedinjenja: 3'-O-b-D-glukopiranozidom dihidrofazeinske kiseline (2) i 3-karboksimetilindol-1-N-b-D-glukopiranozidom (3). Na osnovu detaljnih NMR i MS studija, struktura novog jedinjenja je određena kao 3'-O-b-genciobiozid dihidrofazeinske kiseline.

Lignin changes during plant growth were investigated in a selected Eucalyptus globulus clone. The lignin composition and structure were studied “in situ” by a new procedure enabling the acquisition of 2D-NMR spectra on wood gels formed in the NMR tube, as well as by analytical pyrolysis (Py-GC/MS). In addition, milled-wood lignins were isolated and analyzed by 2D-NMR, Py-GC/MS, and thioacidolysis. The data indicated that p-hydroxyphenyl (H) and guaiacyl (G) units are deposited at the earlier stages, whereas the woods are enriched in syringyl (S) lignin during late lignification. Wood 2D-NMR showed that β-O-4′ and resinol linkages were predominant in the eucalypt lignin, whereas other substructures were present in much lower amounts. Interestingly, open β-1′ structures could be detected in the isolated lignins. Phenylcoumarans and cinnamyl end-groups were depleted with age, while spirodienone abundance increased, and the main substructures (β-O-4′ and resinols) were scarcely modified. Thioacidolysis revealed a higher predominance of S units in the ether-linked lignin than in the total lignin and, in agreement with NMR, also indicated that resinols are the most important non-ether linkages. Dimer analysis showed that most of the resinol-type structures comprised two S units (syringaresinol), the crossed G-S resinol appearing as a minor substructure and pinoresinol being totally absent. Changes in hemicelluloses were also shown by the 2D-NMR spectra of the wood gels, without polysaccharide isolation. These include decreases of methyl galacturonosyl, arabinosyl and galactosyl (anomeric) signals, assigned to pectin and related neutral polysaccharides, and increases of xylosyl (which are ~50% acetylated) and 4-O-methylglucuronosyl signals.

In this paper the first complexes of M(2+) ions (M(2+) = Zn(2+), Cd(2+) and Co(2+)) with N-benzyloxycarbonyl-S-phenylalaninato ligand (1-3) are described. The new complexes were characterized by means of elemental analysis, IR and UV-vis spectroscopy, molar conductivity measurements and (1)H, (13)C and (15)N NMR spectroscopy (1D and 2D). The Co(II) complex adopts an octahedral geometry, and the Zn(II) and Cd(II) complexes adopt a tetrahedral one. For the first time, the antimicrobial activity of N-benzyloxycarbonyl-S-phenylalaninato ligand (N-Boc-S-phe) and the complexes 1-3 was investigated against Gram-positive: Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Bacillus subtilis and Gram-negative bacteria: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and two strains of the yeast Candida albicans. It was shown that the complexes were effective against most strains. The best activity was detected against the yeast C. albicans. (C) 2008 Elsevier Masson SAS. All rights reserved.

Three non-wood lignins differing in their molecular structure were isolated and characterized by 2D-NMR. The Musa textilis milled-wood lignin (MWL), with a syringyl-to-guaiacyl (S/G) ratio of 9, is strongly acylated (near 85% of side-chains) at the γ-carbon by both acetates and p-coumarates, as estimated from 13C-1H correlations in Cγ-esterified and Cγ-OH units. The p-coumarate C3,5-H3,5 signal was completely displaced by acetylation, and disappeared after alkali treatment, indicating that p-coumaric acid was esterified maintaining its free phenolic group. By contrast, the Cannabis sativa MWL (S/G ~0.8) was free of acylating groups, and the Agave sisalana MWL (S/G ~4) showed high acylation degree (near 80%) but exclusively with acetates. Extensive Cγ-acylation results in the absence (in M. textilis lignin) or low abundance (4% in A. sisalana lignin) of β-β' resinol linkages, which require free Cγ-OH to form the double tetrahydrofuran ring. However, minor signals revealed unusual acylated β-β' structures confirming that acylation is produced at the monolignol level, in agreement with chromatographic identification of γ-acetylated sinapyl alcohol among the plant extractives. In contrast, resinol substructures involved 22% side-chains in the C. sativa lignin. The ratio between β-β' and β-O-4' side-chains varied from 0.32 in the latter lignin to 0.02-0.07 in the two other MWL, and was inversely correlated with the degree of acylation. The opposite was observed for the S/G ratio that was directly correlated with the acylation degree. Monolignol acylation in these and other angiosperms is discussed as a mechanism contributing to regulate the structure of lignin., The study was funded by the BIORENEW EU-project (NMP2-CT-2006-26456), and the Spanish projects BIO2005-3569, BIO2007-28719-E, BIO2007-28720-E, BIO2008-01533, AGL2005-01748 and AGL2008-00709/FOR. CELESA (Tortosa, Spain) is acknowledged for providing the plant materials analyzed. J.I. Santos (CIB, CSIC, Madrid) is acknowledged for help in the NMR studies. D.I. and J.R. thank I3P Fellowships of the Spanish CSIC, and G.M. thanks the Spanish MEC for an FPI Fellowship

The structure of lignins isolated from the herbaceous plants sisal ( Agave sisalana), kenaf ( Hibiscus cannabinus), abaca ( Musa textilis) and curaua ( Ananas erectifolius) has been studied upon spectroscopic (2D-NMR) and chemical degradative (derivatization followed by reductive cleavage) methods. The analyses demonstrate that the structure of the lignins from these plants is highly remarkable, being extensively acylated at the gamma-carbon of the lignin side chain (up to 80% acylation) with acetate and/or p-coumarate groups and preferentially over syringyl units. Whereas the lignins from sisal and kenaf are gamma-acylated exclusively with acetate groups, the lignins from abaca and curaua are esterified with acetate and p-coumarate groups. The structures of all these highly acylated lignins are characterized by a very high syringyl/guaiacyl ratio, a large predominance of beta- O-4' linkages (up to 94% of all linkages), and a strikingly low proportion of traditional beta-beta' linkages, which indeed are completely absent in the lignins from abaca and curaua. The occurrence of beta-beta' homocoupling and cross-coupling products of sinapyl acetate in the lignins from sisal and kenaf indicates that sinapyl alcohol is acetylated at the monomer stage and that, therefore, sinapyl acetate should be considered as a real monolignol involved in the lignification reactions.

Modification of eucalypt pulp residual lignin in a totally chlorine free (TCF) bleaching sequence including a laccase-mediator stage, in combination with previous oxygen delignification and subsequent peroxide bleaching, was investigated and compared with a chemical TCF sequence. The enzymatic treatment resulted in a strong oxidative modification, as shown by lignin unit 13C2,6-1H2,6 correlations in HSQC 2D-NMR spectra and presence of oxidized pyrolysis markers. The frequency of inter-unit linkages in residual lignin was also modified, as shown by different side-chain 13C-1H correlations. Moreover, H2,6 correlations with side-chain carbons in HMBC spectra revealed the presence of Cα keto and carboxyl groups in lignin from the oxygen-delignified and especially from the enzymatically-treated pulp, together with normal (Cα-hydroxylated) lignin units. Moreover, the results obtained showed that most of this oxidatively-altered lignin is removed under the alkaline conditions used in the peroxide stage. In this way, the pulp kappa number decreased, and the final residual lignin was more structurally-related to that found before the oxidative stages (although with lower content of resinol structures, and higher presence of aryl-aryl ether structures and carboxyl-bearing terminal units). However, the action of hydrogen peroxide is required to attain the high brightness, over 91% ISO, found in final pulp after the enzyme-containing TCF sequence.