Semi-quantitative method to evaluate the α-carbonyl content in lignin

A method to estimate the content of 0">-carbonyl structures in lignin was developed. This method consists of two successive treatments: NaBD₄ treatment of pulp to reduce an 0">-carbonyl structure in lignin, and nitrobenzene oxidation. NaBD₄ was used to convert an 0">-carbonyl structure to a deuterium-labeled hydroxymethine structure. The ratio of D-vanillin [(HO)(H₃CO)C₆H₃CDO] to H-vanillin [(HO)(H₃CO)C₆H₃CHO] or that of their syringyl analogues obtained by nitrobenzene oxidation was used as the measure of the content of 0">-carbonyl structure. Model experiments demonstrated that when sodium hydroxide was used as alkali for the nitrobenzene oxidation, the retention of deuterium at the side chain 0">-position was very low due to the displacement of deuterium with hydrogen by an unknown reaction mechanism. In order to depress this unexpected displacement, the reaction conditions of the nitrobenzene oxidation were modified. The modified nitrobenzene oxidation employs 0.501.gif" alt="thinsp" align="MIDDLE" BORDER="0">mol/l of lithium hydroxide as a reaction medium instead of 2.001.gif" alt="thinsp" align="MIDDLE" BORDER="0">mol/l sodium hydroxide. By this modification, this method could successfully trace the formation and the degradation of the 0">-carbonyl structure in milled wood lignins.This paper was presented in part at the 11th International Symposium on Wood and Pulping Chemistry, Nice, France, June 2001 and at the 46th Lignin Symposium, Kyoto, Japan, November 2001     

Synthesis of dihydroxyphenacyl glycosides for biological and medicinal study: β-oxoacteoside from Paulownia tomentosa

The protected structure of 0">-oxoacteoside (tomentoside A), 2-oxo-2-(3,4-dihydroxyphenyl)ethyl 3-O-(2,3,4-tri-O-acetyl-0">-l-rhamnopyranosyl)-4-O-caffeoyl-0">-d-glucopyranoside 14 was synthesized in 14% overall yield in 11 steps, starting from d-glucose for biological and medicinal studies of phenylpropanoid glycosides. The first step was the preparation of a 3-O-rhamnopyranosyl disaccharide sugar core 2 from a suitably protected rhamnosyl trichloroacetimidate 10 and glucose derivative (diacetone-d-glucose 1) in 71% yield. To the glucose moiety of this sugar core, several protection/deprotection procedures were performed sequentially to obtain a fully acetylated sugar core 7 with a 4-OH group on the glucose moiety, in 57% yield in five steps. Thereafter, to the 4-OH group of the glucose moiety, selective 4-O-caffeoylation was achieved by proton-transfer esterification with 3,4-di-O-allylcaffeic acid 16 to give the caffeoyl disaccharide 11 in 97% yield. Then, it was converted to trichloroacetimidate 13 for a glycosylation donor in 90% in two steps. Finally, anomeric glycosylation was conducted with 2-oxo-2-(3,4-di-allyloxyphenyl)ethyl alcohol 19 with catalytic amounts of BF₃·Et₂O to give 2-oxo-2-(3,4-di-allyloxyphenyl)ethyl 2,6-di-O-acetyl-3-O-(2,3,4-tri-O-acetyl-0">-l-rhamnopyranosyl)-4-O-(3,4-di-allyloxycaffeoyl)-0">-d-glucopyranoside 14 in 60% yield. Deprotected intermediates of compounds 2, 11, 14, and 19 which were obtained in high yield would be useful for biological and medicinal studies of phenylpropanoid glycosides.Part of this study was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April, 2002     

Salt distribution in response to optical stratification porosity and relative windspeed in a coastal forest in Niigata, Japan

Wind velocity, vertical stand structure and sea05854002w93417/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">salt distribution were measured at various heights inside a plantation of coastal pine forest, with thinning and unthinning, to assess whether any relationships exist between the wind profile, stand structure and sea05854002w93417/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">salt distribution in the coastal pine forest. The vertical stand structure, i.e., optical stratification porosity (OSP), which is defined as vertical distribution of the proportion of sky hemisphere not obscured by tree elements inside a forest stand, was determined for each height by computer analysis of digital images taken with a hemispherical lens. The distribution of OSP in the coastal forest follows the Lambert-Beer's law with absorbency coefficient (05854002w93417/xxlarge957.gif" alt="ngr" align="BASELINE" BORDER="0">). The relative windspeed within canopy can be described using the exponential form with the attenuation coefficient (05854002w93417/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">). The sea-salt was collected using salt gauze (a surgical dressing of loosely woven cotton) both inside and outside the coastal forest, and the distribution of sea-salt within canopy was also in accordance with an exponential function. The relationships among windspeed, OSP and sea-salt indicate that the distributions of both sea-salt and windspeed within canopy were very closely correlated with the distribution of OSP. A linear relationship between OSP and sea-salt has been found. Additionally, linear regression between coefficients 05854002w93417/xxlarge957.gif" alt="ngr" align="BASELINE" BORDER="0"> and 05854002w93417/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> has been obtained as well. Based on these relationships between OSP, wind and sea-salt in the coastal forest, the sea-salt distribution and wind profile within the canopy of the coastal forest can be predicted according to OSP. These results may therefore be useful in analyzing the effects of sea-salt on vegetation and evaluating the filter functions of coastal forests.This revised version was published online in November 2005 with corrections to the Cover Date.     

Crop productivity under differently lopped canopies of multipurpose trees in Central Himalaya, India

Ficus species are multipurpose trees well known by rural populations in Sahelian and Sudanian zones of Africa. Their uses are well documented but their amenability for vegetative propagation has not been extensively studied. This paper compares the rooting ability of stem and aerial root cuttings from thirteen Ficus species found in West Africa. It highlights the differences between species belonging to the sub-genera Sycomorus and Urostigma. The former show no capacity to propagate from cuttings whereas the latter, with epiphytic development, can be propagated by cuttings, although this capacity varies among species. Thus, F. thonningii, F. leprieurii and F. ovata are easily propagated, while F. platyphylla and F. elasticoides are propagated with difficulty. The rooting capacity also varies depending on the cutting material used. It decreases in the following order: long leafless hardwood cuttings (pole) > nodal cuttings > apical cuttings. Rooting potential increases when the cuttings are harvested towards the end of the dry season(March to May). Aerial root can be used for cuttings in all species of the sub-genus Urostigma. The capacity of root cuttings to regenerate is greatest when cuttings are collected at the beginning of the dry season (November). In this case, wound-induced adventitious roots arise at the basal end of the cutting while de novo buds are developed from the cambium at the distal end. The subsequent morphological development is identical to that of a stem cutting. These results clarify and allow the optimal use of the knowledge and methods developed by the indigenous people of the Sahel and could assist and promote fig tree (Ficus sp.) domestication in the dry tropics.This revised version was published online in November 2005 with corrections to the Cover Date.     

Simple method for synthesizing phenolicβ-O-4 dilignols

A modified synthetic method for phenolic01k/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-O-4 lignin substructure model dimers was developed involving protection of the phenolic hydroxyl group of acetophenons with benzoyl chloride, bromination with 4-dimethylaminopyridiniumbromide perbromide, condensation with phenols in the presence of 18-crown-6-ether, condensation with paraformaldehyde, reduction with NaBH₄ and debenzoylation. This method results in shorter reaction times and increasing yields without the application of strict anhydrous and drastic conditions or chloric solvents. This alternative route could be applied to the01k/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-O-4 dilignol syntheses of four combinations of guaiacyl and syringyl derivatives.     

Absolute configuration of arylglycerol-β-aryl ethers obtained by asymmetric reduction of the correspondingα-ketonic compound with intactFusarium solani cells

When (±)-0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-oxo-guaiacylglycerol-0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-(vanillic acid) ether (1) is degraded byFusarium solani M-13-1, the0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-ketone is initially reduced to giveerythro andthreo guaiacylglycerol-0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-(vanillic acid) ethers (2), arylglycerol-0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-aryl ethers, both of which are enantiomerically pure. The absolute configuration in each2 was determined by Mosher's method; the products were converted to0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">,0x0562h3781/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-di-(R)-0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-methoxy-0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-trifluoromethylphenylacetates (MTPA esters) (30x0562h3781/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">) oferythro (-)- andthreo (+)-veratrylglycerol-0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-(methyl vanillate) ethers (3), whose¹H nuclear magnetic resonance (NMR) spectra were examined and compared with those of four di-(R)-MTPA ester (30x0562h3781/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">) diastereomers from chemically synthesizederythro (±)-3 andthreo (±)-3. To assign the0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">- and0x0562h3781/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-MTPA-OCH₃ peaks, the¹H NMR scans of several compounds that have substructures of 30x0562h3781/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0"> and their 3,4,5-trimethoxyphenyl analogues were examined. When a racemic alcohol reacts with (R)-MTPA to give a pair of (R)-MTPA ester diastereomers, the 0x0562h3781/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">0x0562h3781/xxlarge948.gif" alt="delta" align="BASELINE" BORDER="0"> value was defined as the absolute value of the difference in the¹H chemical shifts of the peak between the diastereomers. It was found that the 0x0562h3781/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">0x0562h3781/xxlarge948.gif" alt="delta" align="BASELINE" BORDER="0"> values of0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-MTPA-OCH₃ were larger than those of0x0562h3781/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-MTPA-OCH₃ owing to a shielding effect of the veratryl ring located on the0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-MTPA-OCH₃, and that the0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-MTPA-OCH₃ peaks in the 3,4,5-trimethoxyphenyl compounds shifted downfield relative to those in the veratryl compounds. On the basis of the¹h NMR data of (R)-MTPA esters, the absolute configuration of the four chemically prepared diastereomers (30x0562h3781/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">) were determined. The catabolicerythro 30x0562h3781/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0"> [fromerythro (-)-3] andthreo 30x0562h3781/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0"> [fromthreo (+)-3] were identical to (R, 0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">S, 0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">R)-erythro 30x0562h3781/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0"> and (R, 0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">S, 0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">S)- threo 30x0562h3781/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">, respectively. An hydrogen species in the fungal reduction would attack the0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-ketone fromre-face of both (0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">R)-1 and (0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">S)-1, givingerythro (0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">S, 0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">R)-2 andthreo (0x0562h3781/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">S, 0x0562h3781/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">S)-2, respectively.Part of this paper was presented at the 33rd Lignin Symposium, Tsukuba, November 1988     

Preparation of novel reagents 4-alkoxytrityl chlorides and their reaction with methyl Α-d-glucoside

A series of novel 4-O-alkoxytrityl chlorides (1) with different chain lengths was synthesized as a novel reagent for obtaining 6-O-alkylated cellulose with high regioselectivity via trityl groups in one reaction step without the use of any protective groups. These chlorides were reacted with methyl 0">-d-glucoside, which was used as a model compound, to examine the reactivities toward the primary hydroxyl groups of cellulose to afford a series of 6-O-alkylated methyl 0">-d-glucosides in high yields. The product compounds were found to have interesting solubilities and thermal properties. Thus, newly prepared trityl chloride derivatives were found to be useful regioselective derivatization reagents on the primary hydroxyl group in carbohydrates, especially in cellulose.     

Gas chromatographic and mass spectrometric (GC-MS) analysis of lignin-derived products from <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> treated in supercritical water

Sugi (Cryptomeria japonica D. Don) wood was treated with supercritical water (0">374°C, 0">22.101.gif" alt="thinsp" align="MIDDLE" BORDER="0">MPa), and fractionated into the water-soluble portion, the methanol-soluble portion, and the methanol-insoluble residue. The methanol-soluble portion mainly consisted of the lignin-derived products. To characterize the compounds in the methanol-soluble portion, gel permeation chromatographic (GPC) and gas chromatographic-mass spectrometric (GC-MS) analyses were performed. The GPC analysis indicated that the methanol-soluble portion contained lignin-derived monomeric and dimeric products. GC-MS analysis detected 31 products which were expected to be monomeric compounds, and 18 of these were identified to be guaiacol, methylguaiacol, ethylguaiacol, vinylguaiacol, eugenol, propylguaiacol, vanillin, cis-isoeugenol, homovanillin, trans-isoeugenol, acetoguaiacone, propioguaiacone, guaiacylacetone, 2-methoxy-4-(1-hydroxypropyl)phenol, homovanillic acid, 2-methoxy-4-(prop-1-en-3-one)phenol, coniferyl aldehyde, and ferulic acid. In addition, 22 dimeric products were detected, and 4 of these were believed to be compounds with biphenyl type (5-5), diphenylethane type (0">-1), stilbene type (0">-1), and phenylcoumaran type (0">-5) structures. These results clearly indicated that the methanol-soluble portion included various monomeric and dimeric compounds produced as a result of the cleavage of ether linkages and propyl chains of lignin.     

广西猪瘟病毒E0和E2基因的克隆及序列分析

通过分析目前广西猪瘟病毒(CSFV)的E0和E2基因特征,为了解广西地区CSFV的分子流行病学、遗传变异及综合防控提供科学依据。试验采用RT-PCR方法,对阳性猪瘟样品进行CSFV的E0及E2基因的扩增,经克隆、测序后,利用DNAStar软件对序列进行比对分析,同时绘制系统遗传进化树。结果表明,从阳性猪瘟样品中成功扩增CSFV的E0及E2基因。序列比对分析发现,GX2毒株与参考毒株的E0基因核苷酸同源性在83.1%~94.1%,其推导氨基酸同源性在85.9%~99.6%;与参考毒株的E2基因核苷酸同源性为81.7%~93.7%,其推导氨基酸同源性为89.0%~97.0%;E0与E2基因均属于基因Ⅱ群。氨基酸变异位点分析表明,E0蛋白的RNase活性区域氨基酸基序位点没有发生变异;E2蛋白中15个位点上的半胱氨酸均未发生变异,但单抗识别位点S734R发生变异。遗传进化分析显示测定的GX2毒株与近年来广西CSFV流行毒株的变异趋势相似,与中国传统疫苗株HCLV、经典强毒株Shimen的同源性较低,亲缘关系较远,与广西近年来的流行毒株GXWZ02株的同源性较高,亲缘关系较近。