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Microwave heating was applied to the reactions involved in the synthesis of 6-amino-6-deoxycellulose, 4. These included, cellulose solubilization, bromination at C-6, displacement of bromine with azide ion, and reduction of the azido group to an amino group. Compared to conventional heating, this approach had the advantages of shortening reaction times and retaining the degree of polymerization of 4.

Novel chitosan derivatives with UV-curable functional groups, such as 3-methoxy-4-(2-hydroxy-3-methacryloyloxypropoxy)benzyl, 3,4-bis(2-hydroxy-3-methacryloyloxypropoxy)benzyl, 3-methoxy-4-methacryloyloxybenzyl, and 3,5-dimethacryloyloxybenzyl groups, were prepared. Introduction of photosensitive functional groups to chitosan was accomplished by reductive N -alkylation via Schiff’s bases using corresponding photosensitive aldehydes. Compared to starting chitosan, UV-curable chitosan derivatives showed better solubility in several organic solvents, such as DMSO and 70% methacrylic acid. The solubility of these compounds increased with an increase in the degree of substitution of the N -alkyl side chains. After UV irradiation for 20 s under a high-pressure mercury lamp at a distance of 15 cm from the samples, acidic methanol solutions of these derivatives were transformed to gels in the presence of photo-initiator, and their dried films adsorbed palladium (II) at pH 1.1 and pH 5.3. The UV-curable chitosan derivatives were successfully used as coating materials for electroless plating on non-conductive substances.

Mixtures of diblock co-oligomers of tri-O-methylated and unmodified cello-oligosaccharides have been found to be amphiphilic, as reported before. In order to clarify their accurate amphiphilic property, diblock co-oligomers of tri-O-methylated and unmodified cello-oligosaccharides with monodispersity, methyl β-d-glucopyranosyl-(1→4)-2,3,6–tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6–tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-d-glucopyranoside (1, pentamer), methyl β-d-glucopyranosyl-(1→4)- β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-d-glucopyranoside (2, hexamer), and methyl β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)- 2,3,6-tri-O-methyl-d-glucopyranoside (3, trimer) were synthesized independently. These compounds had higher surface activities compared to the mixture of diblock co-oligomers of tri-O-methylated and unmodified cello-oligosaccharides and commercially available methylcellulose (MC) SM-4. This paper describes the methods of synthesis of these compounds, and the influence of amphiphilic character on their surface activity. A new class of carbohydrate-based nonionic surfactant without long alkyl chain was discovered.

Langmuir-Blodgett films of a cellulose derivative containing porphyrins, porphyrin-cellulose, were fabricated in order to construct a cellulose-based molecular photocurrent generation system. On visible light illumination of the LB monolayer film deposited on an ITO electrode, anodic photocurrents were observed with a quantum yield of 1.6% at an applied potential of 0 V versus SCE, and 3.8-4.6% at 0.2-0.3 V versus SCE. These values indicate that the self-quenching of the photoexcited porphyrins in the cellulose LB film was suppressed, while porphyrin moieties in the LB film had a densely packed structure. This is because the porphyrins are located at a distance of approximately 1.0 nm along the cellulose backbone.

Redox-active Langmuir-Blodgett (LB) films containing dihydrophytyl ferrocenoate (DFc) and beta-carotene (betaC) were fabricated by use of 6-O-dihydrophytylcellulose (DHPC) as a matrix. A mixture of DFc-DHPC formed a stable monolayer. Atomic force microscopy images revealed that the DFc molecules were dispersed uniformly throughout the surface in the ratio DFc:DHPC = 2:8 at 30 mN m-1. The DFc-DHPC monolayer was transferred successfully onto a substrate, yielding Y-type LB films. Cyclic voltammograms for the DFc-DHPC LB films on an indium tin oxide (ITO) electrode exhibited a well-defined surface wave. The voltammograms of the DFc-DHPC LB films exhibited 60-40% redox-active ferrocene moieties, whereas those of the DFc-DHPC-betaC LB films exhibited 90-70%. X-ray diffraction patterns indicated that the distance between layers was independent of betaC molecules incorporated into the LB films. Consequently, these results suggested that betaC can function as a molecular wire.

Bacterial cellulose (BC) nanofibers were acetylated to enhance the properties of optically transparent composites of acrylic resin reinforced with the nanofibers. A series of BC nanofibers acetylated from degree-of-substitution (DS) 0 to 1.76 were obtained. X-ray diffraction profiles indicated that acetylation proceeded from the surface to the core of BC nanofibers, and scanning electron microscopy images showed that the volume of nanofibers increases by the bulky acetyl group. Since acetylation decreased the refractive index of cellulose, regular transmittance of composites comprised of 63% BC nanofiber was improved, and deterioration at 580 nm because of fiber reinforcement was suppressed to only 3.4%. Acetylation of nanofibers changed their surface properties and reduced the moisture content of the composite to about one-third that of untreated composite, although excessive acetylation increased hygroscopicity. Furthermore, acetylation was found to reduce the coefficient of thermal expansion of a BC sheet from 3 x 10(-6) to below 1 x 10(-6) 1/K.

The residual wood meal left after extraction of milled wood lignin (MWL) was extracted with lithium chloride/N,N-dimethylacetamide, which is a well-known cellulose solvent, to afford a soluble fraction (cellulose-lignin fraction; CL) in 36.7% yield. The UV elution curve of CL acetate has the same profile as its refractive index (RI) elution curve. After partial degradation of CL by cellulase, the UV elution curve of CL acetate shifted to the low-molecular-mass region in a similar fashion as its RI elution curve. These results indicate that the lignin in CL (CL lignin) is chemically bonded to cellulose. On the other hand, half of the CL lignin was removed by xylanase treatment. It was concluded that approximately half of the CL lignin existed as a lignin-cellulose-xylan complex.

(E)‐4‐O‐Acetyl coniferyl alcohol was synthesized by the reduction of (E)‐4‐O‐acetyl ferulic acid with sodium borohydride and N,N‐dimethylchloromethylenium chloride in 80.2% yield. The glycosylation of (E)‐4‐O‐acetyl coniferyl alcohol with trichloroacetimidoyl 2,3,4,6‐tetra‐O‐pivaloyl‐α‐D‐glucopyranoside in the presence of BF3-Et2O in anhydrous CH2Cl2, followed by deacylation gave (E)‐isoconiferin in high yield. This synthetic method could be applied to the syntheses of other monolignol β‐glycosides. As a result, (E)‐isoconiferin, (E)‐isosyringin, and (E)‐triandrin were synthesized from vanillin, syringaldehyde, and p‐hydroxybenzaldehyde, respectively, by five reaction steps in high overall yield.

Dehydrogenative polymerization of isoconiferin (IC; coniferyl alcohol γ-O-β-D-glucopyranoside) catalyzed by horseradish peroxidase (HRP) was carried out. The polymerization of IC proceeded in a homogeneous system, resulting in a water-soluble dehydrogenation polymer (IC-DHP). The degree of polymerization (DP) of IC-DHP was significantly higher than that of a standard dehydrogenative polymer (CA-DHP) obtained from coniferyl alcohol (CA) in a heterogeneous system. Under optimum conditions, the DP of IC-DHP was 44 (Mn=1.5×104), whereas that for CA-DHP was only 11 (Mn=3.0×103, as acetate). Spectroscopic analyses confirmed that IC-DHP has a lignin-like structure containing D-glucose moieties attached to the lignin side-chains. The D-glucose unit introduced into γ-O position of CA essentially influenced the water solubility and molecular mass of the resulting DHP.

A synthetic method for obtaining lignin oligomer that contains only the β-O-4 structure is described in detail. This method consists of three reaction steps: (1) the synthesis of t-butoxycarbonylmethyl vanillin (2), (2) the nucleophilic addition oligomerization of compound 2, and (3) the reduction of the oligomeric β-hydroxyl ester. In the first step, compound 2 was synthesized from vanillin in 96.8% yield. In the second step, compound 2 was oligomerized with commercial lithium diisopropylamide (LDA) to obtain oligomeric β-hydroxyl ester (3) in 87.2% yield; the repeating units of this oligomer were joined only by β-O-4 linkages as confirmed by nuclear magnetic resonance (NMR) spectroscopy. In the third step, the oligomeric β-hydroxyl ester (3) was reduced with LiAlH4 to give compound 4 in 42.4% yield. On the basis of NMR, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and gel permeation chromatography analyses of compound 4, it was concluded that compound 4 was an oligomeric lignin model compound containing only β-O-4 interunit linkages. The number average degree of polymerization (DPn) of obtained compound 4 was about 7.0 (Mw/Mn = 1.42). Using this oligomeric lignin model compound, conventional degradation and analytical methods will give new information.

Acetoacetylated wood meal (AAWM) was prepared and a preliminary evaluation of its antifungal activity was carried out. Acetoacetylation of wood meal proceeded almost quantitatively with diketene under optimal reaction conditions, even as a heterogeneous reaction. Diketene concentration was the most important governing factor for this reaction. AAWM with a high weight percentage gain inhibited the fungal growth of Fomitopsis palustris.

Fixation of copper ions to acetoacetylated wood meal (AAWM) was conducted in Cu(OAc)2-MeOH solution. The maximum amount of copper fixed to AAWM was 147.9 mg g−1 under optimum conditions. From FT-IR analyses of AAWM containing copper ions (AAWM-Cu), it was concluded that a chelate was formed between copper and the acetoacetyl group of AAWM. In a leaching test, half of the copper in AAWM-Cu was retained, even at pH 4.0.

To engineer insect-resistant Solanum plants, a peroxidase C2 gene (prxC2) from horseradish was introduced into Solanum integrifolium Poir. cv. Hiranasu. We produced 77 transgenic Hiranasu plants. Peroxidase expression was confirmed at the transcriptional and translational levels by northern blot analysis and by measuring peroxidase activity, respectively. Feeding test results show that transformant no. 180 is more resistant to corn earworm (Heliothis armigera) and common cutworm (Spodoptera litura) than the wild-type plants. We also found a correlation between insect resistance and lignin content in the transgenic plants. In particular, the lignin content of transformant no. 180 was 30% higher than that of wild-type plants. These results further confirm that peroxidase is functionally expressed in transgenic plants and suggest that the increased lignin content is a basis for the insect resistance in transgenic Hiranasu plants.

Novel cellobiose and cellulose (DP n =ca. 30) derivatives, N-(1-pyrenebutyloyl)-4-O-(β-d-glucopyranosyl)-β-d-glucopyranosylamine (6), N-(15-(1-pyrenebutyloylamino)-pentadecanoyl)-4-O-(β-d-glucopyranosyl)-β-d-glucopyranosylamine (7), N-(1-pyrenebutyloyl)-β-cellulosylamine (13), N-(15-(1-pyrenebutyloylamino)-pentadecanoyl)-β-cellulosylamine (14) carrying a pyrene group as a single fluorescent probe at the reducing end, were prepared in order to investigate their self-assembly systems in solutions. The relative intensity of the excimer emission at ca. 480 nm due to dimerized pyrenes (intensity I E) to the monomer emission at ca. 380 nm due to isolated pyrene (intensity I M), i.e., I E/I M, was monitored in various solutions. In water/dimethyl sulfoxide (DMSO) mixed solvent (0–98%, v/v), the ratio I E/I M remained low (0.04) for compound 6 over the range of water concentrations, indicating that pyrenes at C-1 position of compound 6 were diffused. On the other hand, the ratio I E/I M increased (0.04–4.96) for compound 7 with the increase in water concentration, indicating that pyrenes at C-1 position were associated. In aqueous NaOH solutions (4.4–17.5%, w/w), compound 14 showed a large increase in the ratio I E/I M (0.84–8.14) with the increase in NaOH concentration, compared to compound 13 (0.06–0.41). It was found that the association of hydrophobic groups at the reducing-end of cellulose could be controlled by the hydrophilic–hydrophobic balance of compounds and the solvent polarity.

A novel synthetic method for co-oligomers of tri-O-methylated and unmodified cello-oligosaccharides was designed. These oligomers are of importance as model compounds for investigations on the dissolution behavior of commercial methylcelluloses. In this connection, insights into the chemical structure of ‘cross linking loci’ in the thermo reversible gelation of aqueous solution of methylcellulose are of particular significance. The synthetic procedure consists of glycosylation using glycosyl fluoride and oligomerization of sugar orthoester. Thus, phenyl 2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-1-thio-β-d-glucopyranoside (1) as a glycosyl acceptor was glycosylated with 4-O-acetyl-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-d-glucopyranosyl fluoride (2) as a glycosyl donor converted to give a cellotetraose derivative (3). Both reactants have been prepared from commercially available cellobiose. After deacetylation of 3, 3-O-benzyl-6-O-pivaloyl-α-d-glucopyranose 1,2,4-orthopivalate (5) was reacted with 4-hydroxyl group at non-reducing-end of cellotetraose derivative (4) to give the block co-oligomer (6). After the deprotection of compound 6, tri-O-methylated-block-unmodified cello-oligosaccharides (18 and 18′) (DP = 4 − 8, DS = 2.79 − 1.38) were obtained, monitored by MALDI-TOF MS spectra. Chloroform-soluble methylated cellotetraose derivatives (18 and 18′ (DP=4, n=0), DS=2.57, and 2.79, respectively) were also soluble in the water solution of tri-O-methylated-block-unmodified cello-oligosaccharides (DP=4−8, DS=2.79−1.50). This fact indicated that hydrophobic methylated cello-tetraose derivatives were encapsulated within a micelle of amphiphlic tri-O-methylated-block-unmodified cello-oligosaccharides. It was found that solubilities of 18 and 18′ (DP=4−8, DS=2.79−1.38) in water and chloroform were obviously different in the mixtures, depending on their DP and DS values. The substituent distribution of the tri-O-methylated-block-unmodified cello-oligosaccharides along one molecule and between molecules plays an important role in its solubility in water and chloroform.

Multilayer films of 2,3-di-O-acetyl-6-O-(4-stearyloxytrityl)cellulose (ASTC) were prepared and investigated. The fairly high surface pressure (π)–area (A) isotherms (36– 47 mN/m) suggest that the balky and hydrophobic trityl group contribute to form a condensed monolayer. The cellulose derivative formed a homogeneous monolayer at 10 mN/m. The monolayer on the water surface was transferred successfully at 10 mN/m onto various substrates by modifying the preparation methods, to form Z-type multilayer films. The ultraviolet–visible (UV–Vis) absorbance was independent of the number of layers, indicating that each layer is made of definite number of anhydroglucose unit (AGU). The monolayer thickness determined from atomic force microscope (AFM) and ellipsometry was calculated to be about 1.9 nm, suggesting that the long alkyl chain in the film has a so-called hairy-rod type structure. This is the first paper about the Z-type LB film prepared from cellulose derivatives having long mono-alkyl chain only at 6-O-position.

6-Amino-6-deoxycellulose (4) was synthesized from cellulose by three reaction steps, namely bromination at C-6, displacement of bromine by azide ion, and reduction of the azide group to amino group, in 67% overall yield. The 13C NMR spectrum of compound 4 supports the expected structure for 6-amino-6-deoxycellulose. The degree of substitution of compound 4 was 0.96.

The basic strategy to make a well-defined A-block-B type cellulose derivative consisting of cellulose and a hydrophobic part was established. The model experiments using cellobiose derivatives play an important role in an actual synthesis of A-block-B type copolymer consisting of cellulose and a hydrophobic part with well-controlled length. A new hydrophobic building block, 15-azidopentadecanoyl chloride, was converted from a commercially available15-hydroxypentadecanoic acid. The novel hydrophobic linker, 15-azidopentadecanoyl chloride, was twice introduced into the reducing end of the cellobiosylamine derivative. The structures of the model compounds for A-block-B type copolymer consisting of sugar and non-sugar blocks were characterized by use of nuclear magnetic resonance (NMR) spectroscopy and Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS).

The 3-ferrocenoylpropanoyl group, one of the redox species, was introduced at C-2 and/or C-3 positions of 6-O-(4-stearyloxytrityl)cellulose. The spreading behavior of the cellulose derivatives on the water surface and the properties of Langmuir-Blodgett (LB) films were investigated. The surface pressure-area isotherm of the cellulose monolayer was changed by the subphase temperature. Uniform monolayers of 6-O-(4-stearyloxytrityl)cellulose 3-ferrocene propionate (STCFc) could be deposited successively onto several substrates by the horizontal lifting method at 10 mN m -1 , and this produced X-type LB films. The successive uniform depositions of STCFc were confirmed by ultraviolet-visible absorption spectra. X-ray diffraction measurements indicated that the thickness of the STCFc molecules in the LB films was 1.99 nm. Fourier transform infrared spectroscopy measurements supported the idea that hydrocarbon chains in the LB films were highly ordered (trans-zigzag) and oriented considerably perpendicular to the surface of the substrate. Moreover, the C=O group of the ferrocenoyl groups was perpendicular to the surface of the substrate, and the ferrocene group was occupied in the water phase. Cyclic voltammograms for the STCFc monolayer on a gold electrode exhibited surface waves. The interfacial electron-transfer process between the redox site incorporated into the cellulose LB monolayer and the electrode surface was fast enough at a scanning rate lower than 100 mV s -1 .

Monolayer and multilayer Langmuir-Blodgett (LB) films of 6-O-alkylcelluloses with various chain lengths were prepared and studied. The surface pressure (pi)-area (A) isotherms of 6-O-alkylcelluloses exhibited characteristic behaviors depending on the length of the alkyl chain and temperature. 6-O-Stearylcellulose on the subphase formed a homogeneous monolayer at 10 mN m(-1). By transfer ratio, FT-IR, and contact angle measurements, it was proved that the monolayer of 6-O-stearylcellulose on the water surface was transferred successfully onto a substrate by a vertical dipping method to form a Z-type LB film. The transmission and reflection absorption IR spectrum indicated that the hydrocarbon chains had all-trans rotamers and were oriented nearly perpendicular to the surface in the film. AFM section analysis revealed that the thickness per layer was calculated to be 2.35 nm. These results suggested that the hydrocarbon chains were inclined at an angle of about 25.3 degrees to have high packing density in the alkyl region.

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 Α-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 Α-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.

A novel degradation method of arylglycerol-β-aryl (β-O-4) ether substructure in lignins without any secondary condensation reactions named TIZ method was developed. The TIZ method consists of three reaction steps: (1) selective tosylation (T) of primary hydroxyl group, (2) iodination (I), and (3) zinc-metal treatment (Z) to cleave of β-O-4 linkage. This method was applied to two nonphenolic β-O-4 lignin substructure compounds of guaiacyl and syringyl type: benzylguaiacylglycerol-β-guaiacyl ether (1a) and benzylsyringylglycerol-β-syringyl ether (1b). Respective reaction steps were performed quantitatively concerning both guaiacyl and syringyl models. After zinc treatment, almost 1 mole of olefinic compounds, 3-benzylguaiacyl-3-hydroxy-1-propene (4a) and 3-benzylsyringyl-3-hydroxy-1-propene (4b), were formed from 1 mol of compound 1a and 1b, respectively. This indicates that β-O-4 linkage in compound 1a and 1b was cleaved quantitatively without formation of any by-products. The structures of the de...

Seven possible regioselectively methylated cellulose acetates (RS-MCAs)—2,3,6-tri-O-methyl cellulose acetate, 3,6-di-O-methyl cellulose acetate, 2,6-di-O-methyl cellulose acetate, 2,3-di-O-methyl cellulose acetate, 6-O-methyl cellulose acetate, 3-O-methyl cellulose acetate, and 2-O-methyl cellulose acetate—were prepared for the first time from chemically synthesized cellulose derivatives obtained by cationic ring-opening polymerization and then were analyzed by 1H and 13C NMR spectroscopy. The chemical shifts of ring protons and carbons were influenced by substituent groups (methyl or acetyl) and clearly reflected the pattern of substituent distribution in anhydroglucose units. These data may conveniently be used for the determination of the substituent distribution of methyl cellulose. The synthesized RS-MCAs also may be used for the elucidation of the structure–property relationship. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4167–4179, 2002

The structural variety of the condensed tannins (proanthocyanidins) in the fruits of 16Diospyros species are reported. Eleven species contained condensed tannins mostly consisting of a mixture of catechin (CA) and gallocatechin (GCA) repeating units; the other five species did not. The GCA content in the CA-GCA total varied from 0.3% to 84.6%. The number of esterified gallic acid per one flavan repeating unit (degree of galloylation, DG) ranged from 0.01 to 0.89. The GCA content was found to be proportional to the DG values. Thus, 16Diospyros species tested may be classified into five groups by the analytical data of their condensed tannins. It may be interesting to compare their structural characteristics with those of the condensed tannins in other fruits, leaves, woods, and barks from the viewpoint of their biosynthesis and function in the plants.

Chemically synthesized (1 → 5)-β-d-glucofuranan, (1 → 5)-β-d-galactofuranan, (1 → 5)-β-d-xylofuranan, (1 → 5)-α-L-arabinofuranan, natural xylan, and curdlan were sulfated to investigate their inhibitory activities on B16-BL6 lung metastasis and anticoagulant activities. (1 → 5)-β-d-Glucofuranan sulfate, (1 → 5)-β-d-galactofuranan sulfate, xylan sulfate, and curdlan sulfate had binding abilities with B16-BL6 melanoma lysate. The inhibitory activities of sulfated polysaccharides on B16-BL6 lung metastasis selected by heparin binding assay were in the order (1 → 5)-β-d-galactofuranan sulfate > (1 → 5)--β-d-glucofuranan sulfate > xylan sulfate ≫ curdlan sulfate. Furthermore, (1 → 5)-β-d-galactofuranan sulfate, (1 → 5)-β-d-glucofuranan sulfate, and xylan sulfate had not only high inhibitory activity on B16-BL6 lung metastasis but also low anticoagulant activity. The correlation between chemical structure and biological activity is discussed.

The synthetic route to 3- O -benzyl-6- O -pivaloyl-α- d -glucopyranose 1,2,4-orthopivalate ( 1 ), which was previously established, was shortened by introducing two novel reactions, regioselective pivaloylation with dibutyltin oxide in toluene for the regioselective activation of hydroxyl groups, and intramolecular orthoesterification with benzenesulfonyl chloride and triethylamine in dichloromethane. Compound 1 was obtained in 58.8% overall yield from commercially available 1,2:5,6-di- O -isopropylidene-α- d -glucopyranose ( 2 ) via four reaction steps.

To clarify the utility as a protective group of 3-O-allyl group on ring-opening polymerization of alpha-D-glucopyranose 1,2,4-orthopivalate derivatives, four orthopivalate derivatives, 3-O-allyl-6-O-pivaloyl- (1), 3-O-allyl-6-O-benzyl- (2), 3,6-di-O-allyl- (3), and 3-O-allyl-6-O-methyl-alpha-D-glucopyranose 1,2,4-orthopivalates (4), were selected as starting monomers and were polymerized under -30 degrees C in CH2Cl2 using BF3.Et2O as a catalyst. All the orthopivalate derivatives 1-4 were found to give stereoregular polysaccharides, (1--4)-beta-D-glucopyranans. Thus, it was concluded that the allyl group as a protective group at 3-O position of glucose othropivalate is acceptable to yield stereoregular (1--4)-beta-D-glucopyranans, cellulose derivatives.

Residual wood meal after extraction of milled wood lignin (WMEM) ofEucalyptus globulus was extracted with alkali and LiCl/N,N-Dimethylacetamide (DMAc). These agents dissolve mainly hemicellulose and cellulose, respectively. The extractability of WMEM in alkali solutions was influenced by the degree of swelling of the cellulose. Under good swelling conditions, considerable amounts of cellulose and lignin were extracted with the hemicellulose. Maximum extractability was about 60% of the WMEM under optimum conditions (3 M or 5 M LiOH or 3M NaOH solution). Some portion of cellulose was extracted with LiCl/DMAc at room temperature. Thus, lignin inE. globulus WMEM was divided into three fractions: hemicellulose-lignin fraction, cellulose-lignin fraction, and insoluble-lignin fraction.

The nitrobenzene oxidation method was modified to obtain more reproducible data and more structural information about lignin, not only by gas chromatography (GC) but also by proton nuclear magnetic resonance (1H-NMR) spectroscopy for quantitative determination of the oxidation products and to simplify the procedures. The nitrobenzene oxidation mixture was directly extracted after acidification without preextraction of by-products. The direct extraction made the extractive step easy and gave reproducible data. 5-Iodovanillin was selected as a new internal standard. The reason for this selection was that 5-iodovanillin did not exist in the nitrobenzene oxidation products from any plant species and had an aldehyde group whose peak did not overlap with the other aldehyde peaks on an1H-NMR spectrum. Thus, the use of 5-iodovanillin enabled us to quantifyp-hydroxybenzaldehyde, vanillin, and syringaldehyde in oxidation products on the basis of1H-NMR analysis as well as GC. Furthermore, more information about the condensed structure of lignin was derived by comparing the1H-NMR and GC analyses.

Cellulose isolated from wood is more susceptible than cotton cellulose to homogeneous hydrolysis in phosphoric acid. The influence of carboxyl group introduction at the C6 position on the hydrolysis rate of cellulose in 82.5% phosphoric acid was studied as a model of the oxidation of cellulose during pulping. The rate constant of hydrolysis for dissolving pulp was larger than that of cotton cellulose at temperatures of 25°–35°C. Mercerized cotton cellulose was partially oxidized regioselectively at the C6 position by a free radical system using 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). The oxidized cellulose was obtained at a range of 1.7–12.7 mEq carboxyl content per 100 g of cellulose. The hydrolysis rate of the oxidized cellulose samples accelerated with increasing carboxyl content in the samples.

We studied the effect of the C6-substituent on the ring-opening polymerizations of ortho esters using the novel starting ortho ester derivative, 3-O-benzyl-6-deoxy-α-D-glucopyranose 1,2,4-orthopivalate (1). The ring-opening polymerization of orthopivalate 1 by Ph 3 CBF 4 gave the new stereoregular polysaccharide derivative, 3-O-benzyl-6-deoxy-2-O-pivaloyl-(1→4)-β-D-glucopyranan with [α] D 25 -26.7° and a number-average degree of polymerization (DP n ) of approximately 34. Thus, the electronic, not steric, effect of the substituent at the C6-position was the important factor for forming stereoregular (1→4)-β-pyranan in the ring-opening polymerization of ortho esters.

Heartwood of pernambuco (Guilandina echinata Spreng, synCaesalpinia echinata Lam.), which has been used as material for violin bows, was extracted by soaking in water, and the obtained extractives were analyzed. The main components of the extractives were identified to be protosappanin B and brazilin. In particular, protosappanin B occupied about 40% of the pernambuco extractives. The loss tangent (tanδ) of spruce wood impregnated with protosappanin B decreased markedly, the same as that of specimens impregnated with extractives before being purified. It is expected that protosappanin B can make a contribution to the decrease in tanδ due to impregnation with extractives.

To clarify the lowering mechanism of loss tangen (tanδ) of sitka spruce (Picea sitchensis Carr.) wood impregnated with extractives of pernambuco (Guilandina echinata Spreng. synCaesalpinia echinata Lam.), we examined the vibrational properties of the impregnated wood in relation to the adsorbed water. The results obtained were as follows: (1) The equilibrium moisture content (EMC) of impregnated sitka spruce decreased to some extent compared with untreated wood. (2) Frequency dependencies of tanδ a about 400–8000Hz showed that impregnated wood has much lower tan δ than untreated wood at around 9% mois ture content (MC), except for the high-frequency region. At high relative humidity, impregnated wood has a minimum tanδ (at around 4000Hz); and at other frequency ranges the tanδ of impregnated wood did not differ considerably from that of untreated wood. (3) The apparent activation energy of the mechanical relaxation process (ΔE) concerned with adsorbed water molecules was higher for impregnated specimens than for untreated ones at moderately high relative humidity, whereas at high relative humidity the difference was not observed. Based on these results, it is thought that the tanδ of impregnated wood decreased at low rela tive humidity because of the formation of direct hydrogen bonds between impregnated extractives and wood components. However, when the specimen is at higher relative

The ring-opening polymerization of 3-O-benzyl-β-L-arabinofuranose 1,2,5-orthopivalate (1) by BF 3 .Et 2 O gave stereoregular 3-O-benzyl-2-O-pivaloyl-(1→5)-α-L-arabinofuranan with [α] 25 D -151.4° and a number-average degree of polymerization (DPn) of approximately 91. These results indicate that the substituted effects derived from the chemical synthesis of cellulose by ring-opening polymerization can be also applied to that of the arabinose ortho ester derivative. Removal of the pivaloyl and benzyl groups gave a linear stereoregular polysaccharide (1→5)-α-L-arabinofuranan.

We have studied the ring-opening polymerizations of a variety of glucose orthoester derivatives and found that substituents on the monomer play an important role in stereo- and regioregularity of the resulting polymers.1-3 These substituent effects open the possibility of application to ring-opening polymerizations of other sugar orthoesters to give stereo- and regioregular polysaccharides. Additionally, the ring-opening polymerization of the galactose orthoester derivative4 gave stereoregular (1→5)-β-D-galactofuranan.

Sitka spruce (Picea sitchensis Carr.) was treated with water-soluble extractive components of pernambuco (Guilandina echinata Spreng. syn Caesalpinia echinata Lam.) by two methods: impregnation under evacuation using an aspirator and repetitive surface application using a brush. The influence of these treatments on the vibrational properties were examined. The loss tangent (tan δ) of the impregnated specimen decreased, up to nearly a half of its original value, with increasing weight gain. It is suggested that the decrease in tan δ results from impregnation of the extractive components into the amorphous region of cell walls, forming secondary bonds between matrix substances. The surface application of the extractive components, on the other hand, hardly brought about the desirable change in vibrational properties.

The impregnation of various simple phenolic and natural polycyclic compounds into wood was investigated from the viewpoints of vibrational property and dimensional stabilizing effect. When simple phenolic compounds were impregnated, the loss tangent (tan δ) in the longitudinal direction increased linearly with increasing weight gain. Meanwhile, among the natural polycyclic compounds hematoxylin decreased the tan δ drastically by impregnation. It was suggested that the five hydroxyl groups and the pyran ring oxygen in the hematoxylin molecule contribute to formation of the crosslinkage-type hydrogen bonds between wood components. The rigidity of hematoxylin molecules may also be important. By impregnation of about 10% catechol, resorcinol, and saligenin, a 40% level of antiswelling efficiency (ASE) was attained, although a significant dimensional stabilizing effect was not observed after impregnation of natural polycyclic compounds.

The reaction of (+)-catechin with formaldehyde vapor was investigated as a model reaction of formaldehyde adsorption of (+)-catechin. It was found by H nuclear magnetic resonance spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and gel permeation chromatography of the product that the vapor reaction of (+)-catechin with formaldehyde without a solvent or a catalyst proceeds via methylolation, condensation, and polymerization. This is the same as the reaction in a solvent in the presence of an acid or a base. The formation of polyoxymethylenes such as paraformaldehyde was not confirmed.

The enzymatic dehydrogenative polymerizations of monolignols, mainly using horseradish peroxidase (HRP)/hydrogen peroxide as a catalytic system, has been widely used as a model to study lignifi cation, yet there still remain several points to be clarifi ed. One of them is the peculiar behavior of sinapyl alcohol (SA) in the in vitro polymerizations. Many researchers have reported that enzymatic dehydrogenative polymerizations of SA afforded synthetic lignin (dehydrogenation polymer: DHP), but in extremely low yields, whereas the polymerizations of coniferyl alcohol (CA) or p-coumaryl alcohol (PA) gave their DHPs in high yields. Enzymatic dehydrogenative polymerizations of monolignols proceed mainly by three steps: (1) radical formation by enzymatic dehydrogenation of phenolic hydroxyl groups; (2) radical coupling; (3) nucleophilic addition of nucleophiles to the quinone methide intermediates (QMs), re sulting in the reproduction of phenolic compounds for subsequent oxidative couplings. The polymerization of SA is shown in Figure 1. Until now, the problems regarding the polymerizations of SA have been mainly discussed in terms of the reaction steps (1) and (2): the low reactivity of HRP to SA and preferential b-b coupling reactions to b-O-4. However, there is no report focused on reaction step (3) concerning the low polymerizability of SA. Brunow et al. reported that syringyl-type (S-type) quinone methide model compound was signifi cantly less

Summary The storage modulus (E′) and the loss tangent (tanδ) of reed (Arundo donax L.) used for woodwinds were measured at 20°C and 60% relative humidity and the effects of water soluble extractives on these properties were discussed. The extractives increased both the E′ and tanδof reed. There was a linear relationship between the tanδ change and the weight loss due to extraction. By using an uniaxial rheological model considering the anatomical structure of reed, the E′ and tanδ of reed were described using the storage moduli, loss tangents, and volume fractions of bundle sheaths and parenchyma cells. It was suggested that the extractives in parenchyma cells increased the modulus of elasticity for parenchyma cells by 25% and reduced the relaxation time of parenchyma cells by a factor of three. The main constituents of extractives were glucose, fructose and sucrose.

Diospyros species distributed widely in Thailand were classified into four ecotypes, according to their habitat; constantly humid area, alternately dry and wet area, mountainous cool area and all area. Some of them inhabit near dwelling areas or in the paddy field in the village. The young fruit is covered with dense pubescence in most species. The size, shape, and color of mature fruit greatly vary greatly with the species. In most species, the mature fruit has a soft pulp and hard skin. The fruit of six species has been used for dying. Four species produce edible fruits, with color and flavor favorable for breeding of edibleDiospyros species. The fruit of some species contains some chemicals useful as fish poisoning or of medicines, although the active components have not yet been identified. The edible fruit contained many tannin cells, but the fruit used as fish poisoning and medicines had only a few.

Ring-opening polymerizations of both 1,4-anhydro-3-O-benzyl-2-O-pivaloyl- (1) and 1,4-anhydro-3-O-benzyl-2-O-acetyl-α-d-xylopyranose (2) gave their respective (1→5)-β-d-xylofuranan derivatives. Sub...

Two novel methods for the syntheses of 1,4-anhydro-3- O -benzyl-2- O -pivaloyl- ( 1 ) and 2- O -acetyl-1,4-anhydro-3- O -benzyl- α - d -xylopyranose ( 2 ), starting materials for synthesizing stereoregular β -( 1 → 5)-xylofuranan by ring-opening polymerization are reported. Both synthetic routes start from d -xylopyranose, involve nine reaction steps, and give approximately 30–35% overall yields. The key reaction in the novel synthetic routes is the intramolecular nucleophilic attack of C-1 oxyanion on the C-5 position of 3- O -benzyl-5- O -( p -toluenesulfonyl)- α - d -xylofuranose ( 10 ), resulting in 1,5-acetal bond formation in high yield. The present synthetic routes enable us to prepare 1,4-anhydro- α - d -xylopyranose derivatives having different substituents at the 2- O - and the 3- O -positions.

We studied the effects of the hydroxylation patterns and the degrees of polymerization of condensed tannins on their metal-chelating capacity. These effects were evaluated by the relative stability of aluminium complexes with proanthocyanidin. The relative stability of aluminium complexes was determined qualitatively in methanol solution by the competition with the metallochromic reagent (chrome azurol S). A comparison of these capacities indicates the following results: 1) phenolic hydroxy groups in tannins are essential sites for the chelation with metal. 2) the sites of tannins interacting with metal ions are mainly o-dihydroxyphenyl groups in B-ring. 3) increasing degrees of polymerization of tannins tends to increase the relative stability of condensed tannin-aluminium chelate.

In order to synthesize ( 1 → 5)-β- d -galactofuranan by rig-opening polymerization, 3,6-di-O-benzyl-α- d -galactofuranose 1,2,5-orthopivalate (9) the most appropriate monomer was synthesized from d -galactose via 10 reaction steps. Novel intramolecular orthoesterification, which is a key reaction for sythesizing compound 9, was accomplished by treatment of 5-O-monocholoacetyl-2,3,6-tri-O-pivaloyl- d -galactofuranosyl chloride (6) with thiourea in pyridine at 80 °C to give the expected orthoester (7) in good yield without any side reactions.

Methyl 4-O-ethyl-β-D-glucopyranoside was treated with ozone both in anhydrous CH 2 Cl 2 and in aqueous solutions, to investigate the participation of radical species in the degradation of the polysaccharide during ozone bleaching. The reactivity of C in the model compound during ozonation was compared with that during oxidation with Fenton's reagent. It was found that ozone itself brings about glycosidic bond cleavage with a high degree of selectivity. The degradation of the model compound during ozonation in distilled water is due in part to radical species, and in part to ozone itself. The contribution of radical species to the degradation in distilled water is estimated to be about 40-70 %. Initial high pH and Fe 2+ ions enhanced the degradation of the model compound, and the contribution of radical species increased. However, the degradation of the model compound with radical species generated by Fe 2+ ions can be inhibited by adjusting to pH 2 without the removal of Fe 2+ ions. Vanillyl alcohol also enhanced the degradation of the model compound during ozonation. Radical reactions initiated by vanillyl alcohol participate in the degradation of the model compound even at pH 2. although the additional degradation of the model compound was inhibited by the low pH. Inhibition of the degradation of carbohydrates by radical species is one of the keys to prevent the viscosity drop in ozone bleaching of pulp.

Methyl 4-O-ethyl-β-D-glucopyranoside was used as a model for cellulose, and treated with hydrogen peroxide in the presence of Fe 2+ ions (Fenton's reagent) at room temperature for 2h, to investigate the free-radical reactions of polysaccharides during non-chlorine bleaching. Reaction products were analyzed by gas chromatography. The following products were determined: methyl β-D-glucoside, 4-O-ethyl-D-gluconic acid, gluconic acid. methyl 4-O-ethyl-glucuronoside, methyl glucuronoside, methyl 4-O-ethyl-2-keto-glucoside, methyl 4-O-ethyl-3-keto-glucoside, methyl 4-O-ethyl-6-aldehyde-glucoside. methyl 6-aldehyde-glucoside. 4-O-ethyl-glucose and glucose. The degradation of the model compound and the relative reactivities of the carbon atoms at Cl-C6 positions in the model compound were affected very much by the initial pH and oxygen content. Higher initial pH inhibited the degradation of the model compound. The reactivity at Cl, that is, glycosidic bond cleavage decreased with an increase of initial pH. Oxygen also inhibited drastically the degradation of model compound compared with that under nitrogen. The glycosidic bond cleavage was also inhibited by oxygen. The model compound was recovered unchanged in the presence of Mn 2+ or Cu 2+ instead of Fe 2+ .

Rubiadin (4) (1,3-dihydroxy-2-methylanthraquinone), which is one of the natural dyes from the roots of Rubiaceae, was synthesized from phthalic anhydride (1) and 2,6-dihydroxytoluene (3) by two reaction steps, that is, a Friedel-Crafts reaction with AlCl3 and a cyclization with H2SO4/HBO2. Microwave heating resulted in remarkable acceleration of the reaction rate in the first reaction, and had an effect in reducing the reaction time and increasing the yield of rubiadin (4) in the second reaction.

Effects of environmental factors on two-stage co-precipitation of tetragalloylglucose with three different proteins [bovine serum albumin (BSA), lysozyme, and myoglobin] were investigated. Factors such as pH, temperature, and ionic strength, mainly affected the second precipitation stage. On the other hand, protein concentration mainly affected the initial complexation stage. Precipitability of the galloylglucose-protein complexes is directly related to the solubility of the original protein under each environmental condition.

Solubility of bovine serum albumin (BSA) (P) precipitated with tetragalloylglucose (T) was investigated by successive washing over the pH range of 3–7. The solubility was highly dependent on pH (4 T/P(R) (pH 4 and 5), the precipitates were very stable, while when NSB 15(tetra) > 0(tri)].