Selective cross-metathesis of cellobiose derivatives with amido-functionalized olefinic structures: A model study for synthesis of cellulosic diblock copolymers.

This work describes a model study for synthesis of cellulose-based block copolymers, investigating selective coupling of peracetyl β-d-cellobiose and perethyl β-d-cellobiose at their reducing-ends by olefin cross-metathesis (CM). Herein we explore suitable pairs of ω-alkenamides that permit selective, quantitative coupling by CM. Condensation reactions of hepta-O-acetyl-β-d-cellobiosylamine or hepta-O-ethyl-β-d-cellobiosylamine with acyl chlorides afforded the corresponding N-(β-d-cellobiosyl)-ω-alkenamide derivatives with an aromatic olefin or linear olefinic structures.

Synthesis-property-performance relationships of multifunctional bacterial cellulose composites fermented in situ alkali lignin medium.

This work demonstrates a unique approach of utilizing alkali lignin (AL), as smart additive to in situ BC fermentation in which it concurrently acts as promoter to microbial growth as well as reinforcing filler for fabrication of multifunctional composites. Traditionally, BC fermentation is accompanied by inhibitor formation with sudden drop in pH leading to low yield and biomass growth. AL due to its antioxidant nature prevents formation of gluconic acid as byproduct, at ∼0.

Possible mechanisms for the generation of phenyl glycoside-type lignin-carbohydrate linkages in lignification with monolignol glucosides.

The existence and formation of covalent lignin-carbohydrate (LC) linkages in plant cell walls has long been a matter of debate in terms of their roles in cell wall development and biomass use. Of the various putative LC linkages proposed to date, evidence of the native existence and formation mechanism of phenyl glycoside (PG)-type LC linkages in planta is particularly scarce. The present study aimed to explore previously overlooked mechanisms for the formation of PG-type LC linkages through the incorporation of monolignol glucosides, which are possible lignin precursors, into lignin polymers during lignification.

Analysis of Fruit Lignin Content, Composition, and Linkage Types in Pear Cultivars and Related Species.

Lignin content, composition, and linkage types were investigated in pear fruit cultivars and related species. Lignin content increased during early stages and then decreased toward ripening in the core and flesh of "Gold Nijisseiki" and "Alexandrine Douillard". The lignin content was highest at harvest in Chinese quince.

Synthesis of polysaccharide-based block copolymers via olefin cross-metathesis.

Polysaccharide-based copolymers with brush-like, graft architectures have been prepared by many investigators. In contrast, it is challenging to prepare linear polysaccharide-based block copolymers. Only a few approaches have been reported for preparation of such architectures, despite the clear application potential of renewable-based, linear block copolymers.

Basic study for acyl chitosan isothiocyanates synthesis by model experiments using glucosamine derivatives.

Affecting factors to the acyl chitosan isothiocyanate synthesis by N-phenylthiocarbamoylation and the following acylation was investigated using octyl 2-amino-2-deoxy-β-D-glucopyranoside as a model compound. It was found from the acetylation of N-phenylthiocarbamoyl glucosamine derivative with acetic anhydride/pyridine that the glucosamine isothiocyanate was formed via N,N-(acetyl)phenylthiocarbamoyl glucosamine derivative and the conversion of N,N-(acetyl)phenylthiocarbamoyl glucosamine derivative to the glucosamine isothiocyanate proceeded mainly by thermal degradation of N,N-(acetyl)phenylthiocarbamoyl groups. The reaction temperature was an important factor to the isothiocyanate synthesis.

Preparation and electro-optical properties of triphenylamine-bound chitosan derivative.

3,6-Di-O-hexanoyl-N-[4-(N,N-diphenylamino)-1-phenyl] thiocarbamoyl chitosan was prepared from 3,6-di-O-hexanoyl chitosan isothiocyanate in a 78% yield, and spin-coated films of the chitosan derivative and tris(2-phenylpyridine)iridium (Ir(ppy)) were fabricated. Ultraviolet-visible absorption spectra and photoluminescence spectra of the films indicated efficient Förster energy transfer from the chitosan derivative to the Ir(ppy). An electroluminescent device using both compounds emitted green luminescence when voltage was applied.

Two-dimensional NMR analysis of Angiopteris evecta rhizome and improved extraction method for angiopteroside.

Introduction: The rhizome of Angiopteris evecta is of academic interest in Kalimantan, Indonesia, from an ethnobotanical perspective. Angiopteroside is a substance of pharmaceutical importance that is found in the rhizome of A. evecta.

Thermo-reversible supramolecular hydrogels of trehalose-type diblock methylcellulose analogues.

This paper describes the design and synthesis of new trehalose-type diblock methylcellulose analogues with nonionic, cationic, and anionic cellobiosyl segments, namely 1-(tri-O-methyl-cellulosyl)-4-[β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyloxymethyl]-1H-1,2,3-triazole (1), 1-(tri-O-methyl-cellulosyl)-4-[(6-amino-6-deoxy-β-d-glucopyranosyl)-(1→4)- 6-amino-6-deoxy-β-d-glucopyranosyloxymethyl]-1H-1,2,3-triazole (2), and 4-(tri-O-methyl-cellulosyloxymethyl)-1-[β-d-glucopyranuronosyl-(1→4)-β-d-glucopyranuronosyl]-1H-1,2,3-triazole (3), respectively. Aqueous solutions of all of the 1,2,3-triazole-linked diblock methylcellulose analogues possessed higher surface activities than that of industrially produced methylcellulose and exhibited lower critical solution temperatures, that allowed the formation of thermoresponsive supramolecular hydrogels at close to human body temperature. Supramolecular structures of thermo-reversible hydrogels based on compounds 1, 2, and 3 were investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Pyrene conjugation and spectroscopic analysis of hydroxypropyl methylcellulose compounds successfully demonstrated a local dielectric difference associated with in vivo anti-prion activity.

Our previous study on prion-infected rodents revealed that hydroxypropyl methylcellulose compounds (HPMCs) with different molecular weights but similar composition and degree of substitution have different levels of long-lasting anti-prion activity. In this study, we searched these HPMCs for a parameter specifically associated with in vivo anti-prion activity by analyzing in vitro chemical properties and in vivo tissue distributions. Infrared spectroscopic and thermal analyses revealed no differences among HPMCs, whereas pyrene conjugation and spectroscopic analysis revealed that the fluorescence intensity ratio of peak III/peak I correlated with anti-prion activity.

A Single Subcutaneous Injection of Cellulose Ethers Administered Long before Infection Confers Sustained Protection against Prion Diseases in Rodents.

Prion diseases are fatal, progressive, neurodegenerative diseases caused by prion accumulation in the brain and lymphoreticular system. Here we report that a single subcutaneous injection of cellulose ethers (CEs), which are commonly used as inactive ingredients in foods and pharmaceuticals, markedly prolonged the lives of mice and hamsters intracerebrally or intraperitoneally infected with the 263K hamster prion. CEs provided sustained protection even when a single injection was given as long as one year before infection.

A versatile pathway to end-functionalized cellulose ethers for click chemistry applications.

This paper describes a versatile pathway to heterobifunctional/telechelic cellulose ethers, such as tri-O-methyl cellulosyl azide and propargyl tri-O-methyl celluloside, having one free C-4 hydroxyl group attached to the glucosyl residue at the non-reducing end for the use in Huisgen 1,3-dipolar cycloaddition and copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The one-step end-functionalization of cellulose ethers for molecular rod synthesis involves the introduction of two reactive groups at both ends of the cellulose molecule, and can afford linear triblock copolymers via CuAAC and further reactions. We were able to tailor the degree of polymerization of end-functionalized cellulose ethers with controlled amounts of a Lewis acid, namely SnCl4.

Preparation of a squaraine-bounded cellulose derivative for photocurrent generation system.

A regio-selectively squaraine (SQ)-bounded cellulose derivative (4) with a degree of substitution of SQ (DSSQ) of 0.55 was prepared from 6-O-(4-methoxytrityl) cellulose (1) by three reaction steps in 77% total yield. Lauryl SQ carboxylate (8) was also prepared as a reference sample.

Preparation of a Near-Infrared Ray Absorption Film from N-Phenylthiocarbamoyl Chitosan Derivative.

We recently observed that the decanoylation of N-phenylthiocarbamoyl chitosan (2) with a mixture of decanoic anhydride and pyridine at 60 °C for 24 h afforded N,N-(decanoyl)phenythiocarbamoyl-/2-isothiocynato chitosan decanoate (3b) rather than the expected product N,N-(decanoyl)phenylthiocarbamoyl chitosan decanoate (3a). This result suggested that some of the N,N-(decanoyl)phenylthiocarmbamoyl groups had been converted to isothiocyanate groups during the decanoylation process. The subsequent reaction of compound 3b with aniline gave N,N-(decanoyl)phenylthiocarbamoyl/N-phenylthiocarbamoyl chitosan decanoate (4) in high yield.

Distribution of coniferin in differentiating normal and compression woods using MALDI mass spectrometric imaging coupled with osmium tetroxide vapor treatment.

Matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) was employed to detect monolignol glucosides in differentiating normal and compression woods of two Japanese softwoods, Chamaecyparis obtusa and Cryptomeria japonica Comparison of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry collision-induced dissociation fragmentation analysis and structural time-of-flight (MALDI-TOF CID-FAST) spectra between coniferin and differentiating xylem also confirmed the presence of coniferin in differentiating xylem. However, as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and MALDI-TOF CID-FAST spectra of sucrose were similar to those of coniferin, it was difficult to distinguish the distribution of coniferin and sucrose using MALDI-MSI and collision-induced dissociation measurement only. To solve this problem, osmium tetroxide vapor was applied to sections of differentiating xylem.

Facile synthesis of acyl chitosan isothiocyanates and their application to porphyrin-appended chitosan derivative.

Chitosan (1) was reacted with phenylisothiocyanate in 5% AcOH/H2O to give N-phenylthiocarbamoyl chitosan (2) with a degree of substitution (DS) of N-phenylthiocarbamoyl groups of 0.86 in 87.1% yield.

Tandem Staudinger/aza-Wittig reaction of 6-azido-6-deoxycellulose derivative.

The tandem Staudinger/aza-Wittig reaction of the 6-azido-6-deoxycellulose derivative (2) with triphenylphosphine and carbon disulfide afforded the corresponding 6-isothiocyanato-6-deoxycellulose derivative (3) in 47.3% yield. Compound 3 was further reacted with 4'-aminobenzo-15-crown ether to afford the crown ether-containing 6-N-thioureido-6-deoxycellulose derivative (4) in 70.

Immunolocalization of 8-5' and 8-8' linked structures of lignin in cell walls of Chamaecyparis obtusa using monoclonal antibodies.

Mouse monoclonal antibodies were generated against dehydrodiconiferyl alcohol- or pinoresinol-p-aminohippuric acid (pAHA)-bovine serum albumin (BSA) conjugate as probes that specifically react with 8-5' or 8-8' linked structure of lignin in plant cell walls. Hybridoma clones were selected that produced antibodies that positively reacted with dehydrodiconiferyl alcohol- or pinoresinol-pAHA-BSA and negatively reacted with pAHA-BSA and guaiacylglycerol-beta-guaiacyl ether-pAHA-BSA conjugates containing 8-O-4' linkage. Eight clones were established for each antigen and one of each clone that positively reacted with wood sections was selected.

Thermoresponsive hydrogel of diblock methylcellulose: formation of ribbonlike supramolecular nanostructures by self-assembly.

This article provides detailed insight into the thermoresponsive gelation mechanism of industrially produced methylcellulose (MC), highlighting the importance of diblock structure with a hydrophobic sequence of 2,3,6-tri-O-methyl-glucopyranosyl units for this physicochemical property. We show herein, for the first time, that well-defined diblock MC self-assembles thermoresponsively into ribbonlike nanostructures in water. A cryogenic transmission electron microscopy (cryo-TEM) technique was used to detect the ribbonlike nanostructures formed by the diblock copolymers consisting of hydrophilic glucosyl or cellobiosyl and hydrophobic 2,3,6-tri-O-methyl-cellulosyl blocks, methyl β-D-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-celluloside 1 (G-236MC, DP(n) = 10.

2-O-Methyl- and 3,6-di-O-methyl-cellulose from natural cellulose: synthesis and structure characterization.

For the first time, 2-O-methyl- (2MC) and 3,6-di-O-methyl-cellulose (36MC) were synthesized via 3-O-allyl- and 3-O-methyl-cellulose, respectively. Position 6 of 3-O-allyl- and 3-O-methyl-cellulose was protected with the 4-methoxytrityl groups. The reaction time and temperature were optimized to achieve a high regioselectivity at C-6 and to prevent the introduction of the 4-methoxytrityl group at C-2 of the polymer.

Preparation of 6-azafulleroid-6-deoxy-2,3-di-O-myristoylcellulose.

6-Azafulleroid-6-deoxy-2,3-di-O-myristoylcellulose (3) was synthesized from 6-azido-6-deoxycellulose (1) by two reaction steps. The myristoylation of compound 1 with myristoyl chloride/pyridine proceeded smoothly to give 6-azido-6-deoxy-2,3-di-O-myristoylcellulose (2) in 97.0% yield.

Synthesis of blockwise alkylated (1→4) linked trisaccharides as surfactants: influence of configuration of anomeric position on their surface activities.

New carbohydrate-based surfactants consisting of hydrophilic cellobiosyl and hydrophobic glucosyl residues, methyl β-d-glucopyranosyl-(1→4)-α-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-α-d-glucopyranoside 1 (GβGαMα, G: glucopyranosyl residue, α and β: α-(1→4)- and β-(1→4) glycosidic bonds, M: methyl group), 2 (G(β)G(β)M(α)), 3 (G(β)G(α)M(β)), 4 (G(β)G(β)M(β)), 5 (G(β)G(α)E(α), E: ethyl group), 6 (G(β)G(β)E(α)), 7 (G(β)G(α)E(β)), 8 (G(β)G(β)E(β)) and eight α-and β-glycoside mixtures (a mixture of 1 and 2: 1/2=62/38 (9), 32/68 (10); a mixture of 3 and 4: 3/4=69/31 (11), 32/68 (12); a mixture of 5 and 6: 5/6=62/38 (13), 33/67 (14); a mixture of 7 and 8: 7/8=59/41 (15), 29/71 (16)) were synthesized via combined methods consisting of acid-catalyzed alcoholysis of cellulose ethers and glycosylation of phenyl thio-cellobioside derivatives. Their surface activities in aqueous solution depended on their chemical structures: α- or β-(1→4) linkage between hydrophilic cellobiosyl and hydrophobic glucosyl blocks, methyl or ethyl groups of hydrophobic glucosyl block, and α- or β-linked ether group at the C-1 of hydrophobic glucosyl block. The mixing effect of α- and β-glycosides on surface activities was also investigated.

Synthesis and structure/property relationships of regioselective 2-O-, 3-O- and 6-O-ethyl celluloses.

Regioselectively ethylated celluloses, 2-O- (1), 3-O- (2), and 6-O-ethyl- (3) celluloses were synthesized via ring-opening polymerization of glucopyranose orthopivalate derivatives. The number-average degrees of polymerization (DP(n)s) of compounds 1 and 2 were calculated to be 10.6 and 49.