Synthesis of Guaiacylglycerol-β-Coniferyl and β-Coniferyl Aldehyde Ethers

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。A new synthetic method for the preparation of guaiacylglycerol-β-coniferyl and β-coniferyl aldehyde ethers, representing the most important lignin substructure are described as one in a series of synthetic studies of lignin model compounds

セルロースの還元性未端基の反応性 I : フェニルセルロシドの調製

As the first step in a project to synthesize cellulose derivatives with highly regioselelective functionality, we planned to introduce a specific functional group into only the reducing-end group of a cellulose derivative. Glycosylation reactions, which are specific for the hemiacetal hydroxyl group, were carried out using cellulose triacetate (CTA) as the starting material and phenol, a simple and easily identifiable compound, as the aglycon. CTA was reacted with phenol in the presence of boron trifluoride etherate to obtain phenyl peracetyl celluloside (PPAC), which contains the phenyl group in only the reducing-end group, in high yield. Based on the molecular weight of the product, calculated both from viscosity and from the absorbance at 274 nm, it was concluded that under these reaction conditions a certain degree of depolymerization also occurs. However, it is clear that a phenyl group was introduced into each new reducing-end group formed by the cleavage of a glycosidic bond. Thus, the reaction proceeding under these conditions is a sort of henolysis of CTA. The present method offers one means to introduce a specific functional group into only the reducing-end group of CTAセルロースの高位置選抗的置換誘導体の合成研究の一環として, まずセルロースの還元性未端基のみにある特定の官能基を導入することを計画した。出発物質としてセルローストリアセテー卜 (CTA), アグリコンとして最も簡単で, 同定しやすいフェノールを用いて, ヘミアセタール性水酸基に特異的であるグリコシル化反応を試みた。三フッ化ホウ素エーテル錯塩の存在下, CTAとフェノールを反応させたところ, フェノールがCTAの還元性未端基のみに導入されたフェニルパーアセチルセルロシド (PPAC) が高収率で得られた。生成物の溶液粘度および274nmの吸光度から求めた分子量から, この反応条件下ではある程度の解重合が進行するが, グリコシド結合が切断した後に新たに生成した還元性未端基には必らずフェノールが導入されることが判明した。すなわち, この反応は一種のCTAのフェノール分解であり, 本法はCTAの還元性未端基のみにある特定の官能基を導入するための一つの手段を提供するものと考えられる

Chiroptical properties of an alternatingly functionalized cellotriose bearing two porphyrin groups.

Right-handedness derived from bisporphyrins attached to a cellotriose backbone at O-6 and O''-6 positions is revealed for the first time. This cellotriose is proposed as a model of alternatingly functionalized cellulosics, which have promising properties for applications in optoelectronics and molecular receptors owing to the chirality and rigid backbone effects

<Review Article>Enzymic Dehydrogenation of p-Coumaryl Alcohol and Syntheses of Oligolignols

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました

Enzymic Dehydrogenation of p-Coumaryl Alcohol. : III. Analysis of Dilignols by Gas Chromatography and NMR Spectrometry

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。p-Coumaryl alcohol was dehydrogenated with peroxidase and H_2O_2 system. Five dilignols, p-coumarylresinol (I), dehydrodi-p-coumaryl alcohol (II), p-hydroxyphenyl-glycerol-β-coumaryl ether (III), monoepoxylignan (IV) and 5-5'-dilignol (V) were identified and determined by both gas chromatography and NMR spectrometry, and the ratio of the amounts of the three main dilignols (I, II and III) was 31 : 49 : 20. The dilignol (V) was trace in amount (0.6%), and 1, 2-diarylpropane-l, 3-diol (VI) could not be found. The ratio of the racemoid and mesoid couplings at C-β and C-β' carbons was about 9.4 : 1, and the dilignol (III) was a mixture consisting of erythro and threo isomers (1:4.7) whose ratio was determined by gas chromatography. From these results, it was concluded that coniferyl and p-coumaryl alcohols had almost the same reactivity on enzymic dehydrogenation

P - クマリル アルコール ノ コウソテキ ダッスイソ ハンノウ ト オリゴリグノールルイ ノ ゴウセイ

京都大学0048新制・論文博士農学博士乙第4266号論農博第876号新制||農||308(附属図書館)学位論文||S55||N1190(農学部図書室)UT51-57-E331(主査)教授 樋口 隆昌, 教授 横田 德郎, 教授 井上 雄三学位規則第5条第2項該当Kyoto UniversityDFA

Synthesis of p-Coumar-, Coniferyl- and Sinap Aldehydes

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。p-Coumar-, coniferyl- and sinap aldehydes were synthesized in good yields by new two synthetic methods. 1) The aldehydes were prepared by a two-carbon homologation of p-hydroxybenzaldehyde, vanillin and syringaldehyde with 2, 4, 4, 6-tetramethyl-5, 6-dihydro-1, 3-oxazine in the presence of n-butyllithium in anhydrous tetrahydrofurane at -77℃. 2) The aldehydes were also prepared by reduction of the corresponding p-hydroxycinnamic acid chlorides with lithium tri-t-butoxyaluminohydride in anhydrous diglyme at -77℃

Synthesis of methylcellulose model copolymers with heterogeneous distribution and their solution properties

In order to elucidate the characteristic features of commercial methylcellulose precisely, O-methylcellulose model copolymers consisting of 2, 3, 6-tri-O-methylanhydroglucose unit (236MeAGU) and 2-O-methylanhydroglucose unit (2MeAGU) with various composition ratios were synthesized via cationic ring-opening copolymerization of the corresponding glucose orthoester derivatives, subsequent removal of pivaloyl and allyl groups, and methylation. The structure of the obtained copolymers was confirmed by 1H-, 13C-NMR, and FT-IR. Temperature-dependent turbidity measurement verified their thermoresponsive behavior in aqueous solution. The lower critical solution temperature was tuned from 63 to 45 °C above 47 mol-% 236MeAGU content. The hydrophobicity along the cellulose chain was dominant to determine their physical properties. However, the aqueous properties of the MC model copolymers were strongly affected by the slight difference of the composition ratio. The present method would provide further details of the structure–property relationship of O-methylcellulose

Structural Elucidation of Bamboo Lignin by Acidolysis and Ozonolysis I.

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。Bamboo lignin was completely degraded into the oligomers composed of monomeric to pentameric products by acidolysis and mild ozonolysis. Model experiment showed that the phenylcoumarone moiety which is known to be produced from the phenylcoumarane structure in lignin in acidolysis is cleaved almost quantitatively to 5-acetyl derivatives and p-hydroxybenzoic acid derivatives by the mild ozonolysis (-70℃). From the monomer fraction of the ozonolysis products of the lignin residue by acidolysis p-hydroxybenzoic acid derivatives (XXI, XVII), methyl p-hydroxybenzoate derivatives (XXII, XXVI, XXVIII), p-cresol derivatives (XVIII, XXIII), p-hydroxybenzaldehyde derivatives (XX, XXV, XXVII), p-hydroxybenzylmetyl ether derivatives (XIX, XXIV) and dimethyloxalate (XXIX) were obtained, respectively

Acidolysis of Bamboo Lignin II : Isolation and Identification of Acidolysis Products

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。Guaiacyl, syringyl and ρ-hydroxyphenyl monomers which are expected by cleavage of the β-ether bonds in arylglycerol-β aryl ether structures have been isolated and identified in the acidolysis products of a bamboo MWL by various methods such as IR and NMR spectrometry. ω-Hydroxysyringylacetone was the predominant product in monomeric fraction followed by w-hydroxyguaiacylacetone. DL-Syringaresinol and DL-episyringaresinol were isolated from dimeric fraction and identified by melting point, UV, IR, NMR and mass spectrometry. These findings in addition to previous results indicate that the bamboo MWL is a mixed polymer of guaiacyl and syringyl propanes and a small amount of ρ-hydroxyphenylpropane connected through similar linkages found in spruce MWL