9 research outputs found
Anti-Allergic Activity of Monoacylated Ascorbic Acid 2-Glucosides
2-O-α-D-Glucopyranosyl-L-ascorbic acid (AA-2G) is one of the stable ascorbic acid (AA) derivatives known as provitamin C agents. We have previously synthesized two types of monoacylated derivatives of AA-2G, 6-O-acyl-2-O-α-D-glucopyranosyl-L-ascorbic acids having a straight-acyl chain of varying length from C4 to C18 (6-sAcyl-AA-2G) and a branched-acyl chain of varying length from C6 to C16 (6-bAcyl-AA-2G) in order to improve the bioavailability of AA-2G. In this study, 6-sAcyl-AA-2G and 6-bAcyl-AA-2G per se showed the inhibitory effects on hyaluronidase activity and degranulation. 6-sAcyl-AA-2G exhibited strong inhibitory effects on hyaluronidase activity and degranulation in a concentration-dependent manner, and the inhibitory effects tended to become stronger with increasing length of the acyl chain. 2-O-α-D-Glucopyranosyl-6-O-hexadecanoyl-L-ascorbic acid (6-sPalm-AA-2G), which has a straight C16 acyl chain, was the most potent effective for inhibition of hyaluronidase activity and for inhibition of degranulation among the 6-sAcyl-AA-2G derivatives and the two isomers of 6-sPalm-AA-2G. Furthermore, percutaneous administration of 6-sPalm-AA-2G significantly inhibited IgE-mediated passive cutaneous anaphylaxis reaction in mice. These findings suggest that 6-sPalm-AA-2G will be useful for treatment of allergies
Electrical Conductivities of Narrow-Bandgap Polymers with Two Types of π-Conjugated Post-Crosslinking
Bandgap energy is one of the most important properties for developing electronic devices because of its influence on the electrical conductivity of substances. Many methods have been developed to control bandgap, one of which is the realization of conducting polymers using narrow-bandgap polymers; however, the preparation of these polymers is complex. In this study, water-soluble, narrow-bandgap polymers with reactive groups were prepared by the addition–condensation reaction of pyrrole (Pyr), benzaldehyde-2-sulfonic acid sodium salt (BS), and aldehydecontaining reactive groups (aldehyde and pyridine) for post-crosslinking. Two types of reactions, aldehyde with p-phenylenediamine and pyridine with 1,2-dibromoethylene, were carried out for the π-conjugated post-crosslinking between polymers. The polymers were characterized by proton nuclear magnetic resonance (1H-NMR), thermogravimetric/differential thermal analysis (TG/DTA), UltraViolet-Visible-Near InfraRed spectroscopy (UV-Vis-NIR), and other analyses. The bandgaps of the polymers, calculated from their absorption, were less than 0.5 eV. Post-crosslinking prevents resolubility and develops electron-conducting routes between the polymer chains for π-conjugated systems. Moreover, the post-crosslinked polymers maintain their narrow bandgaps. The electrical conductivities of the as-prepared polymers were two orders of magnitude higher than those before the crosslinking.This is a product of research that was financially supported (in part) by the Kansai University Fund for Supporting Young Scholars, 2018. “Syntheses of amphiphilic polymer and its application to artificial photosynthesis”.関西大学若手研究者育成経
炭素―硫黄結合形成反応によるスルホキシイミンの不斉合成法の開発
京都大学0048新制・課程博士博士(理学)甲第22267号理博第4581号新制||理||1658(附属図書館)京都大学大学院理学研究科化学専攻(主査)准教授 加納 太一, 教授 依光 英樹, 教授 大須賀 篤弘学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA
Synthesis of Reactive Water-Soluble Narrow-Band-Gap Polymers for Post-Crosslinking
In this study, water-soluble, narrow-band-gap polymers containing reactive groups were prepared by the addition-condensation of pyrrole (Pyr), benzaldehyde-2-sulfonic acid sodium salt (BS), and terephthalaldehydic acid (TPA) or p-hydroxybenzaldehyde (p-HB). TPA and p-HB were used for the post-crosslinking reaction between polymers. The polymers were characterized by employing various analyses such as 1H-NMR, thermal gravimetric analysis (TGA), and UV-Vis-NIR. The Eg values of polymers estimated from the absorption edges were 0.55 and 0.62 eV. The post-crosslinking reaction is important for preventing resolubilization and for developing an electron conducting route between the polymer chains. Herein, the post-crosslinked polymer was observed to maintain its narrow-band-gap and conductivity was increased 46 times compared to that observed before crosslinking
Electrical Conductivities of Narrow-Bandgap Polymers with Two Types of π-Conjugated Post-Crosslinking
Bandgap energy is one of the most important properties for developing electronic devices because of its influence on the electrical conductivity of substances. Many methods have been developed to control bandgap, one of which is the realization of conducting polymers using narrow-bandgap polymers; however, the preparation of these polymers is complex. In this study, water-soluble, narrow-bandgap polymers with reactive groups were prepared by the addition–condensation reaction of pyrrole (Pyr), benzaldehyde-2-sulfonic acid sodium salt (BS), and aldehyde-containing reactive groups (aldehyde and pyridine) for post-crosslinking. Two types of reactions, aldehyde with p-phenylenediamine and pyridine with 1,2-dibromoethylene, were carried out for the π-conjugated post-crosslinking between polymers. The polymers were characterized by proton nuclear magnetic resonance ((1)H-NMR), thermogravimetric/differential thermal analysis (TG/DTA), UltraViolet-Visible-Near InfraRed spectroscopy (UV-Vis-NIR), and other analyses. The bandgaps of the polymers, calculated from their absorption, were less than 0.5 eV. Post-crosslinking prevents resolubility and develops electron-conducting routes between the polymer chains for π-conjugated systems. Moreover, the post-crosslinked polymers maintain their narrow bandgaps. The electrical conductivities of the as-prepared polymers were two orders of magnitude higher than those before the crosslinking
Dynamic Kinetic Resolution of Aldehydes by Hydroacylation
We report a dynamic kinetic resolution (DKR) of chiral 4-pentenals by olefin hydroacylation. A primary amine racemizes the aldehyde substrate via enamine formation and hydrolysis. Then, a cationic rhodium catalyst promotes hydroacylation to generate α,γ-disubstituted cyclopentanones with high enantio- and diastereoselectivities
Anti-Allergic Activity of Monoacylated Ascorbic Acid 2-Glucosides
2-O-α-d-Glucopyranosyl-l-ascorbic acid (AA-2G) is one of the stable ascorbic acid (AA) derivatives known as provitamin C agents. We have previously synthesized two types of monoacylated derivatives of AA-2G, 6-O-acyl-2-O-α-d-glucopyranosyl-l-ascorbic acids having a straight-acyl chain of varying length from C4 to C18 (6-sAcyl-AA-2G) and a branched-acyl chain of varying length from C6 to C16 (6-bAcyl-AA-2G) in order to improve the bioavailability of AA-2G. In this study, 6-sAcyl-AA-2G and 6-bAcyl-AA-2G per se showed the inhibitory effects on hyaluronidase activity and degranulation. 6-sAcyl-AA-2G exhibited strong inhibitory effects on hyaluronidase activity and degranulation in a concentration-dependent manner, and the inhibitory effects tended to become stronger with increasing length of the acyl chain. 2-O-α-d-Glucopyranosyl-6-O-hexadecanoyl-l-ascorbic acid (6-sPalm-AA-2G), which has a straight C16 acyl chain, was the most potent effective for inhibition of hyaluronidase activity and for inhibition of degranulation among the 6-sAcyl-AA-2G derivatives and the two isomers of 6-sPalm-AA-2G. Furthermore, percutaneous administration of 6-sPalm-AA-2G significantly inhibited IgE-mediated passive cutaneous anaphylaxis reaction in mice. These findings suggest that 6-sPalm-AA-2G will be useful for treatment of allergies