نتایج جستجو برای: acetal chemistry

تعداد نتایج: 109309  

Journal: :Green Chemistry 2022

Aldehyde assisted fractionation of biomass produces an acetal-stabilised lignin that is fully upgradeable. We exploit the aldehyde to control lignin's physical properties, producing lignins can be soluble in both polar and apolar solvents.

2013
Zhijun Zhang Shujuan Sui Jianping Sun Qingwen Wang

Catalytic refining of bio-oil by reacting with olefin/alcohol over solid acids can convert bio-oil to oxygen-containing fuels. Reactivities of groups of compounds typically present in bio-oil with 1-octene (or 1-butanol) were studied at 120 °C/3 h over Dowex50WX2, Amberlyst15, Amberlyst36, silica sulfuric acid (SSA) and Cs2.5H0.5PW12O40 supported on K10 clay (Cs2.5/K10, 30 wt. %). These compoun...

Journal: :Journal of Strain Analysis for Engineering Design 2021

Helical Auxetic Yarns (HAYs) can be used in a variety of applications from healthcare to blast and impact resistance. This work focuses on the effect use different core materials (e.g. rubber, polyurethane, polytetrafluoroethylene/teflon, polypropylene, polyetheretherketone, polycarbonate, acetal) with nitinol wire wrap component maximum Negative Poisson Ratio (NPR) produced thus auxetic perfor...

Journal: :Organic & biomolecular chemistry 2011
Amit Nathubhai Richard Patterson Timothy J Woodman Harriet E C Sharp Miranda T Y Chui Hugo H K Chung Stephanie W S Lau Jun Zheng Matthew D Lloyd Andrew S Thompson Michael D Threadgill

Dimethylformamide dimethylacetal (DMFDMA) is widely used as a source of electrophilic one-carbon units at the formate oxidation level; however, electrophilic methylation with this reagent is previously unreported. Reaction of anthranilamide with DMFDMA at 150 °C for short periods gives mainly quinazolin-4-one. However, prolonged reaction with dimethylformamide di(primary-alkyl)acetals leads to ...

Journal: :Journal of the American Chemical Society 2002
Bozo Plesnicar Janez Cerkovnik Tell Tuttle Elfi Kraka Dieter Cremer

Low-temperature ozonation (-78 degrees C) of 2-methyl-1,3-dioxolane (1a) in acetone-d6, methyl acetate, and tert-butyl methyl ether produced both the corresponding acetal hydrotrioxide (3a, ROOOH) and the hemiortho ester (2a, ROH) in molar ratio 1:5. Both intermediates were fully characterized by 1H, 13C, and 17O NMR spectroscopy, and they both decomposed to the corresponding hydroxy ester at h...

2015
Xiaheng Zhang Yu Zhou Jianping Zuo Biao Yu

Periploside A is a pregnane hexasaccharide identified from the Chinese medicinal plant Periploca sepium, which features a unique seven-membered formyl acetal bridged orthoester (FABO) motif and potent immunosuppressive activities. Here, we show the synthesis of this molecule in a total of 76 steps with the longest linear sequence of 29 steps and 9.2% overall yield. The FABO motif is constructed...

2015

Asymmetric Conjugate Addition of ortho-Quinone Methides as a Pathway to the Core of Nomofungin Introduction: Tetracyclic structures are found at the core of many biologically active molecules. One class of compounds with a tetracyclic core is the family of communesin products. 1 These products have shown cytotoxicity against several leukemia cell lines as well as insecticidal activity against s...

Journal: :The Journal of antibiotics 1985
S Sakamoto T Tsuchiya A Tanaka S Umezawa M Hamada H Umezawa

23-Amino-4',23-dideoxymycaminosyl tylonolide diethyl acetal (5) has been prepared from 4',23-dideoxy-23-iodomycaminosyl tylonolide diethyl acetal (3) by treatment with sodium azide followed by selective reduction of the resulting azide (4). 23-Acylamino-23-deoxy (6 approximately 8) and 23-deoxy-23-urethane-type compounds (12 approximately 15) were further prepared. Treatment of the 23-alkylamin...

Journal: :Journal of Photopolymer Science and Technology 2000

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