[EN] DEHYDRATIVE CYCLIZATION OF PENTITOLS USING WATER-TOLERANT LEWIS ACID CATALYSTS UNDER MILD CONDITIONS AND DERIVATIVES [FR] CYCLISATION PAR DÉSHYDRATATION DE PENTITOLS À L'AIDE DE CATALYSEURS DE TYPE ACIDE DE LEWIS TOLÉRANTS À L'EAU DANS DES CONDITIONS DOUCES, ET DÉRIVÉS CORRESPONDANTS
investigation we chose α- and β-methyl-, β-allyl- and β-phenyl D-glucopyranose as well as four 1-deoxy-pentoses. In order to be able to classify the results, more ionicliquids with different structural motives were examined for cytotoxicity. Here, we present data that confirm the biocompatibility of such ILs consisting of naturally occurring molecules or their derivatives. The synthesized carbohydrate
大量天然存在的碳水化合物及其手性和结构的多样性导致了对基于碳水化合物的 IL 进行系统研究的想法。为此,我们研究了不同醚基(主要是甲基或乙基醚)对仲 OH 基团的影响,以及不同构型对物理性质(如熔点、热稳定性,尤其是对细胞毒性的影响)的影响。在本次调查中,我们选择了 α-和 β-甲基-、β-烯丙基-和 β-苯基D-吡喃葡萄糖以及四种 1-脱氧戊糖。为了能够对结果进行分类,检查了更多具有不同结构动机的离子液体的细胞毒性。在这里,我们提供的数据证实了这种由天然分子或其衍生物组成的 ILs 的生物相容性。测试了合成的基于碳水化合物的 ILs 作为药物洗脱球囊等医疗应用涂层添加剂的适用性。
Scope of the directed dihydroxylation: application to cyclic homoallylic alcohols and trihaloacetamides
作者:Timothy J. Donohoe、Lee Mitchell、Michael J. Waring、Madeleine Helliwell、Andrew Bell、Nicholas J. Newcombe
DOI:10.1039/b303081d
日期:——
The synthesis and directed dihydroxylation of a range of cyclic alkenes was investigated. Both homoallylic alcohols and homoallylic trihaloacetamides were found to be efficient directing groups, giving rise to good to excellent levels of remote asymmetric induction with OsO4–TMEDA. Interestingly, in all cases examined, trifluoroacetamides were found to be superior to trichloroacetamides as directing groups and an argument is presented which rationalises this observation.
Functionalised tetrahydrofuran fragments from carbohydrates or sugar beet pulp biomass
作者:Laure Benhamou、Robert W. Foster、David P. Ward、Katherine Wheelhouse、Lisa Sloan、Christopher J. Tame、Dejan-Krešimir Bučar、Gary J. Lye、Helen C. Hailes、Tom D. Sheppard
DOI:10.1039/c9gc00448c
日期:——
Carbohydrate biomass represents a potentially valuable sustainable source of raw materials for chemical synthesis, but for many applications, selective deoxygenation/dehydration of the sugars present is necessary to access compounds with useful chemical and physical properties. Selectivedehydration of pentose sugars to give tetrahydrofurans can be achieved by treatment of the corresponding N,N-dimethylhydrazones
Intramolecular dehydration of biomass-derived sugar alcohols in high-temperature water
作者:Aritomo Yamaguchi、Natsumi Muramatsu、Naoki Mimura、Masayuki Shirai、Osamu Sato
DOI:10.1039/c6cp06831f
日期:——
The intramolecular dehydration of biomass-derivedsugaralcohols D-sorbitol, D-mannitol, galactitol, xylitol, ribitol, L-arabitol, erythritol, L-threitol, and DL-threitol was investigated in high-temperature water at 523–573 K without the addition of any acid catalysts. D-Sorbitol and D-mannitol were dehydrated into isosorbide and isomannide, respectively, as dianhydrohexitol products. Galactitol was
Abstract The products of dehydration of pentitols in aqueous sulfuric acid have been studied by g.l.c.-m.s. Four isomeric 1,4-anhydropentitols were formed from d -arabinitol, but only two from xylitol and ribitol. The number of products could only be explained by assuming inversion of configuration at C-2 or C-4 during 1,4- or 2,5-cyclisation reactions. No product which involved inversion of configuration