Synthese und ¹H‐NMR‐Studie der vier unverzweigten peracetylierten β‐D‐Glucopyranosyl‐β‐gentiobiosen

Abstract

Synthesis and 'H-NMR Study of the Four Unbranched Peracetyl-p-D-glucopyranosyl-p-gentiobioses SummaryWith regard to the structure elucidation of an unknown trisaccharide isolated from the stigmas of garden crocusses (Crocus neapolitanus var.) , the four unbranched (1 +6)-, (1 +4)-, (1 +3)-, and (1 +2)-connected 8-D-glucopyranosyl-P-gentiobiose peracetates were synthesized. A complete analysis of the 'H-NMR spectra of the four trisaccharide peracetates was carried out.Einleitung. ~ Aus den Stempeln der Gartenkrokus-Sorte cr Blauer Vogel)) (Crocus neapolitanus uar.) konnten neben Crocetin-mono@-gentiobiosyl)ester, Crocetin-(paglucosyl)@-gentiobiosy1)ester und Crocetin-di@-gentiobiosy1)ester (Crocin), die wir bereits fruher auch aus Safran isoliert hatten [l] Aus den Kopplungskonstanten der anomeren Protonen von 8 Hz im 'H-NMR-Spektrum des peracetylierten Crocetin-di(triglucosy1)esters konnte auf die P-Verknupfung der drei Glucoseeinheiten geschlossen werden. Im Hinblick auf die Strukturaufklarung der isolierten Verbindung haben wir eine Reihe von Trisacchariden synthetisiert und einer systematischen 'H-NMR-Studie unterzogen. Aufgrund der Vorversuche war es naheliegend, dass vorerst Trisaccharide mit Gentiobiose als Baustein untersucht wurden. In der vorliegenden Arbeit berichten wir uber die Synthese und die 'H-NMR-Studie der unuerzweigten, peracetylierten 8-D-Glucopyranosyl-8-gentiobiosen.

Metabolism of the Plant Growth Regulator (E)-[3H]2-Ethylhex-2-enoic Acid in Hordeum vulgare

“…The spectrum of E H A -G entA c7 confirmed the presence of seven acetyl groups, indicating two hexose units. The chemical shifts of the carbohydrate protons agreed well with those of the model compound G entA c8 (Table II) and with 'H-NM R data for re lated triglucoses, published by Rychener et al [9,10]. The ester linkages of EHA-G1cA c4 and EH A -…”

Synthesis and Haemolytic Activity of Randianin Isomers

“…After addition of 100 mg I 2 , a solution of 430 mg (0.61 mmol) acetobromolaminaribiose in 5 ml dry CHCl 3 was added. (Acetobromolaminaribiose was obtained by bromination [15] of peracetyllaminaribiose which was prepared from diacetone glucose as described [17,18]). This mixture was stirred under Ar for 48 h, ®ltered, and CHCl 3 was evaporated.…”

“…The solution was heated to 50 C, and two thirds of the solvent were evaporated. Thereafter, 1.6 g (6.3 mmol) Hg(CN) 2 and 900 mg (1.3 mmol) acetobromocellobiose (obtained from octaacetylcellobioside [15,17]) dissolved in 20 ml of benzene:CH 3 NO 2 1:1 were added. The mixture was heated under Ar to 100 C and stirred for 3 h. After cooling to room temperature, CHCl 3 was added, and the solution was washed three times with 5% aqueous KJ, twice with 10% NaHCO 3 , and twice with water.…”

Hydrophilic Carotenoids: Surface Properties and Aggregation of Crocin as a Biosurfactant

“…Carotenoid glycosides can be synthesized, but in spite of reported high yields, the properties of these biodegradable surfactants have not been investigated [17]. Crocin (1) has antioxidant [18] and radical-scavenging [19] properties, acts as a singlet-oxygen ( 1 O 2 ) quencher [20] [21], inhibits cancer-cell growth [22] [23] and arthritis [24], and prevents neurodegenerative disorders [25].…”