Regioselective access to 3^I-O-substituted-β-cyclodextrin derivatives

Abstract

Formation of a copper(ii)-beta-cyclodextrin (beta-CD) complex in an aqueous medium allowed the regioselective introduction into the oligosaccharide of a benzyl or a bromo-allyl substituent at O-3.

Cyclodextrin-based multivalent glycodisplays: covalent and supramolecular conjugates to assess carbohydrate–protein interactions

“…Differences in the steric accessibility and acidity of the three types of hydroxyls in the molecule have been taken into account to conceive efficient position-selective and face-selective chemical functionalization methodologies. [17][18][19][20][21][22][23][24][25][26][27] A variety of multivalent conjugates with diverse architectures becomes then accessible through appropriate ligation chemistries (Fig. 1).…”

A HTS Assay for the Detection of Organophosphorus Nerve Agent Scavengers

“…As evaluated in the HTS fluorescent assay summarised in Figure 5, most of the tested nucleophiles exhibit a weak phosphonothioate activity. Thus, as shown by the colour-coded pattern ( Figure 5), HOBt (65), peracids 68 and 69, iodosobenzoic acid (IBA, 71), which according to the literature survey and to our previous experiments give satisfactory results with Gtype agents and the HTS assay using fluorogenic probes bearing the coumarin unit directly linked to the phosphorus, [13] in our case provided very disappointing results (which were further confirmed for the hydrolysis of PhX (3 b)). As we expected, the quaternised pyridinealdoximes, which are described as being the best OP-poisoned AChE reactivators, display the highest phosphonothioate activity, 2-PAM (11) being slightly better.…”

“…Our library contained oximes (such as pralidoxime (2-PAM, 11) and its derivatives (12)(13)(14)(15)(16)(17)(18)(19), trimedoxime (TMB-4, 20), obidoxime (21) and HI-6 (22)) already known for their ability to reactivate OPNA-inhibited AChE. Their efficiencies were compared with those of other oximes and strong nucleophiles such as hydroxy-or mercaptopyridines, hydroxypyridinones, hydroxylamines, pyrimidines, hydroxamic acids, quinazolines and peracids.…”

“…[5] For now the most promising agents are still strong oxidants that act as a nucleophiles, [9][10][11][12] for example, hydrogen peroxide, peracids or oxidative chlorides or peroxides. The phosphorolytic reactivity of o-iodosylcarboxylates and related nucleophiles has also received a lot of interest, [13] yet such very efficient G nerve agent scavengers are poorly active towards V nerve agents.…”

Efficient regioselective O3-monodesilylation by hydrochloric acid in cyclodextrins

“…Jind rich and Tislerova later reported 24 a direct synthesis of mono-3-O-cinnamylated b-CD (29% yield) in aqueous sodium hydroxide along with the formation of a large amount of polysubstituted by-products. More recently, Masurier et al reported 25 a novel method to regioselectively modify one of the O3-positions of native b-CD based on the formation of a temporary copper(II)-b-CD complex; the methodology appears to be only suitable for bulky electrophiles such as benzylic and 3-brominated allyl groups to afford the O3-monoalkylated b-CDs in 38e42% yields, together with some O2-substituted by-products. Remarkably, a de-O-benzylation method by using iodineetriethylsilane (I 2 eEt 3 SiH) as the reagent has been reported to regioselectively deprotected all O3-benzyl groups from per-2,3,6-benzylated a-CD.…”