Branched Thiocyclodextrins

Alternative routes to branched CDs have also been investigated. The branched thiocyclomaltoheptaoses 50 and 51 have also been obtained in 64 and 60% yield, respectively, from 6-O-tosylcyclomaltoheptaose (58) by Sn2 displacement with the 1-thiolates 59 and 60 [43]. The utility of such a reaction for tethering cyclodextrins 

A new and exciting application to the synthesis of branched cyclodextrins has recently been reported, whereby acarbose (68), the known potent inhibitor of glu-coamylase, has been tethered to a cyclodextrin via flexible spacers of different length [46]. The functionalized spacers (69 and 70) were S-deacetylated and the corresponding thiolates coupled easily to 6-deoxy-6-iodocyclodextrin (53), affording the branched fully acetylated cyclodextrins 71 (76%) and 72 (64%), respectively. 

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The in vitro flocculation of the yeast Kluyveromyces bulgaricus was inhibited by the branched thiocyclodextrin 64 (Scheme 15) with the same efficiency as the best known ligand [45]. On the other hand, the 4-thiogalabioside 90 (Scheme 18) has been shown to be ten times less recognized than its oxygen analog by a bacterial pilus adhesin [48]. 

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