Cyclodextrin action pattern

Cyclodextrin Action Pattern. The action pattern of alpha-, beta-, or gamma-cyclodextrin was determined by BioRad Aminex Carbohydrate HPX-42A HPLC with two columns in tandem at 85 C eluting with glass distilled water as at a flow rate of 0.6 ml/minute. Detection was by refractive index. 

During secondary liquefaction at 95 C or 90 C, a r id reduction in viscosity was observed. At 90 C, the viscosity reduction was monitored over time with a Nametre viscometer. The results demonstrated there was a r id reduction in viscosity to 400 centipoise x gm/cm by 7 minutes into secondary liquefaction (Figure 6). The action patterns of the liquefied starches following secondary liquefaction demonstrated the characteristic cyclodextrin action pattern at both temperatures. DE values were < 1.0 indicating the absence of reducing end-groups consistent with the mechanism of a CGTase. 

When subjected to the action of trimethylsilyl triflate and acetic anhydride, careful control of the reaction conditions leads to cyclodextrin 11 by selective replacement of the ben2yl groups from the primary rim by acetates (Scheme 9.5) [19]. The position 3 can also be selectively deprotected by the action of triethylsilane and iodine at low temperature, giving access to cyclodextrin 12 bearing a functionahzation pattern similar to cyclodextrin 9a [20]. These reactions illustrate another approach toward the selective modification of cyclodextrins selective removal of already installed groups, which is the counterpart to the selective installation of functional groups. 

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