A recent paper has dicussed a novel approach for the functionalization of β-cyclodextrin (BCD).
A continuous flow method was developed for the synthesis of 6-monoamino-6-monodeoxy-β-CD starting from native BCD through three reaction steps, such as monotosylation, azidation and reduction. The three steps were coupled in a semi-continuous flow system, where a solvent exchange was performed after the tosylation step, while the azidation and the reduction steps were coupled in one flow system obtaining the desired product in a high yield. Comparing the continuous flow processes with batch methods, similar yields can be achieved, however, under flow conditions, the reaction time can be reduced from hours to minutes. Moreover, by the semi-flow method developed, the production 6-monoamino-6-monodeoxy-β-cyclodextrin could be carried out in a safer way due to the easier handling of toxic derivatives (sodium azide, tosyl chloride) and with more precise parameter control.
Orosz, J. M.; Ujj, D.; Kasal, P.; Benkovics, G.; Bálint, E. Continuous flow synthesis of 6-monoamino-6-monodeoxy-β-cyclodextrin. Beilstein J Org Chem 19, 294 (2023). https://doi.org/10.3762/bjoc.19.25