Facile synthesis of mono-6-amino-6-deoxy-α-, β-, γ-cyclodextrin hydrochlorides for molecular recognition, chiral separation and drug delivery
We describe a protocol for the synthesis of mono-6-amino-6-deoxy-cyclodextrin hydrochloride (CD-NH3Cl), applicable to α-, β- and γ-cyclodextrin. These structurally simplest, highly water-soluble cationic cyclodextrins can be widely used in molecular recognition, chiral separation and drug delivery studies. Starting from commercially available chemicals, CD-NH3Cl is synthesized in four steps: (i) selective tosylation of cyclodextrin by the use of p-toluenesulfonyl chloride to afford mono-6-(p-toluenesulfonyl)-6-deoxy-cyclodextrin (Ts-CD); (ii) azide substitution of Ts-CD with sodium azide to afford mono-6-azido-6-deoxy-cyclodextrin (CD-N3); (iii) reduction of CD-N3 with triphenylphospine followed by hydrolysis to prepare mono-6-amino-6-deoxy-cyclodextrin (CD-NH2); and (iv) treatment of CD-NH2 with hydrochloric acid to afford the titled CD-NH3Cl with good yield. The overall protocol requires ∼2 weeks.
Comments
We are preparing some p-toluenesulfonyl cyclodextrin (Ts-CD) from cyclodextrin according your paper on Nature Protocol, 2008, page 691. Every thing was OK when we treated beta-CD. But we have many trouble to dissolve alfa-CD in dry pyridine. The alfa-CD looks not solube in pyridine at all. We have repeated the experiments several times and got the same phenomena. Now we are feeling very frustrate about these fails.
I really need your help. It will be very nice if you can give me some suggestion or advice.
Posted by: Yongbin Han | April 30, 2009 09:36 AM