Investigation of acylation of β-cyclodextrin and its silyl derivative with benzoyl and acetylsalicyloyl chlorides

Acylation of β-cyclodextrin and its silyl derivative with benzoic and acetylsalicylic acid chlorides results in formation of the conjugates containing rests of benzoic and acetylsalicylic acids interesting in pharmacological aspect. It is found that heating slightly increases conversion at this reaction but effect of the solvent nature on the conversion is complicated. Thus, acylation of free β-cyclodextrin in pyridine and DMF proceeds at the primary hydroxyl groups, but after its treatment with sodium hydride in DMF this process carries out with formation of the products due to substitution at the secondary hydroxyls in not high yield. The inclusion complex of “guest-host” type of acetylsalicylic acid with β-cyclodextrin which composition is determined as 1:1 is prepared. On the whole, the conjugation and formation of the inclusion compound lead to increase in its solubility in water compared to acetylsalicylic acid.