β-cyclodextrin and its silyl derivative inclusion complexes and conjugates with medicine preparation “Ibuprofen” and its synthetic precursors

Acylation of per-6-O-(tert-butyl)(dimethyl)silyl-α-cyclodextrin with acetylsalicylic chloride

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Earlier, aiming to synthesize the conjugates of α-and β-cyclodextrins containing drug residues at the cyclodextrin torus side occupied with secondary hydroxyl groups, we have performed acylation of per-6-О-(tert-butyl)(dimethyl)silyl derivatives of α-(I) and β-cyclodextrin (II) at the second hydroxyl groups with chloroanhydrides of a series of aromatic monocarpboxylic acids, followed removal of protecting silyl groups [1,2]. Acylation of the silyl derivatives I and II occurred with good yields in pyridine as well as (in the case of compound II) in DMF in the presence of N,Ndimethylaniline (method а) or С 6 Н 6 (method b) in the presence of Et 3 N, the amines acting as the formed hydrogen chloride scavengers (Scheme 1).

The trials to perform analogous acylation of the silyl derivative of α-cyclodextrin I with acetylsacicylic chloride III using the methods а and b unexpectedly led to the products of substitution of a substantial part of the protecting silyl groups with acetylsalicylic acid residues.

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“…), R f 0.7. 1 1 Н NMR spectra were recorded using the Jeol-ECX400 spectrometer (400 MHz). TLC analysis was carried out on alumina plates Silufol UV-254 with fixed silica layer; eluent: 6% NH 3 in Н 2 О-BuOHEtOH 5 : 4 : 5.…”

Inclusion complexes of β-cyclodextrin with some dicarboxylic acids

“…Apart from protection of the guest molecule from biodegradation and increase of the solubility in water, β-cyclodextrin in some cases favors efficient targeted drug delivery [1][2][3][4][5]. We previously proposed practical procedures for the synthesis of stable inclusion complexes of cyclodextrins with some aromatic monocarboxylic acids and determined the effects of the size of the cavity, solvent nature, and substitution pattern in the cyclodextrin framework on their stability [6][7][8].…”