23739-88-0Relevant articles and documents
Characterization of peracylated β-cyclodextrins with different chain lengths as a novel sustained release carrier for water-soluble drugs
Hirayama,Yamanaka,Horikawa,Uekama
, p. 130 - 136 (1995)
A new series of peracylated β-cyclodextrins(β-CyDs) with different alkyl chains (acetyl-lauroyl) was prepared in high purity by acylating all hydroxyl groups of β-CyD using acid anhydrides in pyridine, and their physicochemical properties of solubility, hydrolysis and release and interaction capacity were evaluated. The solubility of peracylated β-CyDs in water decreased with lengthening alkyl chain, whereas that in ethanol/water increased with increase in ethanol concentration, but tended to decrease at higher ethanol concentration. The solubility parameter of peracylated β-CyDs was determined by analyzing the peak-solubility phenomenon by a modified Hildebrand equation. The alkaline hydrolysis rate of peracylated β-CyDs decreased with lengthening alkyl chain, and was about 4-fold faster than that of the corresponding fatty acid ethyl esters. The interaction of perbutanoyl-β-CyD (TB-β-CyD) with a water-soluble drug, molsidomine, in the solid state was investigated by differential scanning calorimetry (DSC). The analysis of DSC curves suggested that molsidomine and TB-β-CyD form a binary solid dispersion with a 2:1 (drug: TB-β-CyD) molar ratio. The rate of drug release was markedly retarded by the combination with peracylated β-CyDs in the increasing order of the hydrophobicity of host molecules.
13C NMR study on peracetylated derivatives of cyclomaltoheptaose (β- cyclodextrin, β-CD) and its methylated derivative
Tezuka,Hermawan
, p. 181 - 188 (1994)
Peracetylated samples of cyclomaltoheptaose (β-cyclodextrin, β-CD) and its methylated derivative were studied by 13C NMR. The acetyl carbonyl carbon signal in peracetylated β-CD was resolved into a triplet, and the three peaks were assigned by long-range C-H COSY and INAPT techniques. The individual carbonyl peak was found to be indicative of the location of the acetyl group on the 2, 3, and 6 position in the glucose residues. An acetylated derivative of a partly methylated β-CD was also subjected to 13C NMR analysis to determine the distribution of acetyl and, subsequently, methyl groups on the glucose residues.
Complexes of peracetylated cyclodextrin in a non-aqueous aprotic medium: the role of residual water
Jicsinszky, Laszlo,Martina, Katia,Caporaso, Marina,Cintas, Pedro,Zanichelli, Andrea,Cravotto, Giancarlo
, p. 17380 - 17390 (2015/07/02)
This paper describes the interaction between aromatic esters and peracetylated cyclodextrins (CDs) studied by NMR spectroscopy in deuterochloroform (CDCl3). The observed chemical shift changes highlight the existence of interactions between an aromatic alkyl ester, water and peracetylated CDs. In some cases, substituent chemical shift determination was influenced by the low water content of CDCl3 and/or the host molecule. Higher CD concentrations resulted in water signal drifts in all studied cases. It was not possible to obtain a completely dry sample of peracetyl γCD: ～1 mol of water remained and the water signal showed reversed movement, with respect to the other two CD analogues, upon increasing host concentration. The estimated 1 : 1 stability constants for the water : peracetyl CD complexes are in the 50-150 M-1 range in CDCl3, but show a relatively large calculation error. The calculated 1 : 1 stability constants for the peracetyl CD : ester complexes are also in this range, but 1 : 2 and 2 : 1 complex compositions are also possible. Overall, our results highlight dynamic aspects of water nanoconfined in a highly hydrophobic environment, thus mimicking biological recognition where a few water molecules often play a pivotal role.
Acetylation of α- And β-cyclodextrines
Grachev,Edunov,Kurochkina,Popkov,Levina,Nifant'Ev
experimental part, p. 284 - 289 (2011/05/04)
Applying acetyl chloride and versatile bases and solvents per- and regioacetylated derivatives of α- and β-cyclodextrines were prepared. Conditions were established for performing regiodirected acetylation of the primary hydroxy groups of α- and β-cyclodextrines in the presence of free secondary hydroxy groups.
H2SO4-SiO2: Highly efficient and reusable catalyst for per-O-acetylation of carbohydrates under solvent-free conditions
Zhang, Jianbo,Zhang, Bo,Zhou, Jiafen,Li, Juan,Shi, Chunjuan,Huang, Ting,Wang, Zhongfu,Tang, Jie
experimental part, p. 165 - 177 (2012/01/19)
Sulfuric acid immobilized on silica gel (H2SO 4-SiO2) was used as an efficient promoter for per-O-acetylation of carbohydrates with acetic anhydride under solvent-free conditions. The substrates include not only monosaccharides and disaccharides, but also glycosides. The catalyst is recyclable and stable at room temperature, and the reaction protocol is simple, is cost-effective, and gives good isolated yield with high purity. The large-scale reactions also proceeded conveniently and in high yields. Taylor & Francis Group, LLC.
