Kurita Keisuke, Akao Hirofumi, Yang Jin, Shimojoh Manabu
Department of Applied Chemistry, Faculty of Engineering, Seikei University, Musashino-shi, Tokyo 180-8633, Japan.
Biomacromolecules. 2003 Sep-Oct;4(5):1264-8. doi: 10.1021/bm034074p.
Synthesis and properties of chitin and chitosan derivatives having beta-maltoside branches at C-6 have been studied. Chitosan was first transformed into an organosoluble acceptor having a reactive group only at C-6, 3-O-acetyl-2-N-phthaloyl-6-O-trimethylsilylchitosan. Glycosylation with an ortho ester from d-maltose was performed successfully at room temperature in dichloromethane in the presence of trimethylsilyl trifluoromethanesulfonate as the catalyst. The degree of substitution could be controlled by the reaction conditions and was up to 0.56. Full deprotection gave chitosan with maltoside branches, and the subsequent N-acetylation resulted in the formation of the corresponding chitin derivative. The introduced disaccharide unit improved hydrophilic properties considerably compared to monosaccharide units as confirmed by high solubility in water and moisture absorption and retention ability. The enzymatic degradability and antimicrobial activity were moderate probably because of the bulky nature of the branches.
对在C-6位具有β-麦芽糖苷支链的几丁质和壳聚糖衍生物的合成及性质进行了研究。壳聚糖首先被转化为仅在C-6位具有反应性基团的有机可溶性受体，即3-O-乙酰基-2-N-邻苯二甲酰基-6-O-三甲基甲硅烷基壳聚糖。在三甲基甲硅烷基三氟甲磺酸酯作为催化剂的存在下，于室温在二氯甲烷中成功地用来自d-麦芽糖的原酸酯进行了糖基化反应。取代度可通过反应条件控制，最高可达0.56。完全脱保护得到具有麦芽糖苷支链的壳聚糖，随后进行N-乙酰化反应生成相应的几丁质衍生物。如在水中的高溶解度以及吸湿和保水能力所证实的，与单糖单元相比，引入的二糖单元显著改善了亲水性。酶促降解性和抗菌活性适中，这可能是由于支链体积较大的缘故。
