Synthesis of 6-O-(3-alkylamino-2-hydroxypropyl) derivatives of chitosan was achieved using a four-step strategy of N-protection, O-epoxide addition, epoxide ring opening using an amine and N-deprotection. Benzaldehyde and phthalic anhydride were used for the N-protection step, producing N-benzylidene and N-phthaloyl protected derivatives, respectively, resulting in two corresponding final 6-O-(3-alkylamino-2-hydroxypropyl) derivative series, BD1-BD6 and PD1-PD14. All the compounds were characterized using FTIR, XPS and PXRD studies and tested for antibacterial efficacy. The phthalimide protection strategy was found to be easier to apply and effective in terms of the synthetic process and improvement in antibacterial activity. Amongst the newly synthesized compounds, PD13 (6-O-(3-(2-(N,N-dimethylamino)ethylamino)-2-hydroxypropyl)chitosan) was the most active with eight times greater activity compared to the unmodified chitosan and, PD7 6-O-(3-(3-(N-(3-aminopropyl)propane-1,3-diamino)propylamino)-2-hydroxypropyl)chitosan) having a four-fold activity than chitosan, was found to be the second most potent derivative. This work has produced new chitosan derivatives those are more potent than chitosan itself and show promise in antimicrobial applications.

壳聚糖的 6- O- (3-烷基氨基-2-羟丙基) 衍生物的合成是使用N-保护、O-环氧化物加成、使用胺和N-脱保护的环氧化物开环的四步策略实现的。苯甲醛和邻苯二甲酸酐用于N-保护步骤，分别产生N-亚苄基和N-邻苯二甲酰基保护的衍生物，产生两个相应的最终6- O-(3-烷基氨基-2-羟丙基)衍生物系列，BD1-BD6和PD1-PD14。使用 FTIR、XPS 和 PXRD 研究对所有化合物进行了表征，并测试了抗菌功效。发现邻苯二甲酰亚胺保护策略在合成过程和抗菌活性的提高方面更易于应用和有效。在新合成的化合物中，PD13（6- O -（3-（2-（N，N-二甲基氨基）乙基氨基）-2-羟丙基）壳聚糖）是最活跃的，与未修饰的壳聚糖相比，活性高八倍，并且， PD7 6- O -(3-(3-( N-(3-氨基丙基)丙烷-1,3-二氨基)丙氨基)-2-羟丙基)壳聚糖)比壳聚糖具有四倍的活性，被发现是第二个最有效的衍生物。这项工作产生了新的壳聚糖衍生物，它们比壳聚糖本身更有效，并在抗菌应用中显示出前景。