کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7782970 | 1500568 | 2018 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Selective synthesis of curdlan Ï-carboxyamides by Staudinger ylide nucleophilic ring-opening
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Chemoselective modification of polysaccharides is a significant challenge, and regioselective modification is even more difficult, due to the low and similar reactivity of the various polysaccharide hydroxyl groups. Bromination of glycans that possess free 6-OH groups is exceptional in that regard, giving regiospecific, high-yield access to 6-bromo-6-deoxyglycans. Herein we report a simple and efficient pathway for synthesizing 6-Ï-carboxyalkanamido-6-deoxy-containing polysaccharide derivatives in a sequence starting from 6-bromo-6-deoxycurdlan, via azide displacement, then conversion of the azide to the iminophosphorane ylide by triphenylphosphine (Ph3P). We take advantage of the nucleophilicity of the iminophosphorane nitrogen by subsequent regioselective ring-opening reactions of cyclic anhydrides. These reactions of the useful polysaccharide curdlan were essentially completely regio- and chemo-selective, proceeding under mild conditions in the presence of ester groups, yet preserving those groups. These interesting polysaccharide-based materials have pendant carboxyls attached through a hydrocarbon tether and hydrolytically stable amide linkage; as such they are promising for diverse application areas, including aqueous dispersions for coatings, adhesives, and other consumer products, and for amorphous solid dispersions in oral drug delivery.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Carbohydrate Polymers - Volume 190, 15 June 2018, Pages 222-231
Journal: Carbohydrate Polymers - Volume 190, 15 June 2018, Pages 222-231
نویسندگان
Shu Liu, Chengzhe Gao, Laura I. Mosquera-Giraldo, Lynne S. Taylor, Kevin J. Edgar,