Alkyne cellulose for Huisgen [3+2] cycloaddition with azido-terminated targets

作者：Cao, Liangcheng^*; Wang, Yuechuan

来源：Journal of Applied Polymer Science, 2017, 134(4): 44410.

DOI：10.1002/app.44410

• biopolymers and renewable polymers
• cellulose and other wood products
• grafting
• synthesis and processing

Azido-grafted cellulose has been reported widely applied for further functionalization by click chemistry. As an alternative method, we proposed alkyne-grafted cellulose as a prototype molecule for Huisgen [3+2] cycloaddition with azido-terminated target compounds. Alkyne cellulose was synthesized by acylation with prop-2-ynyl 5-chloro-5-oxopentanoate and, subsequently cycloaddition with 4-aminophenylazide, ethyl 2-azidoacetate, and (S)-2-(Azidomethyl)-1-(tert-butoxycarbonyl)pyrrolidine (Boc-pyrrolidine azide) to form triazole cellulose in a click manner. The reactions were confirmed qualitatively by Fourier transform infrared and NMR spectroscopy and analyzed quantitatively with elemental analysis data. The results show that a degree of substitution of up to 1.91 was obtained for esterification and, in most cases, was preferred completely in a selective way for the primary hydroxyl groups at the O-6 position and partially at the O-2 and O-3 positions. Cycloaddition conversions were found as high as 0.95, 0.99, and 0.99 for aniline-triazole cellulose, acetate-triazole cellulose, and Boc-pyrrolidine-triazole cellulose, respectively. Both esterification and cycloaddition were undertaken under mild conditions without additional heating.

• 出版日期2017-1-20
• 单位四川大学; 中国科学院重庆绿色智能技术研究院