Guanidine masked catechol initiator promoted ring-opening polymerization of sarcosine N-carboxyanhydride

Abstract

The synthesis of catechol polymers often demands tedious protection and deprotection steps. In this work, the role of a guanidine base to subdue the catechol functions and promote the ring-opening polymerization (ROP) is suggested. Accordingly, guanidine, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), was employed to mediate ROP of N-carboxyanhydride (NCA) from a catechol initiator. MTBD played a dual-role in ROP of sarcosine-NCA (Sar-NCA) and masking the catechol initiator concurrently. Catechol-ended polysarcosine (PSar) was synthesized with a predicted molecular weight (M_n,SEC = 3.5 kg mol⁻¹, M_n,NMR = 3.7 kg mol⁻¹) and narrow dispersities (Đ < 1.11). This one base two-function strategy showed a new path for the synthesis of catechol functionalized polymers.

Graphical Abstract

Keywords:

• Guanidine
• catechol
• polypeptoid
• ring-opening polymerization
• sarcosine

Additional information

Funding

The support of this work by the National Natural Science Foundation of China (U1463201 and 21522604), the National Key Research and Development Program of China (2017YFC1104802), the Natural Science Foundation of Jiangsu Province, China (BK20150031), the Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and the Top-Notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP) is gratefully acknowledged.