Aminal Protection of Epoxide Monomer Permits the Introduction of Multiple Secondary Amine Moieties at Poly(ethylene glycol). Issue 12 (20th March 2019)

• Record Type: Journal Article
• Authors: Blankenburg, Jan; Frey, Holger
• Is Part Of: Macromolecular rapid communications. Volume 40:Issue 12(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-03-20
• Subjects: aminals -- amine protecting groups -- anionic ring‐opening polymerization -- epoxides -- multifunctional poly(ethylene glycol); Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.201900057
• Languages: English
• ISSNs: 1022-1336

Abstract

Abstract: In contrast to acetal groups, aminal moieties are almost unknown in polymer chemistry. The aminal‐protected isopropyl‐hexahydro‐pyrimidine glycidyl amine (PyGA) for the anionic ring‐opening polymerization (AROP) is introduced. The monomer is prepared in a two‐step synthesis and can be polymerized in a well‐controlled manner under AROP conditions. Several poly(ethylene glycol) block and triblock copolymers are synthesized in a molecular weight range from 2 700 to 11 400 g mol −1 with up to 11 mol% PyGA. The molecular weight distributions are monomodal with low dispersity ( Đ = M w / M n ) below 1.2. After the polymerization, the acid‐labile hexahydro‐pyrimidine rings can be conveniently cleaved in acidic media, liberating two secondary amines per PyGA monomer unit. The released 1, 3‐diamine functionalities can be addressed via post‐polymerization modification and show complexation of copper(II) ions in aqueous solution. The compounds are promising for water‐soluble catalyst systems, the removal of transition metals from water, and as a building block for complexing polyethers for biomedical application. Abstract : The novel epoxide monomer isopropyl‐hexahydro‐pyrimidine glycidyl amine containing an aminal protecting group is developed and successfully utilized for the synthesis of poly(ethylene glycol) block copolymers under the conditions of the anionic ring‐opening polymerization. Subsequent acidic hydrolysis of the aminal groups releases multiple 1, 3‐diamine functionalities, which can undergo post‐polymerization modification reactions or act as a multifunctional complexation agent for transition metals.