title: Reaction Pathways in Catechol/Primary Amine Mixtures: A Window on Crosslinking Chemistry.
abstract: Catechol chemistry is used as a crosslinking tool abundantly in both natural organisms (e.g. mussels, sandcastle worms) and synthetic systems to achieve the desired mechanical properties. Despite this abundance and success, the crosslinking chemistry is still poorly understood. In this study, to simplify the system, yet to capture the essential chemistry, model compounds 4-methyl catechol and propylamine are used. The reaction of 4-methyl catechol (2 mM) with propylamine (6 mM) is carried out in the presence of NaIO4 (2 mM) in 10 mM Na2CO3 aqueous solution. A variety of spectroscopic/spectrometric and chromatographic methods such as 1H NMR, LC-MS, and UV-VIS are used to track the reaction and identify the products/intermediates. It is found that the crosslinking chemistry of a catechol and an amine is both fast and complicated. Within five minutes, more than 60 products are formed. These products encompass 19 different masses ranging from molecular weight of 179 to 704. By combining time-dependent data, it is inferred that the dominant reaction pathways: the majority is formed via aryloxyl-phenol coupling and Michael-type addition, whereas a small fraction of products is formed via Schiff base reactions.
authors.affiliation: Laboratory of Physical Chemistry and Soft Matter, Wageningen University, Wageningen, the Netherlands.
authors.forename: Juan
authors.initials: J
authors.lastname: Yang
authors.affiliation: Laboratory of BioNanoTechnology, Wageningen University, Wageningen, The Netherlands.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Saggiomo
authors.affiliation: Laboratory of BioNanoTechnology, Wageningen University, Wageningen, The Netherlands.
authors.forename: Aldrik H
authors.initials: AH
authors.lastname: Velders
authors.affiliation: Laboratory of Physical Chemistry and Soft Matter, Wageningen University, Wageningen, the Netherlands.
authors.forename: Martien A
authors.initials: MA
authors.lastname: Cohen Stuart
authors.affiliation: Laboratory of Physical Chemistry and Soft Matter, Wageningen University, Wageningen, the Netherlands.
authors.forename: Marleen
authors.initials: M
authors.lastname: Kamperman
mesh_terms: D001679:Biogenic Amines / Q000737:chemistry*; D002395:Catecholamines / Q000737:chemistry*; D002396:Catechols / Q000737:chemistry; D002853:Chromatography, Liquid; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010504:Periodic Acid / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D012545:Schiff Bases / Q000737:chemistry; D011436:Spermidine Synthase / Q000737:chemistry
chemical_list: D001679:Biogenic Amines; D002395:Catecholamines; D002396:Catechols; D012545:Schiff Bases; D010504:Periodic Acid; C018599:4-methylcatechol; C009288:metaperiodate; D011436:Spermidine Synthase