Oxygen‐mediated polymerization initiated by oltipraz‐derived thiones |
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Authors: | Scott R Zavada Joseph C Furgal Nathan D Wood Timothy F Scott |
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Institution: | 1. Macromolecular Science and Engineering Program, University of Michigan, Ann Arbor, Michigan;2. Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan |
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Abstract: | A pyrrolopyrazine‐thione derived from oltipraz, a compound that has been investigated as a chemopreventive agent, affords radicals in the presence of thiols and oxygen via a redox cycle, an attribute that suggests its suitability as an initiator for oxygen‐mediated polymerization. Here, we explore the utilization of this pyrrolopyrazine‐thione, generated in situ from a precursor, as an initiator for the radical‐mediated thiol–ene polymerization. While the pyrrolopyrazine‐thione was shown to be capable of generating radicals in the presence of atmospheric oxygen and thiol groups, the reaction extents achievable were lower than desired owing to the presence of unwanted side reactions that would quench radical production and, subsequently, suppress polymerization. Moreover, we found that complex interactions between the pyrrolopyrazine‐thione, its precursor, oxygen, and thiol groups determine whether or not the quenching reaction dominates over those favorable to polymerization. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1373–1382 |
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Keywords: | oxygen activated polymerization radical polymerization thiol– ene |
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