Impact of Preferential 蟺-Binding in Catalyst-Transfer Polycondensation of Thiazole Derivatives was written by Smith, Mitchell L.;Leone, Amanda K.;Zimmerman, Paul M.;McNeil, Anne J.. And the article was included in ACS Macro Letters in 2016.Name: Methyl 2-amino-5-bromothiazole-4-carboxylate This article mentions the following:
Polymerizing electron-deficient arenes in a controlled, chain-growth fashion remains a significant challenge despite a decade of research on catalyst-transfer polycondensation. The prevailing hypothesis is that the chain-growth mechanism stalls at a strongly associated metal-polymer 蟺-complex, preventing catalyst turnover. To evaluate this hypothesis, we performed mechanistic studies using thiazole derivatives and identified approaches to improve their chain-growth polymerization These studies revealed a surprisingly high barrier for chain-walking toward the reactive C-X bond. In addition, a competitive pathway involving chain-transfer to monomer was identified. This pathway is facilitated by ancillary ligand dissociation and N-coordination to the incoming monomer. We found that this chain-transfer pathway can be attenuated by using a rigid ancillary ligand, leading to an improved polymerization Combined, these studies provide mechanistic insight into the challenges associated with electron-deficient monomers and ways to improve their living, chain-growth polymerization Our mechanistic studies also revealed an unexpected radical anion-mediated oligomerization in the absence of catalyst, and a surprising oxidative addition into the thiazole C-S bond in a model system. In the experiment, the researchers used many compounds, for example, Methyl 2-amino-5-bromothiazole-4-carboxylate (cas: 850429-60-6Name: Methyl 2-amino-5-bromothiazole-4-carboxylate).
Methyl 2-amino-5-bromothiazole-4-carboxylate (cas: 850429-60-6) belongs to thiazole derivatives. Thiazole rings are planar and aromatic. Thiazoles are characterized by larger pi-electron delocalization than the corresponding oxazoles and have therefore greater aromaticity. Thiazole sulfonation occurs only under forcing conditions: the action of oleum at 250 掳C for 3 hours in the presence of mercury(II) sulfate leads to 65% formation of 5-thiazole sulfonic acid.Name: Methyl 2-amino-5-bromothiazole-4-carboxylate
Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica