α,α-diacetyl ketene thioacetals had been investigated as odorless thiol equivalents in thia-Michael addition reaction.Under solvent-free conditions,a series of reactions between α,α-diacetyl ketene thioacetals and...α,α-diacetyl ketene thioacetals had been investigated as odorless thiol equivalents in thia-Michael addition reaction.Under solvent-free conditions,a series of reactions between α,α-diacetyl ketene thioacetals and α,β-unsaturated ketones were carried out promoting by concentrated hydrochloric acid.The corresponding thia-Michael adducts in high yields were obtained.Furthermore,a mechanism for this thia-Michael addition reaction was proposed preliminary.展开更多
Potassium tert-butoxide has been found to be a highly efficient catalyst for one-pot,three-component reaction of aryl aldehydes, acetophenones,and thiols via Claisen-Schmidt/Michael addition reactions for the synthesi...Potassium tert-butoxide has been found to be a highly efficient catalyst for one-pot,three-component reaction of aryl aldehydes, acetophenones,and thiols via Claisen-Schmidt/Michael addition reactions for the synthesis of thia-Michael adducts in high yields. The reactions are best carried out in tert-butyl alcohol at room temperature.展开更多
This study focuses on the synthesis of new liquid aromatic bismaleimide monomers in order to improve self-curing on demand(SCOD)systems previously based on aliphatic bismaleimides.These SCOD systems are based on Diels...This study focuses on the synthesis of new liquid aromatic bismaleimide monomers in order to improve self-curing on demand(SCOD)systems previously based on aliphatic bismaleimides.These SCOD systems are based on Diels-Alder(DA)/retro-DA reactions.The syntheses of new different aromatic bismaleimides with ester and amide bonds are presented.These maleimides have been protected using DA reaction and characterized by 1H NMR analysis to determine protection rate and diastereomer ratios.The retro-DA reactions of both aromatic and aliphatic DA adducts in presence of thiol molecules were studied.Kinetic analysis was monitored by 1H NMR and compared to model study.Finally,both aromatic and aliphatic bismaleimides-based polymers were synthesized with 2-mercaptoethyl ether and thermal properties of polymers were compared.The glass transition temperature values ranged from–20°C to 14°C and very good thermal stabilities were observed(up to 300°C).展开更多
文摘α,α-diacetyl ketene thioacetals had been investigated as odorless thiol equivalents in thia-Michael addition reaction.Under solvent-free conditions,a series of reactions between α,α-diacetyl ketene thioacetals and α,β-unsaturated ketones were carried out promoting by concentrated hydrochloric acid.The corresponding thia-Michael adducts in high yields were obtained.Furthermore,a mechanism for this thia-Michael addition reaction was proposed preliminary.
文摘Potassium tert-butoxide has been found to be a highly efficient catalyst for one-pot,three-component reaction of aryl aldehydes, acetophenones,and thiols via Claisen-Schmidt/Michael addition reactions for the synthesis of thia-Michael adducts in high yields. The reactions are best carried out in tert-butyl alcohol at room temperature.
基金The authors thank the Hutchinson Company for its financial support,Biobased Polymer Company for reactants supply.
文摘This study focuses on the synthesis of new liquid aromatic bismaleimide monomers in order to improve self-curing on demand(SCOD)systems previously based on aliphatic bismaleimides.These SCOD systems are based on Diels-Alder(DA)/retro-DA reactions.The syntheses of new different aromatic bismaleimides with ester and amide bonds are presented.These maleimides have been protected using DA reaction and characterized by 1H NMR analysis to determine protection rate and diastereomer ratios.The retro-DA reactions of both aromatic and aliphatic DA adducts in presence of thiol molecules were studied.Kinetic analysis was monitored by 1H NMR and compared to model study.Finally,both aromatic and aliphatic bismaleimides-based polymers were synthesized with 2-mercaptoethyl ether and thermal properties of polymers were compared.The glass transition temperature values ranged from–20°C to 14°C and very good thermal stabilities were observed(up to 300°C).
