2-Methyl-3-butyn-2-ol → 2-{3-Methyl-3-hydroxybutynyl}-5-{2-(4-pyridyl)ethynyl}thiophene

Beteiligte Stoffe

Reaktionsschritte

The 2-ethynyl-5-(4-pyridyl)ethynyl thiophene is synthesized by the reaction sequence shown below. In the first step, bromination of 1-(2-thienyl)-2-(4-pyridyl)ethene followed by base-catalyzed dehydrohalogenation gives 2-bromo-5-{2-(4-pyridyl)ethynyl}thiophene (I): ##STR5## In the second step, the palladium catalyzed addition of 2-methyl-3-butyn-2-ol to compound I gives 2-{3-methyl-3-hydroxybutynyl}-5-{2-(4-pyridyl)ethynyl}thiophene (II): ##STR6## The term "Ph" in the palladium catalyst formula means "phenyl". In the third step, removal of the protecting group using KOH in methanol gives the acetylene-terminated thermoset monomer 2-ethynyl-5-(4-pyridyl)ethynyl thiophene (III): ##STR7##

Herkunft & Nachweise