title: Characterization and Synthesis of a 6-Substituted Benzo[b]thiophene.
abstract: An impurity observed during the synthesis of zileuton (Zyflo) has been isolated and characterized as a benzo[b]thiophene derivative that has undergone electrophilic substitution in the 6 position (4). A nine-step synthesis confirms the structural assignment. Key steps in the synthesis include a regioselective Friedel-Crafts coupling between 2-hydroxythioanisole, 8, and 1-(benzo[b]thien-2-yl)ethanol, 1, and formation of a benzo[b]thiophene from an o-methylthiobenzaldehyde, 14, and chloroacetone. The synthesis provides a potentially general route to substituted benzo[b]thiophenes.
authors.affiliation: Chemical Process Research, D54P, and Structural Chemistry, D-418, Abbott Laboratories, North Chicago, Illinois 60064.
authors.forename: Anthony R.
authors.initials: AR
authors.lastname: Haight
authors.forename: Gregory S.
authors.initials: GS
authors.lastname: Wayne
authors.forename: Gregory S.
authors.initials: GS
authors.lastname: Lannoye
authors.forename: Shyamal I.
authors.initials: SI
authors.lastname: Parekh
authors.forename: Weijiang
authors.initials: W
authors.lastname: Zhang
authors.forename: Richard R.
authors.initials: RR
authors.lastname: Copp
authors.forename: L. Steven
authors.initials: LS
authors.lastname: Hollis