Fluorine as an ortho-directing group in aromatic metalation: a two step preparation of substituted benzo[b]thiophene-2-carboxylates was written by Bridges, Alexander J.;Lee, Arthur;Maduakor, Emmanuel C.;Schwartz, C. Eric. And the article was included in Tetrahedron Letters in 1992.Synthetic Route of C11H10O3S This article mentions the following:
A simple 2-step synthesis of B-ring substituted benzo[b]thiophene-2-carboxylates from aryl fluorides has been developed. The route involves a selective lithiation ortho to fluorine, followed by formylation, and subsequently, displacement of fluorine with thioglycollate and base-induced ring closure in a single operation. Thus, 3-fluoroiodobenzene was formylated to give 2-fluoro-6-iodobenzaldehyde (I) in 92% yield. I cyclized with Me thioglycolate in DMSO to give iodobenzothiophenecarboxylate II in 81% yield. In the experiment, the researchers used many compounds, for example, Methyl 5-methoxybenzo[b]thiophene-2-carboxylate (cas: 19492-99-0Synthetic Route of C11H10O3S).
Methyl 5-methoxybenzo[b]thiophene-2-carboxylate (cas: 19492-99-0) belongs to benzothiophene derivatives. Benzothiophene is relatively a stable molecule. The core structure is a part of various pharmaceutical substances and natural products. It is also used in the manufacturing of dyes such as thioindigo.Synthetic Route of C11H10O3S
Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem