Dimethylformamide → Methyl 7-chlorobenzo[b]thiophene-2-carboxylate

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Reaction Steps

In a similar manner to Example 18, methylthioglycolate (13 g) was reacted with 3-chloro-2-fluorobenzaldehyde (19.57 g) in dimethylformamide to give methyl 7-chlorobenzo[b]thiophene-2-carboxylate, which was hydrolysed, chlorinated and reacted with N,O-dimethylhydroxylamine hydrochloride to give 7-chloro-N-methoxy-N-methylbenzo[b]thiophene-2-carboxamide, which was reacted with ethylmagnesium bromide to give 1-(7-chlorobenzo[b]thiophen-2-yl)propan-1-one. This ketone (1.17 g) was reacted with phenyltrimethylammonium tribromide (2.15 g) to give 2-bromo-1-(7-chlorobenzo[b]thiophen-2-yl)propan-1-one (2.32 g) which was used without further purification.

Provenance & Evidence