Methyl Thioglycolate → Methyl 4,5-dichlorobenzo[b]thiophene-2-carboxylate

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Reaction Steps

In a similar manner to Example 18, methyl thioglycolate (9.3 ml) was reacted with 2,3-dichloro-6-fluorobenzaldehyde (15.46 g) in dimethylformamide to give methyl 4,5-dichlorobenzo[b]thiophene-2-carboxylate (7.28 g) as an off-white solid which was hydrolysed, chlorinated and reacted with N,O-dimethylhydroxylamine hydrochloride to give 4,5-dichloro-N-methoxy-N-methylbenzo[b]thiophene-2-carboxamide (1.96 g) as a colourless solid. Reaction of this amide with ethylmagnesium bromide gave 1-(4,5-dichlorobenzo[b]thiophen-2-yl)propan-1-one (1.09 g) as an oil which was used without further purification.

Provenance & Evidence