Thiophene → Cyclopentyl-2-thienylmethanone

Participants

Reaction Steps

Graphite (6.0 g) was added to a mixture of thiophene (2.46 g, 29.2 mmol) and cyclopentanecarboxylic acid chloride (29.2 mmol assumed--the crude mixture from Example 1) in 50 mL of o-dichlorobenzene. The mixture was heated and kept at 80° C. for 1.5 hours. It is understood that lower temperatures can be used for longer times, or higher temperatures for shorter times while achieving good yields of cyclopentyl 2-thienyl ketone. After cooling down to room temperature, graphite was removed by filtration and washed with a small portion of the o-dichlorobenzene solvent. The product mixture was subjected to mild heating to remove the residual amount of HCl. The crude cyclopentyl 2-thienyl ketone of 84% purity (GC, area % analysis) was transferred, without purification, to the bromination step of Example 3.

Provenance & Evidence