p-Toluenesulfonic acid → (4-amino-6-methyl-2,3-dihydro-1H-8-thia-7-aza-cyclopenta[a]inden-5-yl)-cyclopropyl-methanone

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Reaction Steps

To a stirred solution of 0.30 g (1.83 mmol) of 2-amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile in 6 ml toluene was added 0.30 g (2.14 mmol) 1-cyclopropyl-3-methoxy-but-2-en-1-one and 3 mg of p-toluenesulfonic acid. The mixture was heated at reflux for 2 hours, concentrated in vacuo, partitioned between ethyl acetate and water. The combined organic phases were dried over sodium sulfate and evaporated to dryness. The residue was taken up in n-butyl acetate 6 ml and 1.018 g (3.91 mmol) tin (IV) chloride was heated under reflux for 30 minute and allowed to cool. The mixture was partitioned between aqueous sodium hydroxide and ethyl acetate. Flash chromatography (heptane/ethyl acetate 3:1) afforded 25 mg (5%) (4-amino-6-methyl-2,3-dihydro-1H-8-thia-7-aza-cyclopenta[a]inden-5-yl)-cyclopropyl-methanone as a white solid. ES-MS m/e (%): 273 (M+H+, 100).

Provenance & Evidence