| Popis: |
An improved route to substituted cyclopenta[c]thiophenes was accomplished by treating 1,3-dimethyl-5,6-dihydro-4H-cyclopenta[c]thiophene-5-one (1) with alkyl Grignard reagents to obtain the 5-alkyl-1,3-dimethyl-4H-cyclopenta[c]thiophenes, 5-methyl-1,3-dimethyl-4H-cyclopenta[c]thiophene (2) and 5-ethyl-1,3-dimethyl-4H-cyclopenta[c]thiophene (3), in good yield (60% and 65%, respectively). An important cyclopenta[c]thiophene precursor, 5-carbomethoxy-5-phenylsulfonyl–1,3-dimethyl-5,6-dihydro-4H-cyclopenta[c]thiophene (9) was synthesized, in an alternate route, by treating 3,4-bis(chloromethyl)-2,5-dimethylthiophene (7) with methyl phenyl sulfonyl acetate (8). |
