2,5-Dimethyl-3-phenyl-6H-cyclopenta[b]thiophene synthesis

Yield:345306-43-6 50%

Reaction Conditions:

with toluene-4-sulfonic acid in benzene at 45; for 0.25 h;

Steps:

3 2,5-dimethyl-3-phenyl-6H-cyclopenta[b]thiophene

A 250 mL flask was charged 9.1 g (37 mmol) of 5,6-Dihydro-2,5-dimethyl-3-phenyl-4H-cyclopenta[b]thiophene-4-ol followed by 175 mg (0.9 mmol) of p-toluenesulfonic acid and 50 mL of benzene. The mixture was sparged with nitrogen and heated to 45° C. for 15 min-the reaction was then cooled and quenched by adding 150 mL of a ice cold saturated water/sodium bicarbonate mixture. The organic layer was separated, the extract dried over magnesium sulfate, filtered and the volatiles removed in vacuo. The compound was dissolved in hexanes and purified by column chromatography to give 4.2 g of the desired material (50 percent). 1H NMR (CD2Cl2): 7.55-7.25 (m, 5H), 6.44/6.35 (2 s, 1H), 3.14 (s, 2H), 2.5 (m, 3H), 2.15 (s, 3H). 13C{1H} NMR (CD2Cl2): 145.72, 145.65, 140.72, 136.76, 133.42, 129.22, 128.85, 126.92, 126.76, 122.08, 121.79, 40.61, 16.88, 14.84, 14.18.

References:

US2005/10039,2005,A1 Location in patent:Page 17