Synthesis
The general procedure for the synthesis of 2-methylindene (6) from 2-methylindan-1-one (5) was as follows: 5.0 g (34 mmol) of 2-methyl-1-indanone (5) was reacted with 1.94 g (51 mmol) of NaBH4 in a reduction reaction according to the method of Example G. Subsequently, the unpurified alcohol was further reacted in 100 g of toluene catalyzed by 0.2 g of p-toluenesulfonic acid at 80 °C. The reaction mixture was purified by column chromatography on 100 g silica gel with hexane/dichloromethane (9:1) as eluent to give 3.68 g (82% yield) of the target product 2-methylindene (6). The product was characterized by 1H-NMR (100 MHz, CDCl3): δ 7.2 (4H, m), 6.45 (1H, m), 3.25 (2H, m), 2.1 (3H, m). Mass spectrometry analysis showed a molecular ion peak of 130 M+ and a cleavage pattern as expected.
References
[1] Journal of Chemical Research, 2010, # 6, p. 325 - 329
[2] Journal of Organic Chemistry, 1980, vol. 45, # 23, p. 4564 - 4572
[3] Journal of Organic Chemistry, 1984, vol. 49, # 22, p. 4226 - 4237
[4] Journal of Organic Chemistry, 1982, vol. 47, # 6, p. 1051 - 1058
[5] Collection of Czechoslovak Chemical Communications, 1983, vol. 48, # 1, p. 60 - 70
