反应详情

140 ml (0.35 mol) of a 2.5 M solution of n-butyllithium in toluene were added dropwise to a solution of 45.0 g of indene (0.35 mol) in 200 ml of THF at 0° C. in the course of 30 min in a 500 ml four-necked flask having a dropping funnel. After warming up to room temperature, the solution was stirred for a further hour. Thereafter, it was again cooled to 0° C., and 99.4 g (0.70 mol) of iodomethane were added dropwise in the course of 2 h. After warming up to room temperature, stirring was effected for a further 24 h. The solvents were distilled off on a rotary evaporator at a bath temperature of 40° C. and 100 mbar. The black residue was extracted by shaking three times with 200 ml of pentane each time. After concentration of the combined pentane fractions on a rotary evaporator, the crude product was fractionated over a 25 cm Vigreux column. 28.6 g (0.22 mol; 63% yield) of colorless methylindene were obtained under a vacuum from a diaphragm pump at 19 mbar and a top temperature of 71-73° C. The 1H-NMR spectrum shows an isomer mixture of 1- and 3-methylindene in the ratio of 1:1.

1. temperatureThereafter, it was again cooled to 0° C.
2. temperatureAfter warming up to room temperature
3. stirringstirring
4. distillationThe solvents were distilled off on a rotary evaporator at a bath temperature of 40° C. and 100 mbar
5. extractionThe black residue was extracted
6. stirringby shaking three times with 200 ml of pentane each time
7. customAfter concentration of the combined pentane fractions on a rotary evaporator