反应详情

A mixture of 5.5 g (25.0 mmol) of 7-tert-butyl-3-hydroxy-5-methyl-3H-benzofuran-2-one (compound (102), Example 2), 3 ml (50.0 retool) of methyl isocyanate and 2 drops of methanesulfonic acid is refluxed for 3 i/4 hours. Then 3 ml (50.0 retool) of methyl isocyanate and 2 drops of methanesulfonic acid are again added. The reaction mixture is refluxed for a further 16 hours, then cooled, diluted with dichloromethane and washed with water and 5% aqueous sodium hydrogencarbonate solution. The organic phases are combined, dried over magnesium sulfate and concentrated on a vacuum rotary evaporator. Crystallisation of the residue from toluene yields 4.45 g (65%) of 3-(N-methylcarbamoyloxy)-5-methyl-7-tert-butyl-3H-benzofuran-2-one (corn pound (112), Table 1 ), m.p. 138°-143° C.

1. temperatureis refluxed for 3 i/4 hours
2. temperatureThe reaction mixture is refluxed for a further 16 hours
3. temperaturecooled
4. washwashed with water and 5% aqueous sodium hydrogencarbonate solution
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated on a vacuum rotary evaporator
7. customCrystallisation of the residue from toluene