Trimethyltin chloride → 2-Trimethylstannyl-3-methoxyquinoline

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반응 단계

3.00 g (131 mmol) of sodium are introduced in a sealed Schlenck-type apparatus under argon inert gas into 3 ml of DMEabs. (=absolute dimethoxyethane). The sodium is cut into very small pieces and, before being added to the reaction solution washed with DMEabs to remove any adhering paraffin. During addition of the sodium to the reaction solution, the DMEabs. slightly foams. The reaction solution is then cooled to -10° C. using an ice/common salt mixture. 0.83 g (4.18 mmol) of trimethyltin chloride is added to this solution. After a reaction time of 2 hours, the reaction solution is colorless, milky and cloudy. After a total of 3 hours, the reaction solution has become milky, cloudy and green. This can be considered as an indication of the formation of sodium trimethylstannate. Excess sodium is removed from the reaction solution under argon via a D-2 Schlenck-type frit. 0.35 g (1.45 mmol) of 2-bromo-3-methoxyquinoline (20) dissolved in 3 ml of DMEabs. is added dropwise to the filtered cloudy green reaction solution. Upon dropwise addition of the educt, the reaction solution spontaneously turns blood red. After a short time, the reaction solution has a brown color. After 30 minutes, the reaction solution finally turns beige. The solution is stirred at -10° C. for a total of 3 hours, during which the color of the reaction solution no longer changes. After the reaction is complete, the product mixture is filtered through a D-4 frit to remove the precipitate. The precipitate is washed with DMEabs. without vacuum, the runoff being dark brown. A colorless solid remains in the frit. Upon evaporation of the filtrate in a rotary evaporator, a dark-brown oil is obtained whose composition is analyzed by 1H-NMR spectroscopy. Explicit purification of the product is omitted due to the sensitivity to hydrolysis. The product content is determined by spectroscopy. The hydrolysis product 3-methoxyquinoline can be detected as a by-product of this reaction. This finding is confirmed by the 1H-NMR experiments described below.

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