2-Bromopyridine → Pyridine, 2-(trimethylstannyl)-

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Reaction Conditions

Reaction Steps

To a reaction vessel equipped with a mechanically driven agitator, water-cooled condenser, addition funnel, thermometer, and nitrogen inlet was added a solution containing 40.0 g. (0.316 mole) of 2-bromopyridine in 400 cc. of anhydrous ether. The solution was cooled to -50° C. using a dry ice-acetone bath. By a dropwise addition, 127 cc. (0.316 mole) of n-butyllithium in n-hexane was added over 25 minutes. The resulting black mixture was stirred for additional 30 minutes. A solution containing 59.8 g. (0.30 mole) of trimethyltin chloride in 200 cc. of anhydrous benzene was added over 40 minutes, followed by a one-hour stirring period. The dark orange solution was warmed to -30° C. over a one-hour period, held at -30° C. for one hour and warmed to room temperature before being hydrolyzed with a saturated aqueous solution of ammonium chloride. The aqueous phase was separated from the organic phase and washed with 200 cc. of ether. The organic portions were combined, dried over a quantity of anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. A dark red liquid (73.9 g.) was isolated and distilled under reduced pressure (0.22 mm.). A light yellow liquid fraction boiling at 38°-40° C. was collected and analyzed. The tin content was found to be 47.97%. The calculated tin content for trimethyl-2-pyridyltin is 49.07%. Gas chromatographic analysis indicated a purity of 97% and the nuclear magnetic resonance spectrum contained a singlet at 0 ppm. (CH3 --Sn, 9H's), a complex multiplet centered at 7.0 ppm. (β- and γ-pyridyl H's, 3H's) and a complex doublet at 8.4 ppm. (α-pyridyl H, 1H).

Provenance & Evidence