Trimethyltin chloride → 5-Trimethylstannyl-pyrimidine

Participants

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 47.7 g. (0.3 mole) of 5-bromopyrimidine in 300 cc. of anhydrous ether and 300 cc. of anhydrous tetrahydrofuran. The solution was cooled to -110° C. using an ethyl alcohol-liquid nitrogen bath. By a dropwise addition, 120 cc. (0.3 mole) of n-butyllithium in n-hexane was added over 50 minutes. The solution was stirred for an additional 3.5 hours. A solution containing 49.8 g. (0.25 mole) of trimethyltin chloride in 150 cc. of anhydrous tetrahydrofuran was added over 60 minutes. After 10 minutes of stirring at -110° C. the orange mixture solidified and stirring was discontinued. The mixture was allowed to warm to -32° C. over 16 hours during which time it liquified and stirring was resumed for 4 hours. The mixture was hydrolyzed with 300 cc. of a saturated aqueous solution of ammonium chloride plus an additional 100 cc. of water. The aqueous phase was separated from the organic phase and washed with 250 cc. of ether. The organic portions were combined, washed twice with 500 cc. of water, separated, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The dark orange residue was distilled under reduced pressure (19 mm.). A clear colorless liquid fraction (35.2 g.) boiling at 118°-122° C. was collected and found to be 90% pure by gas chromatography. The liquid was redistilled under reduced pressure (19 mm.) and the clear fraction boiling between 119°-120° C. was collected and analyzed. The tin content was found to be 48.14% while the nitrogen content was 11.82%. The calculated tin and nitrogen contents for trimethyl-5-pyrimidyltin are 48.87% and 11.53%, respectively. Gas chromatographic analysis indicated a purity of 97% and the refractive index was recorded as 1.5349 at 25° C. The nuclear magnetic resonance spectrum contained a singlet at 0.38 pp. (CH3 --Sn, 9H's), a triplet at 8.7 ppm. (α-pyrimidyl H's, 2H's), and a singlet at 9.12 ppm. (γ-pyrimidyl H, 1H), all consistent with the expected structure.

Provenance & Evidence