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

Temperature

-50 °C

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-pryidyl H's, 3H's) and a complex doublet at 8.4 ppm. (α-pyridyl H, 1H).

1. temperaturecooled
2. additioncondenser, addition funnel
3. additionthermometer, and nitrogen inlet was added a solution
4. additioncontaining 40.0 g
5. additionBy a dropwise addition, 127 cc
6. additionA solution containing 59.8 g
7. waitfollowed by a one-hour
8. stirringstirring period
9. temperatureThe dark orange solution was warmed to -30° C. over a one-hour period
10. waitheld at -30° C. for one hour
11. temperaturewarmed to room temperature
12. customThe aqueous phase was separated from the organic phase
13. washwashed with 200 cc
14. dry with materialdried over a quantity of anhydrous magnesium sulfate
15. filtrationfiltered
16. concentrationconcentrated under reduced pressure
17. customA dark red liquid (73.9 g.) was isolated
18. distillationdistilled under reduced pressure (0.22 mm)
19. customA light yellow liquid fraction boiling at 38°-40° C. was collected

ORD record

ord-2ceecca5d3b5487597db69a9abce7e9d

Source dataset

uspto-grants-1979_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04138483