Benzoxazole → 2-(Tributylstannyl)-1,3-benzoxazole

Temperature

-78 °C

20 ml of freshly distilled THF was flushed for 30 min with a stream of nitrogen after which benzoxazole (1.0 g, 8.3 mmol) was added. After being flushed for another 30 min, the solution was cooled to −78° C. and placed under inert nitrogen atmosphere. 0.9 equivalents of n-BuLi (2 M solution in hexane, 3.0 ml, 7.6 mmol) was added dropwise over a period of 1 h, during which the solution turned to pink. The solution was kept at −78° C. for 30 min and then tri-n-butyltin chloride (2.3 ml, 8.3 mmol) was added dropwise over a period of 1 h. During this addition, the solution shifted from pink to brown. After yet another hour at −78° C., the solution was allowed to reach room temperature, at which it turned to deep red. The THF was removed on a rotary evaporator and the product, an orange oil, was isolated by distillation in vacuo. Yield: 1.37 g, 40%. 1H NMR (CDCl3): δ 0.90 (t, J=7, 9H, Bu3Sn), 1.30 (m, 6H, Bu3Sn), 1.35 (m, 6H, Bu3Sn), 1.62 (t, J=7, 6H, Bu3Sn), 7.29 (t, 2H, ArH), 7.55 (d, 1H, ArH), 7.77 (d, 1H, ArH).

1. additionwas added
2. customAfter being flushed for another 30 min
3. additionDuring this addition
4. waitAfter yet another hour at −78° C.
5. customto reach room temperature, at which it
6. customThe THF was removed on a rotary evaporator
7. customthe product, an orange oil, was isolated by distillation in vacuo

ORD record

ord-0dd3667c56774c3dbbae60ba539608a4

Source dataset

uspto-grants-2008_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07378240B2