1-Butyl-4-iodo-1H-pyrazole synthesis

Yield:918487-10-2 100%

Reaction Conditions:

with sodium hydride in tetrahydrofuran at 70;

Steps:

47.A

To a stirred suspension of 4-iodopyrazole (0.3 g, 1 .55 mmol) and 60% NaH (0.08 g, 2 mmol) in anhydrous THF (1 ml) butyl bromide (0.5 ml) was added and the mixture was stirred overnight at 70 ⁵C. The mixture was quenched with saturated NH₄CI and extracted with EtOAc (50 ml). The organic layer was washed with H₂O, dried over MgSO₄ and filtered. The filtrate was distilled off and the residue was dried in vacuo to give 1 -butyl-4-iodo-1 H-pyrazole (0.39 g, 100%), as colourless oil. ¹H NMR (CDCI₃) 7.47 (s, 1 H); 7.39 (s, 1 H); 4.09 (t, 2H, J = 7.14 Hz); 1 .85 - 1 .75 (m, 2H); 1 .35 - 1.23 (m, 2H); 0.91 (t, 3H, J = 7.32 Hz).

References:

WO2010/43000,2010,A1 Location in patent:Page/Page column 99