Diisobutylaluminum hydride → 3-(4-Iodopyrazol-1-yl)-2,2-dimethylpropan-1-ol

A cold (−20° C.) solution of 3-(4-Iodopyrazol-1-yl)-2,2-dimethylpropionic acid methyl ester (Compound 47F, 6.0 g, 19.48 mmol) in THF (80 mL) was treated with DIBAL (42.85 mL, 42.85 mmol, 1M solution in toluene) and allowed to warm to RT over a period of 2 h. The reaction mixture was treated with aq. ammonium hydroxide (20 mL) and the solids were filtered through celite. The filtrate was diluted with ethyl acetate (50 mL) and washed with brine (2×50 mL). The organic layer was dried over Na2SO4, filtered and concentrated to give 4.9 g (90%) as an oil which crystallized upon standing. 1H NMR (500 MHz, CDCl3) δ 7.50 (s, 1H), 7.41 (s, 1H), 4.0 (s, 2H), 3.17 (s, 3H), 0.9 (s, 6H).