tert-Butanol → N-benzyloxycarbonyl-5-aminomethyl-4-(4-pyridyl)-3-(4-fluorophenyl)pyrazole

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A 3 L round bottom flask fitted with a mechanical stirrer, N2 inlet and an addition funnel was was charged wtih 557 mL (0.56 mol) of 1 M t-BuOK in THF and 53 mL (0.56 mol) of t-BuOH. The ketone, 1 (60 g, 0.28 mol) was dissolved in 600 mL of THF and added to the stirred mixture at room temperature. A yellow precipitate formed and the mixture was stirred for 1 h. N-benzyloxycarbonyl-glycinyl N-hydroxysuccinimide (128.6 g, 0.42 mol) was dissolved in 600 mL of THF and added dropwise at r.t. over 1 h. The mixture was stirred for another 5 minutes and 150 mL of water was added. The pH was adjusted to 6.7 with 70 mL of AcOH. Hydrazine monohydrate (41 mL in 100 mL of water) was added via an addition funnel. The mixture was stirred for 1 h and was diluted with 500 mL of water and 500 mL of ethyl acetate. The biphasic mixture was transferred to a sep funnel and the layers were separated. The aqueous layer was extracted with EtOAc (3×300 mL). The organic layer was dried (Na2SO4), filtered and evaporated to leave 157 g of a crude reddish oil.

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