Acetonitrile → 1-(t-Butoxycarbonyl)-4-(3-benzyl-1-ethyl-(1H)-pyrazol-5-yl)piperidine

Participants

Reaction Conditions

Reaction Steps

A 100 L cylindrical flask with a bottom valve was equipped with a mechanical stirrer, internal heating coil, 5 L dropping funnel, and thermocouple was charged with the acetonitrile (39 L) and 1-(1-(t-butoxycarbonyl)piperidin-4-yl)-4-phenylbutane-1,3-dione 4 (3.00 Kg, 8.68 mol). To the resulting clear light yellow solution was added water (18.6 l). The mixture was warmed to 19° C. and the mixture became clear. An ethyl hydrazine solution (35% in water, 1.66 Kg, 1.71 L, 9.55 mol) was added via a dropping funnel over 100 min. The batch temperature after the addition was 20° C. The reaction solution was aged for 1 h at 20° C. then checked for completion by HPLC. If any 4 remained, additional ethyl hydrazine was added to complete the reaction. At the end of reaction the ratio of products 5:6:7 is 83.6:14.3:2.1 with complete consumption of 4.

Provenance & Evidence