Acetyl chloride → HCID 53485869, compound

Participants

Reaction Conditions

Reaction Steps

To a 200 L reactor was charged: tert-butyl 2′-tert-butyl-7′-oxo-6′,7′-dihydro-2′H-spiro[piperidine-4,5′-pyrano[3,2-c]pyrazole]-1-carboxylate (8.3 kg, 22.8 moles), ethyl acetate (89 L), and methanol (24 L). Solution was cooled to 0° C., and acetyl chloride (11.0 L, 155 moles) was added over 30 minutes. After addition, reaction was allowed to warm to ambient temperature and react for 4 hours. Heated solution in order to distill to a 41 L reaction volume, slowly refilling with ethyl acetate (˜0.22 L) until an internal temperature of 72° C. was reached. Cooled to ambient temperature over 3 hours, filtered the solids through a Nutsche Filter, washed with ethyl acetate (5.3 L), and dried under vacuum at 50° C. for 12 hours. Isolated 6.6 kg (22.0 moles, 96%) of 2′-tert-butyl-2′H-spiro[piperidine-4,5′-pyrano[3,2-c]pyrazol]-7′(6′H)-one as a white crystalline solid.

Provenance & Evidence