Trifluoroacetic acid → HCID 58551532, compound

Participants

Reaction Steps

A mixture of tert-butyl N-amino-N-isopropyl-carbamate (530.4 mg, 3.0 mmol), (Z)-benzyl 3-(hydroxymethylene)-4-oxospiro[chroman-2,4′-piperidine]-1′-carboxylate (1.10 g, 2.9 mmol) and TFA (223.4 μL, 2.9 mmol) in dichloromethane (10 mL) was stirred 2 h. The reaction was concentrated to ⅓ volume, then TFA (˜1.5 mL) was added. The mixture was stirred for 30 min, then concentrated, neutralized with excess Et3N, re-concentrated, and purified by column chromatography (0-60% EtOAc/hexanes) to give benzyl 1-isopropyl-1H-spiro[chromeno[4,3-c]pyrazole-4,4′-piperidine]-1′-carboxylate (1.1 g, 91%) as a pale yellow oil. ESI-MS m/z calc. 417.2, found 418.3 (M+1)+; Retention time: 2.07 minutes (3 min run).

Provenance & Evidence