Hydrochloric Acid → N-(4-Oxospiro[chroman-2,4'-piperidine]-6-yl)methanesulfonamide hydrochloride

Participants

Reaction Conditions

Reaction Steps

N-(1′-Benzoyl-4-oxospiro[chroman-2,4′-piperidine]-6-yl)methanesulfonamide (10, 0.81 g, 1.95 mmol) was suspended in a mixture of absolute ethanol (10 mL) and 6 M aqueous hydrochloric acid (10 mL) and stirred at 85-90° C. in an oil bath. After 1 hour the oil bath temperature was increased to 95° C. After ˜3.5 hours at 95° C. the reaction was allowed to cool to room temperature. TLC (silica gel, 10% methanol in dichloromethane, UV visualization) showed no remaining starting material [Rf (10)=0.65−0.7]. Solvent was removed under reduced pressure on a rotary evaporator. Ethanol was added to the residue and then evaporated to dryness under reduced pressure on a rotary evaporator. The ethanol addition and evaporation to dryness was repeated two more times. The residue was dried in vacuo to afford 0.77 g (114% yield) of N-(4-oxospiro[chroman-2,4′-piperidine]-6-yl)methanesulfonamide hydrochloride (11) as a light yellow solid that was homogeneous by TLC [silica gel, 10% methanol in dichloromethane containing a small amount of concentrated aqueous ammonium hydroxide, UV visualization, Rf (11)=0.12−0.19]. Mass spec: m/z=311.2 [M+H]+

Provenance & Evidence