202826-52-6

76857-06-2

202826-52-6

A suspension of 1-benzyl-1'H-spiro[piperidine-4,2'-quinazolin]-4'(3'H)-one (5.0 g) was formed with 10% palladium-carbon catalyst (500 mg) in methanol (200 mL). The reaction mixture was stirred at room temperature for 48 hours under hydrogen atmosphere. Upon completion of the reaction, the catalyst was filtered through a diatomaceous earth pad to remove the catalyst. The filtrate was concentrated under reduced pressure to remove the solvent, and the resulting residue was recrystallized using a solvent mixture of ethanol/ether to afford 1H-spiro[piperidin-4,2-quinazolin]-4(3H)-one (2.34 g, 41% yield). The structure of the product was confirmed by 1H NMR (300 MHz, CDCl3): δ 1.81-2.03 (m, 5H), 2.84-2.99 (m, 4H), 4.47 (s, 1H), 6.62-6.85 (m, 2H), 7.24-7.32 (m, 1H), 7.84-7.88 (m, 1H).