1-Chloroethyl chloroformate → 3,4-Dihydro-2H-spiro[naphthalene-1,4'-piperidine]--hydrogen chloride (1/1)

Participants

Reaction Conditions

Reaction Steps

To a solution of the N-methylpiperidine (A1) (37 g, 172 mmol) in 1,2-dichloroethane (250 ml) was added 1-chloroethyl chloroformate (20.7 ml, 190 mmol) at 0° C. The solution turned to a solid. After 0.5 hours at room temperature, the reaction mixture was heated under reflux for 15 hours. After concentration, the residue was dissolved in methanol (250 ml) and heated at 50° C. for 2 hours. The mixture was cooled to room temperature, the precipitate was filtered and washed with ether to produce 3,4-dihydro-2H-spiro[naphthalene-1,4′-piperidine] HCl salt (A2). The filtrate was concentrated, suspended in ether, filtered, and the solid washed with MeOH and ether to give additional 3,4-dihydro-2H-spiro[naphthalene-1,4′-piperidine] HCl salt (A2). LC-MS: m/e=202.1 (M+H). Rt=1.61 min. 1H-NMR (500 MHz, CDCl3): 9.74 (s, 2H), 7.58 (d, J=7.9, 1H), 7.22 (t, J=7.8, 1H), 7.14 (t, J=7.9, 1H), 7.08 (d, J=8.0, 1H), 3.47 (d, J=12.4, 2H), 3.22-3.18 (m, 2H), 2.88 (t, J=4.9, 2H), 2.81 (t, J=6.2, H), 2.60 (td, 2H), 1.93-1.89 (m, 2H), 1.83-1.77 (m, 2H).

Provenance & Evidence