N,N-Dimethylaniline → Methyl 7-chloro-5-oxo-1,2,3,5-tetrahydroindolizine-8-carboxylate

Reaction equation

O[C:2]1[C:10]([C:11]([O:13][CH3:14])=[O:12])=[C:9]2[N:5]([CH2:6][CH2:7][CH2:8]2)[C:4](=[O:15])[CH:3]=1.P(Cl)(Cl)([Cl:18])=O.CN(C)C1C=CC=CC=1>>[Cl:18][C:2]1[C:10]([C:11]([O:13][CH3:14])=[O:12])=[C:9]2[N:5]([CH2:6][CH2:7][CH2:8]2)[C:4](=[O:15])[CH:3]=1

Participants

Reactant 3

HCID 949N,N-Dimethylaniline

HCID 24813Phosphorus oxychloride

HCID 54694252Methyl 7-hydroxy-5-oxo-1,2,3,5-tetrahydroindolizine-8-carboxylate

Product 1

HCID 57689810Methyl 7-chloro-5-oxo-1,2,3,5-tetrahydroindolizine-8-carboxylateYield 69%

Procedure

Compound 1a (8.0 g, 38.3 mmol) was stirred in phosphorous oxychloride (20 mL, 218 mmol) at RT. Dimethylaniline (1 mL, 7.9 mmol) was added, and the reaction stirred for 16 h. The solution was concentrated in vacuo, quenched with ice, and made basic with sat. NaHCO3 solution. The aqueous solution was concentrated in vacuo. The residue was taken up in a 20% MeOH/CH2Cl2 and insoluble inorganic salts were removed by filtration. Organics were concentrated and purified by silica gel chromatography (75% EtOAc/CH2Cl2) to give 6.02 g (69%) of compound 1b as a white solid. 1H NMR (400 MHz, DMSO-d6): δ 6.46 (s, 1H), 3.99 (t, 2H, J=7.6 Hz), 3.78 (s, 3H), 3.30 (t, 2H, J=7.6 Hz), 2.04-2.14 (m, 2H). MS (ES) [m⇄H] calc'd for C10H10ClNO3, 228, 230. found 228, 230.