Triethylamine → 2,3-Dihydrothieno[3,2-b]quinolin-9-amine

Participants

Reaction Steps

To a stirred solution of tetrahydrothiophen-3-one (1.1 g, 11 mmole) in methylene chloride (10 ml) at -78° C., a 1M solution of titanium (IV) chloride in methylene chloride (11 ml) was added. A mixture of triethylamine (2.2 g, 22 mmole) and anthranilonitrile (1.2 gms, 10.0 mmole) in methylene chloride (30 ml) was then added to the reaction mixture over a period of 5 minutes. The reaction mixture was then slowly warmed to room temperature and stirred for 2 hours. Tetrahydrothiophen-3-one (1 ml) and titanium(IV) chloride (1.0 ml) was then added to the reaction mixture and the mixture was stirred at 25° C. for 16 hours. Thereafter, the reaction mixture was quenched with 12% aqueous NaOH (100 ml) and the reaction mixture was then stirred vigorously with additional methylene chloride (300 ml). The reaction mixture was then filtered through diatomaceous earth (Celite (trademark)) and the organic phase was separated. The organic solvents were removed under vacuum to afford a residue which was loaded on a flash chromatography column. Elution with 5% methanol in methylene chloride containing 1% triethylamine, afforded the title compound (1.3 gms, 64%) which was crystallized from chloroform (560 mg, 32%, m.p. 208°-210° C.). 1H-NMR (CDCl3, 300 MHz, δ): 4H, m, 3.4-3.56 ppm; 2H, bs, 4.51 ppm; 1H, dt, 7.37 ppm (J=7.0, 1.0 Hz); 1H, dt, 7.52 ppm (J=7.0, 1.10 ppm); 1H, dd, 7.61 ppm (J=7.0, 1.0 ppm); 1H, dd, 7.61 ppm (J=7.0, 1.0 ppm), 1H, dd, 7.86 ppm (J=7.0, 1.0 ppm). HRMS: Calculated--202.0575; Found--202.0545.

Provenance & Evidence