1,2,3,4-Tetrahydroisoquinoline → 3,4-Dihydro-1H-isoquinoline-2-carboxylic acid 2,2,2-trichloro-ethyl Ester

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Reaction Steps

Tetrahydroisoquinoline [Aldrich] (39.9 g, 300 mmol) was dissolved in dichloromethane (400 ml) and treated with triethylamine (32 g, 315 mmol). The mixture was cooled in an ice bath and a solution of 2,2,2-trichloroethylchloroformate (65.0 g, 306 mmol) in dichloromethane (100 ml) introduced dropwise over 15 minutes. After addition, the mixture was allowed to warm to room temperature and stirred for a further 30 minutes. The solution was washed with 1M aqueous hydrochloric acid (2×100 ml), then washed successively with water (100 ml), sodium bicarbonate (100 ml) and brine (50 ml), then dried (MgSO4), filtered and evaporated to give the title compound (D6) as a pale orange oil 92.5 g; δH (CDCl3 rotomers observed) ppm 2.90 (2H, app.t), 3.74-3.81 (2H, m), 4.67, 4.72 (2H, 2s), 4.80 (2H, s), 7.12-7.21 (4H, m).

Provenance & Evidence