1,4-Dioxane hydrochloride → ethyl 4-(2-fluorophenyl)-7-(morpholine-4-carbonyl)-9H-pyrido[3,4-b]indole-1-carboxylate

Participants

Reaction Steps

To a yellow, homogeneous solution of (3-(2-amino-1-(2-fluorophenyl)ethyl)-1H-indol-6-yl)(morpholino)methanone (0.270 g, 0.736 mmol) and 50% ethyl 2-oxoacetate/toluene (0.321 mL, 1.619 mmol) in 1,4-dioxane (30 mL) was added 4 N HCl/dioxane (0.368 mL, 1.472 mmol) under nitrogen, and the reaction was stirred overnight. The reaction was concentrated in vacuo, diluted with water and basified to pH ˜10 (by litmus paper) with NaHCO3. This was extracted with EtOAc (3×), and the organic layers were combined and washed with brine, dried over MgSO4, filtered and concentrated in vacuo to give crude product which was used in the subsequent step. This was combined with 10% Pd/C (0.710 g, 0.668 mmol) in toluene (10 mL), and the solution was refluxed. After 45 min, the reaction was cooled to room temperature and filtered through a pad of CELITE®, rinsing with EtOAc. The filtrate was washed with brine, dried over MgSO4, filtered and concentrated in vacuo to give a residue which was purified by flash chromatography using an ISCO 24 g column eluting with 0-100% EtOAc/hexanes. Appropriate fractions were collected and concentrated in vacuo to give the desired product (0.0592 g, 0.132 mmol, 19.8% yield) as an off-white solid.

Provenance & Evidence