Diisopropylethylamine → 6-(methyloxy)-1-(1-methyl-L-prolyl)-7-nitro-1,2,3,4-tetrahydroquinoline

Participants

Reaction Steps

A solution of 6-(methyloxy)-7-nitro-1,2,3,4-tetrahydroquinoline (3.0 g, 14.41 mmol), 1-methyl-L-proline (2.140 g, 16.57 mmol), HATU (7.12 g, 18.73 mmol), and DIPEA (6.29 mL, 36.0 mmol) in N,N-Dimethylformamide (DMF) (25 mL) was stirred for 2.5 days at room temperature. Reaction was poured into ethyl acetate and washed successively with 5% lithium chloride (aq) and saturated sodium chloride (aq). The organic layer was dried over sodium sulfate, filtered, and purified by column chromatography (10% MeOH/CH2Cl2) to afford 6-(methyloxy)-1-(1-methyl-L-prolyl)-7-nitro-1,2,3,4-tetrahydroquinoline (2.09 g, 6.54 mmol, 45.4% yield). The residue was suspended in ethanol (300 mL) and N,N-dimethylacetamide (50 mL) was added followed by tin(II)chloride dihydrate (6.78 g, 30.1 mmol) and 1.0M HCl (2.505 mL, 2.505 mmol). After overnight stirring the reaction was quenched with excess saturated NaHCO3 (300 mL) and allowed to stir at rt for 30 min. The solids were removed through a celite pad, rinsed with Me0H, and evaporated. The aqueous layer was extracted with DCM (2×100 mL). The combined organic layers were filtered through a cotton plug, and concentrated by rotary evaporation to provide 6-(methyloxy)-1-(1-methyl-L-prolyl)-1,2,3,4-tetrahydro-7-quinolinamine (1.1 g, 26% over two steps). ESIMS (M+H)+=290.

Provenance & Evidence