Triethylamine → (S)-1-((10-chloro-6,7-dihydro-4-oxo-3-phenyl-4H-benzo(a)quinolizin-1-yl)carbonyl)-3-ethoxypyrrolidine

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Reaction Steps

A suspension of 8.79 g (25 mmol) of 10-chloro-4-oxo-3-phenyl-6,7-dihydro-4H-benzo[a]quinolizine-1-carboxylic acid (X) in 125 ml of ethyl acetate was treated with 0.076 g (0.625 mmol) of dimethylaminopyridine and 3.49 g (27.5 mmol) of oxalyl chloride. The mixture was then stirred at 600 for 3 hours. The yellow solution (XI) was concentrated and the residue was taken up in 125 ml of toluene. This was treated either with 5.26 g (52 mmol) of triethylamine and 3.94 g (26 mmol) of (S)-3-ethoxypyrrolidine hydrochloride or with 2.63 g (26 mmol) of triethylamine and 3.0 g (26 mmol) of (S)-3-ethoxypyrrolidine and stirred for 4 hours. Subsequently, the solution was washed in succession with 100 ml of water, 100 ml of 1N HCl, 100 ml of 0.5N KHCO3 and then again with 100 ml of water. The individual aqueous phases were extracted with 100 ml of toluene and the combined organic extracts were dried with 20 g of Na2SO4. The residue obtained after filtration and concentration was dried at 50°/0.1 mbar/2 h. Compound I was obtained in 85% yield, based on the acid, after purification by recrystallization from acetone/water and acetone/hexane. M.p. 133°-134°.

Provenance & Evidence