Diisopropylethylamine → 2-{4-[(R)-(1H-benzimidazol-2-ylmethyl)-5,6,7,8-tetrahydro-quinolin-8-yl-amino]-butyl}-isoindole-1,3-dione

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Reaction Conditions

Reaction Steps

To a solution of 2-{4-[(R)-(5,6,7,8-tetrahydro-quinolin-8-yl)amino]-butyl}-isoindole-1,3-dione (135.3 g, 0.39 mol) and 2-chloromethyl-benzimidazole-1-carboxylic acid tert-butyl ester (103 g, 0.39 mol) in acetonitrile (780 mL) at room temperature was added diisopropylethylamine (101 mL, 0.58 mol) and potassium iodide (6.4 g, 0.04 mol) and the mixture heated to 50° C. for 3 hours. The mixture was then concentrated under reduced pressure and redissolved in methyl t-butyl ether (500 mL) and water (500 mL). The pH was adjusted to 2 with 6N HCl then the phases were separated. The aqueous layer was washed with methyl t-butyl ether (500 mL). The aqueous phase was stirred for 22 hours, adding 6N HCl as needed to maintain pH=2. The solution was basified to pH 10-11 with 10N NaOH and extracted with toluene (2×1.5 L). The organic phase was washed with 1N NaOH (1×200 mL) and brine (1×200 mL). The organic phase was dried (Na2SO4), filtered and concentrated under reduced pressure to give 2-{4-[(R)-(1H-benzimidazol-2-ylmethyl)-5,6,7,8-tetrahydro-quinolin-8-yl-amino]-butyl}-isoindole-1,3-dione (209 g). 1H NMR (300 MHz, CDCl3, δ ppm) 0.75-1.75 (series of m, 5H), 1.80-2.10 (2m, 2H), 2.15-2.25 (m, 1H), 2.55-2.90 (m, 4H), 3.52 (t, 2H, J=7.0 Hz), 3.95-4.10 (m, 1H), 4.01 (d, 1H, J=17.0 Hz), 4.11 (d, 1H, J=17.0 Hz), 7.10-7.30 (m, 4H), 7.39 (d, 1H, J=7.5 Hz), 7.50-7.55 (m, 1H), 7.60-7.70 (m, 2H), 7.70-7.80 (m, 2H), 8.60 (d, 1H, J=3.5 Hz).

Provenance & Evidence