Trichloroacetonitrile → 7-{1-[4-(7-Methyl-1H-indol-3-yl)-2,5-dioxo-2,5-dihydro-1H-pyrrol-3-yl]-isoquinolin-3-yl}-4,7-diaza-spiro[2.5]octane-4-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a solution of 7-{1-[1-hydroxymethyl-4-(7-methyl-1H-indol-3-yl)-2,5-dioxo-2,5-dihydro-1H-pyrrol-3-yl]-isoquinolin-3-yl}-4,7-diaza-spiro[2.5]octane-4-carboxylic acid tert-butyl ester (7.30 g, 12.30 mmol) in acetonitrile (60 mL) was added dropwise a solution of DBU (0.374 g, 0.371 mL, 2.46 mmol) in trichloroacetonitrile (17.8 g, 12.3 mL, 123 mmol) at r.t. under argon. The reaction mixture was stirred for 5 h at r.t. until TLC (SiO2, EtOAc/cyclohexane 6:4) indicated complete conversion. The reaction mixture was evaporated to dryness at reduced pressure and the residue was suspended in acetonitrile (60 mL). Phosphoric acid di-tert-butyl ester (3.36 g, 15.99 mmol) was added and the reaction mixture was stirred for approximately 3.5 h at r.t. under argon until TLC (SiO2, EtOAc/cyclohexane 6:4) indicated that the reaction was complete. The reaction mixture was concentrated at reduced pressure and the residue was partitioned between EtOAc and water. The layers were separated and the organic phase was washed with water (5 times). The organic phase was dried over Na2SO4 and concentrated at reduced pressure to afford a red solid. The crude product was purified by FCC (Biotage SP4™ system, SiO2, cyclohexane/EtOAc 20:80) to yield the title compound as a red solid. 1H-NMR (400 MHz, DMSO-d6): 12.03 (s, 1H), 8.08 (d, 1H), 7.70-7.65 (m, 2H), 7.47 (t, 1H), 7.11 (s, 1H), 7.11-7.07 (m, 1H), 6.77 (d, 1H), 6.44 (t, 1H), 5.97 (d, 1H), 5.39 (d, 1H), 3.49-3.08 (m, 6H), 2.39 (s, 3H), 1.45 (s, 18H), 1.41 (s, 9H), 0.87-0.56 (m, 4H). 31P-NMR (162 MHz, DMSO-d6): −12.1. LCMS: [M+1]+=786.4, Rt(1)=2.53 min., Rt(2)=1.62 min.

Provenance & Evidence