Diisopropylethylamine → 3-(1-{[2-(6-chloro-1-methyl-1H-indazol-3-yl)-5-(2-trimethylsilanyl-ethoxymethyl)-5H-pyrrolo[2,3-b]pyrazine-7-carbonyl]-amino}-ethyl)-azetidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a solution of 3-(1-amino-ethyl)-azetidine-1-carboxylic acid tert-butyl ester (crude from step 3, 63 mg, 0.31 mmol) in DMF (2 mL) were added N,N-diisopropylethylamine (69 μL, 0.39 mmol), 2-(6-chloro-1-methyl-1H-indazol-3-yl)-5-(2-trimethylsilanyl-ethoxymethyl)-5H-pyrrolo[2,3-b]pyrazine-7-carboxylic acid (120 mg, 0.26 mmol), and HATU (110 mg, 0.29 mmol). The yellow reaction mixture was stirred at room temperature overnight then quenched with water and extracted with EtOAc (3×). The combined organics were washed with water (3×) and brine then dried over MgSO4 and concentrated. The residue was purified by silica gel chromatography with 30% to 60% EtOAc/hexanes to afford 158 mg (94%) of 3-(1-{[2-(6-chloro-1-methyl-1H-indazol-3-yl)-5-(2-trimethylsilanyl-ethoxymethyl)-5H-pyrrolo[2,3-b]pyrazine-7-carbonyl]-amino}-ethyl)-azetidine-1-carboxylic acid tert-butyl ester as a white foam. 1H NMR (CDCl3, 300 MHz): δ (ppm) 9.23 (s, 1H), 8.36 (t, J=4.3 Hz, 2H), 8.18 (d, J=9.1 Hz, 1H), 7.52 (s, 1H), 7.24-7.29 (m, 1H), 5.73 (s, 2H), 4.57-4.68 (m, 1H), 4.18 (s, 3H), 3.87-4.08 (m, 3H), 3.79 (dd, J=8.7, 6.0 Hz, 1H), 3.55-3.65 (m, 2H), 2.73 (br. s., 1H), 1.39 (s, 9H), 1.36 (d, J=6.8 Hz, 6H), 0.89-1.01 (m, 2H), −0.03 (s, 9H).

Provenance & Evidence