Sulfuric acid magnesium salt (1:1) → 2-[1-(Tert-butoxycarbonylamino-methyl)-6,8-dimethoxy-isoquinolin-4-ylamino]thiazole-4-carboxylic acid ethyl ester

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Reaktionsschritte

To a solution of (6,8-dimethoxy-4-thioureido-isoquinolin-1-ylmethyl)carbamic acid tert-butyl ester (62 mg, 0.158 mmol) and ethyl bromopyruvate (37.7 mg, 0.174 mmol) in acetone (1.6 mL) was added MgSO4 (9.5 mg, 0.079 mmol). The resulting suspension was stirred at 60° C. for 3 h. The reaction was cooled to RT and concentrated. The residue was purified by passing through a 5 g silica cartridge eluting with 2% MeOH in DCM to give 2-[1-(tert-butoxycarbonylamino-methyl)-6,8-dimethoxy-isoquinolin-4-ylamino]thiazole-4-carboxylic acid ethyl ester as a pale yellow solid (32.5 mg, 42%). 1H-NMR (CDCl3): δ, 8.53 (s, 1H), 7.47 (s, 1H), 6.82 (s, 1H), 6.61 (s, 1H), 5.07 (d, 2H, J=4.2 Hz), 4.41 (q, 2H, J=7.2 Hz), 4.00 (s, 3H), 3.89 (s, 3H), 1.52 (s, 9H), 1.41 (t, 3H, J=7.3 Hz); MS: calculated for C23H28N4O6S+H 489.0; found: 489.0.

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