Diethyl Ether → (4-Amino-6,7-dimethoxy-isoquinolin-1-ylmethyl)carbamic acid tert-butyl ester

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A solution of [1-(tert-Butoxycarbonylamino-methyl)-6,7-dimethoxy-isoquinolin-4-yl]-carbamic acid benzyl ester, in 45 mL of EtOH and 20 mL THF was hydrogenated at 1 atm (balloon) over 60 mg of 10% Pd—C for 3 h. The catalyst was removed by filtration through a plug of celite and the filtrate was concentrated to give a white film. Trituration with ether gave 534 mg (89%) of the 4-aminoisoquinoline as a white granular solid. H1-NMR (CDCl3): δ 7.84 (s, 1H), 7.36 (s, 1H), 7.02 (s, 1H), 6.00 (s, 1H), 4.78 (d, J=5.1 Hz, 1H), 4.03 (s, 3H), 4.01 (s, 3H), (s, 1H), 3.89 (s, 2H), 1.48 (s, 9H). MS: APCI (M+H) calc' d for C18H24N2O4+H 334.4; found 334.0.

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