Benzoyl isothiocyanate → (6,8-Dimethoxy-4-thioureido-isoquinolin-1-ylmethyl)carbamic acid tert-butyl ester

Participants

Reaction Steps

(4-Amino-6,8-dimethoxy-isoquinolin-1-ylmethyl)carbamic acid tert-butyl ester (225 mg, 0.675 mmol) was taken up in 10 mL of dry acetone, and benzoylisothiocyanate (121 mg, 0.742 mmol) was added dropwise. The reaction was stirred at room temperature for 2 h, and was then concentrated to a yellow solid. This solid was triturated with 50% aqueous EtOH, filtered, and suspended in 10% NaOH (5.0 mL). The reaction mixture was placed in an oil bath that was pre-heated to 98° C. for 1 h, (the solid was dissolved in 10 min). The mixture was cooled, acidified to pH 6-7 by 2.0 N aqueous HCl solution, and filtered. The yellow solid was washed with water, and dried in vacuo to give 126 mg (48%) of (6,8-dimethoxy-4-thioureido-isoquinolin-1-ylmethyl)carbamic acid tert-butyl ester. 1H-NMR (CDCl3): δ, 8.34 (s, 1H), 7.60 (s, 1H), 6.78 (d, 1H, J=2.1 Hz), 6.63 (d, 1H, J=1.9 Hz), 5.06 (d, 2H, J=3.7 Hz), 4.00 (s, 3H), 3.96 (s, 3H), 3.65 (s, 2H), 1.51 (s, 9H); MS: calculated for C18H24N4O4S+H 393.0; found: 393.0.

Provenance & Evidence