6-Amino-3,4-dihydro-1(2H)-naphthalenone could be produced through the following synthetic routes.

A. 2-Bromo-2-methylpropanamide (CAS NO.: ): A 250-mL, three-necked, round-bottomed flask, fitted with a thermometer, pressure-equalizing dropping funnel and equipped with a mechanical stirrer is charged with 28.0–30.0% aqueous ammonium hydroxide (35.7 mL, approximately 600 mmol) and (44.3 mL). The dropping funnel is charged with 2-bromo-2-methylpropanoyl bromide (50.0 g, 217.5 mmol), and the mixture is cooled below 5 °C (internal temperature) using a brine/ice bath with stirring. The 2-bromo-2-methylpropanoyl bromide is added dropwise slowly with stirring so that the internal temperature does not rise above 15 °C with cooling using a brine/ice bath (Caution: Exothermic reaction!). Stirring is continued for 1 h after the addition is complete, with the temperature of the reaction mixture maintained between 0 and 5 °C. The resulting white precipitate is collected by filtration on a glass filter funnel and washed three times with 40 mL of water to give 1 (33.0–33.5 g, 91.4–93.8 %) as a white crystalline powder.

B. 6-Amino-3,4-dihydro-1(2H)-naphthalenone: A 500-mL, three-necked, round-bottomed flask, fitted with a reflux condenser, thermometer, addition funnel and equipped with a large magnetic stirring bar is charged with 3,4-dihydro-6-hydroxy-1(2H)-naphthalenone (10.0 g, 61.7 mmol) and N,N-dimethylacetamide (90 mL). hydroxide (7.40 g, 185 mmol) is added into the flask by temporarily removing the addition funnel and the resulting mixture is stirred at 20–30 °C for 1 h. 2-Bromo-2-methylpropanamide (30.7 g, 185 mmol) is added to the reaction mixture through the addition funnel, and the resulting mixture is stirred at 25–35 °C for 5 h. After the reaction period, (22.2 g, 555 mmol) is added, and the resulting mixture is stirred for 1 h with heating to 50–60 °C (internal temperature) using an oil bath. After the reaction period, water (90 mL) is added by use of an addition funnel, and the mixture is heated at reflux using an oil bath for 1 h (internal temperature is 85–95 °C). Water (180 mL) is added to the reaction solution using an addition funnel, and the resulting precipitated mixture is allowed to cool slowly to 20–30 °C. The precipitated crystalline powder is collected by filtration on a glass filter funnel and washed three times with 90 mL of water to give 5 (6.28 g, 63.2%) as a brown crystalline powder.