Ammonia → HCID 46449, compound

Participants

Reaction Conditions

Reaction Steps

3,4-Dihydro-5,8-dimethoxynaphthalen-1(2H)-one (5 g, 24.2 mmol), titanium(IV) isopropoxide (14.2 mL, 48.5 mmol) and 2 M solution of ammonia in ethanol (60.6 mL, 121.2 mmol) were stirred at room temperature for 6 h. The reaction was cooled to 0° C. and sodium borohydride was added portionwise during 10 min (1.4 g, 36.4 mmol); the resultant mixture was stirred at rt for an additional 3 h. The reaction was quenched by pouring it into ammonium hydroxide (2 M, 60 mL), the precipitate that formed was filtered off and washed with ethyl acetate (15 mL×3). The organic layer was separated and the remaining aqueous layer was extracted with ethyl acetate (15 mL×2). The combined organic extracts were washed with 1 M HCl (25 mL). The acidic aqueous extracts were washed with ethyl acetate (50 mL), then treated with aqueous sodium hydroxide (2 M) to pH 10-12, and extracted with ethyl acetate (40 mL×3). The combined organic extracts were washed with brine, dried (Na2SO4), and concentrated in vacuo to afford 1,2,3,4-tetrahydro-5,8-dimethoxynaphthalen-1-amine as an oil (4.68 g, 93% yield). 1H NMR (400 MHz, CDCl3) δ 6.66 (s, 2H), 4.18 (br tr, 1H), 3.82 (s, 3H), 3.77 (s, 3H), 2.85-2.79 (m, 1H), 2.47-2.38 (m, 1H), 1.90-176 (m, 6H).

Provenance & Evidence