Reaction Steps
PNMR (300 MHz, CDCl3) δ 1.28 (s, 6 H), 1.38 (t, 3 H, J=7.1 Hz), 2.06 (s, 3 H), 2.19 (d, 2 H, J=4.3 Hz), 4.35 (q, 2 H J=7.1 Hz), 5.68 (t, 1 H, J=4.3 Hz), 6.04 (s 1 H, NH), 6.98 (overlapping d & dd, 3 H), 7.11 (d, 1 H, J=2.3 Hz), 7.21 (d, 1 H, J=8.2 Hz), 7.93 (d, 2 H, J=8.8 Hz). 4-Methyl-(5,8,8-trimethyl-7,8-dihydro-naphthalen-2-yl)-amino]-benzoic acid ethyl ester (Compound 66) General Procedure M To a solution of4-(5,8,8-trimethyl-7,8-dihydro-naphthalen-2-ylamino)-benzoic acid ethyl ester (Compound 65, 31 mg, 0.09 mmol) in a 10% acetic acid in acetonitrile solution (1.0 mL) and 1.0 mL of ether were added formaldehyde (0.10 mL, 3.60 mmol) and then sodium cyanoborohydride (14 mg, 0.22 mmol) and the reaction stirred at room temperature for 1 h. 1 M aqueous NaOH was added until pH=6 and the resulting mixture was extracted twice with ethyl ether. The combined organic extracts were washed with brine, dried over Na2SO4, filtered, and the solvents were removed in vacuo. The crude product was purified by silica gel chromatography (10% ethyl acetate in hexanes) to give the title compound as yellow oil. PNMR (300 MHz, CDCl3) δ 1.24 (s, 6 H), 1.37 (t, 3 H, J=7.1 Hz), 2.08 (s, 3 H), 2.23 (d, 2 H, J=4.4 Hz), 3.38 (s, 3 H), 4.34 (q, 2 H, J=7.1 Hz), 5.78 (t, 1 H, J=4.4 Hz), 6.79 (d, 2 H, J=9.0 Hz), 7.03 (dd, 1 H, J=2.3 & 8.2 Hz), 7.16 (d, 1 H, J=2.3 Hz), 7.28 (d, 1 H, J=8.2 Hz), 7.88 (d, 2 H, J=9.0 Hz). 4-[Methyl-(5,8,8-trimethyl-7,8-dihydro-naphthalen-2-yl)-amino]-benzoic acid (Compound 67) General Procedure N A solution of 4-[methyl-(5,8,8-trimethyl-7,8-dihydro-naphthalen-2-yl)-amino]-benzoic acid ethyl ester (Compound 66, 12 mg, 0.03 mmol) in 3.0 mL of ethanol was treated with 0.55 M KOH (1.0 mL). The solution was heated to 40 ° C. and stirred for 20 h. The solution was cooled and concentrated under reduced pressure. The residue was diluted with water, acidified with 10% HCl, and extracted twice with ether. The combined organic extracts were washed with brine, dried over MgSO4, filtered, and the solvents were removed in vacuo to give the title compound as a solid. 4-[Ethyl-(5,8,8-trimethyl-7,8-dihydro-naphthalen-2-yl)-amino]-benzoic acid ethyl ester (Compound 68)
