4-[(5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carboxamido]benzoic acid

102121-59-5

102121-60-8

To a 25 mL round-bottomed flask equipped with a reflux condenser tube was added methyl 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphthalene-2-carboxamido)benzoate (0.200 g, 0.547 mmol), methanol (10 mL) and potassium hydroxide (0.122 g, 2.18 mmol). The reaction mixture was stirred under reflux conditions for 16 h and subsequently evaporated to dryness. The residue was partitioned between ethyl acetate and deionized water and adjusted to acidic pH with 6 N hydrochloric acid. the organic layer was separated, washed sequentially with deionized water, saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated by rotary evaporation to afford 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphthalene-2-carboxamido)benzoic acid as a white solid (0.151 g, 78% yield ). Molecular weight: 351.43; melting point: 265°C; Rf value: 0.3 (ethyl acetate:cyclohexane=50:50).1H NMR (CDCl3, δ): 1.32 (s, 6H, 2×CH3), 1.34 (s, 6H, 2×CH3), 1.73 (s, 4H, 2×CH2), 7.43 (d, 1H, J=8.53 Hz. ArH), 7.57 (d, 1H, J=8.25 Hz, J=1.98 Hz, ArH), 7.78 (d, 2H, J=8.74 Hz, ArH), 7.88 (d, 1H, J=8.74 Hz, ArH), 7.92 (s, 1H, NH), 8.13 (d, 2H, J=8.70 Hz, ArH), and no observed carboxylic acid proton signal.MS-ESI: m/z (relative intensity) 352.1 ([M+H]+, 100).HPLC analysis (Method A, detection wavelength 254 nm): retention time = 6.66 min, peak area = 96.3%.