Hydrochloric Acid → 4-[1-Pentyl-3-(5,5,8,8-Tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-ureido]-benzoic Acid

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Reaction Steps

A solution of methyl 4-[1-pentyl-3-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-ureido]-benzoate (190 mg) in 20 mL THF, 5 mL methanol 5 mL water was treated with lithium hydroxide hydrate (0.3 g) and stirred at room temperature for two hours. The mixture was diluted with 20 mL water, the pH adjusted to 2 with concentrated HCl and extracted with three 25 mL portions of ethyl acetate. The combined organic extracts were dried over MgSO4, filtered and concentrated in vacuo, to give a pale yellow solid. The product was purified by flash chromatography (SiO2, 10% methanol/dichloromethane), to yield 75 mg of 4-[1-pentyl-3-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-ureido]-benzoic acid (42) as a white solid. M.P.: 201-202° C.

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