Hydrochloric Acid → 5-Methyl-6-phenyl-1,3-benzoxazole-4-carbonitrile hydrochloride

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Reaction Steps

2-[2-(Benzyloxy)-1,1-dimethylethyl]-7-[(3S)-3-(dimethylamino)pyrrolidin-1-yl]-5-methyl-6-phenyl-1,3-benzoxazole-4-carbonitrile (#13) (150 mg, 0.295 mmol) was dissolved in diethyl ether (5 ml), a 1,4-dioxane solution of 4 N hydrogen chloride (111 μl, 0.442 mmol) was added, followed by stirring at room temperature for 10 minutes. The reaction liquid was concentrated under reduced pressure to obtain a pale pink, amorphous 2-[2-(benzyloxy)-1,1-dimethylethyl]-7-(3-dimethylamino)pyrrolidin-1-yl)-5-methyl-6-phenyl-1,3-benzoxazole-4-carbonitrile hydrochloride (129 mg). The hydrochloride (118 mg, 0.216 mmol) was dissolved in methanol (7 ml), and catalytically hydrogenated at room temperature under 5 atmospheres on 10%-palladium carbon (50% wet, 75 mg), for 30 minutes. The catalyst was separated by filtration, the filtrate was concentrated under reduced pressure, the residue was dissolved in chloroform, washed with an aqueous saturated sodium hydrogencarbonate solution. The organic layer was washed with saturated brine, dried on anhydrous magnesium sulfate, concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (chloroform:methanol=50:1) to obtain the entitled compound (48 mg, 53%) as a colorless solid.

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