Formaldehyde → HCID 13755881, compound

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Reaction Steps

This Example illustrates the preparation of 6-tert-butyl-3-piperidinomethyl-1,2-dihydronaphthalene (Compound number 4 of Table I). Piperidine hydrochloride (8.9 g, 0.073 mol), 7-tert-butyl-1,2,3,4-tetrahydronaphthalen-1-one (7.0 g, 0.035 mol) and paraformaldehyde (2.2 g, 0.073 mol) were refluxed together in ethanol (150 ml) along with concentrated hydrochloric acid (1 ml) as a catalyst for 16 hours. The reaction mixture was concentrated under reduced pressure and the residue dissolved in water then extracted with diethyl ether. The resulting aqueous solution was neutralized with sodium bicarbonate and extracted with diethyl ether (2×200 ml); the ethereal extracts were dried over magnesium sulphate and concentrated under reduced pressure to give 7-tert-butyl-2-piperidinomethyl-1,2,3,4-tetrahydronaphthalen-1-one (4.5 g, 43% yield) as a buff coloured solid melting at 62°-3°. The 7-tert-butyl-2-piperidinomethyl-1,2,3,4-tetrahydronaphthalen-1-one (4.5 g, 0.015 mol) was dissolved in methanol (100 ml) and sodium borohydride (0.6 g, 0.016 mol) was added portionwise over 30 minutes at room temperature. It was stirred for 3 hours at room temperature then the methanol was evaporated under reduced pressure and the residue treated with water (100 ml) and extracted with ether (2×100 ml) which was washed with brine, dried over magnesium sulphate and evaporated under reduced pressure to give a viscous oil (4.0 g) which crystallised on standing. Separation by column chromatography on silica gel (Merck 60) using a gradient elution of petrol 60°-80° to ethyl acetate gave the alcohol as two isomers:

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