Naphthyl methyl ether hydrogenation

Tetralone has been prepared by a variety of methods, but the only practical procedures are relatively recent ones involving reduction of /9-naphthyl methyl ether with sodium and alcohol2 or with sodium and liquid ammonia,3 high-pressure catalytic hydrogenation of /9-naphthol,4 or catalytic oxidation of 2-tetralol by hydrogen transfer with ethylene.6... 

A wide variety of substituents are tolerated. The group R can be alkyl, halogen, alkoxy, -amido, azi-domethyl, ester, aryl, aryloxy and aryloyl, and at least one ortho substituent is permissible with no loss in yield. TTie aromatic ring can also be 2-naphthyl, 9,10-dihydro-2-phenanthryl, 3-pyridyl, thiophen-2-yl or pyrrol-3-yl. The group R can be hydrogen, yl, acyl or acetic acid. Beyond Ae antiinflammatory targets, successful reaction substrates include the methyl ketones of a binaphthyl crown ether, a morphinane and a polyaromatic hydrocarbon. The preparation of ibuprofen methyl ester (38) is shown in equation (37) as a typical example. ... 

A soln. of crude methyl 1-naphthyl ketone and ethyl formate in dry ether added slowly with shaking to Na-wire in dry ether, and refluxed 4 hrs. perinaphthe-none (Y 64%) in dioxane hydrogenated 8 hrs. at 260° with copper chromite at an initial Ha pressure of 120 atm. in a glass-lined autoclave perinaphthane (Y 80%). — The amount of Gu-chromite is critical. I. K. Lewis and R. D. Top-som, Australian J. Ghem. 18, 923 (1965). 

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