2- Naphthyl methyl ether, preparation

Acetylation of naphthalene gives methyl naphthyl ketone, and sulfonation followed by alkaline fusion gives naphthol (Scheme 4.60). The methyl and ethyl ethers of naphthol are prepared from naphthol by reaction with the corresponding alkyl sulfate under basic conditions. These ethers are usually known by the shorter names of yara and nerolin, respectively. Yara, nerolin and methyl naphthyl ketone possess floral odours and are moderately important perfume ingredients. 

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... 

Other methyl ethers may be prepared in a similar manner e.g., f-naphthyl methyl ether (M.P. 71°) is formed in good yield from /3-naphthol. 

Other methyl ethers may be prepared by a similar procedure. /3-Naphthyl methyl ether is obtained in a 65-73 per cent yield by adding the dimethyl sulfate over a period of thirty minutes to equivalent quantities of /3-naphthol and sodium hydroxide kept cool by an ice-water bath, then heating for one hour at 75-78°, and, finally, crystallizing from benzene to obtain the pure methyl ether which melts at 71°. 

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. ... 

Fieser and Seligman231 describe the preparation of a very stable ketimine. The Grignard reagent prepared from l-bromo-8-methylnaphthalene (66 g) and the equivalent of magnesium is mixed with 0-chlorobenzonitrile (26 g) in benzene and heated with stirring for 16 h under reflux. Then dilute hydrochloric acid is added and the o-chlorophenyl 8-methyl-l-naphthyl ketimine hydrochloride is filtered off and washed successively with cold water, alcohol, and ether. The yield amounts to 60 g. This ketimine is stable to hot hydrochloric acid of various concentrations. 

In the area of cyclodextrin ethers the -compound has been converted into a set of five tris-Tbdms ethers, all substituted at their various 6-positions, which were separated by hplc and characterized by n.m.r. spectroscopy. Related work applied to y-cyclodextrin gave the various 6,6 -disubstituted ethers. 5-Bromo-l-pentene was used to produce the 2-0-mono-4-pentenyl ether of P-cyclodextrin which was then permethylated and the product was chemically bonded to silica gel to form an efficient hplc stationary phrase for the separation of enantiomers. Peroctyl a-cyclodextrin has been studied as a chiral receptor for the ephedrinium ion. Various octyl ethers of a-, P- and y-cyclodextrin ranging in their substitution from the diethers to completely alkylated products were characterized by electrospray mass spectrometry and n.m.r. methods applied to methylated derivatives. The 2,6-didodecyl derivative of p-cyclodextrin has been used as a potentiometric sensor. In the field of aromatic ethers, naphthyl carboxylate substituents have been bonded at the 6-positions and the products were able to transfer excitation energy to complexed merocyanine held in the cavities of those molecules. These phototransfer processes were extremely efficient.P-Substituted cyclodextrin derivatives with p-allyloxybenzoyl or various benzyl substituents at 0-2 or 0-3 were incorporated by hydrosilylation to give hydromethylpolysiloxane polymers used as chiral phases for chromatographic resolution of enantiomers. Cyclodextrins with complex benzyl-like eth are illustrated in 22 and 23. The latter were prepared as artificial redox enzymes. 

Methyl 8-benzhydryl-l-naphthoate added to excess methyllithium prepared from methyl iodide and lithium in ether, and the product isolated after 5 hrs. refluxing methyl 8-benzhydryl-l-naphthyl ketone. Y 92%.—A second mole of methyllithium enolizes the ketone with formation of methane, a general type of reaction of hindered alkyl ketones. Phenyllithium yields a tert. carbinol since enolization of the intermediate is not possible. R. L. Letsinger and P. T. Lans-bury, Am. Soc. 81, 935 (1959). 

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