2-Naphthyl acetate, preparation

Naphthylacetic acid derivatives, showiag antiinflammatory, analgesic, and antipyretic activities ate prepared by Ftiedel-Crafts acylation of methyl 1-naphthyl acetate at the 4 position with (CH2)2CHCOCl followed by Clemmensen reduction (97). 

Decahydro-/3-naphthyl acetate is prepared by esterifieation of technical-grade decahydro-/3-naphthol (e.g., with acetic anhydride). The acetate is used for perfuming household products. 

Naproxen is prepared (13) by the acylation of 6 substituted naphthalenes by AcCI forming the 2-acetyl derivative, which is further converted to 2-naphthyl acetic acid. Esterification and alkylation of 2-naphthyl acetic acid in the prescence of H2SO4, MeOH, NaH, Mel and with NaOH gave after hydrolysis the naphthyl propionic acid. Resolution of 2-(6-methoxy-2-naphthyl) propionic (Naproxen) was readily achieved by crystallization of the cinchonidine salt. 

Both a-(1-naphthyl)-butyric acid (LXXXV) and a-(2-naphthyl)-butyric acid (LXXXVI) have been prepared and tested in the rat rendered hyper-cholesterolemic with triton and were found to be more potent than -phenyl-butyric acid [216]. In addition, the s5mthesis of 21 a, a-dialkyl-substituted 1-naphthylacetic acid derivatives [253] and eleven 2-naphthyl acetic acid derivatives has been described [254]. Among these compounds, LXXXVII (DA-808) has been reported to inhibit triton-induced hypercholesterolemia but did not alter cholesterol and triglyceride contejit in the blood and hver of rats treated with steatogenic diets [255]. 

Photolysis of the telluroester in the presence of thiophenol isolation of benzaldehyde. A solution of the telluroester (Ar = 1-naphthyl) (15 mg, 41.7 jjmol) and thiophenol (17 mg, 154 jjmol) in CDCI3 (0.6 mL) was photolysed with a 250 W white light source at 8°C for 2 h. Preparative TLC on silica gel of the reaction mixture, eluting with ethyl acetate/hexa-nes, 1 9, gave benzaldehyde (3.5 mg, 80%). 

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. ... 

Aryl-substituted glycolic acids have been successfully reduced in high yields by several procedures. Refluxing with phosphorus and iodine in glacial acetic acid is described for the preparations of diphenylacetic acid (97%), 4-fluorenecarboxylic acid (92%), ° and a series of a-naphthyl-alkylacetic acids and biphenylalkylacetic acids. In a slight variation of this procedure, a mixture of potassium iodide, phosphorus, and phosphoric acid is used. Stannous chloride in a mixture of hydrochloric, hydriodie, and acetic acids has been employed in the preparation of... 

In this reaction, most efficient catalysts in the naphthyl series have been confirmed to be Pd(OAc)2+l BINAP and NiCl2(dppf). On the other hand, the single C-0 bond in a-hydroxy ketones and their acetate and mesylate derivatives has been cleaved to form the corresponding ketones by the promotion of a vanadi-um(II) complex prepared in situ from the reaction of VC13(THF)3 and zinc (Eq.48) [111]. 

To a solution of corresponding imine freshly prepared (1.0 equiv) in dried dichlor omethane at 0 °C, catalyst (13c) (0.1 equiv), (3 naphthol (0.1 equiv), and P naphthyl acrylate (2.0 equiv) were added. The reaction mixture was stirred under argon atmosphere at 0 °C for the required time indicated in the tables. The reaction was stopped by passing the mixture through a short pad of silica gel using ethyle acetate for the elution. Solvents were removed in vacuo and the residue was purified by flash chromatography on silica gel (eluent n Hept/EtOAc = 90/10) to afford the corre spending pure product. 

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