2- Naphthylacetate

Introduce a solution of 15 g. of the diazo ketone in 100 ml. of dioxan dropwise and with stirring into a mixture of 2 g. of silver oxide (1), 3 g. of sodium thiosulphate and 5 g. of anhydrous sodium carbonate in 200 ml. of water at 50-60°. When the addition is complete, continue the stirring for 1 hour and raise the temperature of the mixture gradually to 90-100°. Cool the reaction mixture, dilute with water and acidify with dilute nitric acid. Filter off the a-naphthylacetic acid which separates and recrys-talhse it from water. The yield is 12 g., m.p. 130°. 

Ethyl a-naphthylacetate is prepared as follows. To a solution of 10 g. of the diazo ketone in 150 ml. of ethanol at 55-60°, add a small amount of aslurry of silver oxide, prepared from 10 ml. of 10 per cent, aqueous silver nitrate and stirred with 25 ml. of ethanol. As soon as the evolution of nitrogen subsides, introduce more of the silver oxide and continue the process until all the slurry has been added. Reflux the mixture for 15 minutes, add 2-3 g. of decolourising carbon, filter and evaporate the alcohol on a water bath. Distil the residue and collect the ethyl a-naph-thylacetate at 176-178°/ 1 mm. the yield is 9 g. 

Naphthylacetic acid. In a conical or round-bottomed flask, fitted with a reflux condenser by means of a ground glass joint, place a mixture of 128 g. of )3-naphthyl methyl ketone (Section IV,136), 35 g. of sulphur and... 

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). 

C18H20O4 101743-90-2) see Methallenestril 6-methoxy-2-naphthylacetic acid (C13H12OJ 23981-47-7) see Naproxen... 

Mix 130 g. of the crude thiomorpholide with 270 ml. of glacial acetic acid, 40 ml. of concentrated sulphuric acid and 60 ml. of water raise the temperature of the mixture carefully to the boiling point and reflux for 6 hours. Decant the solution from a little tarry matter into 2 litres of water and keep overnight. Collect the solid by suction filtration and wash it well with cold water. Digest the solid with a solution of 50 g. of sodium hydroxide in 1 litre of water, filter and acidify the filtrate with hydrochloric acid filter off the crude p-naphthylacetic acid, wash with water and dry. The yield of the crude acid, m.p. 137-140°, is 75 g. RecrystaUisation from benzene raises the m.p. to 142-143° the loss is about 10 per cent. 

ETHYL 1 -NAPHTHYLACETATE ESTER HOMOLOGATION VIA YNOLATE ANIONS... 

The pot material in this distillation is rather viscous and tends to bump, so good stirring and extra care should be employed to avoid this problem. A low-boiling fraction (0.67-0.78 g, 95-133°C, 0.2 mm) is collected that is mostly a mixture of hydrocarbons and ethyl 1 -naphthylacetate (ca. 1% yield). More than 90% of the product distils at 134-138°C, 0.2 mm. For the final few drops of product the bath temperature must be raised by 15-20°C, resulting in a slight rise in product boiling... 

Rajarathnam E. Reddy and Conrad J. Kowalski 146 ETHYL 1 -NAPHTHYLACETATE ESTER HOMOLOGATION VIA YNOLATE ANIONS... 

After the quench is complete, the mixture is diluted with 2 L of ether and washed in a separatory funnel with 1.25 L of aqueous 10% hydrochloric acid. The aqueous layer is reextracted with a 2-L portion of ether. The combined ethereal layers are washed with 1.25 L of saturated brine solution and dried over anhydrous magnesium sulfate. After filtration and removal of solvent using a rotary evaporator there remains 26 g of crude product as a reddish-brown oil. Distillation of this material under reduced pressure through an unpacked, 2-Inch distillation apparatus affords 17.3 g (81%) of ethyl 1-naphthylacetate as a yellow liquid, (bp 134-138°C, 0.2 mm) (Notes 17,18). 

Ethyl 1-naphthylacetate 1-Naphthaleneacetic acid, ethyl ester (8,9) (2122-70-5) Lithium 2,2,6,6-tetramethylpiperidide Piperidine, 2,2,6,6-tetramethyl-, lithium salt (9) (38227-87-1)... 

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