Ethyl a-naphthylacetate

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. 

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... 

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). 

Fig. 19- The efficiency, q, of the Amberlite IR-120 ion exchanger catalyst in ester hydrolysis as a function of the entropy, S, of the parent hydrocarbon RH or R H of the substituents, (a) Hydrolysis (at 25—45°C) of methyl esters RCOOCH3 [366] 1, acetate 2, chloroacetate 3, benzoate 4, cyclopentanecarboxylate 5, phenylacetate 6, a-naphthylacetate 7, 1-octanoate. (b) Hydrolysis (at 35°C) of acetates CH3COOR [480] 1, methyl 2, ethyl 3, cyclopentyl 4, cyclohexyl 5, 1-butyl 6, 2-pentyl 7, 1 -pentyl 8, 1 -hexyl 9, 1 -octyl,...

This compound is a severe skin irritant, hence great care should be exercised to avoid any contact. For best yields in the rearrangement step this crystallization is recommended, since I he yield of ethyl 1-naphthylacetate is reduced by about 20% if the crude product is used in the rearrangement. A sample of crystallized l-(diazoacetyl)naphthalene, m.p. 52-53°, that had been stored in a screw-top bottle in a refrigerator for about 2 weeks afforded the same yield of ethyl 1-naphthylacetate as a freshly prepared sample. 

Sample preparation 0.5 mL Plasma -I- 2.5 pL 400 pg/mL 6-chloro-2-naphthylacetic acid in acetone, mix on a whirlmixer, add 6 mL n-hexane ethyl acetate 50 50, add 0.7 mL 1.5 M HCl, shake mechanically for 30 min, centrifuge at 1500 g for 10 min. mover organic layer and evaporate it to dryness at 37 under a stream of nitrogen. Dissolve residue in mobile phase, centrifuge, inject a 20 pL aliquot. 

The monomeric 2-(l-naphthylacetyl)ethyl acrylate was synthesized by esterification of 1-naphthylacetic acid (NAA) and 2-hydroxyethyl acrylate and then polymerized to obtain the polymer which is potentially useful as a plant growth regulator through hydrolytic release of NAA. Copolymers with hydrophilic comonomers were also prepared by solution polymerization and the influence of their microstructure on the behavior of controlled release was investigated (Scheme 3.15) [149]. 

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