A Naphthoic acid

This method may be used for the preparation of larger quantities, a batch twenty times this size giving a yield of 87 per cent. It may be used also for the preparation of other aromatic acids where suitable ketones are available. Methyl a-naphthyl ketone prepared by Caille s method is not suitable for the preparation of a-naphthoic acid as it contains at least 30 per cent of the methyl d-naphthyl ketone. 

Upon acidifying the alkaline washings, about 1 g. of a-naphthoic acid may be isolated. 

For initial experience in the use of Utbium, the preparation of either p-toluic acid or of a-naphthoic acid may be xmdertaken. For the former, p-bromotoluene is converted into the Uthium derivative and the latter carbonated with soUd carbon dioxide ... 

Feldman and Campbell, on the other hand, used hydrogen-bonding interactions to enforce a particular stereo- and regiochemical outcome of the sohd-state photocycloaddition of a naphthoic acid-derived cinnamic acid [45]. In a conceptually similar approach, Scheffer demonstrated that diamines can form double salts with a variety of trans-cinnamic acid derivatives. The locking in place of the double bonds steers the sohd-state [2+2] photodimerization [46]. 

The solution is cooled and acidified strongly with 50 per cent sulfuric acid. The crude a-naphthoic acid is collected on a Buchner funnel, washed until free from sulfate, and dried. The yield of crude material melting at 142-155° is 130-135 g. This is dissolved in 400 cc. of hot toluene, a small amount of filter-cel is added, and the solution is filtered through a hot Biichncr fun-... 

Into a solution containing a-naphthoic acid chloride in benzene with agitation and cooling for 0.5 h a benzene solution of N,N-diethylamine-ethyl-N -(n-butyl)amine is dropped. As the dropping is ended, the solution is kept under agitation in a water bath for 3 h. 

A mixture of 540 grams (9.0 mols) of ethylenediamine, 270 grams (1.53 mols) of l,2,3,4tetrahydro-a-naphthoic acid, and 360 ml (4.32 mols) of concentrated hydrochloric acid was introduced into a two-liter, three-necked flask fitted with a thermometer, stirrer, and distillation takeoff. The mixture was distilled under a pressure of about 20 mm of mercury absolute until the temperature rose to 210°C. Thereafter, heating was continued under atmospheric pressure and when the temperature reached about 260°C, an exothermic reaction was initiated. The heat was then adjusted to maintain a reaction temperature of 275° to 280°C for 45 minutes and the mixture thereafter cooled to room temperature. 

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