210 



AROMATIC ALDEHYDES AND KETONES [114 E-G. 



maim and Sachse, Ber. 24, 4113, note). 

 The latter yields benzoylacetic acid, 

 phenyl-/3-lactic acid, and benzaldehyde 

 as above under B and C. Or the phenyl 

 dibrompropionie ester by the limited 

 action of alcoholic potash gives a mixture 

 of two bromcinnamic esters, of which 

 the a-ester (i 2 -bromcinnamic ester) 

 yields benzoylacetic ester when treated 

 successively with strong sulphuric acid 

 and water (Michael and Browne, Ber. 



. 



Cinnamic acid can also be brominated 

 (Michael, Journ. pr. Ch. [2] 52, 292), 

 and the dibromo-acid debrominated in 

 two stages by successive treatment with 

 alkali (Ibid. Ber. 34, 3648). The final 

 product is phenylpropiolic acid, which 

 can be treated as above. 



Or the dibromo-acid on heating with 

 10 per cent, sodium carbonate solution at 

 1 00 gives i 2 -(oo)-bromstyrene, and this 

 on heating with strong alcoholic potash 

 at 130-135 yields phenylacetylene (Nef, 

 Ann. 308, 267). The latter gives aceto- 

 phenone as below (Friedel and Balsohn, 

 Bull. Soc. [2] 35, 55), and benzaldehyde 

 as under G. Or the dibromo-ester by 

 the action of sodium ethylate gives 

 ^3-ethoxycinnamic acid (Leighton, Am. 

 Ch. Journ. 20, 136), and this on heating 

 with alcoholic hydrochloric acid yields 

 benzoylacetic acid (Ibid. 137). 



The /3-iodo-cinnamic acid obtained 

 by iodising the acid in presence of 

 pyridine gives benzoylacetic acid and 

 acetophenone on treatment with sodium 

 hydroxide solution (Ortoleva, Gazz. 29, 



53)- 



Or phenylpropiolic acid can be con- 

 verted into phenylacetylene by heating 

 with water or phenol (Glaser, Ann. 

 154, 155; Holleman, Ber. 20, 3081). 

 Phenylacetylene on treatment with sul- 

 phuric acid and water gives acetophe- 

 none (Friedel and Balsohn, as above), 

 which can be treated as below under G. 



Or from cinnamic acid through 

 phenylnitroethylene by distilling the 

 acid with sodium nitrite in steam (Erd- 

 mann, Ber. 24, 2773), and then as 

 above under B. Or by the direct oxi- 

 dation of cinnamic acid with potassium 

 permanganate phenylglyceric acid is 

 obtained (Fittig and Riir, Ann. 268, 



27) ; benzaldehyde is among the pro- 

 ducts of the electrolysis of the potassium 

 salt of this acid in strong aqueous 

 solution (v. Miller and Hofer, Ber. 27, 

 470). 



NOTE : Phenylglyceric acid is also obtained 

 from cinnamic acid through phenyl-a-chlor-/3- 

 lactic acid (see above), and the action of 

 aqueous alkali on the latter (Lipp, Ber. 16, 

 1286). 



[P.] Vulpic acid [Vol. II] can be 

 converted into pulvic anhydride by 

 heating, and the latter into pulvic acid 

 by the action of caustic potash solution ; 

 or vulpic acid is directly convertible 

 into pulvic acid by boiling with milk of 

 lime (Spiegel, Ann. 219, 6). Pulvic 

 acid on oxidation with alkaline per- 

 manganate gives phenylglyoxylic acid 

 (Ibid. Ber. 14, 1689), and this yields 

 benzaldehyde as above under C. 



[G.] From acetic and benzoic acids 

 [Vol. II] through acetophenone (Friedel, 

 Ann. 108, 122), phenylglyoxylic acid 

 by oxidation with alkaline permanganate 

 (Grliicksmann, Monats. 11, 248), and 

 then as above under C. 



Or acetophenone can be converted 

 into i 2 : i 2 -dibromacetophenone by 

 bromination (Hunnius, Ber. 10, 2010), 

 and this on heating with dilute caustic 

 potash solution gives mandelic acid 

 (Engler and Wohrle, Ber. 20, 2202), 

 from which benzaldehyde can be ob- 

 tained as above under B. 



Or acetophenone can be converted 

 into the J 2 -nitroso-derivative by the 

 action of amyl nitrite and sodium 

 (Claisen, Ber. 20, 656). The sodium 

 bisulphite compound of the nitroso-ke- 

 tone gives benzoylformaldehyde (phen- 

 ethylal = pheny Iglyoxal) on heating with 

 dilute sulphuric acid(v. Pechmann, Ber. 

 2O, 2904; Miiller and v. Pechmann, 

 Ber. 22, 2557), and the aldehyde yields 

 mandelic acid on heating with aqueous 

 alkali (v. Pechmann, Ber. 2O, 2905). 



Or the nitroso-ketone gives benzoyl 

 cyanide on heating with acetyl chloride 

 or acetic anhydride (Claisen and Ma- 

 nasse, Ber. 20, 2196). The cyanide 

 yields benzaldehyde as above under C. 



From acetophenone through benzoyl- 

 acetic acid by the action of diethyl 



