208 



AROMATIC ALDEHYDES AND KETONES [114 A C. 



Or from benzene and oxalic acid 

 [Vol. II] by the action of ethyloxalyl 

 chloride = chlorethanalic ester, C1CO . 

 CO 2 . C 2 H 5 , on the hydrocarbon in the 

 presence of aluminium chloride. Phenyl- 

 glyoxylic ester is synthesised by this 

 method, and the acid gives benzalde- 

 hyde as below under C (Bouveault, 

 Bull. Soc. [3] 15, 1017; 17, 363: see 

 also Roser, Ber. 14, 940). 



Or from benzene and acetic aldehyde 

 [92] through aniline and phenylhydiv 

 azine and acetaldehydephenylhydrazone. 

 The latter gives acetophenone when 

 oxidised by air in alcoholic potash solu- 

 tion (Biltz and Wienands, Ann. 3O8, 

 1 6 : see also v. Pechmann, Ber. 31, 

 3125). 



[B.] Styrene [7] on heating with 

 nitric acid, or by the action of ' nitrous ' 

 gas, gives phenylnitroethylene, C 6 H 5 . 

 CH : CH.NO 2 (Simon, Ann. 31, 269; 

 Blyth and Hofmann, Ann. 53, 297 ; 

 Priebs, Ann. 225, 328). The latter 

 yields benzoic aldehyde on heating with 

 water, aqueous alkali, or dilute sulphuric 

 acid (Priebs, loc. cit.]. Or phenylnitro- 

 ethylene, on heating with strong hydro- 

 chloric acid, gives phenylchloracetic acid 

 (Priebs, loc. cit. 337), and this yields 

 mandelic acid on boiling with aqueous 

 alkali (Spiegel, Ber. 14, 239). The 

 latter acid gives benzoic aldehyde on dry 

 distillation, on oxidation (Liebig, Ann. 

 18, 321), or on electrolysis of a solution 

 of the potassium salt (v. Miller and 

 Hofer, Ber. 27, 469). 



Or styrene can be converted into the 

 bromide by bromination (Blyth and 

 Hofmann, Ann. 53, 306 ; Glaser, Ann. 

 154, 154; Zincke, Ann. 216, 288), the 

 corresponding phenylglycol by boiling 

 with aqueous potassium carbonate 

 (Zincke, loc. cit. 293), and into benzoic 

 aldehyde by oxidising the glycol with 

 chromic acid mixture. Or on oxidation 

 with nitric acid the glycol gives phenyl- 

 glyoxylic acid (Zincke and Hunaus, Ber. 

 10, 1488), from which benzoic aldehyde 

 can be obtained as below under C. 



Or styrene bromide on heating with 

 strong alcoholic potash gives phenyl- 

 acetylene (Glaser, Ann. 154, 155 ; Frie- 

 del and Balsohn, Bull. Soc. [2] 35, 55 ; 

 Holleman, Ber. 2O ; 3081), which can 



be converted into acetophenone as under 

 E, and the latter treated as under G. 



Or styrene bromide on heating with 

 water, alcoholic potash, or potassium 

 acetate gives i 1 -bromstyrene (Radzis- 

 zewski, Ber. 6, 493 ; Glaser, Ann. 154, 

 1 68 ; Zincke, Ann. 216, 290 : according 

 to Nef, Ann. 303, 273, i 2 -(<o)-bromsty- 

 rene is also formed by these methods), 

 and this, by the action of sodium and 

 carbon dioxide, yields phenylpropiolic 

 acid (Erlenmeyer, Ber, 16, 152), the 

 ester of which, when dissolved in strong 

 sulphuric acid and the solution poured 

 on to ice, gives benzoylacetic ester 

 (Baeyer, Ber. 15, 2705). The latter can 

 be reduced to phenyl-^-lactic acid, and 

 the acid converted into benzaldehyde 

 as below under C. Or phenylpropiolic 

 ester can be converted into benzoylacetic 

 ester by the action of dilute caustic 

 alkali (Baeyer and W. H. Perkin, junr., 

 Ber. 16, 2128 ; W. H. P., junr., Trans. 

 Ch. Soc. 45, 174). 



Or i 1 -bromstyrene on heating with 

 water at 180 gives acetophenone (Frie- 

 del and Balsohn, Bull. Soc. [2] 32, 614), 

 which can be treated as below under Gr. 

 Or phenylpropiolic acid can be con- 

 verted into phenylacetylene and aceto- 

 phenone as below under E. 



[C.] From benzoic and formic acids 

 [Vol. II] by distilling a mixture of the 

 calcium salts (Piria, Ann. 100, 104) ; 

 by reduction of benzoic acid with sodium 

 amalgam in dilute acid solution (Kolbe, 

 Ann. 118, 122), or with stannous com- 

 pounds (Dusart, Comp. Rend. 55, 448) ; 

 or by electrolytic reduction (Nithack, 

 Germ. Pat. 123554 of 1899 ; Ch. Centr. 

 1901,2,715); or by heating with zincdust 

 (Baeyer, Ann. 14O, 296). Also through 

 benzoyl chloride and benzoyl cyanide 

 and the action of zinc and hydrochloric 

 acid on the latter (Kolbe, Ann. 98, 344). 

 Or from benzoyl chloride and copper 

 hydride (Chiozza, Ann. 85, 232). 



Benzoyl cyanide by the action of 

 hydrochloric acid in the cold gives 

 phenylglyoxylic = benzoylformic acid 

 (Claisen, Ber. 1O, 430 ; 845 ; H iibner 

 and Buchka, Ibid. 479). The latter 

 yields benzoic aldehyde among other 

 products on distillation (Claisen, loc. 

 cit. 1666). Or phenylglyoxylic acid 



