188 ALDEHYDES AND KETONES : FATTY GROUP [96///L-Q. 



distillation of the calcium salt of the 

 latter with calcium formate. 



Or from alcohol and formic acid 

 [Vol. II] through diethyl carbinol by 

 the action of zinc on ethyl iodide and 

 formic ester, and decomposition of the 

 product with water (Saytzeff and 

 Wagner, Ann. 175, 351). The car- 

 binyl iodide gives symmetrical methyl- 

 ethylethylene (= 3-pentene) on treat- 

 ment with alcoholic potash (S. and W. 

 loc. cit. 373 ; 179, 302), and the corre- 

 sponding 2 : 3-dibrompentane yields 

 symmetrical methylethylethylene glycol 

 (= 2 : 3-dihydroxypentane) on treat- 

 ment with silver acetate and hydrolysis 

 of the acetate (Ibid. 179, 308). The 

 glycol gives a-hydroxybutyric acid on 

 oxidation by dilute nitric acid. Sub- 

 sequent steps as below under N. 



NOTES : The amylene fromzmc ethyl&nd chloro- 

 form may be symmetrical methylethylethylene 

 (Beilstein and Rieth, Ann. 124, 245 ; Beilstein's 

 ' Handbuch,' I, 116). 



Diethyl oxalate interacts with zinc ethyl to form 

 diethoxalic ester [21 ; G]. The latter by the 

 action of phosphorus trichloride gives a-ethyl- 

 crotonic ester (Frankland and Duppa, Journ. 

 Ch. Soc. 18, 133 ; Fittig and Howe, Ann. 200, 

 22), and the free acid combines with hydrogen 

 bromide to form bromhydro-ethylcrotonic = 

 bromhexoic acid (F. and H. loc.cit. 23). The latter 

 acid is decomposed by cold sodium carbonate 

 solution with the formation of symmetrical 

 methylethylethylene (Ibid. 30). 



Ethyl alcohol and acetic acid give ethylaceto- 

 acetic ester and, by the action of nitrous acid, 

 the latter yields an isonitroso-derivative which 

 is decomposed on heating with dilute sul- 

 phuric acid with the formation of acetyl-pro- 

 pionyl = 2 : 3-pentadione (v. Pechmann, Ber. 

 21, 1412 ; 24, 3956). The diketone on reduction 

 with zinc and dilute sulphuric acid gives 

 methylethylketol (v. P. and Dahl, Ber. 23, 

 2425) and, on further reduction with sodium 

 amalgam, symmetrical methylethylethylene 

 glycol (Ibid. 2426). 



Methylpropyl ketone [21 ; A] and diethyl ketone 

 [21 ; G ; H] give acetyl-propionyl on heating 

 with nitric acid (Fileti and Ponzio, Gazz. 25, 

 239 ; Journ. pr. Ch. [2] 55, 194). 



[M.] From aconitic acid [Vol. II] 

 through itaconic acid by heating with 

 water at 180 (Pebal, Ann. 98, 94), and 

 then as above under C. 



[N.] From normal butyric acid [Vol. 

 II] through propanal by electrolysis of 

 the sodium salt (v. Miller and Hofer, 

 Ber. 27, 468 ; Hofer and Moest, Ann. 

 323, 284). Or through the a-chloro- or 

 a-bromo-acid and a-hydroxy-acid (Nau- 



mann, Ann. 119, 115; Friedel and 

 Machuca, Ann. 120, 279; Markowni- 

 koff, Ann. 153, 242). The latter gives 

 propanal on oxidation (Ley, Journ. 

 Russ. Soc. 9, 131). Propanal can be 

 converted as under A above. 



NOTE : Since crotonic acid gives a- with 

 some )3-brombutyric acid on combination with 

 hydrogen bromide (Hemilian, Ann. 174, 325), 

 the generators of crotonic aldehyde and acid 

 referred to under normal butyl alcohol [17 ; G, 

 &c.] and benzyl alcohol [54 ; G ; H, &c.] thus 

 become generators of a-hydroxybutyric acid 

 and propanal. These generators are : malonic 

 acid and acetaldehyde ; acetoacetic ester ; glycerol ; 

 allyl isothiocyanate ; @-hydroxybutyric acid ; ery- 

 thritol fundformic acid ; n-butyric acid ; acetylene and 

 ethylene. 



Crotonic acid on combination with hypo- 

 bromous acid gives also (with the a-) some 

 /3-brom-a-hydroxybutyric acid, which yields 

 propanal on heating the sodium salt with 

 water (Melikoff, Journ. pr. Ch. [2] 61, 556). 



Or crotonic acid combines with chlorine to 

 form ojS-dichlorbutyric acid, the sodium salt of 

 which, on heating with water, gives propanal 

 among other products (Wislicenus, Ann. 248, 

 283 ; Michael and Browne, Am. Ch. Journ. 9, 

 282). 



Or crotonic acid combines with hypochlorous 

 acid to form <z-chlor-j8-hydroxybutyric acid 

 (Erlenmeyer and Miiller, Ber. 15, 49 ; Melikoff, 

 Ann. 234, 198), which, by the action of alco- 

 holic potash, gives /3-methylglycidic acid (Meli- 

 koff, loc. cit. 204). The latter combines with 

 hydrogen bromide to form /3-brom-a-hydroxy- 

 butyric acid, which is decomposed into propanal 

 as above (Melikoff, Journ. pr. Ch. [2] 61, 556). 



Or from butyric acid through butyr- 

 one or methylpropyl or ethylpropyl 

 ketone, dinitropropane, and propanal 

 (see under n-propyl alcohol [15 ; P ; 

 AA]). 



[O.] Mann it ol [51] on distillation 

 with lime gives, among other products, 

 ' metacetone/ which is a mixture con- 

 taining propanal (Favre, Ann. Chim. 

 [3] 11, 71 ; Fischer and Laycock, Ber. 

 22, 101). From propanal to 2-methyl- 

 pentanal as above under A. 



[P.] From acetic aldehyde [92], the 

 oxime of which combines with acid 

 sodium sulphite to form a salt, which, 

 on heating with hydrochloric acid, gives 

 methylglyoxal (v. Pechmann, Ber. 20, 

 2543). The dioxime of the latter yields 

 propylene glycol by electrolytic reduc- 

 tion (Tafel and Pfeffermann, Ber. 35, 

 1510). From the glycol through pro- 

 panal as above under B, &c. 



[Q.] From acetol [43], which gives 



