Ill A-113.J 



METHYLHEPTENONE 



203 



ing amylenc (see under acetone [106; 

 EJ). Or the fusel oil amylene (tri- 

 methylethylene) may be combined 

 directly with bromine to form 2:3- 

 dibrom-3-methylbutane (Wurtz, Ann* 

 Chim. [3] 55, 458 ; Bauer, Bull Soc. 

 2, M9)> an d the latter treated as above. 

 Or fusel oil amyl alcohol may be 

 converted into isopropylacetylene (as 

 under acetone [106 ; E]), and the latter 

 into dimethylallylene by heating with 

 alcoholic potash to 150 (Faworsky, 

 Jouvn. pr. Ch. [2] 37, 392). Subsequent 

 steps as above. 



Or from ethyl alcohol and acetic acid 

 through acetoacetic ester [Vol. II] and 

 the above dimethyltrimethylene brom- 

 ide. The latter interacts with sodio- 

 aeetoacetic ester and sodium ethoxide 

 to form dimethylallylacetoacetic ester, 

 which, on heating with barium hydrox- 

 ide solution or dilute alcoholic potash, 

 gives methylheptenone (Ipatieff, Ber. 

 34,594). 



Or from ethyl alcohol, acetic acid, 

 and acetone through acetopropyl alco- 

 hol by the action of sodium ethylate 

 on acetoacetic ester and ethylene brom- 

 ide, and decomposition of the product 

 (bromethylacetoacetic ester) by boiling 

 with dilute hydrochloric acid (W. H. 

 Perkin, junr., and Freer, Trans. Ch. 

 Soc. 51, 833; Lipp, Ber. 22, 1197). 

 Acetopropyl alcohol is converted by the 

 action of fuming hydriodic acid into 

 the corresponding iodide, CH 3 .CO. 

 [CH 2 ] 2 . CH 2 I ; the latter, by the action 

 of zinc and acetone and the decom- 

 position of the intermediate product 

 with water, into the tertiary alcohol, 

 CH 3 . CO . [CH 2 ] 3 . C(CH 3 ) 2 . OH ; the 

 tertiary alcohol into the oxide by dry 

 distillation, and then into the iodide, 

 CH 3 .CO.[CH 2 ] 3 .C(CH 3 ) 2 .I, by the 

 addition of hydrogen iodide. The 

 tertiary iodide gives methylheptenone 

 by the action of caustic alkali in dilute 

 solution (Verley, Bull. Soc. [3] 17, 122). 



[B.] Isovaleric aldehyde [95] and 

 acetone [106] condense in the presence 

 of alkali to form methylheptenone 

 (Leser, Bull. Soc. [3] 17, 108 : accord- 

 ing to Tiemann, Ber. 31, 817, note 5, 

 this productis not a pure ketone : seealso 

 Tiemann and Kriiger, Ber. 28, 2115). 



[C.] Cineole [40] on oxidation with 

 potassium permanganate gives cineolic 

 acid, C !0 H 1( .O 5 (Wallach and (lilde^ 

 meister, Ann. 246, 268), the anhydride 

 of which on dry distillation yields 

 methylheptenone (Wallach, Ann. 258, 

 325). The latter is identical with the 

 natural product (Tiemann and Semmler, 

 Ber. 28, 2126, note i ; also SchimmeFs 

 Ber. Oct. 1894). 



[D.] Dimethylheptenol [35] gives me- 

 thylheptenone among the products' of 

 its oxidation by chromic acid mixture 

 (Barbier, Comp. Rend. 126, 1424: see 

 also SchimmeFs Ber. Oct. 1898, and 

 Tiemann, Ber. 31, 2991). 



[E.] Citral [104] gives methyl- 

 heptenone (with acetic aldehyde) on 

 boiling with sodium carbonate solution 

 (Verley, Bull. Soc. [3] 17, 175)- 



[F.] Geraniol [36], on heating with 

 strong alcoholic potash at 150, gives 

 methylheptenol, and this yields methyl- 

 heptenone on oxidation (Tiemann, Ber. 

 31, 2989 ; 32, in). 



112. Fhorone ; 



2 ; 6-Dimethyl-2 : 5-heptadienone-4. 



(CH 3 ) 2 : C : CH . CO . CH : C(CH 3 ) 2 



A phorone (C 9 H 14 O) is said to have 

 been obtained from glycerol by bacterial 

 fermentation (hay bacilli : Schulze, Ber. 

 15, 64). This has been regarded as 

 possibly identical with the phorone 

 obtained from acetone [106] by heating 

 with lime or with hydrochloric acid 

 followed by alcoholic potash (Fittig, 

 Ann. 110, 32; Baeyer, Ann. 140, 301 : 

 also 61; B,p. 126). The phorone obtained 

 byFittig's method is isophorone (Bredt 

 and Riibel, Ann. 289, 10; 299, 160). 



The identity of the biochemical with 

 the synthetical product has net been 

 fully established. 



113. Diacetyl ; Dimetliylcliketoiie ; 

 Diketobutane ; Butadiene. 



CH 3 .CO.CO.CH 3 



NATURAL SOURCES. 



This diketone has been found in 

 aqueous distillates from oil of caraway 

 (SchimmePs Ber. Oct. 1899; Ch. Centr. 



