Notes on scientific research. 141 



Pulegone (sheet lead being used as cathode) yielded from 50 to 60 p. c. menthone, 

 as well as a heavy, plumbiferous, red oil. With copper electrodes from 95 to 100 p. c. 

 menthone was obtained. Carvone, when reduced with copper-foil-cathodes and copper 

 sulphate, was almost entirely converted into dihydrocarvone. 



Phenylacetaldehyde. E. Spath 1 ) reports on a «-hydroxylactone of phenyl- 

 acetaldehyde. He has observed that this aldehyde does not react with cyanide of 

 potassium in the ordinary way, but that while condensing it unites with one molecule 

 of hydrocyanic acid: — 



2 C 8 H 8 + KCN + H 2 = C 17 H 17 2 N + KOH 



phenylacet- 

 aldehyde. 



Saponification of the nitrile yields a lactone, Ci 7 Hi 6 3 , «-hydroxy-/?-phenyl-y-benzyl 

 butyrolactone, which E. Erlenmeyer jun. and F. Reis 2 ) prepared several years ago by 

 a different method. Hence the nitrile prepared from phenylacetaldehyde must be regarded 

 as ol, /-diphenyl-/5-hydroxybutyraldehyde cyanohydrine. C 6 H 5 • CH 2 • CHOH 



C 6 H 5 CHCH(OH)CN. 



On the arterio-necrotic action of certain aldehydes and ketones, see p. 132. 



Ketones. 



M ethyl nonyl ketone. E. Clemmensen 3 ) has discovered that the reduction of 

 aromatic ketones by heating them with amalgamated zinc and hydrochloric acid leads 

 to the corresponding hydrocarbons. In the case of aliphatic ketones also the reaction 

 takes place readily, albeit slowly. Thus, methylnonyl ketone from oil of rue afforded 

 n-undecane, b.p. 193 to 195°; d 20 o 0,741. Here the heating must be continued for 24 hours. 

 In order to prepare the zinc amalgam, granulated zinc should be allowed to lie for 

 about 2 hours in a 5 p. c. aqueous solution of corrosive sublimate. 



Methylheptenone. It was formerly supposed that when water is split off from 

 methylheptenone (I), — a reaction which takes place with ring formation — , dihydro- 

 m-xylene (II) is generated 4 ). But, as Wallach 5 ) has now discovered, the actual outcome 

 of the reaction is a mixture of equal parts of xylene and tetrahydroxylene. It is 

 impossible to prove this fact analytically, for the mixture gives values which agree 

 for dihydroxylene. Wallach condensed methylheptenone by heating with zinc chloride 

 or phosphorus pentoxide. The resulting mixture of hydrocarbons boiled principally 

 between 130 and 140°. When treated with dilute permanganate solution a hydro- 

 carbon remained behind which was stable towards permanganate. This hydrocarbon, 

 which constituted pretty nearly one-half of the original hydrocarbon mixture, proved 

 to be m-xylene (III). The oxidation-liquors filtered off from the manganese dioxide, 

 when extracted with chloroform yielded l,3-dimethyl-3,4-dihydroxyc^t7ohexane (m. p. S9°) 

 which when warmed with dilute sulphuric acid was converted into 1,3-dimethylcf/c/o- 

 hexanone. The ketone was identified by resolution into ^-methyladipic acid, as well 

 as by the preparation of its semicarbazone (m. p. 189°) and its oxime (m. p. 9S to 99°). 

 The generation of dimethyldihydroxyq/dohexane from the condensation-products of 



*) Monatsh. f. Chem. 33 (1912), 1029. — 2 ) Liebigs Annalen 333 (1904), 276. — s ) 8th International 

 Congress of Applied Chemistry, New York and Washington, 1912. Vol. VI. 68. — *) Comp. O. Wallach, Terpen* 

 und Campher, Leipzig 1909, p. 341. — 5 ) Liebigs Annalen 395 (1913), 74. 



