et oe Th pita A eee eh BS Me cae gaa 
Vig taken Rrar Sate 2 , 
cop ba Sore NoTEs oN SCIENTIFIC RESEARCH. Bert ine 157 
is s soluble. in Daikaties: turns dark when exposed to the air Owing to Abeoraton of 
Bs vier and yields after acidulating | a yellow compound, volatile with steam, possibly 
a eer Thence it seems possible to generalise the newly-described reactions. 
On the inversion of menthone, we refer to p. 98 of this “Report 
A short time ago, H. Rupe, in; aGauniny with M. Iselin*) and E. Burckhardt, 
described numerous derivatives of methylene camphor. The optical investigation of these 
highly rotating bodies led to the discovery of various new and interesting facts. In 
- this connection, the authors were much interested in the preparation of an unsaturated 
_ketonic derivative of camphor starting from a derivative of methylene camphor. The 
results of this extensive oa ait have now been published by H. Rupe, M. Werder, 
_and K. Tagaki’). ; 
__-The authors started from srdiansehiicns camphor (!) Venren they converted, by 
_ treatment with dry hydrocyanic acid and with finely powdered potassium cyanide, into 
the nitrile of camphorylidene-3-acetic acid (II), m. p. 119 to 120°. The saponification 
of the nitrile was performed with a mixture of hydrochloric and glacial acetic acid. 
 Camphorylidene acetic acid (III)*) forms lemon-yellow prisms, m. p. 99.5 to 101°; 
b. p. 185.5 to 187° (11.5 mm.); [@]p 182.29°°) in a 10 per cent. benzene solution. The e 
diluted solution of the alkali salts is colourless. 
The chloride of camphorylidene acetic acid (IV), m. p. 734 to 350, b. p. 140 to 141° 
(13 mm.), is readily formed on treatment of the free acid with thionyl! chloride. 
With hydrogen bromide in glacial acetic acid, camphorylidene acetic acid yields 
the hydrobromide (V), m. p. 153 to 154°. Evidently, the addition of HBr is a reversible 
‘reaction; in the cold, HBr is added, and at 100° it is Split off again with quantitative 
formation of camphorylidene acetic acid. The addition of bromine to the acid does 
“not pass off in the normal manner, and the constitution of the bromo derivative | 
_(m. p. 73 to 75°) could not yet be ascertained. The ethyl ester boils at 149.5 to 150° 
(12 mm.); [«], 170.10°*) (undiluted); 160.39°°) in a 10 per cent. benzene solution. 
Reduction of camphorylidene acetic acid with sodium amalgam or better with 
_ hydrogen in presence of nickel leads to camphoryl-3-acetic acid (methyl camphor 
_ carboxylic acid, VI); m. p. 83 to 84°; b. p. 191.5 to 192.59 (12 mm.); [@]p 38.06°%) in a 
10 per cent. benzene solution; ethyl ester, b. p. 154 to 155° (10 mm.);  [@], ue 53° undi- 
_ luted); 37.18°°) in a 10 per cent. benzene solution. 
When trying to reduce the chloride of camphorylidene abetic. acid with zinc and 
acetic acid, a strange reaction took place, 1.¢., formation of a mixed anhydride of 
acetic and camphorylidene acetic acids (VII); m. p. 118-to 120°, The constitution of 
_ this compound could be elucidated by quantitative dégradation to both acids. 
> The authors then treated camphorylidene acetic chloride (IV) with diethyl sodio- 
malonate and obtained a pure compound formed by condensation of two molecules 
of the chloride with one molecule of diethyl sodiomalonate:— the diethyl ester of di- 
ee stapborylidenc-3-accty!)malonate ([dimethylene camphor carbonyl]-malonate) (VIII); 
m.p. 90 to 91°. 
They further succeeded, with some difficulties, to saponify this high-molecular body 
_ to camphorylidene-3-acetone (IX) and camphorylidene-3-acetic acid (Ill), by boiling with 
1) Berl. Berichte 49 (1916), 25; Report 1916, 123. — 7) Berl. Berichte 49 (1916), 2547; Report 1917, 155. 
— *) Helvet. chim. acta 1 (1918), 309. — *) Bishop, Claisen, and Sinclair, Liebig’s Annalen 281 (1894), 387. — 
3) It is not stated whether the acid is dextro- or lavorotatory. — %) The direction of the rotation is not stated. 
