987 
ether-benzene or by precipitation of the ethereal solution with 
petroleum ether. Amyl acetate as recommended by Tortrn *) is less 
suitable because glutaconie acid is still too soluble therein. 
The acid melted finally without decomposition at 186°—138°. 
B. Very splendid results are obtained by the process of von Prcn- 
MANN—Brarse. Starting with citric acid, acetodicarboxylic acid was 
prepared according to the directions of JurDAN *) and this was reduced 
to g-oxyglutarie acid by von PRrCHMANN's process, after which the 
glutaconic diethylester was obtained according to Buaise via p-oxy- 
glutaric ester and acetyl-3-oxyglutaric acid. The yields are those 
stated by Braise: 500 grams of crude acetonedicarboxylic acid gave 
+140 grams of glutaconic ester b.p. 125°—132° at 15 m.m. 
I saponified this ester by boiling with 10°/, aqueous potassium 
hydroxide, using a little more than the theoretical quantity, until all 
had dissolved. The solution was then acidified with sulphurie acid 
and continuously extracted with ether. This saponification was fairly 
well quantitative. 
The acid when recrystalised as stated above melted at 186°—138°. 
C. According to the method of MORGENsTERN and ZERNER a 
prolonged boiling with strony aqueous potassium hydroxide of B-oxy- 
glutaricdinitrilene we should expect, « priort, no glutaconic acid but 
g-oxyglutarie acid instead. However, FicureR and Dreyevus *) showed 
that g-oxyglutarie acid (analogous to the monobasic oxy-acids inves- 
tigated by Fuirtig*) is converted on boiling with alkali into gluta- 
conic acid. In the synthesis of MoRGENSTERN and ZERNER, glutaconie 
acid is, therefore, a secondary product and I only needed to inves- 
tigate the acid obtained by Ficuter and Dreyrus method. 
Pure g-oxyglutarie acid was obtained from the crude syrup of this 
acid *) by warming for a few days with copper acetate. The Cu-salt 
was filtered off, washed with water and alcohol and decomposed 
with H‚S, when the aqueous solution of the acid was evaporated 
to dryness in vacuum. 
10 grams of that acid yielded, after 24 hours boiling with 50 
grams of 10°/, potassium hydroxide, on extraction with ether 5 grams 
of glutaconie which after purification melted at 135°—1387°. 
2) Soc. 75. 809 (note) (1899). 
3) Ber. 33, 1452 (1900). 
4) Ann. 283, 58 (1894). 
5) The non-crystallisation of this crude syrup is attributed by von PECHMANN 
JeniscH (loc. cit.) to the presence of a hypothetical lactide-like substance. In 
reality, this syrup contains considerable quantities of 6-oxyglutaric ester (formed 
on evaporation of the alcoholic extracts) as was convincingly shown on distillation. 
