981 
Chemistry. — “Glutaconic acid’. (D. By Dr. P. E. VERKADE. (Com- 
municated by Prof. J. BörseKEN). 
(Communicated in the meeting of November 27, 1915), 
In a series of very interesting communications *) entitled: “The 
chemistry of the glutaconie acids” J. F. Trorer has given a fairly 
complete survey of the peculiar structure and isomerism phenomena 
noticed more in particular in the case of the alkyl and aryl deriva- 
tives of glutaconie acid and their anhydrides, dicarboxy-esters etc. 
A short time before the appearance of the first publication of this 
series (in 1911) I had noticed, in an effort to determine the hydration 
constant of the glutaconie anhydride, deviations in the normal pro- 
gress of the hydration process which could not then be explained, 
but the explanation of which is now very simple owing to the 
above mentioned investigations of THorpp (according to which this 
anhydride must be regarded as 6. hydroxy- «. pyrone). In other 
words the results obtained by Trorern by means of a purely chemi- 
cal process were confirmed by a physico-chemical method. 
It speaks for itself that I subsequently tried to also confirm other 
peculiarities of these acids by a physico-chemical investigation; in 
the subjoined, a start is made with the publication of the results 
attained. 
By various ways, which need not be discussed here, THORPE *) 
has demonstrated that in the glutaconie acid molecule: 
COOH — CH, — CH = CH — COOH 
a B bi 
the « and the y position are identical. It appeared, for instance, 
that from the « Et. y Me. a-carbethoxyglutaconate : 
(Et OOC), . C Et — CH = CMe — COO Et 
as well as from a Me. y Et. a-carbethoxyglutaconate : 
(Et OOC), . CMe — CH = C Et — COO Et 
the same acid was formed by a very careful hydrolysis (where a 
reversal was excluded). A true methylene group (CH,—) is not 
present in these acids; one of the H-atoms of this group is mobile 
1) THoRPE, Soc. 87, 1669 (1905) ete. 
THorPE and THOLE, ibid. 99, 2187, 2208 (1911). 
THoRPE and BLAND, ibid. 101, 856, 871, 1557, 1739 (1912). 
THorPE and Woon, ibid. 103, 276, 1579, 1752 (1913); 105, 282 (1914), 
Soc. 87, 1669 etc.; 99, 2187, 
