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Chemistry. — Dr. C. Prey: “Synthesis of triowybutyric acid 
(erythric acid)”. (Communicated by Prof. C, A. LOBRY 
DE BRUYN). 
The synthesis of erythric- or trioxybutyric acid 
CH,OH CHOH CHOI COOH 
from a substance with three C-atoms 
(or more correctly, that of one or more of its four possible isomers) 
cbtained by oxidation of erythrite, had not as yet been accomplished, 
Its realisation would not only be interesting in itself but also extend 
our knowledge of the sugars with four atoms of carbon. Then if one 
or more trioxybutyric acids should have become readily accessible, 
the transition to the corresponding tetroses could present but few 
difficulties. 
The starting point in Dr. PRey’s research was acroldehyde (acrolein). 
In different ways it could be attempted to realize the synthesis of 
trioxybutyric acid by means of this substance of which about 35 
Kilos were used in the investigation. 
First of all the acroldehyde was converted into the dibromide, the 
latter treated with nascent HCN and the nitrile thus obtained treated 
with strong hydrochloric acid. It appeared that the dibromonitrile is 
very unstable and very readily eliminates HCN ; the numerous exper- 
iments made with this nitrile did certainly lead to the formation 
of the dibromo-amide : CH,Br.CHBr.CHOH . CONH,, but the yield 
was so small that the object could not be satisfactorily gained in 
this way. 
Therefore, Dr. PREY now used the method which had been applied 
by VAN DER SLEEN !). From the acroldehyde was first prepared the 
nitrile of a-hydroxybutenoie acid: CH): CH. CHOH CN and this was 
then converted by concentrated hydrochloric acid into the amide?) and 
from the latter the dihalogen derivatives CH, X CH X CHOH. CONH, 
were obtained. Besides the well defined crystals of the dibromo-amide 
already known by VAN DER SLEEN, Dr. Prey prepared the crystal- 
line dichloro- and diiodo derivatives. The first is formed by acting 
on the amide with one mol. of chlorine dissolved in carbontetra- 
chloride; a simultaneously occurring substitution diminishes the yield. 
The diiodo derivative is formed quantitatively and very rapidly 
1) See following article. 
2) From 2.8 Kg. acroldehyde + 250 grs. of amide. 
