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Chemistry. “On the ahnonnal reduction of an aromatic nitro¬ 
compound with tin and hydrochloric acid and an interesting 
case of dimorphism”. By Dr. Otto de Vries. (Communicated 
by Prof. A. P. N. Franchimont). 
(Communicated in the meeting of September 25, 1909). 
In the synthesis of isocreosole, one of the methyl esters of homo- 
pyrocatechol, 3-amino- 4-methoxytoluene had to be prepared by 
reduction of the corresponding nitro-compound. It appeared that this 
reduction proceeds very neatly and quantitatively when carried out 
with iron and acetic acid; if, however, tin and hydrochloric acid 
is used, a mixture of amiho-compounds is formed from which a 
second, chlorinated, substance could be isolated in addition to the 
normal product of the reaction. 
The formation of amino-compounds chlorinated in the nucleus, in 
the reduction of aromatic nitro-compounds with tin and hydrochloric 
acid, has been observed several times, and it was, therefore, interesting 
to determine which place the chlorine atom had occupied in this case. 
This could be ascertained by substituting the amino-group by 
chlorine. The dichloro- 4-methoxytoluene formed appeared to be 
identical with 3-6-dichloro- 4-methoxytoluene, which had been prepared 
synthetically by substituting in Limpach’s 3-amino- 4-methoxy- 6-nitro- 
toluene first the amino-group in 3 by chlorine, then the nitro-group 
in 6 by NH 2 and subsequently also by chlorine. From this it appears 
that, as might be expected from analogous cases, the chlorine atom 
had occupied the para-position in regard to tfie amino-group. 
The 3-6-dichloro- 4-methoxytoluene just mentioned exhibited a 
peculiar case of dimorphism. In the various preparations, partly 
described, it was always obtained in the form of needles melting at 
29°, which always behaved as a perfectly stable substance. At the 
close of the investigations, however, another form occurred, namely, 
flat crystals melting at 44° and from that moment, the needles 
melting at 29° were no longer stable; they fell to powder and then 
exhibited the melting point 44°. The labile form (29°) may be easily 
regenerated by cooling a fused mass, or by recrystallisation from 
dilute alcohol. After the appearance of the stable form (44°) it was, 
at first, impossible to isolate the needles so obtained, for as soon as 
they were exposed to the air of the laboratory, conversion set in. 
Even the precautionary measures taken by Liebermann and Biillmann 
in their investigations of the cinnamic acids proved inadequate. 
Only by heating the substance for some length of time above 44° 
