208 REPORT—1904. 
Schmidt! has prepared from trimethylethylene three nitroso- compounds, 
which he formulates as 
CMeH.NO CMeH.NO CMeH.NO 
| | and : 
| 
CMe,.0.NO CMe;.0.NO, CMe,Cl 
These are converted by heating or by alkalies into the isomeric oximes, 
X.CMe,.CMe:NOH, but the change proceeds so slowly that there has 
been some hesitation in accepting the formule proposed. The unexpected 
behaviour of these nitroso- compounds is probably due to the stability of 
the colourless polymerides, which must be resolved before isomeric change 
can take place. Piloty’s chloronitrosoethane? behaves in a precisely 
similar manner as indicated in the scheme 
(CH,.CHCI.NO],220H;.CHCI.NO =”,.2CH;.CCl : NOH. 
In the nitrosoaldehydrazones studied by Bamberger and Pemsel? the 
conversion of the nitroso- compound into the oxime involves the change 
of the hydrazone into an azo- compound, and the stability of the nitroso- 
compound is greatly increased — 
CH,.C(NO) : N.NH.C,H;—?CH;.C( : NOH).N : N.C,H;. 
The further equilibrium between the hydroximes >C : NOH and 
NH 
pseudoximes >Cg | has been so little studied that no definite con- 
O 
clusions can be drawn as to the effects of substitution ; in the cases 
studied by Dr. Whiteley * the stability of the two solid forms appears to 
be determined mainly by their solubility, and nothing is known at 
present of the proportions in which they are present in the solutions. 
8. Other cases.—The alkyl cyanides are only known in one form, but 
cyanocamphor appears to exist to some extent in the acid psewdo- form, 
CH aN CC SINE 
C,H vid OPEL 
8 Ee <—Us do 
and psewdo-cyanoform is an even stronger acid than psewdo-nitroform,” 
CH(CN);2(CN),C :C : NH. 
Dynamic isomerism is also common amongst the hydrazones and azo- 
compounds and the amidines. A review of all the groups in which 
dynamic isomerism has been observed is given by Wislicenus,® but the 
examples quoted above will suffice to show the general character of the 
observations that have been made. 
9. Isodynamic salts.—Unlike hydrogen, the metallic radicles have a 
strong tendency to attach themselves to the most negative groups in the 
molecule, and isomeric change is usually both rapid and complete. By 
1 Ber. 1903, 36, 1765. 2 Ber. 1902, 85, 3113. 
3 Ber, 1903, 86, 57-84. * Trans. 1903, 83, 24. 
5 Hantzsch and Ostwald, Ber. 1899, 32, 641. 
6 ‘Ueber Tautomerie,’ Alzen’s Sammlung, 1898. 
