ON THE STEREOCHEMISTRY OF NITROGEN. Vie 
‘Beckmann transformation,’! by which the oximes are transformed into 
substituted acid amides, thus :— 
a—C—b a—C=O a—C—b O=C—b 
l| = | and | hz | 
N—OH NH—d HO—N a.HN 
The hypothesis predicts four isomerides of compounds of the form 
a—C 
| | but until quite recently no instance of this had been 
HON NOH 
observed. Manasse” obtained three dioximes of camphorquinone, and 
Dr. Forster * re-examined these and obtained a fourth. 
In the case of the ketoximes the predictions of the hypothesis have 
been experimentally verified for all kinds of ketones of the aromatic but 
not for those of the fatty series. Most of the attempts to get isomeric 
oximes of fatty aldehydes and ketones have been unsuccessful ;4 the only 
case definitely observed is that of the oximes of oxalacetic acid,°® of which 
there are two definite isomers differing in melting point and in their 
behaviour towards ferric chloride ; with which the a acid givesa yellowish 
brown and the (3 a violet colour. 
(b) Aldoximes —The case of the aldoximes cannot be regarded with 
the same complacency. Beckmann ® observed that benzaldoxime when 
treated with sulphuric acid or with an ethereal solution of hydrogen 
chloride was converted into an isomeride. A long controversy then 
ensued between chemists who claimed that the isomerides were structurally 
NH 
different, as represented by C;,H;CH=NOH and CyH,CHC | , and 
O 
those who held the view that the differences were stereochemical, as in 
the case of the ketoximes. The work has been confined mainly to 
benzaldoxime and substituted benzaldoximes. The two benzaldoximes 
give respectively an oxygen and a nitrogen ester when treated with alkyl 
haloid compounds—a fact regarded as evidence in favour of structural 
isomerism. The work of H. Goldschmidt’ on the action of phenyliso- 
cyanate on the two oximes and that of Professors Hartley and Dobbie 8 
on their absorption spectra, however, is in favour of structural identity. 
Fa The hypothesis of stereoisomerism is now almost universally accepted, 
and is supported by the phenomena exhibited by the esters, which were 
at first so difficult to reconcile with this view. 
““f- Beckmann ® treated a (anti) benzaldoxime with sodium ethylate and 
benzyl chloride in the cold and obtained an oily ester which on treatment 
with hydrochloric acid split up partially into benzaldehyde and a benzyl- 
hydroxylamine and was therefore an oxygen ester, whereas by similar 
treatment of the @ (syn) oxime he obtained a crystalline ester which 
) Ber., 1883, 16, 2176. 2 Ber., 1893, 26, 243. 
3 Trans. Chem. Soc., 1903, 83, 514. 
+ Franchimont (Ree. trav. Pays-Bas, 10, 236); Dunstan and Dymond, Zyans. 
Chem. Soc., 1892, 61, 470; 1894, 65, 206. 
5 Piutti (Gazz., 1888, 18, 457); Ebert (Ann., 1885, 229, 76) ; Cramer (Ber., 1891, 
24, 1206); Dollfus (Ber., 1892, 25, 1915); Fenton and Jones (Zrans. Chem. Soc., 
1901, 79, 95). 
® Ber., 1887, 20, 2766; 1889, 22, 429. 7 Ber., 1889, 22, 3112. 
8 Trans. Chem. Soc., 1900, 77, 509. 9 Ber., 1889, 22, 435, 1534. 
