l94 REPORT— 1902. 



but vdn Pechmann's experiments ^ indicate that the product is a tauto- 

 meric substance behaving also as if it had the formula 



CgHgN : NOCOCeHg. 



Thus, when condensed with sodium /3-naphthoxide, it yields benzeneazo- 

 /3-naphthol, and on treatment with cold potassium hydroxide solution 

 Undergoes hydrolysis, giving rise to potassium benzenediazo-oxide, a certain 

 amount of this salt being also formed during the benzoylatiou of the iso- 

 diazo- oxide. 



Blomstrand, who advocated the diazoniura formula CgHj.N.OK for the 



N 

 normal diazo-bxide,^ supposed that the production of nitrosobenzanilide 

 is due to the transformation of the benzoate CgHj-NCCOCgHj ; this, 



N 

 however, is not the case, for the ester when prepai-ed from benzene- 

 diazonium chlotide and silver benzoate does not yield any trace of nitroso- 

 compOuttd under similar experimental conditions.^ 



Synthesis of IsOdiazo-oxides. — The oxime formula for the metallic iso* 

 disLzo-oxides also derives support from the fact that the alkali benzene-iso- 

 diazo-oxide is produced by the action of hydroxylamine on nitrosobenzene 

 in alkaline solutions, 



R.NO + H2NOH + KOH = R.N : NOK + 2H2O. •» 



Since the isodiazo- oxide may be oxidised to the corresponding benzene- 

 diazoate, and reproduced from this substance or its alkyl ester by reduction 

 with sodium amalgam, the cycle of changes may be thus indicated : — 



^^ R.N : NOOK ^^ 

 R.N : NOK'"--^ ^ ^" R.NiNOOCH., 



B. Stereo-chemical Helationship of the Isomeric Diazo'Oxides, 



The behaviour of the isomeric alkali diazo- oxides in the reactions 

 described in the preceding section justities the belief that the two series are 

 structurally identical, and that the comparatively slight differences between 

 the diazo- and isodiazo-derivatives are due to a different spatial arrange- 

 ment of the radicles associated with the diazo-group, N=N. Accordingly, 

 Hantzsch suggested that this isomerism is comparable with that which 

 obtains among the oximes, the latter kind of isomerism being explained by 

 supposing that the labile and stable modilications contain the associated 

 radicles differently arranged about the complex N=CH in the manner 

 indicated. 



R.CH R.CH 



Stable oxime || Labile oxime || 



HO.N N.OH 



' Her., 1802, 25, 3199. 



* Journ.prakt. Cliem., 1896, 64, 329. 



=■ See also Bamberger, Ber., 1897, 30. 366. 



' Bamberger, Btr., 1895, 28, 1218. 



