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X. 



SOME DEEIVATI.VES OF STILBENE. 



By HUGH RYAN, D.Sg,and NICHOLAS CULLINANE, Ph.D., 

 University College, Dublin. - , 



[HuAD Febkuauv 11. Published Mav 23, 1024.] 



The object of tbe present investigation was the direct preparation of 

 derivatives of. phenantlirene from stilbenes containing no carboxylic acid 

 group, as was the case in Pschorr's syntheses in the phenanthreiie series 

 (compare, ('.,y., Ber. d. Dtscb. Chem. Ges., xxix, 1886, p. 497). However, 

 although experiments were carried out under varying conditions, no 

 phenanthrenes were obtained. Tlius, the diazonium salt of 2-aiuinostilbeue, 

 when, treated with copper bronze iu the presence of alcohol, gave even at 

 ordinary "temperatures stilbene itself, the diazo-group being reduced to 

 hydrogen. When the experimental conditions were changed, some benzal- 

 dehyde was formed, but no phenantlirene cdiild be isolated. Jn like manner 

 Sachs and. Hilpert (Ber. d. Dtsch. Chem. Ges., xxxix, 1906, p. 904), by treating 

 the diazo-compouild with copper powder, and Ullmann and Gschwind (Ber. 

 d. Dtsch. Chem. Ges., xli, 190S, p. 2291), by the action of heat on the 

 diazo-derivative, were unable to obtain phenanthreiie. 



In a siniilar , fashion 4-nitrostilbene-2-diazoiriuin sulphate when treated 

 with copper bronze in the presence of alcohol gave 4-nitrostilbene. 



The nitro-deiivatives of stilbene which were synthesized in the course of 

 the preseut work were prepared by condensing, in the presence' of a small 

 quantity of.piperidiue,. nitrotoluenes, and aromatic aldehydes. Thense of this 

 condensing agent in .such reactions is due to Thiele and Escales (Ber. d. Dtsch. 

 Chem. Ges., xxxiv, 1901, p. 2842), who obtained 2-4-dinitrostilbene in this way 

 from 2'4-dinitrotoluene and benzaldehyde. The. dinitrostilbene on partial 

 reduction by means of alcoholic ammonium, sulphide was converted into 

 2-iiitro-4-aminostilbene, the sulphate of which yielded the corresponding 

 diazonium salt on treatment with aiiiyl nitrite or nitrous acid (compare Thiele 

 and Escales, loc. cit.). The diazo-compound by boiling with ethyl alcohol 

 (Sachs and Hilpert, luc. cit.) or with amyl alcohol (Pfeift'er and others, Liebig's 

 Annalen der Chemie, ccccxi, 1916, pp. 72-158) formed, 2-nitrostilbene, wliich 

 was also produced by the action of alkaUne stannite on the diazonium chloride 

 (Pfeiffer.and Monath,; Ber. d., Dtsch. Chem. Ges., xxxix, 1906, p. 1305). The 



K.l.A. PKOC, VOL. XXXVI, SECT. B. [TJ 



