510 REPORT—1904. 
chemists. J luorescein, being coloured both in the free state and in the form of 
salts, is regarded as being quinonoid either when free or combined. 
Quinolphthalein (I), the constitution of which has been confirmed by work 
dene in the author’s laboratory, does not come into quite the same category, and 
its red alkali salts must be supposed to possess a meta-quinonoid constitution 
(II or III). 
C,4,.CO 
44 C,H,.COOH 
| 
+N e 7 ~ Haw 
a 4 x FO ae 
ue A ye \ou Ho % D\ \ Neo 
| I | | Lae | 
aos IRIN 29 fade \ iL ARTO Se a 
—y \Y my, or Nid wy 
O O 
Metaquinones being at present unknown, further work on the above substances 
was desirable, and the author and his assistant, Mr. O. Sprengler, have therefore 
studied the ethers and oximes of phenol- and quinol-phthalein, preparing these 
substances in alkaline solution; the results of this work point to the lactonic 
formula of the alkali salts as being correct, both in the case of quinolphthalein 
and of phenolphthalein. They drew attention recently to the fact that the 
anilides of the phthaleins dissolve in alkali without giving rise to coloration; if 
these anilides have the same constitution as the phthaleins themselves, this dis- 
tinction might arise from a difference in basicity. They therefore endeavoured to 
ascertain the equivalents of these substances. A measured volume of standard 
caustic-soda solution was treated for two hours at the ordinary temperature with an 
excess of phenolphthalein; in a second and a third experiment quinolphthalein 
and phenolphthalein anilide were subjected to similar treatment. The undis- 
solved residue was filtered off and washed, the filtrate being then precipitated 
with dilute sulphuric acid; the precipitates were filtered, washed, dried, and 
weighed. The results agreed with the formulee— 
C,,H,,0,Nay, O,,H,,0,Na,, and C,,H,,0,(NC,H,)Na,. 
Thus all three compounds behave alike as dibasic acids, and from this point of 
view no difference is traceable between the anilide and the free phthaleins; the 
anilide is, however, more feebly acidic than the phthaleins, being precipitated by 
the latter from its alkaline solution. 
These experiments have some bearing on those described recently by A. G. 
Green and A. G. Perkin; but the results of these investigators differ from the 
present because they worked under different conditions. 
The authors have made many attempts, under varied conditions, to obtain a 
quinonoid ether of phenol- or quinol-phthalein, employing methyl iodide and 
methyl sulphate both in aqueous and alcoholic solutions, and using an excess of 
alkali and also of sodium methoxide. In each case the same di-ethers as before 
