1189 



the following observations: A mixture of Ihe t\vo forms at 100° — 105° 

 scarcely exhibits any change, but melts at 107,5° — 108°, just like 

 the form with the highest melting point: samples that have been 

 fused before, melt either at 100,5°— 101,5°, or al 107,5°— 108' ; a 

 few times we even saw the metaslable form liquefy at 100,5^ — 101,5°, 

 solidify completely on slowly heating higher, to melt anew at 

 106,5°— 108,5°. 



Indene-oxyd 



-^^H 







On treating indene in a solution in moist ether with mercuric 

 oxide and iodine, and after shaking the resulting solutioji of indene 

 iodoiiydrin with powdered ])0tassium hydroxide, we obtained the oxide 

 as a deep brown liquid. At our first attempt this liquid decomposed 

 spontaneously, a second time during the distillation under diminished 

 pressure. We ascribed this decomposition to the impurity of our 

 solution of the iodohydrin and in consequence we treated indene 

 bromohydrin, which can readily be got in a pure state according to 

 the prescription of W. J. Popk and J. Read '), in ether with 

 powdered potassium hydroxide. Actually we now obtained, by 

 distillation under reduced pressure in a nearly theoretical yield, 

 indene oxide as a colourless liquid, poorly soluble in water, with a 

 naphtalene-like odour, b.p. 113°/19,5 mm., d^^ 1/1258, ;?Ai 1,5627, 

 71/ „ found 38,05 J/ calc. 37,40. The oxide crystallises spontaneously 



in big rhombic plates, melting at 31°— 31,5°. In a few^ days the 

 crystals begin to become soft, which is likely to be due to a poly- 

 merisation. Indene oxide may become an important intermediate 

 product for the preparation of 1,-or 2. -mono- and 1.2.-di-derivatives 

 of hydrindene. 



Rearrangement into l.-keto-hydrindene (i?-hydrindone). 



Hkusler and Schieffer (I.e.), by boiling with dilute sulphuric acid, 

 converted their glycol into /^-hydrindone, m.p. 58°. Weiszgerber 

 observed the same reaction of his substance, and wrongly interpi-eted 

 this as a proof of identity. 



By treating both our diols and the oxide in the same way, we 

 got each time /?-hydrindone, which in all three cases melted at 



»j W. J. Pope and J. Read, Journ. Ghem. Soc, Traas. 101, 758 (1912). 



82* 



