OH 



CIS 



trans 



Cis-hydrindene-\. 2. diol. 



First of all we repealed the oxidation of a dilute emulsion of 

 indene in water with potassium permanganate, conformable to 

 Hkusler and Schieffer. We too obtained in a verj pooi- yield (less 

 than 13 7o of the theoretical one) hjdrindene glycol, which liowevei-, 

 after crystallising once from benzene, melted at 105° — 106° after 

 sintering strongly from 95°. By executing the oxidation in a solution 

 in aqueous acetone or methylalcohol, and at — 40°, the yield could 

 but little be increased, e.g. to 18,5 "/„ (m. p. 103,5°— 104,5°). Recrys- 

 tallising again and again from benzene leads to felt-forming needles, 

 which sinter slightly at 105,5° and melt at 107,5°— 108° '); the 

 substance could be sublimated in a vacuum, by which the m. p. 

 was not altered. 



On the strength of a preliminary determination of the influence 

 of this diol, and of the one to be described, on the conductivity of 

 boric acid, we assign — provisionally — the cis-coufiguiation to 

 the glycol with the m. p. 107,5°— 108° ^). 



Trans-hy dr indene A . 2. diol. 



Weiszgerber's diol having the more divergent properties, we sur- 

 mised it to be the other stereomer. We prepared it in a more usual 

 way : By boiling indene dibromide ') with a solution of potassium 

 acetate in acetic acid a fraction is obtained, boiling at 169° — 174°/13 mm., 

 (the yield being 52 — 66 °/„ of the theoretically possible one), from 

 which we could isolate by fractional distillation a pure hydrindene- 

 1.2. diol-diacetate : 



6./>.169"— 169,5°/13mm., ^P^ 1,1771 w^'y; 1,5170,3//) found 60,15,^1//) 

 calc. 59,74. 



1) All melting points were determined by means of thermometers according to 

 Anschütz, and were corrected when necessary. 



2) BöESEKEN has already mentioned this: these Proc. 26, 6. 



8) A. Spilker and Dombrowsky, Ber. d. D. chem. Ges. 42, 572—3 (1909). 



82 

 Proceedings Royal Acad. Amsterdam. Vol. XX. 



