336 



contain two vicinal OH-p,ronps) van Rombukgh and van Maankn 



OH 



I i f 



proposed among others the formula CH,.CH.CH.CH .CH. CH, for 



J ^ I 



OH 



OH 



-0 r ! 



isomannide, and CH, . CH . CH . CH . CH . CH,OH 



OH OH 

 for mannitane, the formate of which gave onlj carbon dioxide. 



The compound C^HgO might therefore be represented by the formula 

 CH, . CH : CH . CH . CH : CH,, hence it would be «-viriyldihydrofurane. 

 I I 



In 1917 Windaus and Tomich ') too studied the componnd CgHgO, 

 and could obtain by its reduction with hydrogen under the influence 

 of palladium, an addition of two mol. of hydrogen, so that (/gHj,0 

 was formed, which substance according to them should be identical 

 with a d-hexylene oxide described by Lipp'), in which not a 5-ring, 

 but a 6-ring occurs: CH, . CH, . CH, . CH, . CH— CH„ so that the 



! ^ 



original oxide would have the formula CH : CH . CH : CH . CH . CH,. 



I -^ 



They concluded to the identity of the two saturated oxides by 

 the equality of the boiling-point, both of the oxides and of the di- 

 bromides derived from them. Windaus rejects the possibility of the 

 oxide being a furane-derivative, because then no asymmetric formula 

 would be possible. This argument is, however, not valid with regard 

 to the formula drawn up above. 



It has appeared from investigations on the action of ozone on 

 the oxide C„HgO, undertaken by Mr. Bruins in the Utrecht Labor- 

 atory after the publishing of Windaus and Tomich's paper, that 

 in this reaction only carbonic acid, formaldehyde, and formic acid 

 could be found, but no products in which a CH, -group occurs, 

 which pleads against Windaus's formula. This, howevei', did not 

 give a rigorous proof for the «-vinyldihydrofurane-formula. To 

 obtain perfect certainty, we have followed another cotirse. 



First of all by reduction of C^H^O with hydrogen of a pressure 

 of two atmospheres in the presence of palladiumsol the saturated 



1) Göltinger Nachrichte Math. Phys. Kl. 1917, S. 462. 

 «) B. 18, 3275 (1885). 



