80 REPORTS ON THE STATE OP SCIENCE.— 1915. 



diol (I) by the reduction of phenyldihydroresorcin with sodium and 

 alcohol, and the only other paper 



CHPh 



HO . HCk JCU . OH 



deahng with this subject is one by Zelinsky and Uspenski/ who also 

 employed the same reducing-agent. Numerous experiments have con- 

 firmed the fact that sodium and alcohol give the best results, and the 

 yields are highest when the reaction is carried out energetically by 

 heating in an oil bath to 110°, as stated by Zehnsky and Uspenski. 



The amounts of the dihydric alcohols produced vary considerably 

 with different dihydroresorcins, as is seen from the following table: — 



Yield pfir Cent. 

 Methyldihydroresorcin ...... 43 



Dimethyldihydi ore.sorcin 

 Trimethyldihydioresorcin 

 Isopropyldihydroresoicin 

 Phenyldihydroresorcin . 



66-68 



20 



40 



47-50 



This is partly due to the nature of the dihydroresorcins themselves, 

 but also to the fact that the reactions are somewhat complicated, and 

 it is interesting to note that, in all cases, small quantities of the corre- 

 sponding monohydric alcohols are formed. For example, 1 : 1-dimethyl- 

 cyclohexan-3-ol (II) from dimethyldihydroresorcin (III). 



CMe, CMe. 



HXr ^CH^ >. B^Cf ^CH, 



HO.Ck y'CO H,CV yCH.OH 



CH CH, 



(III) (II) 



Further, owing to the unsymmetric structure of all the molecules 

 except that of dimethyldihydroresorcin, isomeric forms of the diols are 

 produced, the separation of which is always tedious and sometimes has 

 been found impracticable. 



The dihydric alcohols are crystalline compounds, neutral to litmus, 

 readily forming dibenzoyl derivatives and not absorbing bromine in 

 chloroform solution. In many properties they strongly resemble 

 glycols, as they possess a sweet taste, are easily soluble in water, and 

 not readily soluble in ether. 



4. l:l-Dimethylcyclohexane. In a paper entitled gfe)?i-dimethyl- 

 hexamethylene,* Zelinsky and Lepeschkin describe the preparation of 

 1 : l-dimetliylcyclohexane from 1 :l-dimethylcyclohexan-3-one, which 

 was obtained from acetylmethylheptenone.' These authors conclude that 



' Ber.. 1013. 46. 1430 « Jomn. Rhxs. PJii/s. Chem. So'-., 1913, 45. fil3. 



» Bull. Soc. Chim., 1899 (3). 21, 54(5. 



