ON HYDRO-AROMATIC COMPOUNDS WITH SINGLE NUCLEUS. 123 



(ii.) From substituted dihydroresorcins (p. 127), which on reduction 

 yield dihydric alcohols, and these readily give up the elements of water.' 



yCH, . CO yCHj . CHOH 



C,H,.CH \CH C,H,.CH ^CH, 



\CH.. . COH "^CH^ . CHOH 



,CH = CH ^CH, - CH 



C„H,.CH \CH„ or C„H, . CH ^CH 



'5 



\CH = CH Vh = CH 



(iii.) From substituted dihydroresorcins by treatment with phosphorus 

 pentachloride and reduction of the resulting dichlorodihydrobenzenes.^ 

 ,CH, . CO .CH = CCl yCH = CH 



(CH3),.C \CH (CH3), .0 \CH (CH^X.O ^CH 



\CH„ . C . OH \CH„ - CCl ^CH„ - CH 



(iv.) From the hydi'oxylaminoximes of ketotetrahydrobenzenes, which 

 on reduction give diamines, and these on heating with phosphoric acid 

 give the hydrocarbons.^ 



^CH - CO .CH., . C = NOII yCH„ . CHNH, 



CH3 . C \CH, CH3 . C . NHOh'^CHj CH3 . C . NH2 \CH2 



\CH„ - CH, \CH, . CH„ ^CH„ . CH, 



^CH - CH 

 CH3 . C ^CH 



\CH„ . CH„ 



Methods (ii.) and (iii.) have only been so far worked out in one 

 case each, and it cannot be said if they are of general applicability. 

 Methods (iii.) and (iv.) possess the advantage of giving pure hydrocarbons, 

 as has been shown from a careful study of their oxidation products. 



Alcohols. 



Hydroxyhexahydrobenzene was obtained by Baeyer ■• as a reduction 

 product of ketohexahydrobenzene (pimeloketone, p. 125), or from 1 : 4- 

 dihydroxyhexahydrobenzene (quinite, p. 124), which, with hydriodic acid, 

 gives 1 : 4-iodohydroxyhexahydrobenzene, and this latter, on reduction 

 with zinc dust and acetic acid, gives the alcohol : — " 



.CH„ . CHo .CH„ . CH, .CH, . CH, 



HO.CH \CH0H ICH ^CHOH CH, ^CHOH 



\CH, . CIL, \CH, . CH,, \CH, . CH, 



It has an odour like fusel oil, melts at 15°, and is more readily soluble 

 in water than the aliphatic alcohols containing six carbon atoms. It is 

 unacted upon by potassium permanganate, but nitric acid readily oxidises 

 it to adipic acid. 



' Knoevenagel, Ajinalen, 1896, 289, 137. 

 = Crossley and Le Sueur, J.C.S., 1902, 81, 821. 

 ' Harries, Ber., 1901, 34, 300 ; 1902, 35, 1166. 

 * Ber., 1893, 26, 229 ; Annaleii, 1894, 278, 98. 

 ^ See also Annalen, 1898, 302, 20. 



