128 REPORT — 1902. 



barium hydroxide seems to be somewhat limited, as exceptions are found 

 in the cases of dimethyl- and trimethyl-dihydroresorcins 



,CH. . CO .CHCCHa) . CO 

 (CH3), . C ^CH (CH3), . C \CH 



\CH, .COH \CH„ COH 



ij 



neither of which gives the corresponding ketonic acids. Apparently it is 

 the presence of two alkyl groups attached to one carbon atom which 

 determines the behaviour of barium hydroxide,' as this is the only 

 difference in constitution between the above and other dehydroresorcins 

 which are hydrolysed when heated with barium hydroxide.- From a 

 consideration of the electric conductivities Schilling and Vorlander-* 

 conclude that the acidic properties of dihydroresorcins are as strongly 

 marked as those of c-ketonic acids, although the carboxyl group is absent 

 in the former. Structural difference between the two classes of compounds 

 does not amount to much more than ring formation 



,CH, . CO 



CH., \CH 



\CH, . COH 



and 



CH, . CO 



CH, \CH, 



"^CH, . COOH 



and cyclic organic compounds containing oxygen exhibit acidic properties 

 more pronounced than those open-chain compounds of similar constitution. 



Substituted glutaric acids result from the oxidation of substituted 

 dihydroresorcins, a reaction best carried out by the employment of sodium 

 hypobromite as oxidising agent.' 



1 : \-Diketohexahydrohenzene results when dry succinosuccinic acid is 

 heated,"' and from the saponihcation of ethyl succinosuccinate (p. 133) 

 with strong sulphuric acid.'' 



+ 

 .CH(C0,C,H5) . CH, .CH, . CH, 



CO ^ ^CO -». CO "^CO 



\CH, . CHCCOjC.Hj) \CH, . CH, 



As the hydrogen atoms marked -f are replaceable by sodium, this 

 reaction may be extended to the preparation of substituted diketohexa- 

 hydrobenzenes. Allusion has been already made to the properties and 

 transformations of these bodies. 



Halogen derivatives of the above ketones may be obtained by the 

 continuous action of chlorine or bromine on phenols, quinones, Ac." 



Ketotetrahydrobenzenes have been found in the lieavy oil produced 

 by the distillation of wood tar.^ 



' Crossley, J.C.S., 1902, 81, 675. 



■■i Vorliinder, Annalen, 1897, 294, 317. » Annalen, 1899, 308, 184. 



' Komppa, Ber., 1899, 32, 1421 ; Crossley, J.C.S., 1901, 79, 146 ; 1902, 81, 680, 



■■* Ber., 1889, 22, 2168. •■■ Baeyer, Annalen, 1894, 278, 88. 



' Ber., 1889, 22. 1473 ; 1891, 24, 912 ; 1892, 28, 845. 



9 Compt. Rend., 1897, 125, 1036; 1901, 132, 342. 



