228 



KEPOUTS ON THE STATE OF SCIENCE. 



resulting methylcyclohexylcarbinol 

 acid. 



CgHii.CHOH.CHj with chromic 



In the preparation of ketones by elimination of carbon dioxide from 

 ketocarboxylic acids Kotz ' liiids that the reaction takes place readily in 

 the case of l-ketohexahydrobenzene-2-carboxylic acid, but it does not 

 proceed at all with acids and less readily with alkalis, as the hydrogen 

 atom marked with a x is replaced by methyl, ethyl, or isopropyl. 



CH., 



CH, 



H,C I . CO 



UH.COOH 



CH, 

 H.,C /\ CH., 



H.C v^/ CO 

 CH, 



1 ■ keto-3-raethyl- A^-tetrahydrobenzene - 



CH C.CH3 

 \CH, 



CH.. CH.. 



0C<^' 



exists in two isomeric forms, which must have the same structure, as on 

 oxidation with potassium permanganate both yield y-acetobutyric acid. 

 The molecular refraction would lead to the conclusion that both are 

 doubly unsaturated alcohols and not ketonic in nature. Chemically the 

 two forms are identical except in their behaviour towards ferric chloride, 

 when the one gives a pale wine-red colour, whereas the other becomes 

 violet. The present data do not suffice to explain this case of isomerism. 

 Dimethyldihydroresorcin (I) reacts towards nitrous acid as a di- 



C(CH3), 

 H..C ^^ CH., 



HOC ... CO 



H..C 



C(CH,)., 



-/NcH, 



CCCH,)., 



H.,C 



/\ 



CH 



(I) 



OC . . CO 



V = N.OH 

 (II) 



CH., 



HON:C .y C = NOH 



C=:N.OH 



(III) 



ketone,-' for the resulting isonitrosodimethyldihydroresorcin (II) reacts 

 with two molecular proportions of hydroxylamine to give a compound of 

 formula III. Oxides of nitrogen convert dimethyldihydroresorcin into 

 the nitre- derivative (IV), which substance, on reduction, yields an amine. 



CCCH,), 

 H.,C /^ CH.. 



OC 



CCCH,)., 

 H„0 /\ CH., 



^/CO 



CH NO, 

 (IV) 



\ 



OC I /j c- , 

 C-— N/^ 



and this gives with nitrous acid a compound whose constitution may be 

 represented by formula V. The relation of colour to constitution in 



' An»a!m, 1907, 357, 102. 



Uans,J.r.S., 1007, SJ, l43;-{. 



= Rabe, Bcr., 1907, 40, 2482. 



