82 Reports on the state op science. 



The Study of Hydro-aromatic Substances.— Report of the Committee, con' 

 sisting of Dr. E. Divers (Chairman), Professor A. W. Crossley 

 (Secretary), Professor W. H. Perkin, Dr. M. 0. Forster, and 

 Dr. H. K. Le Sueur. 



Action of ethyl cyanoacetate on 5-cldoro-l : 1-dimethyl- k^-cyclo- 

 hexen-3-one.- — The action of ethyl cyanoacetate on chlorodimethyl- 

 cyclohexenone 1 might be expected, by analogy with the action of 

 ethyl sodiomalonate on the same ketone, 2 to give rise to ethyl 1 : 1* 

 dimethyl- A 4 -cyclohexen-3-one-5-cyanoacetate (I). But although the 

 reaction product possesses this empirical formula, it has properties 

 which are incompatible with those of a substance of this constitution, 

 for it behaves as a monobasic acid, forming compounds by elimination 

 of water with aniline and monomethylaniline, and giving esters when 

 heated with alcohol containing 5 per cent, sulphuric acid. In the latter 

 case two isomeric methyl or ethyl derivatives are produced. When 

 hydrolysed with acids, both the original condensation product and 

 either of its ethyl or methyl derivatives are transformed into trimethyl- 

 cyclohexenone (II). 



(CH 3 ),C< C C %- C C °>CH CI) (CH 8 ),C< C c I J| i l C c >CH <"> 



I A 



CN.CH.C0 2 C..H 5 CH 8 



An explanation of the behaviour of the condensation product is afforded 

 by adopting Thorpe's formula for ethyl sodiocyanoacetate," when the 

 reaction would be formulated in the following manner. The initial 

 additive compound (III) would lose the elements of sodium chloride 

 forming ethyl 1: l-dimethylcyclohexan-3-onylidene-5-cyanoacetate 

 (IV) and by tautomeric change, ethyl 3-hydroxy-l : 1-dimethyl- A 3 - 

 cyclohexenylidene-5-cyanoacetate (V). 



(CH s ) g c<°f^™>cir s (C h 3 ),c< c c h h2 - c c °>ch 2 (ch 3 ). 2 c< c c h h ^° c h >ch 



"I II 'II 



CN.C:C(0Na).0C 2 H 5 CN.C.COAHj CN.C.CO.,C 2 H 5 



(III) (IV) (V) 



The last formula accounts for all the observed properties of the sub- 

 stance, including its ability to form two ethyl derivatives which can be 

 represented as cis and trans modifications. When either of these ethyl 

 derivatives is hydrolysed with potassium hydroxide in ethyl alcoholic 

 solution, 3-ethoxy-l : 1-dimethyl- A 3 -cyclohexenylidene-5-cyanoacetic 

 acid (VI) is produced, which on heating loses the elements of carbon 



1 Crossley and Gilling. J.C.S., 1910, 97, 518. 



2 Ibid., J.C.S., 1909, 95, 19, 8 J.C.S., 1900, 77, 925. 



