— ii7 — 



Pentacyclic compounds: methene-cyclopentane, 



CH 9 CH 2 \ 



>C=CH 2 , b. p. 78 to 8i°; d 0,78; n D190 1,4355. The 

 CH 2 CH./ 



CH 2 CH 2 \ 

 glycol, J >C(OH)CH 9 OH, melts at 30 to 41 , and owing to 



CH 2 CH/ 

 its exceptional solubility cannot be obtained in crystalline form. The 

 semicarbazone of the pentanone isolated from the non-oxidised portions 



CH 2 CH 2 v 

 melted at 205 to 207 . Cyclopentane aldehyde, J p CH - CHO, 



CH 2 CH/ 

 split off from the glycol with sulphuric acid (1 in 10), yielded a 

 semicarbazone of the m. p. 123 to 124 . — The nitrolpiperidide of 

 menthene-cyclopentane produced from the nitrosochloride, melted at 

 116 to 1 1 7 . From the nitrosochloride treated with sodium methylate, 

 there is obtained the unsaturated oxime C 6 H 8 NOH, from which sulphuric 



CH 2 • CH 2 v 

 acid splits off cyclopentene aldehyde, I j, C • CHO , whose 



CH 2 • CH ' 



semicarbazone melts at 208 . The aldehyde regenerated from it was 

 oxidised by silver oxide into cyclopentene carboxylic acid, C 5 H 7 CO OH, 

 m. p. 1 1 9 . 



Hexacyclic compounds: methene-cyclohexane, 



/ CH 2~ CH 2 \ 



CH 2 ( >C = CH 2 



\CH 2 -CH/ 



(b. p. 105 to 106 ; d 0,8025; n D20° 1,4501), has in its properties an extra- 

 ordinary resemblance to tetrahydrotoluene. The glycol, alongside of which 

 cyclohexanone is formed, crystallises very well, melts at 76 to 77 , and 

 yields, with an equal volume dilute sulphuric acid, by means of steam- 



/ CH CW \ 

 distillation, hexahydrobenzaldehyde, CH 2 / 2 ' 2 ) CH . CHO, 



\ CH 2 • CH 2 / 



after rectification passing over at ordinary pressure from 161 to 

 163 ; d 0,9263; nDi9° i?4495; semicarbazone, m. p. 167 to 168 . The 

 aldehyde has a great capacity for condensation. — The nitroso- 

 chloride of methene-cyclohexane yields a nitrolpiperidide of the 

 m. p. 1 2 7 , and an oxime giving on distillation with dilute sulphuric acid 



/ CH CH \ 



cyclohexene aldehyde, CH 2 <^ 2 2 )C«CHO, whose semicar- 



\ C H 2 C H // 



bazone melts at 2 1 2 to2i3°. — 1,2-methene-methylcyclohexane, 



CH 3 

 I 

 / C H 2 • C H v 

 CH 2 < >C = CH 9 



X CH 9 -CH 9 



