— 174 — 



A small quantity is formed of an acid, volatile with steam, of 

 the m. p. 91 to 9 2 . On oxidation it yields cyclohexanone and it 

 has therefore the formula II (zli^-cyclohexene acetic acid). 

 With glacial acetic and hydrobromic acids it yields the same addition- 

 product (m. p. 89 to 90 ) as the non-volatile acid (m. p. 3 8°), which 

 is formed in the larger proportion, and to which Wallach provisionally 

 allots the formula I (zli^-cyclohexene acetic acid). In like 

 manner, hexanol acetic acid yields the same compound if treated 

 with glacial acetic acid and hydrobromic acid. In both isomeric 

 acids the double linking is consequently attached to the same carbon 

 atom. Oxidation of the hexenic acid (m. p. 3 8°) with potassium per- 

 manganate led to an aldehyde (or ketone) of the formula C 7 H 10 O, 

 which could be further oxidised with silver oxide into glutaric acid. 

 The peculiar progress of this oxidation, which it is intended to study 

 still further, induced the author to refrain for the present from an 

 interpretation. Cyclohexyl acetic acid, corresponding to the 

 unsaturated acids, was produced in this manner, that cyclohexanol 

 acetic ester was dissolved in glacial acetic and hydrobromic acids, 

 the bromide formed after 48 hours reduced directly with zinc dust, 

 and the resulting ester saponified. The crude acid obtained contained 

 unsaturated hexenic acids, which were removed by oxidation with 

 potassium permanganate. Cyclohexyl acetic acid C 8 H u 2 is stable 

 towards permanganate, melts at 30 to 31 , and boils at 245 to 247 

 without decomposition. Besides various derivatives of the acid, there 

 were produced by distillation of calcium cyclohexylacetate in vacuo, 

 completely hydrated dibenzyl ketone 



CH,.CO.CEL 



and in the same manner, from calcium acetate and calcium cyclo- 

 hexyl acetate, cyclohexyl acetone (b. p. 198 to 200 ). 



2. Compounds from suberone. Suberyl acetic acid (cyclo- 

 heptyl acetic acid) was obtained from suberol acetic ester 1 ) in an 

 analogous manner to cyclohexyl acetic acid. It boils at 165 (19 mm. 

 pressure) and has an unpleasant odour like fatty acids. 



3. Compounds from cyclopentane. Cyclopentyl acetic acid, 

 also produced in the same manner, boils at 226 to 230 , and has 

 an odour like fatty acids. Cyclopentene isobutyric acid was 

 produced from pentanol isobutyric acid ester (from pentanone, 

 bromoisobutyric acid ester, and zinc) by means of potassium 

 bisulphate (b. p. 148 to 150 at 27 mm. pressure). It is converted 

 by distillation at ordinary pressure, with loss of carbonic acid, into 



*) Liebig's Annalen 345 (1906), 146; Report October 1906, 145. 



