— 20Q — 



vatives thereof obtained by Barbier and Grignard. 1 ) The last-named 

 authors 2 ) have recently reported on a conversion of pinonic acid into 

 dimethyl- 1, 3 -phenyl acetic acid. They observed this conversion 

 while engaged in heating for 14 hours in an enamelled autoclave, at ioo°, 

 racemic pinonic acid with an equimolecular quantity of bromine and 

 a quantity of water corresponding to the weight of the other materials, 

 the object of the experiment being the preparation of the monobromo 

 derivative of rac. pinonic acid. After neutralising with bicarbonate of 

 sodium they precipitated carefully by means of diluted hydrochloric 

 acid; brown flocculent masses being at first separated, while a lustrous 

 crystalline deposit was next formed. This precipitate, recrystallised from 

 water, melted at 101 and contained no bromine. It was a monobasic 

 acid C 10 H 12 O 2 which was identified by the amide (m. p. 183 ) and the 

 methylester (b. p. 120 to 121 , 11 mm.) as dimethyl- 1, 3-phenyl- 

 acetic acid -4. The reaction takes place according to the following 

 equation: — 



COOH— CH 2 



( CH 3 ) 2 \ / H i" 3 



CH 8 — CO ^C=-^CH = CH r C ^C— CH^CC^H + H 2 + H 2 



CH^CH, CH=CH 



Pinonic acid Dimethyl- 1, 3 -phenylacetic acid-4 



Campholic acid, of which so far only the dextro-rotatory form was 

 known, has now also been obtained by M. Guerbet 3 ) in the form of 

 its laevo-rotatory isomeride, this result being obtained by heating 

 1-borneol with freshly dehydrated potassium hydroxide in a sealed tube. 

 A small proportion of /^campholate of sodium was formed as a 

 bye-product. 



*\CH0H X CCLK 





L-campholic acid occurs in colourless crystals, m. p. 106 to 107 ; 

 b. p. 225 (760 mm.); [«Jdi5° — 49° (in alcoholic solution). In order 

 to identify it a series of salts and esters was prepared, as well as the 

 anhydride (m. p. 57 to 5 8°), the chloride (b. p. 222 ) and the amide 

 (m. p. 77 to 78 ). 



Guerbet afterwards discovered that the borneol 4 ) which had not 

 been attacked had become partly converted into camphor. In this 

 case a condition of equilibrium probably sets in, for the quantities of 



*) Compt. rend. 147 (1908), 597; Report April 1909, 120. 



2 ) ibidem 148 (1909), 646. 



®) Journ. de Pharm. et Chim. VI. 29 (1909), 225; Compt. rend. 148 (1909), 98. 



4 ) Compt. rend. 148 (1909), 721; Bull. Soc. Chim. IV. 5 (1909), 418. 



14 



