135 — 



in addition to a small quantity of isobutyl borneol. Sodium propylate 

 gives analogous derivatives, although in smaller yield. 

 Propyl borneol 



/ CH • C I±2 • C H 2 • C H 3 

 C 8 H 14 < I 



\CHOH 



m. p. 6i°; Wd -f- 12° 5' in methyl alcohol. The liquid propyl camphor 

 boils at 123 (14 mm. pressure), Wp -\- 55 6'. Propylidene camphor 

 could not be obtained in the pure state; the liquid obtained showed 

 a rotatory power of -(-87° 6'. The nitrosate melted with decomposition 

 at 160 . 



Jointly with K. Burkheiser, J. Bredt 1 ) has worked on the electro- 

 reduction of camphocarboxylic acid to borneol carboxylic acid, and 

 on dehydroborneol carboxylic acid. The electric current reduced 

 the camphocarboxylic acid easily and almost completely in potash 

 solution with a potassium amalgam cathode. (E. M. F. 30 volts, current 

 7 to 7,5 amperes, temperature about 30 .) In this electro-reduction 

 camphocarboxylic acid absorbs two hydrogen atoms, with formation 

 of a /? - oxycamphane carboxylic acid (m. p. 170 to 1 7 1°). The last- 

 named acid, which Bredt for the present, under reserve, addresses 

 as borneol carboxylic acid, is isomeric with the very unstable borneol 

 carbonic acid (carbonic acid mono bornyl ester) produced by Bau- 

 bigny 2 ): — 



CH 9 CH CH- COOH CH, CH CH 



CH, 



CH 



■C-CH, 



CH,-C-CH, 



CH(OH) 



CH, 



CH.O-COOH 



CH 3 



borneol carboxylic acid 



CH 3 



borneol carbonic acid 

 (carbonic acid mono bornyl ester) 



The analysis of the calcium salt, calculated for an acid C n H 18 3 , 

 gave results which agree very well. A second acid formed in the reduction 

 was identified with certainty as an isomeride of borneol carboxylic 

 acid, m. p. 101 to 102 . If the borneol carboxylic acid of the m. p. 170 

 to 1 7 1° is repeatedly slowly distilled in vacuo (13 mm. pressure), there 

 is obtained between 160 and 170 , dehydroborneol carboxylic acid 

 (camphene carboxylic acid?) which, contrary to the first -named, is 

 volatile with water vapour, and can thereby be separated from it; it 

 melts at 112 to 113 and has the formula C u H 16 2 . Its calcium 

 salt crystallises from water, the silver salt dissolves with difficulty, and 



2 ) Liebig's Annalen 348 (1906), 199. 

 2 ) Zeitschr. f. Chemie 1868, 299. 



