— 162 



atory ([o] D — 15,6° in ethereal solution), even when it is produced from 

 dextrorotatory turpentine oil. The original hydrocarbon must therefore 

 be the same in dextro- as well as in lsevorotatory oils. 



In order to obtain nopinone, 10 g. sodium nopinate are dissolved 

 in 100 cc. hot water, and a solution of 3 g. potassium permanganate 

 in 75 g. water added. Next, 2 g. sulphuric acid diluted with 20 cc. 

 water are added, and as soon as the oxidation commences, steam is 

 passed through the liquid, when the nopinone passes over, whose 

 properties are as follows: d 0,981; b. p. 209 ; n D20O 1,4787; mol. refr. 

 found 39,87, calculated for C 9 H 14 39,51; [«b + 18,48° undiluted, 

 -J- 37,3° in 12 per cent, alcoholic solution, -(- 11,02° in 7,15 per 

 cent, ethereal solution, -J- 10,79° m 7> 2 7 P er cent - benzene solution. 

 It solidifies readily in a freezing mixture, and then melts again a little 

 above 0°. 



Nopinone condenses readily with benzaldehyde, forming a benzylidene 

 compound melting at 106 to 107°, and with itself when hydrochloric 

 acid gas is introduced into its alcoholic solution. The body C 18 H 29 0C1 3 

 formed in the last-named manner has the following constitution: — 



O 

 C H 3 \ 



ch/ \ //\ 4a/ 3 



ci \ CHs 



Hydrogen chloride has attached itself not only at the double- 

 linking formed by the condensation, but also at the bridge bonds of 

 the two tetracyclic rings. The trichloride, decomposing at 148°, splits 

 off readily hydrochloric acid, already when boiled with solvents, and is 

 converted into a dichloride C 18 H 28 0C1 2 (m. p. 125 to 126°) which 

 dissolves much more easily in alcohol and ether than the trichloride, 

 and which can again be converted into the latter by addition of 

 hydrochloric acid. The ready formation and the difficult solubility of 

 the trichloride can be utilised for the detection of nopinone. 



When boiled with dilute sulphuric acid, nopinone is converted into 

 isopropylhexenone (m. p. of the semicarbazone 183 to 184°), which 

 with hydrogen sulphide in alcoholic - ammoniacal solution yields a 

 hydrogen sulphide compound (m. p. 119°), and is consequently the 

 already known A 2 -isopropylhexenone 



O = ( )~C,H 7 



By reduction with sodium in moist ethereal solution, nopinone is 

 converted into the corresponding alcohol nopinol, which exists in two 

 modifications: 1. crystallised a -nopinol, b. p. 204 to 205°; m.p. 102°; 

 [a] D — 5,32° in 12,53 P er cent - ethereal solution; long, readily sub- 

 liming needles with a camphor -like odour; it remains unaltered on 



