THE ALKALOIDS 353 



OHC.CH 3 = VCH=CH.CH + HO 



Acetaldehyde. 



! CH=CH.CH 3 + 3H a = H 2 C\J CH . CH 2 . CH 2 . CH 3 



N 

 a-propylpiperidine. 



The inactive coniine was separated into d- and /-coniine by the 

 fractional crystallisation of its tartrate. 



Nicotine. C 10 H 14 N 2 . 



Nicotine occurs to the extent of -6-8 per cent, in tobacco leaves 

 in combination with organic acids (malic or citric). 



Preparation. 



Tobacco leaves are boiled out with water. The aqueous solution is con- 

 centrated, made alkaline with lime and distilled. The distillate is acidified 

 with oxalic acid and evaporated. The concentrated solution is rendered 

 alkaline with soda and extracted with ether. The ethereal extract on distilla- 

 tion leaves the nicotine, which is purified by distillation in a current of 

 hydrogen. 



Properties. 



Nicotine is a colourless oily liquid which boils at 241. It possesses 

 an unpleasant smell and a burning taste. It is intensely poisonous. 

 In air it undergoes oxidation, turning brown. 



It is a ditertiary base and forms salts with acids, which are dextro- 

 rotatory, and combines with two molecules of methyl iodide. 



Constitution. 



On oxidation with chromic acid it yields nicotinic acid showing 

 that it possesses a substituting group in 

 the /3-position of the pyridine ring. This 

 substituting group has been found to be 

 N-methyl-pyrrolidine, the methyl group be- 

 ing attached to the nitrogen atom. It is 

 -N-methyl-pyrrolidine-pyridine. 



Hygrine. 



Hygrine has been shown to be /?-acetyl-N-methyl pyrrolidine. 



CH-COCH 3 

 OH. 



3 t 



12 



