282 SCIENCE PROGRESS 



hydrochloric acid upon codeine, an amorphous chlorinated 

 product which they named chlorocodeide. 



C l6 H 21 3 N + HC1 = CgHooClO.N + H,0 



Codeine Chlorocodeide 



They further state that if this compound is heated with water 

 to 130 , codeine is regenerated; if, on the other hand, it is 

 heated with hydrochloric acid to 150 , methyl chloride is split 

 off and apomorphine remains. 



CgHtfClCN = C, 7 H. 7 2 N + CH 3 C1 



Chlorocodeide Apomorphine 



On examining these two equations, it is seen that when 

 hydrochloric acid acts upon codeine at 150 , a CH 3 group and 

 a molecule of water are split off, the final product being the 

 same as that obtained by the action of dehydrating agents upon 

 morphine. 



The third oxygen atom in morphine and codeine is indifferent 

 and, according to Vongerichten, 1 is doubly bound to carbon 

 as in the ethers; it is sometimes referred to as the "bridge" 

 oxygen atom and will be dealt with in detail later. 



The nitrogen of morphine has been proved by Grimaux, 2 

 Hesse, 3 Vongerichten, 4 and Schrotter to be cyclic, and to be 

 bound to three carbon atoms ; it is therefore tertiary. 



In order to make perfectly clear the rationale of the decom- 

 position processes to which morphine has been subjected in 

 the course of investigations made to determine its structure, 

 it is necessary to say something about a reaction or series 

 of reactions known as " exhaustive methylation." Shortly 

 after the discovery of the quaternary ammonium bases, 

 Hofmann 5 observed that when the hydroxides of these bodies 

 are heated, water is split off with the simultaneous formation 

 of a tertiary amine and a hydrocarbon — 



C 2 H 6 \ /C,H S C,H 5 \ 



QH 5 -^N< ' s = CHAN + CH^ + H 2 



C.,H 5 / X ° H C.Hs/ 



Tetraethylammonium Triethylamine Ethylene 



hydroxide 



This reaction was applied by Hofmann 6 in 1881 to piperidine. 

 This substance is a secondary base, and it is therefore 



1 A/ma/en, 210, 105. 4 Bet: 15, 1480, 1279. 



2 Compt. rend. 93, 591. 5 Annalen, 78, 263. 



3 Annalen, 222, 223. 6 Ber. 14, 494, 659. 



