LOCAL ANESTHETICS 347 



of various groupings in atropine and cocaine. In 1883 

 Emil Fischer, 1 working with the triacetonalkamine obtained 

 by Heintz, came to the conclusion that it was a tetra-methyl- 

 oxypiperidine, and he noticed further that on heating the 

 substance it lost a molecule of water, and became changed 

 into a base, which he termed triacetonine. As this behaviour 

 was very similar to that shown previously by Ladenburg in 

 the case of tropine, it suggested a close relationship between 

 triacetonamine and tropine. And, on the analogy of homa- 

 tropine (mandelyl-tropeine) Fischer combined triacetonamine 

 with mandelic acid, and found that, like homatropine, the new 

 substance produced dilatation of the pupil when applied to 

 the eye. Thirteen years later, when the similarity in the con- 

 stitution of atropine and cocaine was known, Merling prepared 

 a number of alkyl-benzoyl compounds of the carboxylic acid of 

 triacetonamine, and gave them to Vinci 2 for pharmacological 

 investigation. As was expected, some of these produced local 

 anaesthesia, and one (N.methyl-benzoyl-tetramethyl-y.oxy- 

 piperidine carboxylic acid methyl ester), which was found to 

 be considerably less toxic than cocaine, was introduced as a 

 local anaesthetic under the name eucaine. Later, a similar 

 compound was prepared from vinyl-diacetonamine, and was 

 found to be less toxic and less irritant than eucaine. 3 It was 

 introduced into therapeutics as eucaine B. It is benzoyl- 

 trans-vinyl-diacetonalkamine, and is now known as beta- 

 eucaine. 



(CH 3 ) 2 C CH 2 (CH 3 ) 2 C CH 2 



CH,N <X HN CH.O.COC 6 H 5 



coan, 



(CH 3 ) 2 C 



a-ei 



These investigations led to similar preparations being made 



1 Ber. d. deut. diem. Ges., xvi. p. 1604 (1883). 



* Virchow's Archiv, cxlv. p. 78 (1896). 



3 Vinci, Virchow's Archiv, cxlix. p. 217 (1897). 



