Section III., 1892. [ 35 ] Trans. Roy. Soc. Canada. 



VI. — The Syntliesis of (I Neio Diquiiioliii. 

 By E. F. EUTTAN, B.A., M.D. 



(Presented by G. P. Girdwood, M.D., and read May, 1891.) 



Of recent years our knowledge of that important class of natural nitrogenous organic 

 substances called alkaloids has been largely increased through the study of artificial pro- 

 ducts of similar constitution. Their energetic action on the functions of the animal 

 organism and their intricate composition make the vegetable alkaloids objects of the high- 

 est interest both to the physician and the chemist. Until quite recently the difficulties 

 in the way of establishing formulœ for these bodies appeared almost insuperable, owing 

 to the complexity of their molecules and the apparent want of connection between their 

 chemical behaviour and that of the well studied groups of organic substances. Eecently, 

 however, many of the well-known alkaloids have been prepared by synthetical processes 

 from crude material and the molecular structure of others fully elucidated. 



The observation was made many years ago that some alkaloids, such as quinine 

 cinchouine, etc., yielded on decomposition, among other prodixcts, substances which were 

 recognized as identical, or nearly so, with certain bodies called pyridine and qiiinolin, 

 obtained during the destructive distillation of bones and coal tar. 



The chemistry of pyridine, quinolin and their derivatives, for a long time neglected, 

 has recently been engaging the attention of some of the best German investigators with 

 the result of establishing group reactions and other generalizations based upon a large 

 number of independent observations. A very marked similarity has been traced between 

 natural alkaloids and the artificial derivatives of quinolin in regard to composition and 

 chemical behaviour. In both, for instance, the number of acid equivalents with which 

 they can combine depends chiefly upon the number of pyridine or quinolin groups present 

 in their molecule — thus diacid alkaloids are usually diquinolins. The practical outcome 

 of the researches in this field has been the artificial preparation from coal tar products of 

 many alkaloidal bodies of the highest therapeutic value. The same intensity of action 

 on the human system is characteristic of both the artificial and natural alkaloids. The 

 simple quinolius have proved so interesting and their alkaloidal derivatives so rich a 

 field for chemical research that artificial quiuolins with more than one pyridine group, 

 such as the diquinolins, haA^e received but little attention ; indeed, of the few diquinolins 

 that have been prepared artificially most have isolated by such reaction that their chemical 

 relations are by no means clear. 



In the course of some recent studies of the chemical properties of ortho-tolidin and 

 its derivatives a method suggested itsdf by which an interesting diquinolin might be 

 prepared, of whose constitutional formula and chemical relations there could be but little 



