42 ORGANIC MEDICINAL CHEMICALS 



16. ANTHRACENE AND ITS DERIVATIVES. Anthracene contains three con- 



HC CH CH 

 /VV\C/\ 



HC/ x / Xx N:H 



densed rings, Ci 4 Hio, or, graphically, | This 



\ /\ /\. /^-tl 



CH CH CH 



is an increment of 4!^ over naphthalene. The hydrogen can 

 be replaced as in benzene, forming derivatives thus, CuHsC^, 

 anthraquinone; CuHsO^ alizarine. 



17. PHENANTHRENE AND ITS DERIVATIVES. Phenanthrene is an 



isomer of anthracene, containing three condensed rings thus, 

 CH CH 



It can form derivatives in the same way. 



Pyridine derivatives, alkaloids, and compounds related to 

 them. These are compounds that may be considered as derived 

 from benzene, naphthalene, anthracene, by the exchange of 

 N = for CH = in the rings. AU may be considered as derived 

 from benzene on the one hand and from pyridine on the other. 

 1 8. PYRIDINE GROUP. Pyridine may be considered as benzene in which 

 = CH is exchanged for = N . The hydrogen of pyridine is 

 replaceable, forming derivatives such as picoline (methyl-pyri- 

 dine), C 5 H 4 NCH 3 . 



Hydrated pyridine or piperidine, CsHuN; conine, a-normal- 

 propyl-piperidine, C 5 HioN(C 3 H7). 



19. QUINOLINE AND ACRIDINE GROUPS bear the same relation to pyridine 



that naphthalene and anthracene bear to benzene. 



20. ALKALOIDS or COMPLEX OR UNKNOWN COMPOSITION. Included in 



this class are the tropine, opium, narcotine, cinchona, strychnine, 

 and solanine bases. 



21. HYDRATED DERIVATIVES OF BENZENE. Terpenes are hydrocarbons 



of the general formula (CsHs)*, or, most commonly, CioHi 6 . 

 Camphors are oxygen derivatives of the terpenes: CioHi 6 O, 

 camphor. 



22. GLUCOSIDES are vegetable substances that, when treated with alkalies, 



acids, or enzymes, are so broken up that one of the products of 

 the decomposition is a glucose. They are ethereal derivatives 

 of these sugars. 



23. RESINS. The resins are closely related to the terpenes and are formed 



from them. Their composition is as yet unknown. 



24. ALBUMIN AND ALBUMINOIDS make up the greater part of the animal 



