52 BACTERIOLOaiCAL AND ENZYME CHEMISTRY 



CH CH 



A/x 



HC C CH 



quinoline ' 11 I 

 ^ HC C CH 



N CH 



etc., and their derivatives. 



From all of these root compounds derivatives can be 

 built up by well-defined processes, and these derivatives aie 

 characterised by containing certain groups of atoms which are 

 easily recognisable by their reactions. 



It will be useful at this stage to consider the more important 

 classes of derivatives and their reactions in a highly general 

 manner. A knowledge of organic chemistry really consists in 

 being familiar with certain general reactions typical of certam 

 specific atomic groups, rather than in a detailed acquaintance 

 with individual compounds. In what foUows, therefore, 

 reference wiU be made mainly to those atomic groupings, the 

 knowledge of whose properties will be useful in the study 

 of the substances to be considered in the later chapters of 

 the book. 



Alcohols.— These are derivatives of aliphatic hydrocarbons 

 characterised by the presence of the group —OH, known as 

 the hydroxyl group. The simplest alcohol is mihyl alcohol, 

 CH3OH, a hydroxyl derivative of methane, CH4. Ordinary 

 alcohol is the next member of the series, viz., hydroxy-ethane 

 or ethyl alcohol, CH3CH2OH (or C^HgOH). Alcohols may be 

 divided into three classes : — 



Primary alcohols of the general formula E — CHjOH ; 

 Secondary alcohols of the general formula R2=CH0H; 

 Tertiary alcohols of the general formula R3=C— OH. 



