36 ORGANIC MEDICINAL CHEMICALS 



Alcohols with one (OH) group are termed monatomic thus, 

 alcohol, ethyl alcohol, CH 3 CH 2 OH; with two (OH) groups are 

 termed diatomic thus, glycol, CH 2 OH-CH 2 OH; with three 

 (OH) groups are termed triatomic thus, glycerin, CH 2 OH- 

 CHOH-CH 2 OH, etc. Those alcohols with two or more groups 

 are called polyatomic. Alcohols are also divided into three 

 classes. If the hydrogen substituted is in the methyl radical 

 (CH 3 ), making the group CH 2 OH, primary alcohols are formed; 

 or, if the substitution is in the methylene radical (CH 2 ), making 

 the group CHOH, secondary alcohols are formed; or, if the sub- 

 stitution is in the methine radical ( = CH), making the group 

 = COH, tertiary alcohols are formed, f 



The principal groups of organic chemistry are the following: 



Primary alcohols CHiOH. Aldehydes COH. 



Secondary alcohols =CHOH. Ketones =CO. 



Tertiary alcohols =COH. Acids COOH. 



Ethers, =C-O-C= Sulphonic acids, HSO. 



Nitriles C=N. Nitro compounds NOt. 



Amido compounds NHj. Oximes, =NOH. 



Imido compounds, =NH. 



4. DERIVATIVES OF ALCOHOLS. (a) Ethers are compounds of neutral 

 reaction, derived from alcohols by the elimination of one mole- 

 cule of water from two molecules of alcohol. They are analogous 

 to the metallic oxides thus, ether (or di-ethyl-oxide), (C 2 H5) 2 O; 

 ethyl-propyl-ether, C 2 H6-O-C 3 H 7 . 



(b) Sulphur derivatives of alcohols and ethers are formed by 

 replacing one or more atoms of oxygen by sulphur thus, mer- 

 captan, C 2 H 5 SH; ethyl-sulphid, (C 2 H 5 ) 2 S. 



(c) Inorganic esters are compounds derived from the inorganic 

 acids by the exchange of the replaceable hydrogen by an alcohol 

 radical thus, ethyl-nitrate, C 2 H 5 -O-NO 2 . They are analogous 

 to inorganic salts. 



(d) Nitriles are compounds of hydrocyanic acid (HCN) in 

 which the hydrogen is replaced by an alcohol radical thus, 

 aceto-nitrile or methyl-cyanide, CH 3 CN. Iso-nitriles differ in 

 properties from the nitriles by having the radical joined to the 

 nitrogen thus, CH 3 NC, 



(e) Nitrogen bases: Amines ^and ammonium bases are com- 

 pounds formed by the introduction of one or more alcohol rad- 

 icals in place of the hydrogen in ammonia or ammonium salts 

 thus, methylamine, CH 3 NH 2 ; trimethylamine, (CH 3 ) 3 N. 



Amines are designated as primary, secondary (imines), tertiary 

 (nitrile bases), or quarternary (ammonium bases), as one, two, 

 or three atoms of hydrogen are replaced in ammonia, or as the 

 four atoms of hydrogen are replaced in ammonium. 



t Groups of elements like the above are always found to have constant properties, and are said 

 to be the characteristic groups in the^classes in which they are found. 



