84 ORGANIC AGRICULTURAL CHEMISTRY 



Glycine. Amino-acetic Acid. CH2(NH2) — COOH 



When this compound is prepared from chlor-acetic acid by 

 the action of ammonia, the ammonium salt of the amino-acid 

 is formed. 



CH2CI - COOH + 2 NH3 CH2(NH2) - COONH4 + HCl 



Chlor-acetic acid Ammonium salt of amino-acetic acid 



This salt, when boiled with hydrochloric acid, decomposes and 

 forms the amine hydrochloride of the acid. 



CHo(NH2)-COONH4+2 HCl -> CH2(NH2HC1)-C00H+NH4C1 



Ammonium salt of amino-acetic acid Hydrochloride of amino-acetic acid 



Amino-acetic acid is a solid crystalline compound melting 

 at 235° C. It is readily soluble in water. The hydrochloride 

 salt is also a crystalline solid soluble in water. An important 

 derivative of amino-acetic acid should be mentioned. As 

 previously stated the amino group in the compound acts as 

 ammonia and forms compounds in which the amino residue 

 becomes the amide part of an acid amide. With acetic acid 

 or, better, with the acid chloride of acetic acid, ammonia and 

 amino-acetic acid yield the following : 



CH3 - COCl -f NH3 -> CH3 - CONH2 -f HCl 



Acetyl chloride Ammonia Acet-amide 



CH3-COCH-(NH2)-CH2-COOH ~> CH3-CO-NHCH2-COOH+HCI 



Amino-acetic acid Acetyl-amino-acetic acid 



Benzoic acid is a mono-carboxy acid derived from the hydro- 

 carbon benzene, CeHe. It is CeHs — COOH. This forms a 

 benzoyl (CeHsCO) derivative of amino-acetic acid. 



C6H5 - COOH CeHsCO - (NH) CH2 - COOH 



Benzoic acid Benzoyl-amino-acetic acid (Hippuric acid) 



This compound, benzoyl-amino-acetic acid, is the substance known 

 as hippuric acid. It is a constituent of the urine of man but 

 is more abundant in that of horses and cows and of other herbiv- 

 orous animals. When hippuric acid is boiled with hydrochloric 



