carboxy derivatives of pyridine. 95 



is quantitative, a/3/3' trichloro 7 methylpyridine as prepared in 

 this way is practically pure. Recrystallised from alcohol it forms 

 long colourless needles whose melting point is 31 — 31"5°. It 

 exhibits the same general solubility as the chloropyridines, which 

 it closely resembles in appearance and odour. It is volatile at 

 the ordinary temperature and rapidly disappears when left 

 exposed to the air. Several analyses confirm the formula 



C 5 HC1 3 N (OH,). 



When trichloromethylpyridine is subjected to prolonged boiling 

 with a solution of potassium permanganate it is converted into 

 the corresponding acid. The boiling was conducted in a reflux 

 apparatus, a slight excess of permanganate being employed. The 

 excess of permanganate was removed by alcohol and after filtering 

 off the separated hydrated manganese dioxide, the colourless 

 filtrate was evaporated to small bulk and acidified with sulphuric 

 acid. When allowed to remain in a desiccator the solution 

 deposited large colourless crystals of constant melting point 

 188 — 189° C. Analyses agree with the formula 



C 5 HCl 3 NCOOH. 



This trichloroisonicotinic acid is very soluble in hot water 

 and the ordinary organic solvents but only sparingly so in cold 

 water. 



