Mr Sell, The Chlorination of Methyl derivatives, etc. 119 



The Chlorination of Methyl derivatives of Pyridine. Part I : 

 2-Methyl Pyridine. By W. J. Sell, M.A., F.R.S., Christ's College. 



[Read 14 November 1904.] 



Preliminary experiments having shown that 2-methyl pyridine 

 blackens when chlorine is passed into, it and that a similar result 

 attends all attempts at chlorination by means of phosphorus penta- 

 chloride, recourse was had to the method found successful in the 

 case of pyridine, viz. the direct chlorination of the 2-methyl 

 pyridine hydrochloride saturated with hydrochloric acid. This 

 product remains liquid at the ordinary temperature of the 

 laboratory. The work of Ramsay {Phil. Mag. [5] 2, 1876, Ii) led 

 him to the conclusion that picoline hydrochloride was not acted 

 upon by chlorine even when heated with it. The author's results 

 confirm this at the ordinary temperature, but show that at about 

 100 — 105° C. rapid replacement of hydrogen takes place and a 

 number of chlorinated products are produced. After complete 

 chlorination the still liquid products were cooled by ice and a 

 current of air passed through for some hours when a large 

 crystalline precipitate was produced. This precipitate was drained 

 off from the liquid products and recrystallised from spirit. The 

 crystals are prismatic, freely soluble in alcohol and most organic 

 solvents, but insoluble in water. They constitute rather over 

 52 per cent, of the 2-methyl pyridine taken, and so far are the 

 only solid product of the change. Analysis shows that the 

 formula C 6 HC1 6 N should be assigned to this body. The sub- 

 stance melts at 102 — 103° C. and is isomeric with a compound 

 M.p. 60 obtained by Ost (/. Pr. Ghem. [2] 27, 257) by the inter- 

 action of phosphorus pentachloride on comenamic acid. In ad- 

 dition to the compound mentioned above there is a liquid product 

 consisting of compounds less highly chlorinated, the work on 

 which although advanced is still incomplete. 



It is worthy of remark that there is a total absence of the 

 dipyridyl derivative which constituted such a large proportion of 

 the products in the chlorination of pyridine hydrochloride (Trans. 

 Ghem. Soc. 1899, 75, 979 ; 1901, 79, 899). The solid compound 

 mentioned above, M.P. 102 — 103°, heated with eighty per cent, 

 sulphuric acid, gives a nearly quantitative yield of trichlorpicolinic 

 acid CgHCLjNCOOH, showing that three of the six atoms of 

 chlorine in the original compound belong to the side-chain. This 



VOL. XIII. pt. ii. 9 



