Messrs Sell and Dootson, Garboxy derivatives of pyridine. 93 



On the synthesis of carboccy derivatives of pyridine. By 

 W. J. Sell, M.A., Christ's College, and F. W. Dootson, M.A., 

 Trinity Hall. 



[Read 2 March 1903.] 



The great importance which attaches to the derivatives of 

 pyridine, in consequence of its close connection with alkaloids 

 and allied substances, renders a knowledge of the syntheses of 

 carboxy and other pyridines of considerable value. 



The constitution of few of the alkaloids is known, and the 

 problem of their structure may perhaps be more easily approached 

 from the synthetic side. 



Although a considerable number of pyridinoid bodies have 

 been obtained by condensation of open-chain substances, remark- 

 ably little has been accomplished in this direction from pyridine 

 itself. The three monocarboxy derivatives have already been 

 described, but they have been obtained by methods so unproduc- 

 tive that they must be regarded as little more than museum 

 curiosities. 



By the application of well-known processes to those chloro- 

 pyridines already described, many derivatives have been obtained. 

 The present communication deals with some attempts to replace 

 the chlorine in these compounds by the carboxy group. 



The usual methods of procedure for such conversions were not 

 attended with success, such substances as potassium cyanide, zinc 

 ethide, &c, either not reacting at all, or giving unsatisfactory 

 results. Attempts however made with sodiomalonic ester being 

 more successful, a/3/3' y tetrachloropyridine was treated in quantity 

 as follows. 



Rather more than two molecules of sodiomalonic ester, in 

 alcoholic solution, was treated with one molecule of the tetra- 

 chloropyridine mentioned above. The mixture was boiled for 

 about ten hours in a reflux apparatus : at the end of that time the 

 alcohol was distilled off and the residue acidified with sulphuric 

 acid. The separated oil was then washed repeatedly with water, 

 dried in vacuo, and fractionated under a pressure of about 28 mm. 

 till a temperature of 150° C. was reached, when the operation was 



