Structure of Simpler Organic Compounds. 1 1 1 



can be extracted with ether, and as they are generally 

 crystalline substances, they can usually be readily purified 

 by crystallization. Furthermore, they contain two car- 

 boxyl groups attached to the same carbon atom, and there- 

 fore (see above), like malonic acid, they decompose when 

 heated above their melting point, with evolution of carbon 

 dioxide 



CHR = C0 2 + CH 2 RCOOH 



In this way an alkyl derivative of acetic acid is 

 obtained. If methyl iodide had been employed for con- 

 densation with sodio-malonic ester, the final product 

 would be CH 2 (CH 3 ) COOH that is, propionic acid ; if 

 ethyl iodide had been employed, the final product would 

 be CH 2 (C 2 H 5 )COOH that is, normal butyric acid. In 

 this way a large number of complex fatty acids can be 

 built up. 



But this synthetical method can be still further ex- 

 tended. If the alkyl derivative of ethyl malonate is 

 isolated, and instead of being hydrolyzed, is treated with 

 one molecular equivalent of sodium ethoxide in alcohol, 

 a second hydrogen can be replaced with sodium 

 CO-OC 2 H 6 CO-OC 2 H 6 



+ C 2 H 5 ONa = CNaR +C 2 H 5 OH 



X COOC 2 H 8 CO-OC 2 H 5 



This sodio derivative can also react with alkyl halogen 

 derivatives 



COOC 2 H 5 COOC 2 H 5 



CNaR + R'I = CRR' +NaI 



\ \ 



CO- OCA COOC 2 H 5 



