II. CHEMISTRY 



229 



COOCH, 



Br-CH 

 I 

 CH, 







II 



II 



o 







II 



II 

 o 



POCl, 



r^^<°N 



- KXJ 



OH 



I 



C-CH3 



I 



^N 



N-CH 



COOCH e 



/ CHaONa 



CH, 



CHjI 



CHiONa 



OCH, 



I 



c. 



'C-CH, 



I 

 CI 



Sn+HCl 



OCH3 



c. 



'C-CHj 



I 



COOH 



HOOCr^OCH, 



^N' 



Synthesis of Dicarboxy Acid Derived from Pyridoxine Methyl Ether^^ 



D. SYNTHESIS 



a. Kuhn, Westphal, Wendt, and Westphal 



With the structure well established in 1939 by the synthesis of the meth- 

 oxydicarboxylic acid derivative of pyridoxine, the synthesis of the vitamin 

 was accomplished without delay in the same year. The simplest approach 

 to the synthesis of pyridoxine was by reconverting this degradation product 

 to pyridoxine. Kuhn, Westphal, Wendt, and WestphaP^ reported their 

 method for accomplishing this by first converting the dicarboxylic acid to 

 2-methyl-3-methoxy-4,5-dicyanopyridine. On catalytic hydrogenation in 

 which eight hj'drogens were taken up, 2-methyl-3-methoxy-4,5-di(amino- 

 methyl)pyridine was obtained. Nitrous acid converted the aminomethyl 

 groups to hydroxymethyl groups, the resulting compound being identical 



COOH 

 CHsO-^^COOH 



CH 



CN 

 CHsO^^CN 



3\n/ 



CH 



3\N/ 



CH2OH 

 CHaO^^CH^OH 



CH 



CH0NH2 

 CHsO'^^iCHoNHa 



CHzBr 

 HO^^CHzBr 



\N/ 



CH; 



\N/ 



HO 



CUs 



CHoOH 



CH2OH 



\N/ 



Conversion of Pyridoxine Methyl Ether Dicarboxylic Acid to l^ridoxine- 



