VOL. 4 (1950) BIOCHIMICA ET BIOPHYSICA ACTA I99 



CONFIGURATIONAL RELATIONSHIPS BETWEEN NATURALLY 

 OCCURRING CYCLIC PLANT ACIDS AND GLUCOSE 



TRANSFORMATION OF QUINIC ACID INTO SHIKIMIC ACID 



by 



GERDA DANGSCHAT and HERMANN O. L. FISCHER 



Department of Biochemistry, University of California Berkeley 4, 



California {U.S. A .) 



The old idea that meso-inositol could be formed by cyclization of D-glucose gained 

 considerable strength by the determination of the configuration of meso-inositol^ by 

 Gerda Dangschat, which later was confirmed by Th. Posternak. Similar circum- 

 stances could be demonstrated in the field of cyclic plant acids, for instance Quinic Acid 

 and Shikimic Acid. We were able to prove their constitution^ and their planar con- 

 figuration^. 



In 1937 we succeeded* by the degradation of shikimic acid into 2-desoxygluconic 

 acid, IX^ in demonstrating the same configuration for carbon atoms 3, 4 and 5 of 

 shikimic acid as is found for carbon atoms 3, 4 and 5 of D-glucose. 



An analogous relationship between quinic acid^, which is more commonly found 

 in the plant kingdom, and D-glucose, seemed very probable at that time. This phy- 

 siologically important relationship could be established with certainty by transforming 

 quinic acid into shikimic acid. In this communication we describe the successful trans- 

 formation of derivatives of quinic acid into those of shikimic acid'. 



The use of the acetone compounds of quinic acid, which in previous work with 

 these substances had proven highly satisfactory, met with unexpected difficulties. We 

 therefore employed the formaldehyde derivatives which are described in the preceding 

 paper*, after having determined that the methylene group blocked the hydroxyls of 

 carbon atoms 4 and 5 of the quinic acid as did the acetone. 



We used a-toluene sulphonyl derivatives of quinic acid and found that the formation 

 of a double bond by the splitting off of the toluene sulphonic acid by alkali only pro- 

 gressed smoothly after conversion to the nitrile, thus considerably weakening the stabi- 

 lizing influence of the carboxyl group. By prolonged treatment of the 3-acetyl-4,5-formal 

 quinic amide, P with excess of ^-toluene sulphonyl chloride and pyridine we performed 

 three reactions in one operation: toluene sulphonylation of the amide, nitrilization of 

 the amide, and finally the splitting off of the toluene sulphonyl group from the nitrile, 

 with the result that the nitrile of the expected 3-acetyl-4,5-methylene shikimic acid, II, 

 could be isolated. This could be converted by means of alkali into the methylene deriv- 

 ative of shikimic acid, IIP" which was transformed into free shikimic acid, V, in acid 

 solution. The identification of shikimic acid was made by melting points, mixed melting 

 points, and optical determinations. 

 References p. 203I204. 



