Glucophore

Oertly and Myers Auxogluc and Glucophore Components of Sweet-tasting Compounds... 

Fig. 11.—Identity of the Third Structural Feature Comprising the Postulated Glucophore in Some Sweet-tasting Molecules. ...

Lindley proposed an oblique, planar, stereogeometric arrangement between AH,B and y that is strikingly similar to Kier s tripartite glucophore, with distance and direction parameters as shown in Fig. 12. A similar y site for other sweeteners, such as the sweet dipeptides, has also been proposed, and it appears that the location of y in relation to AH,B is directional rather than positional. 

If the assignment of the 1 -hydroxyl group and the 1-carbonyl group as the AH,B glucophore is correct, it is then very likely that the third (y) site is located at C-4, as inspection of a molecular model shows that this carbon atom could be in a position which approximates very closely the Kier or Shallenberger and Lindley tripartite glucophore. This could be readily confirmed by structural-modification studies. 

FIGURE 9. The extreme sweetness of trichlorogalactosucrose is explained by optimal interaction with an AH,B,X tripartite glucophore... 

For example, the trichloro-ga/acto-sucrose 94 is 2000 times sweeter than sucrose. Hough and Khan have rationalized the extreme sweetness of these trichloro analogues on the basis of an optimal interaction with an AH,B,X tripartite glucophore (Figure 9)142. Recent studies have extended examples of these intensely sweet sugars143. 

Fig. 45 The three-dimensional structures of the two observed coirformers of p-D-fructopyranose showing the intramolecular hydrogen-bonding networks and the glucophore unit. (From [226])...

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