Glucometasaccharinic acid formation

This stopping or stabilization reaction with cellulose was presumed to involve a saccharinic acid rearrangement of the reducing group on the terminal D-glucose residue. This mechanism was confirmed by the formation of D-glucometasaccharinic acid, which still remained attached as the terminal unit (73). The stopping reaction is presented in Scheme 13. 

Fig. 2-34. Stopping reaction. 1 —>2, 1,2-Enediol formation 2 — 3, j3-hydroxy elimination 3 —> 4, tautomerization 4 —> 5, benzilic acid rearrangement leading to a glucometasaccharinic acid end group, (cf. Fig. 2-33.)...

Machell and Richards succeeded in isolating 3-deoxy-D-en/fkro-hexos-ulose (52), the postulated dicarbonyl intermediate in the formation of d-glucometasaccharinic acid (68) in the alkaline degradation of 3-0-sub-stituted D-glucose derivatives, from 3-0-benzyl-D-glucose (67). 

The formation of glucometasaccharinic acids by thermal degradation of 3-deoxy-D-eryMro-hexosulose is noted in Chapter 16. 

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