Lactic acid trioses conversion

Now let us consider the further conversion of PEP and of the triose phosphates to glucose 1-phosphate, the key intermediate in biosynthesis of other sugars and polysaccharides. The conversion of PEP to glucose 1-P represents a reversal of part of the glycolysis sequence. It is convenient to discuss this along with gluconeogenesis, the reversal of the complete glycolysis sequence from lactic acid. This is an essential part of the Cori cycle (Section F) in our own bodies, and the same process may be used to convert pyruvate derived from deamination of alanine or serine (Chapter 24) into carbohydrates. 

To conclude, the mie-pot conversion of cellulose-to-lactic acid (or lactate ester in alcoholic media) thus follows a complex cascade reaction network involving at least six reactions. These reactions have different catalytic needs, but, in general, the presence of both Lewis and Brpnsted acidity are paramount for catalytic success. Br0nsted acidity is key to the hydrolysis of cellulose (step 1) at mild temperatures (<200°C), and to some extent to the dehydration of triose (step 4), whereas Lewis acid sites play a vital role in the isomerization reaction of glucose-to-fructose (step 2), the retro-aldol (step 3), and the 1,2-hydride shift (step 6). Steps 4 and 5 are relatively less demanding they are catalyzed by both acid types. 

The conversion of ball-milled cellulose, glucose and fructose into micro-ciystalline lactic acid and 5-hydro g methylfurfural in water, catalysed by lead(ii) nitrate, has been reported (Scheme 22.5). The process involves a multistep cascade including the hydrolysis of cellulose to glucose, the isomerisation of glucose to fructose, retro-aldol fragmentation of fructose to trioses and their subsequent conversion to lactic acid lead(ii) catalyses both the conversion of glucose to fructose and the multistep cascade from fructose to lactic acid. The capacity of lead(ii) to be chelated by... 

Conversion of Trioses and Hexose-Based Sugars to Lactic Acid Under Mild Conditions... 

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