Glyceraldehyde reaction with ammonia

A more recently discovered second pathway starts from ribulose 5-phosphate (49) that is condensed with ammonia and glyceraldehyde phosphate or its isomerization product dihydroxy-acetone phosphate (50), which affords pyridoxal 5 -phosphate in a single enzyme-catalyzed reaction step (Fig. 5B) (28, 29). This pathway seems to be widely distributed it is used in plants (30) and has also been shown to proceed in fungi, archaea, and most eubacteria. 

The preparation of the octa-Q-benzoyl-aldobiononitriles of cellobiose, gentiobiose, lactose, and maltose from the unprotected oximes has been effected by treatment with benzoyl chloride in pyridine at SO C. Reaction of melibiononitrile perbenzoate with methanolic ammonia yielded the 1,1-dibenzamido-derivative (37) as the major product, isolated in 38% yield.The erythro- and threo-cyanohvdrins (38) were obtained in a 4 1 ratio from 2,3-Q-isopropylidene-D-glyceraldehyde on reaction with trimethylsilyl cyanide, and were converted to the four carbon lactone synthons (39). The chiral hexane-1,6-dinitrile (40) has been synthesized CHjOH... 

A non-linear regression analysis is employed using die Solver in Microsoft Excel spreadsheet to determine die values of and in die following examples. Example 1-5 (Chapter 1) involves the enzymatic reaction in the conversion of urea to ammonia and carbon dioxide and Example 11-1 deals with the interconversion of D-glyceraldehyde 3-Phosphate and dihydroxyacetone phosphate. The Solver (EXAMPLEll-l.xls and EXAMPLEll-3.xls) uses the Michaehs-Menten (MM) formula to compute v i- The residual sums of squares between Vg(,j, and v j is then calculated. Using guessed values of and the Solver uses a search optimization technique to determine MM parameters. The values of and in Example 11-1 are ... 

The imidazoles formed in the reaction of aqueous ammonia with other a-hydroxycarbonyl compounds, for example, the triose DL-glyceraldehyde, and such a-dicarbonyl compounds as 3-deoxy-D-glycero-pentosulose (59), and the 3,6-dideoxy-L-erythro-, D-arabino-, and 3-deoxy-D-erytforo-hexosuloses (60, 61, and 62), respectively, are summarized in Table VIII for reactions in which formaldehyde was added, and in Table IX for reactions in which it was not added. 

In addition, the isolation of 4(5)-ethylimidazole (23) from the reactions of L-rhamnose (see Table VI), L-fucose (6-deoxy-L-galactose), and 3-deoxy-L-glyceraldehyde (see Table IX) with aqueous ammonia, led Komoto and Tsuchida39 to believe that the 2-oxobutanal forming the 4(5)-ethylimidazole (23) arose from an aldol reaction of the 3-deoxy-L-glyceraldehyde (formed by dealdolization in the cases of L-rhamnose and L-fucose) with formaldehyde, with subsequent loss of water from the 4-deoxytetrose so formed. 

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