Oxalyl glycine

However, this case is not a common one. A very rare example is the reaction catalyzed by isocitrate dehydrogenase. In this reaction a-ketoglutarate shows a strong uncompetitive substrate inhibition versus NADPH or CO2, which does not result from combination with the enzyme-NADP complex. Presumably, it occurs by imine formation with a lysine in the central complex. The closure of the active site exposes this lysine, which must have a low enough ipKa to form an imine at neutral pH. In support of this model, oxalyl-glycine, a mimic of a-ketoglutarate that binds with equal affinity, does not show the effect (Grissom Cleland, 1988). 

Figure 4.20 Structures of selected HIF-stabilizers (1-6) and sirtuin activators (7-9) isoquinoline model substance (1), isoquinoline model substance (2), 2-oxoglutarate (3), oxalyl glycine (4), 3,4-dihydroxybenzoic acid (5), L-mimosine (6), resveratrol (7), SRT-1720 (8), and SRT-1460 (9).

N-Silylated peptide esters are acylated by the acid chloride of N-Cbo-glycine to N-acylated peptide bonds [11]. Likewise, acid chlorides, prepared by treatment of carboxylic acids with oxalyl chloride, react with HMDS 2 at 24°C in CH2CI2 to give Me3SiCl 14 and primary amides in 50-92% yield [12]. Free amino acids such as L-phenylalanine or /5-alanine are silylated by Me2SiCl2 48 in pyridine to 0,N-protected and activated cyclic intermediates, which are not isolated but reacted in situ with three equivalents of benzylamine to give, after 16 h and subsequent chro-... 

This enzyme catalyzes the conversion of pyruvate to formate and acetyl CoA and is a key enzyme in the anaerobic degradation of carbohydrates in some Enterobacteriaceae. Using an enzyme selectively C-labeled with glycine, it was shown by EPR that the reaction involves production of a free radical at C-2 of glycine (Wagner et al. 1992). This was confirmed by destruction of the radical with O2, and determination of part of the structure of the small protein that contained an oxalyl residue originating from gly-734. 

As second example for the scale-up of solid-phase reactions directly on solid support, we chose an arylsulfonamido-substituted hydroxamic acid derivative stemming from the matrix metalloproteinase inhibitor library (MMP) of our research colleagues (Breitenstein et al. 2001). In this case, there was already a solution-phase synthesis available for comparison (see Scheme 4). The synthesis starts with the inline formation of a benzaldehyde 18 with the glycine methyl ester, which is then reduced to the benzylamine 20 using sodium borohydride in methanol/ THF (2 1). The sulfonamide formation is carried out in dioxane/H20 (2 1) with triethylamine as the base and after neutralisation and evaporation the product 21 can be crystallised from tert. butylmethyl ether. After deprotection with LiOH, the acid is activated by treatment with oxalyl chloride and finally converted into the hyroxamic acid 23 in 33.7% yield overall. 

Bredereck and Schmotzer (1044), from diaminomaleonitrile (DAMN hydrogen cyanide tetramer) and oxalyl chloride, prepared 2,3-dicyano-5,6-dihydroxy-pyrazine but Stetten and Fox (1049) could not prepare 23-diamino-5-hydroxy-pyrazine from glycine amide and oxamide. Section 11.3 lists preparations from a, -diamino or a, -diimino compounds and reagents other than a,0-dicarbonyl compounds (384) with additional data (1050) and oxidation of 23-dichloro-quinoxaline with hot aqueous potassium permanganate gave 23-dicarboxy-5,6-dihydroxypyrazine (1051). 

The (—)-menthyl ester group has been employed as a chiral auxiliary in electrophilic glycine derivatives. Modified Swem oxidation of (—)-menthyl glycolate 1879 using phosphorus pentoxide for activation of DMSO instead of oxalyl chloride gave... 

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