Reaction with asparagine

Dichloroacetamide has been prepared from ethyl dichloroace-tate with alcoholic ammonia1 or aqueous ammonium hydroxide,2 from ethyl dichloromalonate and alcoholic ammonia,3 by the action of ammonia on pentachloroacetone,4 chloral cyanohydrin,5 and hexachloro-i,3,5-cyclohexanetrione,6 from chloral ammonia and potassium cyanide,7 by the action of hydrogen chloride on dichloroacetonitrile,8 from the reaction of asparagine with the sodium salt of N-chloro- -toluenesulfonamide,9 and by the action of an alkali cyanide and ammonia on chloral hydrate.10... 

After reduction and reaction with 2,5-dimethoxytetrahydrofuran, l-Asparagine was converted into a pyrrole derivative which was cyclized with trifluorosulfonyl anhydride into 67 [90H(31)9],... 

Due to the incompatibility of asparagine and glutamine with acid hydrolysis these amino acids can be converted into the corresponding diaminopropanoic and y-diaminobu-tanoic acid by reaction with bis(l,l-trifluoroacetoxy)iodobenzene)25 However, this procedure is generally not applied. 

Since then, Kuhn et al. (99) have optimized the reaction with BTI and have successfully analyzed various pure proteins. They report average recoveries of glutamine (by direct detection of dansylated diaminobutanoic acid) at 93 4%. This study also concludes that analysis of asparagine by this method is inappropriate. 

Wilchek, M., Ariely, S., and Patchornik, A., The reaction of asparagine, glutamine, and derivatives with phosgene, J. Org. Chem. 33, 1258-1259, 1968 Hamilton, R.D. and Lyman, D.J., Preparation of A-carboxy-a-amino acid anhydrides by the reaction of copper(II)-amino acid complexes with phosgene, J. Org. Chem. 34, 243-244,1969 Pohl, L.R., Bhooshan, B.,... 

Figure 2 Snapshots of the overall structure and catalytic machinery of protein kinase A. (a) The overall fold of the catalytic domain is formed by two subdomains, a beta sheet N-terminus (gray) and a C-terminal helical domain (green). ATP binds a cleft between the two lobes, and the phosphoacceptor substrate binds the C-terminal lobe, (b) N-terminal residues Lys 72 and Glu 91 orient the phosphates toward the phosphoacceptor peptide (pink/yellow) in concert with one of two magnesium ions, (c) C-terminal residue Lys 168 acts as an electrostatic catalyst to stabilize the y-phosphate during the reaction while asparagine 171 and aspartate 184 position the phosphates within the active site.

Aspartic acid P-esters are incompatible with this group since cyclization to aspartimide occurs during the base-mediated deprotection. Even aspartic acid P-tert-butyl ester residues undergo this reaction with the related a P transpeptidation (see Section 2.2.2). Similarly, with C-terminal asparagine tert-butyl ester rapid succinimide formation was ob-... 

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