Glycine anhydride

By and large, we have a strong delocalization of the radical nonsatnration within a molecular carcass. This facilitates deprotonation of the initial cation-radicals. The same phenomenon was observed in the anion-radicals of cyclic depnties—glycine anhydride, alanine anhydride, and sar-cosine anhydride (Tarabek et al. 2007). 

Diketopiperazine 3,5-Dioxopiperazine Glycine Anhydride Cycloglycylglycin or Lactam of Glycylglycin... 

Preparation 489.—Glycocoll Ester and Glycine Anhydride [Ethyl ester of amino-ethan add and (2 5-dihetopiperazine). 

For the direct preparation of glycine-anhydride from glycocoll ester hydrochloride, see B., 39, 2930. 

Dihydrouracil, an isomer of glycine anhydride, has two kinds of carbon-bound hydrogen atoms. Those activated by the neighboring NH-group react much more readily (90%) than those next to the carbonyl function (ca. 5% Schuch-mann et al. 1984 for details, see Chap. 10). Thus, a high regioselectivity is again observed. 

Mieden OJ, von Sonntag C (1989) Peptide free-radicals the reactions of OH radicals with glycine anhydride and its methyl derivatives sarcosine and alanine anhydride. A pulse radiolysis and product study. Z Naturforsch 44b 959-974... 

Electrophilic substitutions. The key step in a synthesis of the ring system (6) of the antibiotic bicyclomycin (7) is the reaction of the silver trillatc complex of the glycine anhydride derivative 1 with 2 to give the. vwi-lactonc 3 as the major product, with retention... 

Table 3.1. Rate constants for the reaction of cysteamine thiyi radicals with model peptides in D2O, pD 3.0-3.4 at 37 °C (adapted from Ref [84] abbreviations for the diketopiperazines SarcA = sarcosine anhydride, Gly = glycine anhydride).

Details of this kind of superoxide elimination, including die determination of the p Ta value of the peroxyl radical, have been elucidated in a very similar system, glycine anhydride [43]. An isopyrimidine (see below) is formed in reaction (27). 

Fischer and Fourneau, in 1901, found that 2, 5-diketopiperazine, or glycine anhydride, as it is now best termed, was converted by boiling with concentrated hydrochloric acid into the hydrochloride of an amino acid of the formula C HgNjOs, from which they obtained the free acid by treatment with the calculated quantity of caustic soda, or by means of silver oxide. Its formation is represented by the equation... 

By treating glycine anhydride with alcoholic hydrochloric acid, glycyl-glycine ester resulted —... 

Both the free acid and its ester have a great tendency to become reconverted into glycine anhydride, and both compounds are characterised by... 

Phenylalanyl-glycine anhydride. Valyl-glycine anhydride. Valyl-alanine anhydride. 

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