Alanine 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). 

Kurzlich teilten Matsuura et al. (232) die Bildung von optisch aktivem Poly-a-alanin durch stereospezifische Polymerisation von N-Carboxy-DL-alanin-anhydrid mit. 

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... 

The C-H BDE in peptides is even lower than that of the S-H BDE in thiols as a consequence of the exceptional stability of the radical products due to captoda-tive stabilization (Viehe et al. 1985 Armstrong et al. 1996). Yet, the observed rate constants for the reaction of CH3 and CH2OH with, e.g., alanine anhydride are markedly slower than with a thiol. This behavior has been discussed in terms of the charge and spin polarization in the transition state, as determined by AIM analysis, and in terms of orbital interaction theory (Reid et al. 2003). With respect to the repair of DNA radicals by neighboring proteins, it follows that the reaction must be slow although thermodynamically favorable. 

Table 8.1. pJCa values of radical derived from glycine and alanine anhydrides. Rates of CV -elimination of their peroxyl radical anions. (Mieden and von Sonntag 1989 Mieden et al. ... 

A number of piperazine-2,5-diones (a-amino acid anhydrides ) has been converted to pyrazines by the action of phosphorus halides. Baxter and Spring (312) first described the conversion of isoleucine anhydride (45) with phosphoryl chloride to 2,5-di-s-butyl-3,6-dichloropyrazine (46, X = Cl) and 2,5-di-s-butyl-3-chloropyrazine (46, X = H), and of DL-alanine anhydride (47) similary to 2,5-dichloro-3,6-dimethylpyrazine (48, X = Q) and 3from alanine anhydride does not involve an oxidation step, whereas the formation of 2,5-dichloro-3,6-dimethylpyrazine involves the oxidation of an intermediate dihydropyrazine derivative. Treatment of DL-alanine anhydride with phosphoryl chloride in the presence of a tertiary base (dimethylaniline) gave only the monochloro derivative the intermediate dichlorodihydropyrazine presumably loses hydrogen chloride and gives the stable aromatic 3-chloro-2,5-dimethylpyrazine. 

Chloro-2,S-dimethylpyrazine was not isolated from the reaction of DL-alanine anhydride with a mixture of phosphoryl chloride and phosphorus pentachloride, but the reaction gives a poor yield of (48, X = Q) and a small quantity of (48, X = OH). Gallagher et al. (282) found that DL-phenylglycine with phosphoryl chloride gave 2,5-dichloro-3,6-diphenylpyrazine and 3-hydroxy-2,5-diphenyl-pyrazine (presumably formed by loss of the elements of hydrogen chloride from an intermediate 2-chloro-5-hydroxy-3,6-diphenyldihydropyrazine) and Dunn et al. (95) from DL-leucine anhydride and phosphoryl chloride prepared flavacol, 3-hydroxy-2,5-diisobutylpyrazine, and a mature of chloropyrazines, whereas Ohta (101) used phosphoryl chloride and phosphorus pentachloride and obtained flavacol and a little 2[Pg.26]

Catalyst (1). 4 To a solution of N-carboxy-L-alanine anhydride (2.5 g, 21.7 mmol) in MeCN anh. (50 mL) was added MeCN (20 mL with 0.43 mmol H20). After 4 days stirring at 20 °C the solvent was removed in vacuum and the residue stirred 24 h in Et20, filtered and dried. 

In the same way alanyl-alanine and alanyl-alanine ester, which yielded caibethoxyl-alanyl-alanine ester when treated with ethylchloro-carbonate, can be obtained from alanine anhydride, and leucyl-leucine from leucine anhydride or leucinimide, which was first obtained in 1849 regarded as occurring in the protein molecule, by... 

Mixed Polypeptides. Glycyl-alanine anhydride glycyl-l-tyrosine anhydride glycyl-I-phenylalanine anhydride... 

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

The existence of the -enol form was emphasised by the fact that in the hydrolysis of alanine anhydride by alkali, a transient formation of an alkali compound was observed. 

The proof of the existence of these various forms was commenced in 1906 by Fischer and Raske in the case of the alanine anhydrides. They prepared the inactive trans-anhydride... 

The active d-alanine anhydride had been prepously synthesised in a similar way from d-alanyl-d-alanine ester, and an inactive anhydride... 

From the remainder of the filtrate, glycyl-d-alanine anhydride and a small quantity of glycyl-l-tyrosine anhydride were obtained by the action of ammonia upon the esters, as well as another product which was most probably d-alanyl-l-serine anhydride. 

From gliadin Fischer and Abderhalden have also isolated a dlpep-tide by these methods, namely, 1-leucyl-d-glutamic acid, which they identified with the synthetical substance Abderhalden and Funk have isolated leucinimide, 1-phenylalanyl-d-alanine anhydride by acid hydrolysis from casein, and probably also leucyl-valine anhydride. 

Glycyl-d-alanine anhydride in silk-fibroin. Glycyl-d-alanine in silk-fibroin. Glycyl-l-tyrosine anhydride in silk-fibroin. 

Matsuura, K. Inoue, S. Tsuruta, T. Asymmetric-selective polymerization of DL-propylene oxide with triethylaluminum-V-carboxy-L(-E)-alanine anhydride system. Makmmol. Chem. 1965, 86, 316-319. 

Oxazolinone 6.226, which is also a chiral auxiliary for the propanoic acid moiety, was converted to its enolate anion and condensed with N-Boc alanine anhydride, to give 6,227.133 Reduction of the ketone moiety and acid hydrolysis led to 2S,3S,4R-4-amino-3-hydroxy-2-methylpentanoic acid (6.226).133 This amino acid is an acid hydrolysis product of bleomycin A2.134.135 Although bleomycin can be categorized as an antibiotic, it is best known for its anti-cancer activity.134,135... 

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