Amino group migration

Treatment of the cycloadduct 83a with sodium methoxide afforded a pyrrole derivative 86. It was proposed that the key step involved an amino group migration to the ylide carbon of amino sulfonium ylide intermediate 84 as depicted in Scheme 11 <1999TL95>. 

The stereochemistry of the reaction catalyzed by the lysine 2,3-aminomutase in C. subterminah SB4 was elucidated in detail by Aberhardt and Gould [32]. Incubation experiments with cell-free extracts of C. subterminah SB4 and (2RS)-[3-13C,2-lsN]lysine and NMR spectroscopy of the isolated /Mysine as the di-N-phthaloyl ethyl ester derivative revealed that the amino group migrates in an intramolecular reaction to position 3S in /Mysine 25. 

Bii Coenzyme-Dependent Amino Group Migrations Thressa C. Stadtman... 

Aminomutases. The enzymes L-p-lysine mutase (which is also D-a-lysine mutase) and D-omithine mutase catalyze the transfer of an co-amino group to an adjacent carbon atom (Table 16-1). Two proteins are needed for the reaction pyridoxal phosphate is required and is apparently directly involved in the amino group migration. In the P-lysine mutase the 6-amino group of L-P-lysine replaces the pro-S hydrogen at C-5 but with inversion at C-5 to yield (3S, 5S)-... 

Fincham, J.K., Shaws, R.A. Phosphrmis-nitrogen crunpounds. Part 62. The reactions of 2,2-diamino-4,4,6,6,8,8-hexachloro- and 2,6-diamino-2,4,4,6.8,8- hexachloro-cyclotetraphospha-zatetraene with sodium methoxide in methanoL The first example of amino group migration in the tetramer system. P, H, and C nuclearmagnetic resonance spectroscopic investigations of the products. Phosphorus, Sulfur and Silicon 47,109-117 (1990)... 

Two disadvantages are associated with the use of S-acetyl or 5-benzoyl derivatives in peptide syntheses (a) base-catalyzed hydrolysis of 5-acetyl- and 5-benzoylcys-teine occurs with /S-elimination to give olefinic side products, CH2=C-(NHPG)CO—(b) the yields of peptides formed by coupling an unprotected amino group in an 5-acylcysteine are low because of prior S-N acyl migration. ... 

The reaction of 3-amino-1,2,4-triazine 1-oxide 1 with methyl iodide in the presence of sodium bicarbonate leads to the methylation of the amino group to afford 3-methylamino-l,2,4-tiiazine 1-oxide 123. This iV-oxide 123, under neutral conditions in the presence of Mel, undergoes methyl group migration to the N(2) atom of the 1,2,4-triazine ring, yielding 3-imino-2-methyl-1,2,4-triazine 1-oxide 124. The same product 124 was obtained by direct methylation of compound 1 under neutral conditions (84TL1677). 

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