Amino acids tetrazole analogues

Demko, Z.P. and Sharpless, K.B., An expedient route to the tetrazole analogues of a-amino acids, Org. Lett.,... 

Tetrazole analogues of amino acids have been prepared from Z-protected amino acids, and Z-protected amino nitriles." More recently, the group of Sureshbabu et al. extended this formal [3 -r 2] cycloaddition between a nitrile-containing protected -amino acid 11 and azide to also include Fmoc-amino acids and prepared and y-tetrazolyl -amino acids 12 for incorporation into peptides (see Scheme 10.2). ° The carboxamide side-chains of asparagine and glutamine were dehydrated and converted to the tetrazole by treatment with sodium azide and zinc bromide to afford tetrazole-isosteres of aspartic acid and... 

Scheme 10.2 Tetrazole-analogues of aspartic acid and glutamic acid were prepared from nitrile containing Fmoc-amino acids...

Cefazaflur (58) stands out among this group of analogues because it lacks an arylamide C-7 side chain (see cephacetri 1 e for another example).Cefazaflur (58) is synthesized by reaction of 3-(1-methyl-lB[-tetrazol-5-ylthiomethylene)-7-amino-cephem-4-carboxylic acid (56) with trifluoromethylthioacetyl chloride (57). ... 

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