Synthesis and characterization of amino protected peptides derived from amino-α- hydroxyiminophosphonates

A multifaceted approach towards understanding the peculiar behavior of (α)-hydroxyiminophosphonates

“…In the 90's and early 00's, Eli Breuer and co-workers reported in a series of research papers, as well as in a review, on the preparation, characterization and study of (a)hydroxyiminophosphonate derivatives. [33][34][35][36][37][38][39][40] In their study, they showed that NMR was an invaluable tool for the assessment of the two isomers. In fact, in 31 P NMR, the E-isomer resonates at lower field than the Z-isomer, which is backed by the expected shielding effect of the phosphorus by the lone pairs of the oxime oxygen.…”

Fragmentations and Rearrangements of α-Hydroxyiminoalkylphosphonates

“…The reactions are generally carried out by reacting hydroxylamine hydrochloride with the dialkyl acylphosphonate in the presence of base (pyridine) in an alcohol as solvent. This synthetic method was applied successfully for the synthesis of a variety of -hydroxyiminoalkylphosphonates including those derived from amino acid derivatives [7], as well as peptides [8].…”

“…Similarly to the use of hydroxylamine, alkoxyamines react with acylphosphonates to yield the corresponding alkoxyiminophosphonates [6,10,11,12]. An alternative approach to alkoxyimino compounds is the treatment of diethyl -hydroxyiminoalkylphosphonates (8) with benzyl bromide in the presence of sodium ethoxide in boiling ethanol, which gave pure (E)-O-benzyloxyiminoalkylphosphonates (9) in good yield (scheme 4) [10].…”