1,4-Dihydroxy-2,5-dioxopiperazines from activated N-hydroxyamino acids

Abstract

m, 2), 2.50-2.30 (m, 2); 2H NMR (CHC1,) 6 2.33 (s, NC2H3); exact mass calcd for C11H31H17Nz (M') 267.1813, found 267.1806. Acknowledgment. We thank Dr. R. M. Koenig (Organon) for a generous gift of 5a. We gratefully acknowledge the technical assistance of L. Todisco (NEN) and R. Nugent (NEN) in the conversion of 5b to 5c and the help of Dr. P. Srinivasan (NEN) and L. Thomas (NEN) in obtaining the 3H NMR for 5c and the 2H NMR spectrum for 5d. We also thank Professor S. H. Snyder (Johns Hopkins) for performing receptor binding experiments on 5c and Professor H.-R. Schulten (University of Bonn) for obtaining the field-desorption mass spectrum of 5c. Finally we also gratefully acknowledge the technical assistance of M. Tutunjian (NEN) and R. Wellman (NEN) in performing the HPLC experiments on 5a, 5c, and 5d.

Peptide‐bond modification for metal coordination: Peptides containing two hydroxamate groups

“…Dihydroxamic acids, such as the siderophore rhodotorulic acid and its analogs have been reported to form 1:1 complexes with iron(III) at low pH. [45][46][47] While a cyclic N,NЈ-dihydroxy dipeptide has been reported, 48 to the best of our knowledge, metal-binding properties of N,NЈ-dihydroxypeptides have not been characterized. Compared to hexadentate N,NЈ,NЉ-trihydroxypeptides, tetradentate N,NЈ-dihydroxypeptides possess only two bidentate metal-binding motifs.…”

Synthesis-Guided Structure Revision of the Sarcodonin, Sarcoviolin, and Hydnellin Natural Product Family

“…To test whether 44X might match the spectral data for sarcodonin, 42 was converted to the oxime24 44 (Scheme 4) and its NMR spectra compared with those of sarcodonin α (Figure 7). The spectra of 44 bear surprising parallels with those of sarcodonin α, particularly in the 13 C NMR spectrum where the signals assigned to the two carbonyl carbons (3α, 3β), the oxime carbon (2α) and the aminal carbon (2β) of 44 bear a striking resemblance to the similarly assigned signals for sarcodonin α.…”

A Convenient Synthesis of Dithiolane and Benzyloximates Derivatives for Ligand Studies

“…Based on the success of these reactions, we then attempted a reaction between 1 and 1,2, 4,5-tetrabromo methylbenzene give tetra dithiolane moieties on the benzene ring, was obtained in 66% isolated yield. After getting encouraging results from this reaction, we attempted to synthesize the substituted oximate molecules by treating -Benzyloximino acid chloride 23 5 with commercially available, ortho-, meta-, and para-dihydroxybenzene (6o, 6m, 6p), and cis-2-butene-1.4-diol 9 and 1,3,5trihydroxybenzene 12. In case of meta and para dihydroxybenzene and cis-2-butene-1.4-diol 9, we obtained disubstituted (7m, 7p, 10) and mono substituted product (8m, 8p, 11) in good yields.…”