0000000001302128
AUTHOR
István M. Mándity
VCD studies on cyclic peptides assembled from L-α-amino acids and a trans-2-aminocyclopentane- or trans-2-aminocyclohexane carboxylic acid.
The increasing interest in peptidomimetics of biological relevance prompted us to synthesize a series of cyclic peptides comprising trans-2-aminocyclohexane carboxylic acid (Achc) or trans-2-aminocyclopentane carboxylic acid (Acpc). NMR experiments in combination with MD calculations were performed to investigate the three-dimensional structure of the cyclic peptides. These data were compared to the conformational information obtained by electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) spectroscopy. Experimental VCD spectra were compared to theoretical VCD spectra computed quantum chemically at B3LYP/6-31G(d) density functional theory (DFT) level. The good agreem…
A Domino Ring‐Closure Followed by Retro‐Diels–Alder Reaction for the Preparation of Pyrimido[2,1‐ a ]isoindole Enantiomers
A simple method was developed to prepare pyrimido[2,1-a]isoindole derivatives by using di-endo- and di-exo-ethyl 3-aminobicyclo[2.2.1]hept-5-ene-2-carboxylate enantiomers as chiral sources. The method is based on a domino ring-closure reaction of norbornene 2-aminohydroxamic acid followed by microwave-induced retro-Diels–Alder reaction. In the case of enantiomeric starting substances, the chirality is transferred from norbornene derivatives to pyrimido[2,1-a]isoindoles. The configurations of the synthesized compounds were determined by 1D and 2D NMR spectroscopy [based on 2D NOE cross-peaks and 3JH,H coupling constants] and X-ray crystallography.
Stereocontrolled synthesis of five diastereomers of trimethyl 3-aminocyclopentane-1,2,4-tricarboxylates
Abstract The sterically controlled oxidative cleavage of N - protected di exo - and di endo -substituted norbornene β-amino acids/esters resulted in four trimethyl 3-aminocyclopentane-1,2,4-carboxylate diastereomers. The sodium methoxide mediated isomerization of the four diastereomers in all cases yielded the thermodynamically most stable all- trans stereoisomer as a single product.
CCDC 922681: Experimental Crystal Structure Determination
Related Article: Ferenc Miklós, István M. Mándity, Reijo Sillanpää, Ferenc Fülöp|2013|Tetrahedron Lett.|54|3769|doi:10.1016/j.tetlet.2013.05.009
CCDC 922680: Experimental Crystal Structure Determination
Related Article: Ferenc Miklós, István M. Mándity, Reijo Sillanpää, Ferenc Fülöp|2013|Tetrahedron Lett.|54|3769|doi:10.1016/j.tetlet.2013.05.009