Zur Kenntnis der Oxy‐proline und über die Synthese von Oxy‐hygrinsäuren

Leuchs, Hermann; Felser, Heinrich

doi:10.1002/cber.19080410233

Cited by 15 publications

(3 citation statements)

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“…Since the discovery of N -carboxyanhydrides (NCAs) by Hermann Leuchs in 1906, − NCAs have been used to synthesize a diverse set of materials from stepwise constructed peptides to drug-delivery devices , and polymeric brushes and as templates for inorganic oxides. − As polypeptides are responsive to external stimuli (pH, electrolytes, solvent, and temperature) and offer a wide range of side chain chemistries (thiols, amines, carboxylic acids, etc. ), they are very suitable organic components in hybrid materials for possible applications such as chiral separations, solid asymmetric catalysts, drug delivery, and sensing.…”

Section: Introductionmentioning

confidence: 99%

Peptide Brush—Ordered Mesoporous Silica Nanocomposite Materials

Lunn

Shantz

2009

Chem. Mater.

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Organic-inorganic nanocomposites are synthesized through the surface-initiated polymerization of N-carboxyanhydrides from amine-functionalized ordered mesoporous silica (OMS). Composites with high densities of grafted peptide were obtained which possess dramatically decreased porosity compared to the parent OMS material. The effect of the amine loading, pore size, pore topology, and monomer identity on the peptide brush layer obtained is investigated. Nitrogen porosimetry, thermal gravimetric analysis, elemental analysis, infrared and NMR spectroscopy, and mass spectrometry verify the formation of the peptide brushes and indicate much of the organic phase formed is in the silica mesopores. The L-Lys(Z) peptide brushes can be deprotected on the solid surface as evidenced by thermal gravimetric analysis, infrared spectroscopy, and NMR spectroscopy. L-Ala peptide brushes may also be synthesized, and polymer growth confinement is evidenced by mass spectrometry as the number of alanine units per brush appears dependent on the silica pore size/ topology.

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Section: Introductionmentioning

confidence: 99%

Peptide Brush—Ordered Mesoporous Silica Nanocomposite Materials

Lunn

Shantz

2009

Chem. Mater.

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“…(12), that is, kz[Base] >> k3, the initial rate of reaction is independent of the concentration of EtgN. On the other hand, for the case of Eq.…”

Section: Methodsmentioning

confidence: 98%

Enantiomer selection in the addition reaction of optically active 3‐methyl‐5‐substituted hydantoins to N‐[(S)‐α‐methylbenzyl]glycine N‐Carboxyanhydride: Model Reaction for the Stereoselective Polymerization of α‐amino acid N‐carboxyanhydride

Hashimoto

Imanishi

1981

Biopolymers

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SynopsisIn order to investigate the contribution from the chiral penultimate unit to the enantiomer selection in the activated N-carboxyanhydride (NCA) polymerizations, the addition reaction to N-[(S)-methylbenzyl]glycine NCA of various a-amino acid hydantoins activated by the tertiary amines was investigated in different solvents. The reactions of activated Ala, Val, and Phe hydantoins were stereoselective and suggested the participation of the penultimate unit in the enantiomer selection of the activated NCA type of polymerization. The degree of enantiomer selection was not well correlated with the structure of hydantoins. Taking into account the dipole repulsion and the orbital overlapping between the reaction species, the transition-state model was proposed, which gave a good explanation of the selectivity for (R)-hydantoin in PhN02 and CH&N and the selectivity for (Sbhydantoin in AcNMez and HCONMe2. In these two types of solvents the orientation of the methylbenzyl group with respect to the NCA ring is so different that the direction of the approach of the activated hydantoin to the NCA is different. This difference leads to the inversion of enantiomer selection in amide solvents and in others. Cationic species derived from tertiary amines and the chiral amide compound were found to affect the enantiomer selection in the model reaction. The implications of these findings with regard to enantiomer selection in the activated NCA type of polymerization are discussed.

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“…On treating with ammonia, r-oxyproline was formed; when treated with hydriodic acid, this was reduced to proline. Leuchs and Felser (322) and Leuchs and Bormann (321) have attempted to place the position of the hydroxy group in the pyrrole ring. On heating natural oxyproline with barium hydroxide at 200°, it was only partially racemized, indicating that in oxyproline there are two asymmetric carbon atoms present.…”

Section: Ch-nhx Ch-nhxmentioning

confidence: 99%