Synthetic Evidence of the Amadori-Type Alkylation of Biogenic Amines by the Neurotoxic Metabolite Dopegal.

The neurotransmitter metabolite 3,4-dihydroxy-phenylglycolaldehyde (dopegal) damages neurons and the myocardium by protein cross-linking, resulting in conglomerations and cell death. We investigated this process on a synthetic scale, leading to the discovery of an Amadori-type rearrangement of dopegal in the reaction with several amino acids and neuropeptides. This alkylation also occurs with neurotransmitters, suggesting an influence of dopegal on neurochemical processes.

Aqueous Phase Separation Behavior of Highly Syndiotactic, High Molecular Weight Polymers with Densely Packed Hydroxy-Containing Side Groups.

Herein we describe the Rh-catalyzed C1 polymerization of silyl-protected diazoacetates of the general formula HC(=N)C(=O)O(CH) OSiR, where = 2-5. After polymerization and subsequent desilylation, polymers bearing a hydroxy-containing side group on backbone carbon are obtained. The molecular weight of the desired polymers can be controlled via chain transfer with methanol during the polymerization.

Ligand effects on the hydrogenation of biomass-inspired substrates with bifunctional Ru, Ir, and Rh complexes.

We herein report on the application and structural investigation of a new set of complexes that contain bidentate N-heterocyclic carbenes (NHCs) and primary amine moieties of the type [M(arene)Cl(L)] [M=Ru, Ir, or Rh; arene=p-cymene or pentamethylcyclopentadienyl; L=1-(2-aminophenyl)-3-(n-alkyl)imidazol-2-ylidine]. These complexes were tested and compared in the hydrogenation of acetophenone with hydrogen. Structural variations in the chelate ring size of the heteroditopic ligand revealed that smaller chelate ring sizes in combination with ring conjugation in the ligand are beneficial for the activity of this type of catalyst, favoring an inner-sphere coordination pathway.

N-alkyl functionalised expanded ring N-heterocyclic carbene complexes of rhodium(I) and iridium(I): structural investigations and preliminary catalytic evaluation.

A series of new N-alkyl functionalised 6- and 7-membered expanded ring N-heterocyclic carbene (NHC) pro-ligands 3-6 and their corresponding complexes of rhodium(I) and iridium(I), [M(NHC)(COD)Cl] 7-14 and [M(NHC)(CO)2Cl] 15-22 are described. The complexes have been characterised by (1)H and (13)C{(1)H} NMR, mass spectrometry, IR and X-ray diffraction. It is noted from X-ray diffraction studies that the N-alkyl substituents are found to orientate themselves away from the metal centre due to unfavourable steric interactions resulting in low percent buried volume (%V(bur)) values in the solid state.