Topic
Bicyclic molecule
About: Bicyclic molecule is a research topic. Over the lifetime, 29587 publications have been published within this topic receiving 451252 citations. The topic is also known as: bicyclic molecule.
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105 citations
TL;DR: Molecular dynamics fully support a two-point model involving only the guanidinium and crown ether moieties, which constitute the first examples of chiral selectors for underivatized amino acids acting as carriers under neutral conditions.
Abstract: A number of artificial carriers for the transport of zwitterionic aromatic amino acids across bulk model membranes (U-tube type) have been prepared and evaluated. 1,2-Dichloroethane and dichloromethane were employed in the organic phase. All compounds are based on a bicyclic chiral guanidinium scaffold that ideally complements the carboxylate function. The guanidinium central moiety was attached to crown ethers or lasalocid A as specific subunits for ammonium recognition as well as to aromatic or hydrophobic residues to evaluate their potential interaction with the side chains of the guest amino acids. The subunits were linked to the guanidinium through ester or amide connectors. Amides were found to be better carriers than esters, though less enantioselective. On the other hand, crown ethers were superior to lasalocid derivatives. As expected, transport rates were dependent on the carrier concentration in the liquid membrane. Reciprocally, enantioselectivities were much higher at lower carrier concentrations. The results show that our previously proposed three-point binding model (J. Am. Chem. Soc. 1992, 114, 1511-1512), involving the participation of the aromatic or hydrophobic residue to interact with the side chains of the amino acid guest, is unnecessary to explain the high enantioselectivities observed. Molecular dynamics fully support a two-point model involving only the guanidinium and crown ether moieties. These molecules constitute the first examples of chiral selectors for underivatized amino acids acting as carriers under neutral conditions.
105 citations
TL;DR: N-allylynamides with various functional groups and different substitution patterns can be converted into 3-aza-bicyclo[3.1.0]hexan-2-one derivatives in moderate to high yield using IMesAuCl/AgBF4 as the catalyst and pyridine N-oxide as the oxidant.
105 citations
105 citations
TL;DR: Self-complexing molecular systems are obtained when an arm component is covalently linked to a preformed macrocycle (a pi-acceptor) and have the potential to undergo reversible movements, i.e., the arm can be driven out of or into the cavity of the linked macrocycle in response to temperature or applied voltage.
Abstract: Self-complexing molecular systems are obtained when an arm component (a π-donor) is covalently linked to a preformed macrocycle (a π-acceptor). The resulting self-complexing compounds are not only ...
105 citations