
News
Peptide synthesis using unprotected peptides through orthogonal coupling methods.
AddTime:2019-08-22
Abstract We describe an approach to the synthesis of custom peptide synthesis from segments bearing no protecting groups through an orthogonal coupling method to capture the acyl segment as a thioester that then undergoes an intramolecular acyl transfer to the amine component with formation of a peptide bond. Two orthogonal coupling methods to give the covalent ester intermediate were achieved by either a thiol-thioester exchange mediated by a trialkylphosphine and an alkylthiol or a thioesterification by C alpha-thiocarboxylic acid reacting with a beta-bromo amino acid. With this approach, unprotected segments ranging from 4 to 37 residues were coupled to aqueous solution to give free custom peptide synthesis up to 54 residues long with high efficiency.
Bullvalene is a ten-carbon molecule whose unique bonding pattern endows it with the intriguing ability to spontaneously alter its molecular arrangement through degenerate strain-assisted Cope rearrangements. Hypothesizing that this fluxional molecule could be elaborated to form an adaptive organic molecule capable of responding to external stimuli, an efficient ten-step synthetic route, featuring a key intramolecular cyclopropanation of a novel sulfur ylide, to yield a tetrasubstituted bullvalene has been developed. Elaborate functionality, such as porphyrins, was incorporated onto this shape shifting scaffold using cross metathesis. Cope rearrangements of the bullvalene core allow these molecules to exist in a dynamic equilibrium of more than 800 constitutional isomers. Explorations into the interaction of the shape shifting bisporphyrin bullvalene with Chave revealed an active network of interconverting species that appear to adapt to more tightly bind to the molecular guest.^ Part II. In order for the novel decarboxylative amide forming reaction between α-ketoacids and
Bullvalene is a ten-carbon molecule whose unique bonding pattern endows it with the intriguing ability to spontaneously alter its molecular arrangement through degenerate strain-assisted Cope rearrangements. Hypothesizing that this fluxional molecule could be elaborated to form an adaptive organic molecule capable of responding to external stimuli, an efficient ten-step synthetic route, featuring a key intramolecular cyclopropanation of a novel sulfur ylide, to yield a tetrasubstituted bullvalene has been developed. Elaborate functionality, such as porphyrins, was incorporated onto this shape shifting scaffold using cross metathesis. Cope rearrangements of the bullvalene core allow these molecules to exist in a dynamic equilibrium of more than 800 constitutional isomers. Explorations into the interaction of the shape shifting bisporphyrin bullvalene with Chave revealed an active network of interconverting species that appear to adapt to more tightly bind to the molecular guest.^ Part II. In order for the novel decarboxylative amide forming reaction between α-ketoacids and