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Methylamino Acids (methylamino + acid)

Distribution by Scientific Domains
Chemistry50%

Selected Abstracts

Synthesis of Optically Active ,-Methylamino Acids and Amides Through Biocatalytic Kinetic Resolution of Amides.

CHEMINFORM, Issue 49 2005
Mei-Xiang Wang
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Solid-phase synthesis and characterization of N -methyl-rich peptides

CHEMICAL BIOLOGY & DRUG DESIGN, Issue 2 2005
M. Teixidó
Abstract:, A library of peptides required for a project investigating the factors relevant for blood,brain barrier transport was synthesized on solid phase. As a result of the high N -methylamino acid content in the peptides, their syntheses were challenging and form the basis of the work presented here. The coupling of protected N -methylamino acids with N -methylamino acids generally occurs in low yield. (7-azabenzotriazol-1-yloxy)-tris(pyrrolidino)phosphonium hexafluorophosphate (PyAOP) or PyBOP/1-hydroxy-7-azabenzotriazole (HOAt), are the most promising coupling reagents for these couplings. When a peptide contains an acetylated N -methylamino acid at the N-terminal position, loss of Ac- N -methylamino acid occurs during trifluoroacetic acid (TFA) cleavage of the peptide from the resin. Other side reactions resulting from acidic cleavage are described here, including fragmentation between consecutive N -methylamino acids and formation of diketopiperazines (DKPs). The time of cleavage is shown to greatly influence synthetic results. Finally, high-performance liquid chromatography (HPLC) profiles of N -methyl-rich peptides show multiple peaks because of slow conversion between conformers. [source]

Prolinoamino Acids as Tools to Build Bifunctionalized, Stable ,-Turns in Water

CHEMBIOCHEM, Issue 1 2010
Céline Mothes
,-Turn it on: Peptides incorporating cis -3-prolinoamino acids (prolinoleucine or prolinohomotryptophane) and N -methylamino acids (NMePhe/Arg/Lys) have been synthesized to mimic stable ,-turns in water (see figure). These 3-substituted prolines are valuable peptidomimetic tools for synthesizing ,-turns while keeping the side chain of proteinogenic amino acids. [source]

Solid-phase synthesis and characterization of N -methyl-rich peptides

CHEMICAL BIOLOGY & DRUG DESIGN, Issue 2 2005
M. Teixidó
Abstract:, A library of peptides required for a project investigating the factors relevant for blood,brain barrier transport was synthesized on solid phase. As a result of the high N -methylamino acid content in the peptides, their syntheses were challenging and form the basis of the work presented here. The coupling of protected N -methylamino acids with N -methylamino acids generally occurs in low yield. (7-azabenzotriazol-1-yloxy)-tris(pyrrolidino)phosphonium hexafluorophosphate (PyAOP) or PyBOP/1-hydroxy-7-azabenzotriazole (HOAt), are the most promising coupling reagents for these couplings. When a peptide contains an acetylated N -methylamino acid at the N-terminal position, loss of Ac- N -methylamino acid occurs during trifluoroacetic acid (TFA) cleavage of the peptide from the resin. Other side reactions resulting from acidic cleavage are described here, including fragmentation between consecutive N -methylamino acids and formation of diketopiperazines (DKPs). The time of cleavage is shown to greatly influence synthetic results. Finally, high-performance liquid chromatography (HPLC) profiles of N -methyl-rich peptides show multiple peaks because of slow conversion between conformers. [source]