RESUMO
Unprotected S-acylated cysteine isopeptides containing α-, ß- or γ-amino acid units have been synthesized, and their conversion to native hexapeptides by S- to the N-terminus ligations involving 17-, 18- and 19-membered cyclic transition states have been demonstrated both experimentally and computationally to be more favorable than intermolecular cross-ligations.
Assuntos
Cisteína/química , Peptídeos/química , Enxofre/química , Conformação Molecular , Nitrogênio/química , Peptídeos/síntese químicaRESUMO
Cbz-(protected)-tri- and tetrapeptide conjugates with steroids, sugars, terpenes, and heterocycles were prepared using Cbz-(protected)-tri- and tetrapeptidoylbenzotriazoles as active intermediates.
Assuntos
Peptídeos/síntese química , Sequência de Aminoácidos , Compostos Heterocíclicos/química , Peptídeos/química , Polissacarídeos/química , Estereoisomerismo , Esteroides/química , Terpenos/químicaRESUMO
Novel N-(Cbz-aminoacyl)thiosemicarbazides 3a-c were cyclized by treatment with sulfuric acid to give 1,3,4-thiadiazoles 4a-c. Compounds 4a-c reacted with N-(Cbz-aminoacyl)- and -dipeptidoylbenzotriazoles to afford chirally pure 1,3,4-thiadiazol-2-yl-substituted amino acids 6a-c and dipeptides 7a-c.
