104090-92-8

Nosiheptide is a ribosomally synthesized and post-translationally modified thiopeptide natural product that possesses antibacterial, anticancer, and immunosuppressive properties. It contains a bicyclic structure composed of a large macrocycle and a unique

Nosiheptide is a ribosomally synthesized and post-translationally modified thiopeptide natural product that possesses antibacterial, anticancer, and immunosuppressive properties. It contains a bicyclic structure composed of a large macrocycle and a unique

Specific interactions between Src homology 2 (SH2) domain-containing proteins and the phosphotyrosine-containing counterparts play significant role in cellular protein tyrosine kinase (PTK) signaling pathways. The SH2 domain inhibitors could potentially serve as drug candidates in treating human diseases. Here we have incorporated a novel phosphotyrosine mimetic, which is an unusual amino acid carrying a cyclosaligenyl (cycloSal) phosphodiester moiety, into dipeptides to investigate the inhibitory effect on SH2 domain-containing proteins. A plate-based assay was also established to screen for inhibitors that disrupt the interaction between a phosphopeptide of SLAM (signaling lymphocytic activation molecule) and its interacting protein SAP (SLAM-associated protein). We identified a number of inhibitors with IC50 values in the range of 17-35 μM, implying that the cycloSal phosphodiester-carrying amino acid could mimic the phosphotyrosyl residue. Our results also raise the possibility of integrating the newly developed phosphotyrosine mimetic moiety into inhibitors designed for other SH2 domain-containing proteins.

(matrix presented) The regioselective syntheses and structures are reported for two tris-macrocylic compounds, each possessing two antiparallel loops on a macrocyclic scaffold constrained by two oxazoles and two thiazoles. NMR solution structures show the

A new method for the synthesis of primary amides was developed in which carboxylic acids were treated with ammonium chloride in the presence of peptide synthesis coupling agents and base at room temperature. These mild conditions allow the conversion of carboxyl groups to primary amides on substrates possessing sensitive functional groups such as esters and the base-labile Fmoc protecting group.

Dolastatin 3 (1) has been reported to be a cyclic pentapeptide containing two thiazole amino acids, (gly)Thz (2) and (gln)Thz (3).The syntheses of (R)- and (S)-(glu)Thz (8a,b) and (glu)Thz-(gly)Thz (11a,b) derivatives suitable for elaboration to dolastatin 3 are described.A key feature of the (glu)Thz syntheses is the selective thiation of a primary amide with Lawesson's reagent in the presence of ester and urethane functionalities.