A Constrained Diketopiperazine as a New Scaffold for the Synthesis of Peptidomimetics

Abstract

As a new scaffold for peptidomimetic synthesis, a highly constrained bifunctional diketopiperazine, 4, has been prepared by smooth N‐alkylation with tert‐butyl bromoacetate. As a first application, we describe herein the synthesis of new peptidomimetics of the Arg‐Gly‐Asp (RGD) sequence. The product 30, which shows a selective platelet‐aggregation inhibiting activity, can be used as a lead for the preparation of more potent products.

Characterization of specific noncovalent complexes between guanidinium derivatives and single-stranded DNA by MALDI

“…Guanidinium hydrochloride, agmatine sulfate, and arginine were obtained commercially (Aldrich). All other guanidinium derivatives shown in Table 1 were prepared by guanylation of the corresponding amines [28] and obtained as hydrochloride salts. Their structures were confirmed by 1 H and 13 C NMR and HRMS (high resolution mass spectrometry).…”

Self-Folding Molecules: A Well Defined, Stable Loop Formed by a Carboxylate−Guanidinium Zwitterion in DMSO

“…The C4-linked zwitterion 1a ( n = 4) along with the C2-linked control compound 1b ( n = 2) was synthesized according to Scheme . The acid 2 is reacted with the mono tBoc-protected diamines 3 in methylene chloride with DCC as the coupling reagent and catalytic amounts of DMAP. After deprotection with TFA, the amine 5 is reacted with the acyl chloride 6 , prepared from the corresponding acid by reaction with oxalyl chloride in the presence of catalytic amounts of DMF in methylene chloride.…”

The design, synthesis, and evaluation of molecules that enable or enhance cellular uptake: Peptoid molecular transporters

“…All solvents and other reagents were purchased from commercial sources and used without further purification. The mono-Boc amines were synthesized from the commercially available diamines by using a literature procedure (10 equiv of diamine and 1 equiv of Boc 2 O in chloroform followed by an aqueous work up to remove unreacted diamine) (35 [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58] (RQIKIWFQNRRMKWKK), and homopolymers of L-arginine (R5-R9) and D-arginine (r5-r9) were prepared with an automated peptide synthesizer (ABI433) by using standard solid-phase fluorenylmethoxycarbonyl (Fmoc) chemistry (36) with HATU as the peptide coupling reagent. The fluorescein moiety (Fl) was attached via an aminohexanoic acid spacer by treating a resin-bound peptide (1.0 mmol) with FITC (1.0 mmol) and diisopropyl ethyl amine (5 mmol) in dimethylformamide (DMF; 10 ml) for 12 h. Cleavage from the resin was achieved by using 95:5 trifluoroacetic acid (TFA)͞triisopropylsilane.…”