187977-10-2Relevant academic research and scientific papers
Synthesis of a Novel Esterase-Sensitive Cyclic Prodrug System for Peptides That Utilizes a "Trimethyl Lock"-Facilitated Lactonization Reaction
Wang, Binghe,Gangwar, Sanjeev,Pauletti, Giovanni M.,Siahaan, Teruna J.,Borchardt, Ronald T.
, p. 1363 - 1367 (1997)
This paper describes a unique strategy for preparing cyclic prodrugs of peptides that have increased metabolic stability and increased cell membrane permeability when compared to the linear peptides. By taking advantage of a unique "trimethyl lock"-facilitated lactonization system, an esterase-sensitive cyclic prodrug of a model hexapeptide H-Trp-Ala-Gly-Gly-Asp-Ala-OH was synthesized by linking the N-terminal amino group to the C-terminal carboxyl group. The key intermediate for both approaches was compound 9 with Boc-Ala attached to the phenol hydroxyl group of the "trimethyl lock" linker through an ester bond, which can then be incorporated into the peptide using a normal coupling reagent for peptide synthesis. The synthesis of the linear peptides was accomplished using both solution-phase and solid-phase approaches with the solution-phase approach having the advantage of using the key intermediate 9 most efficiently. Cyclization using standard high-dilution techniques provided cyclic prodrug 13. In 90% human plasma, prodrug 13 released the original peptide, as designed, through an apparent esterase-catalyzed hydrolysis of the phenol ester bond.
Synthesis of a novel esterase-sensitive cyclic prodrug of a hexapeptide using an (acyloxy)alkoxy promoiety
Gangwar, Sanjeev,Pauletti, Giovanni M.,Siahaan, Teruna J.,Stella, Valentino J.,Borchardt, Ronald T.
, p. 1356 - 1362 (2007/10/03)
Synthetic methodology for preparing novel esterase-sensitive cyclic prodrugs of peptides with increased protease stability and cell membrane permeability compared to linear peptides is described. Cyclic prodrug 1 of the hexapeptide H-Trp-Ala-Gly-Gly-Asp-Ala-OH linked by the N-terminal amino group to the C-terminal carboxyl group via an (acyloxy)alkoxy promoiety was synthesized. A convergent synthetic approach involving Boc[[(alaninyloxy)methyl]carbonyl]-N-tryptophan (2) and H-Ala-Gly-Gly-Asp(OBzl)-OTce (3) was used. The key fragment 2 has the promoiety inserted between the Ala and the Trp residues. Fragment 3 was synthesized by a solution-phase approach using standard Boc-amino acid chemistry. These fragments were coupled to produce the protected linear hexapeptide, which after deprotection was cyclized using standard high-dilution techniques to yield cyclic prodrug 1. In pH 7.4 buffer (HBSS) at 37°C, cyclic prodrug 1 was shown to degrade quantitatively to the hexapeptide (t( 1/4 ) = 206 ± 11 min). The rate of hydrolysis of cyclic prodrug 1 was significantly faster in human blood (t( 1/4 ) = 132 ± 4 min) than in HBSS. Paraoxon, a known inhibitor of esterases, slowed this hydrolysis of cyclic prodrug 1 to a value (t( 1/4 ) = 198 ± 9 min) comparable to the chemical stability. In human blood, cyclic prodrug 1 was shown to be 25-fold more stable than the linear hexapeptide.
