Design and Synthesis of Phosphotyrosine Peptidomimetic Prodrugs

Abstract

A novel approach to the intracellular delivery of aryl phosphates has been developed that utilizes a phosphoramidate-based prodrug approach. The prodrugs contain an ester group that undergoes reductive activation intracellularly with concomitant expulsion of a phosphoramidate anion. This anion undergoes intramolecular cyclization and hydrolysis to generate aryl phosphate exclusively with a t1/2 = ∼ 20 min. Phosphoramidate prodrugs (8-10) of phosphate-containing peptidomimetics that target the SH2 domain were synthesized. Evaluation of these peptidomimetic prodrugs in a growth inhibition assay and, in a cell-based transcriptional assay, demonstrated that the prodrugs had IC 50 values in the low micromolar range. Synthesis of phosphorodiamidate analogs containing a P-NH-Ar linker (16 -18) was also carried out in the hope that the phosphoramidates released might be phosphatase-resistant. Comparable activation rates and cell-based activities were observed for these prodrugs, but the intermediate phosphoramidate dianion underwent spontaneous hydrolysis with a t 1/2 = ∼ 30 min.

Prodrugs of Phosphonates and Phosphates: Crossing the Membrane Barrier

“…A similar approach has been taken to prepare aryl phosphoramidates such as compound 99 [224], as prodrugs of SH2 domain analogs for Src/Lck inhibitors. The compounds exhibit low micromolar growth inhibition in Jurkat T cells, and undergo spontaneous hydrolysis with half-lives of approximately 30 minutes.…”

Intracellular targets for a phosphotyrosine peptidomimetic include the mitotic kinesin, MCAK

“…However, relatively little is known how small molecules directed against them affect cellular processes. In the current study, we utilized a prodrug delivery strategy to introduce a ligand into cells that was designed to target group I SH2 domains of Src-family kinases [24]. In fact, the drug is able to bind to the isolated SH2 domain of Lck and to interact with Lyn, which is the predominant Src-family kinase in B cells.…”

Synthesis and characterization of new 1H-pyrazolo[3,4-b]pyridine phosphoramidate derivatives

“…12 In this context, heterocyclic linked to other biologically active molecules, like, e.g., phosphoramidates, can give rise to new derivatives with potential biological applications. [13][14][15][16][17][18] Introduction of a phosphoramidate group essentially changes the physical and chemical properties of the parent molecule, resulting in the The aminoalkylphosphoramidates 7a-d were synthesized from diisopropylphosphonate 5 and aliphatic diamines 6a-d. 25,26 In order to guarantee monophosphorylation of the diamines, at least 2.5-fold excess of diamine in ethanol were used. Keeping alkaline pH and temperature below 55 °C is required to avoid bis-phosphorylation.…”