Organophosphonic acids as drug candidates

Kinetically Controlled Stereoselective Synthesis of 2-Oxo-2-aryl-1,3,2-dioxaphosphorinane Derivatives via a Palladium-Catalyzed Reaction

Chiral phosphonate esters have been widely applied in the fields of organic chemistry, medicine, and photoelectric materials. However, it requires the challenging enantioselective synthesis of cyclic phosphonate esters with the desired chiral configuration. The two epimers of 2-oxo-2H-1,3,2-dioxaphosphorinane derivatives should have different reactivities in Pd-catalyzed coupling reactions, which could lead to an effective methodology for the asymmetric synthesis of 2-oxo-2-aryl-1,3,2-dioxaphosphorinane derivatives. A thorough investigation of the coupling reactions both computationally and experimentally led to the stereoselective synthesis of chiral cyclic phosphonate esters. The axial isomer of products can be obtained with both high diastereoselectivity and good chemical yields from the mixture of 2-oxo-2H-1,3,2-dioxaphosphorinane derivatives under kinetically controlled conditions.

Constructive On-DNA Abramov Reaction and Pudovik Reaction for DEL Synthesis

Organophosphonic compounds are distinctive among natural products in terms of stability and mimicry. Numerous synthetic organophosphonic compounds, including pamidronic acid, fosmidromycin, and zoledronic acid, are approved drugs. DNA encoded library technology (DELT) is a well-established platform for identifying small molecule recognition to target protein of interest (POI). Therefore, it is imperative to create an efficient procedure for the on-DNA synthesis of α-hydroxy phosphonates for DEL builds.

Rational design, synthesis and evaluation of first generation inhibitors of the Giardia lamblia fructose-1,6-biphosphate aldolase

Inhibitors of the Giardia lamblia fructose 1,6-bisphosphate aldolase (GlFBPA), which transforms fructose 1,6-bisphosphate (FBP) to dihydroxyacetone phosphate and glyceraldehyde 3-phosphate, were designed based on 3-hydroxy-2-pyridone and 1,2-dihydroxypyridine scaffolds that position two negatively charged tetrahedral groups for interaction with substrate phosphate binding residues, a hydrogen bond donor to the catalytic Asp83, and a Zn(2+) binding group. The inhibition activities for the GlFBPA catalyzed reaction of FBP of the prepared alkyl phosphonate/phosphate substituted 3-hydroxy-2-pyridinones and a dihydroxypyridine were determined. The 3-hydroxy-2-pyridone inhibitor 8 was found to bind to GlFBPA with an affinity (K(i)=14μM) that is comparable to that of FBP (K(m)=2μM) or its inert analog TBP (K(i)=1μM). The X-ray structure of the GlFBPA-inhibitor 8 complex (2.3Å) shows that 8 binds to the active site in the manner predicted by in silico docking with the exception of coordination with Zn(2+). The observed distances and orientation of the pyridone ring O=C-C-OH relative to Zn(2+) are not consistent with a strong interaction. To determine if Zn(2+)coordination occurs in the GlFBPA-inhibitor 8 complex in solution, EXAFS spectra were measured. A four coordinate geometry comprised of the three enzyme histidine ligands and an oxygen atom from the pyridone ring O=C-C-OH was indicated. Analysis of the Zn(2+) coordination geometries in recently reported structures of class II FBPAs suggests that strong Zn(2+) coordination is reserved for the enediolate-like transition state, accounting for minimal contribution of Zn(2+) coordination to binding of 8 to GlFBPA.

Fructose-1,6-bisphosphatase inhibitors. 1. Purine phosphonic acids as novel AMP mimics

Inhibition of FBPase is considered a promising way to reduce hepatic gluconeogenesis and therefore could be a potential approach to treat type 2 diabetes. Herein we report the discovery of a series of purine phosphonic acids as AMP mimics targeting the AMP site of FBPase, which was achieved using a structure-guided drug design approach. These non-nucleotide purine analogues inhibit FBPase in a similar manner and with similar potency as AMP. More importantly, several purine analogues exhibited potent cellular and in vivo glucose-lowering activities, thus achieving proof-of-concept for inhibiting FBPase as a drug discovery target. For example, compounds 4.11 and 4.13 are as equipotent as AMP with regard to FBPase inhibition. Furthermore, compound 4.11 inhibited glucose production in primary rat hepatocytes and significantly lowered blood glucose levels in fasted rats.

Bis[(para-methoxy)benzyl] phosphonate prodrugs with improved stability and enhanced cell penetration

A series of substituted bis[(para-methoxy)benzyl] (bisPMB) esters of 1-naphthalenemethylphosphonate (NMPA) were synthesized and evaluated as phosphonate prodrugs. BisPMB NMPA esters (4b and 4c) with significantly improved aqueous stability were identified that also resulted in increased intracellular levels of NMPA following prodrug incubation with primary rat hepatocytes.

Synthesis and cell-based activity of a potent and selective protein tyrosine phosphatase 1B inhibitor prodrug

Our laboratory recently reported the development of novel prodrug chemistry for the intracellular delivery of phosphotyrosine mimetics. This chemistry has now been adapted for the synthesis of a prodrug that delivers the nonhydrolyzable difluoromethylphosphonate moiety intracellularly. Activation of the prodrug generates a difluoromethylphosphonamidate anion that undergoes subsequent cyclization and hydrolysis with a t1/2 = 44 min. A highly potent and selective inhibitor of protein tyrosine phosphatase 1B (PTP1B) with a nanomolar Ki has been reported, but this bis(difluoromethylphosphonate) lacks potential utility due to its exceedingly low membrane permeability at physiological pH. A prodrug of this inhibitor has been synthesized and evaluated in a cell-based assay. The prodrug exhibits nanomolar PTP1B inhibitory activity in this assay, confirming the efficacy of intracellular phosphonate delivery using this prodrug approach.