.alpha.-Halo [(phenylphosphinyl)methyl]phosphonates as specific inhibitors of Na+-gradient-dependent Na+-phosphate cotransport across renal brush border membrane

Abstract

Certain phosphonocarboxylate analogues of phosphate are known to inhibit Na(+)-phosphate (Pi) cotransport in renal brush border membrane (BBM), but previously tested potential inhibitors incorporating structurally versatile aryl functionality were inactive. In this work, a series of novel alpha-halogenated [(phenylphosphinyl)methyl]phosphonates [PhpXYMP: X, Y = H, F (2); F, F (3); H, Cl (6); Cl, Cl (4); H, Br (7); Br, Br (5); and Cl, Br (8)] were prepared via synthesis of the corresponding triethyl esters, acid hydrolysis, and isolation as pyridine salts. The compounds were evaluated as inhibitors of Na(+)-gradient-dependent 32Pi uptake by rat renal cortex BBM vesicles (BBMV) in vitro. The PhpFMP racemate 2 had higher activity (-49% delta inhibition) than other members of the series (-22 to -39% delta inhibition). pKa values of 1.5-2.0, 2.7, and 7.1 were estimated for 2 using a 31P delta vs pH plot, indicating that in the activity assays it exists as both dianion and trianion, with the latter form predominant. PhpFMP had no significant inhibitory effect on Na(+)-gradient-dependent uptake of D-glucose or L-proline in the same BBMV, and did not inhibit BBM alkaline phosphatase. Kinetic analysis showed that PhpFMP acts as a strictly competitive inhibitor of Na(+)-Pi cotransport with Ki = 0.358 +/- 0.021 mM (n = 3). The racemate 2 was resolved as its (-)-quinine salt into enantiopure (+)-2 [Na+ salt, [alpha]25D = +6 degrees (aqueous MeOH)] and a Na+ salt of 2 enriched in (-)-2. The two compounds did not differ significantly as inhibitors of Na(+)-gradient dependent 32Pi uptake by rat renal cortex BBM vesicles (BBMV) in vitro. The results are discussed in terms of structural requirements for inhibition.

Synthetic Route to Glycosyl β-1C-(phosphino)-phosphonates as Unprecedented Stable Glycosyl Diphosphate Analogs and Their Preliminary Biological Evaluation

“…Nevertheless, this phosphorus scaffold was synthesized according to ifferent pathways (Figure 4) by nucleophilic substitution of the chlorine atom of a arnesylchlorophosphinate by a lithio phosphonate [28] (Figure 4A) or by the Michaelis-Arbuzov eaction of a phenylphosphite on a (chloromethylene)phosphonate (Figure 4B). However, such a eaction involves rather drastic conditions [29] that might not be the most appropriate for sensitive In this context, our goal was to develop a straightforward access to original analogs of glycosyl diphosphate with an unprecedented β-1-C-(phosphino)-phosphonate structure. On the one hand, the replacement of an oxygen atom at the anomeric position of a saccharidic unit by a methylene group is a well-documented strategy [26,27] to prevent the cleavage of the aglycon part of the molecule during hydrolysis by glycosidases.…”

Design and Synthesis of anα,α-Difluorophosphinate Hapten for Antibody-Catalyzed Hydrolysis of Organophosphorus Nerve Agents

“…[35] * Electrophilic fluorination with perchloryl fluoride as ªF º transfer agent. [36] * [2,3]-Wittig rearrangement of highly electrophilic g,gdifluoroallylphosphinites. [37] None of these methods is of general use; yields are often quite low (except for the first one), and preparation of a completely and conveniently functionalized molecule thus appears tedious and time-consuming.…”

“…Although the hazardous and nonselective nature of the traditional ªF º-transfer reagents such as perchloryl fluoride (FClO 3 ) [36,59] has limited the use of this pathway to fluorinated products, there has been a surge over the last 15 years in the development of stable, mild, and highly selective electrophilic N-fluoro ªF º-transfer reagents. [60] Difluorination of active methylene compounds (such as benzylic phosphinates or phosphonates) still results in generally modest yields since reaction of the excess base with fluorinating agent becomes deleteriously competitive with the second deprotonation and fluorination.…”

Synthesis of Methano[60]fullerenephosphonic- and Methano[60]fullerenediphosphonic Acids

“…1 As a continuation of our interest in the preparation and biological evaluation of polar groups containing fullerene derivatives, 2 we have undertaken the synthesis of methano[60]fullerenephosphonic acid (5) and methano[60]fullerene diphosphonic acid (8). 1 As a continuation of our interest in the preparation and biological evaluation of polar groups containing fullerene derivatives, 2 we have undertaken the synthesis of methano[60]fullerenephosphonic acid (5) and methano[60]fullerene diphosphonic acid (8).…”

“…Thus, tetramethyl bromomethylenediphosphonate (6) 7,8 was submitted to a Bingel-type reaction 9 with 1 in toluene in the presence of DBU at room temperature for 18 h. After chromatographic separation (toluene containing 0-25% acetonitrile), the corresponding monobridged methanofullerene adduct 7 was obtained in 41% isolated yield. Finally, hydrolysis of the phosphonic ester moiety was achieved by reacting 7 with iodotrimethylsilane followed by treatment with water and evaporation of the solvent thus affording methano[60]fullerenediphosphonic acid (8) The structure of the [6,6]closed methanoadduct 7 was assigned on the basis of proton, carbon and phosphorus magnetic resonance as well as MALDI-MS.…”