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PubMed2001

Design and pharmacological activity of phosphinic acid based NAALADase inhibitors.

A novel series of phosphinic acid based inhibitors of the neuropeptidase NAALADase are described in this work. This series of compounds is the most potent series of inhibitors of the enzyme described to date. In addition, we have shown that these compounds are protective in animal models of neurodegeneration. Compound 34 significantly prevented neurodegeneration in a middle cerebral artery occlusion model of cerebral ischemia. In addition, in the chronic constrictive model of neuropathic pain, compound 34 significantly attenuated the hypersensitivity observed with saline-treated animals. These data suggest that NAALADase inhibition may provide a new approach for the treatment of both neurodegenerative disorders and peripheral neuropathies.

Animals↗
PubMed1991

Phosphinic acid analogues of GABA are antagonists at the GABAB receptor in the rat anococcygeus.

CGP 35348 (3-aminopropyl(diethoxymethyl)phosphinic acid) and 3-aminopropyl(n-hexyl)phosphinic acid (3-APHPA) were tested in the rat anococcygeus muscle against CGP 27492 (3-aminopropylphosphinic acid), a selective GABAB agonist, for their antagonist activity. Their antagonist potency was compared with that of 2-hydroxysaclofen. The pA2 values for CGP 35348, 3-APHPA and 2-hydroxysaclofen were 5.38, 4.86, 4.45 respectively in the rat anococcygeus muscle. These results confirm the previous reports of GABAB antagonist activity for these compounds and show a marginal improvement in potency over 2-hydroxysaclofen.

Animals↗
PubMed1994

Phosphinic acid derivatives as baclofen agonists and antagonists in the mammalian spinal cord: an in vivo study.

The actions of a series of derivatives of 3-aminopropyl-phosphinic acid as baclofen agonists and antagonists have been examined on the synaptic excitation of neurones by impulses in primary afferent fibres in the lumbar spinal cords of pentobarbitone-anaesthetised cats and rats. Both the pre- and postsynaptic inhibitory actions of microelectrophoretic (-)-baclofen were reduced by similarly administered CGP 35,348, 36,742, 46,381, 52,432, 54,626 and 55,845, the latter being the most potent antagonist. None of these antagonists either decreased or increased the excitability of spinal neurones, and the inhibitory action of GABA was reduced only by local concentrations of antagonists which also reduced the action of piperidine-4-sulphonic acid, a GABAA agonist. Although the weak inhibitory effect of 3-aminopropylphosphinic acid in both the rat and the cat was not reduced by these baclofen antagonists, the pre- and postsynaptic inhibitory effects of 3-aminopropyl-methyl-phosphinic acid (CGP 35,024), which was more potent than (-)-baclofen, were reduced by the antagonists. Like (-)-baclofen, CGP 35,024 was relatively ineffective in reducing transmitter release in the cord from the terminals of excitatory spinal interneurones, the terminals of excitatory tracts in the dorsolateral funiculus and the cholinergic terminals of motor axon collaterals. In both rat and cat cords, receptors for (-)-baclofen could not be demonstrated to be activated by microelectrophoretic GABA, possibly because of the predominantly dendritic location of GABAB receptors. Spinal pre- and postsynaptic baclofen receptors appeared to be pharmacologically similar but differed from those in the higher central nervous system of the rat, where 3-aminopropylphosphinic acid has been reported to be an effective baclofen agonist. The compounds tested, particularly CGP 55,845 and 46,381, will be of use in further investigations of the physiological relevance of baclofen receptors at central synapses where GABA may be the transmitter.

Action Potentials↗
PubMed1996

Determination of rat brain and plasma levels of the orally active GABAB antagonist 3-amino-propyl-n-butyl-phosphinic acid (CGP 36742) by a new GC/MS method.

An involvement of GABAergic neurons has been suggested in the process of memory consolidation based on anatomical evidence and increasing physiological and biochemical data. With the advent of orally active GABAB antagonists, such as CGP 36742, the question of their therapeutic value, for example in Alzheimer's disease, becomes relevant. Therefore, a new GC/MS method was developed to determine the concentration of CGP 36742 (3-amino-propyl-n-butyl phosphinic acid) in various intra- and extracerebral tissues after different routes of application. The compound was chemically derivatised in a two-step process (acylation of the amino group and esterification of the phosphinic acid). The limit of detection of the method was 0.01 microgram/g tissue and 0.0005 microgram/mL plasma. The time-course after i.p. treatment showed peak levels of CGP 36742 between 30 min and 1 hr after injection. After a dose of 100 mg/kg, the concentration in the brain ranged from 1 to 1.4 microgram/g or 6 to 8 microM, assuming that 1 mg tissue equals 1 microL (i.e., below the IC50 of the interaction with GABAB receptors as measured by [3-3H]-aminopropyl-phosphinic acid binding [35 microM]). These results are discussed in light of the psychopharmacological effects (improvement of cognitive performance of rats) of CGP 36742 observed at very low oral doses.

Administration, Oral↗
PubMed2001

Phosphinic acid pseudopeptides analogous to glutamyl-gamma-glutamate: synthesis and coupling to pteroyl azides leads to potent inhibitors of folylpoly-gamma-glutamate synthetase.

Several routes to a complex phosphinate phosphapeptide analogous to the gamma-glutamyl peptide Glu-gamma-Glu have been investigated. Formation of gamma-phosphono glutamate derivatives via addition of a phosphorus-based radical to protected vinylglycine was found to be of limited value because of the elevated temperatures required. Alkylation and conjugate addition reactions of trivalent phosphorus (P(III)) species were investigated. In situ generation of bis-trimethylsilyl esters of phosphinous acids proved to be an effective route to phosphinates of modest structural complexity. However, this chemistry could not be extended to the incorporation of an amino acid moiety at the N-terminal side of the desired phosphinate. A successful synthesis of the target phosphinate phosphapeptide was effected using P(III) chemistry and dehydrohalogenation to yield an alpha,beta-unsaturated phosphinic acid ester, following which conjugate addition of diethylacetamido malonate and acid-mediated hydrolysis afforded the desired phosphinate phosphapeptide. Coupling of the unprotected phosphinate phosphapeptide with two acyl azides derived from folic acid and methotrexate led to the corresponding pteroylphosphapeptides of interest as possible mimics of tetrahedral intermediates in the reaction catalyzed by folylpolyglutamate synthetase.

Azides↗
PubMed2004

Analogues of acyclic nucleosides derived from tris-(hydroxymethyl)phosphine oxide or bis-(hydroxymethyl)phosphinic acid coupled to DNA nucleobases.

A series of novel acyclic nucleoside analogues containing bis-(hydroxymethyl)phosphinic acid (BHPA) or tris(hydroxymethyl)phosphine oxide (THPO) coupled with DNA nucleobases or with 5-fluorouracil were prepared and their antiviral activity was studied against cytomegalovirus (CMV), varicella-zoster virus (VZV), parainfluenza-virus type 3, reovirus-type 1, sindbis, coxsackie B4, punta toro, vesicular stomatitis and respiratory syncytial virus, herpes simplex virus-type 1 (KOS) and type 2 (G), vaccinia virus and herpes simplex virus-1 (TK- KOS ACVr). No specific antiviral effects were noted for any of test compounds against viruses evaluated, except thymine, cytosine and adenine derivatives of BHPA exerting borderline activity against respiratory syncytial virus at the 80 mg/ml concentration.

Antiviral Agents↗
PubMed2005

Method for the synthesis of phosphinic acids from hypophosphites. V. The synthesis of pseudo-alpha,alpha-dipeptides.

The method for the synthesis of 2-substituted 2-hydroxycarbonylethyl-1-aminoalkylphosphinic acids (I) (pseudo-alpha,alpha-dipeptides) from ammonium and potassium hypophosphites (II) is described. The proposed route to the synthesis of pseudo-alpha,alpha-dipeptides consists in addition hypophosphite to acrylic compounds and formation of the first phosphorus-carbon bond with following addition of aminoacid fragment and formation of the second phosphorus-carbon bond. The key intermediates of the synthesis - phosphonous acids (III) and their silylic esters (IV) were obtained at the first stage of the process as the result of the addition of the bis(trimethylsilyl)hypophosphite in situ to suitably substituted acrylates. The modificated procedure for the Kabachnik-Fields reaction of 2-substituted 2-alkoxycarbonylethyl phosphonous acids (III), acetamide, benzaldehyde in acetic anhydride with following hydrolysis results in 2-substituted 2-hydroxycarbonylethyl-alpha-aminobenzyl phosphinic acids (Ia-c) (pseudo-phenylglycylpeptides). Bis(trimethylsilyl) 2-substituted 2-alkoxycarbonylethylphosphonites (IV) in situ were added to N-tritylmethanimine and following alcoholysis and acid hydrolysis of addition products gave 2-substituted 2-hydroxycarbonylethyl-aminomethylphosphinic acids (Id-f) (pseudo-glycylpeptides).

Dipeptides↗
PubMed1997

Bis[2-(4-carboxyphenoxy)carbonylethyl]phosphinic acid (BCCEP): a new reagent for hemoglobin modification.

The synthesis and hemoglobin cross-linking studies of a novel organic reagent, bis[2-(4-carboxyphenoxy)carbonylethyl]phosphinic acid (BCCEP; 2) has been reported. The reagent was synthesized in four steps from hydroxybenzoic acid. The tri-sodium salt of BCCEP was employed to cross-link oxyHb, and the product was purified by DEAE-cellulose chromatography. The purified material was analyzed by SDS-PAGE, IEF, and HPLC analyses, which clearly showed the formation of covalent, intramolecular cross-links. While SDS-PAGE analyses of individual bands pointed to the molecular weight range of 32 kDa, the HPLC analyses suggested that the cross-links had formed between beta 1-beta 2 subunits. The oxygen equilibrium measurements and the Hill plots were performed on the purified bands to assess oxygen affinity as well as cooperativity of oxygen binding of the modified hemoglobins. All bands corresponding to modified hemoglobins showed significantly reduced oxygen affinity as compared with that of cell-free hemoglobin, as desired. The modified hemoglobins, however, exhibited somewhat reduced oxygen-binding cooperativity as contrasted with human stroma-free hemoglobin. Molecular dynamics simulation studies (Insight II/Discover/Biosym) on the Reagent-HbA0 complex suggested that the most likely amino acid residues involved in the cross-linking are Lys82 or N-terminal Val1 on one of the beta chains, and Lys144 on the other.

Chromatography, DEAE-Cellulose↗
PubMed1992

A phosphinic acid dipeptide analogue to stabilize peptide drugs during their intranasal absorption.

A major challenge in intranasal delivery of peptides is to overcome the enzymatic barrier that limits their absorption. Aminopeptidase inhibitors may be useful for improving systemic delivery of peptide drugs administered nasally. A phosphinic acid dipeptide analogue, a transition-state analogue aminopeptidase inhibitor in which the phosphinate moiety exists in a tetrahedral state mimicking peptides during their enzymatic hydrolysis, was synthesized and tested nasally in situ in rats. This inhibitor was found to inhibit greatly the degradation of the model peptide leucine-enkephalin in the nasal perfusate at less than or equal to 2 microM concentrations. The nasal peptidase hydrolytic activity was reversible after exposure to the inhibitor. This inhibitor has the advantage of efficacy at very low concentrations and reversibility of effects.

Absorption↗
PubMed1995

Phosphinic acid analogues of GABA. 1. New potent and selective GABAB agonists.

The antispastic agent and muscle relaxant baclofen 1 is a potent and selective agonist for bicuculline-insensitive GABAB receptors. For many years efforts to obtain superior GABAB agonists were unsuccessful. We describe the syntheses and biological properties of two new series of GABAB agonists, the best compounds of which are more potent than baclofen in vitro and in vivo. They were obtained by replacing the carboxylic acid group of GABA or baclofen derivatives with either the phosphinic acid or the methylphosphinic acid residue. Surprisingly, ethyl- and higher alkylphosphinic acid derivatives of GABA yielded novel GABAB antagonists, which are described in part 2 of this series. Structure-activity relationships of the novel GABAB agonists are discussed with respect to their affinities to GABAB receptors as well as to their effects in many functional tests in vitro and in vivo providing new muscle relaxant drugs with significantly improved side effect profiles.

Animals↗
PubMed1998

Bis[2-(4-carboxyphenoxy)carbonylethyl]phosphinic acid (BCCEP): a novel affinity reagent for the beta-cleft modification of human hemoglobin.

The design, synthesis, and hemoglobin cross-linking studies of a novel organic reagent, bis[2-(4-carboxyphenoxy)carbonylethyl]phosphinic acid (BCCEP, 1) have been reported. The reagent was designed with the aid of molecular modeling, employing crystal coordinates of human hemoglobin A0. It was synthesized in three steps commencing from 4-t-butoxycarbonylphenol. The tri-sodium salt of 1 was employed to cross-link human oxyHb. While SDS-PAGE analyses of the modified hemoglobin product pointed to the molecular mass range of 32 kDa, the HPLC analyse suggested that the cross-link had formed between the beta 1-beta 2 subunits. The oxygen equilibrium measurements of the modified hemoglobin at 37 degrees C showed significantly reduced oxygen affinity (P50 = 31.3 Torr) as compared with that of cell-free hemoglobin (P50 = 6.6 Torr). The sigmoidal shape of O2 curves of the modified Hb pointed to reasonable retainment of oxygen-binding cooperativity after the cross-link formation. Molecular dynamics simulation studies on the reagent-HbA0 complex suggested that the most likely amino acid residues involved in the cross-linking are N-terminus Val-1 or Lys-82 on one of the-chains, and Lys-144 on the other. These predictions were consistent with the results of MALDI-MS analyses of the peptide fragments obtained from tryptic digestion of the cross-linked product.

Chromatography, High Pressure Liquid↗
PubMed1987

Bacterial carbon-phosphorus lyase: products, rates, and regulation of phosphonic and phosphinic acid metabolism.

Carbon-phosphorus bond cleavage activity, found in bacteria that utilize alkyl- and phenylphosphonic acids, has not yet been obtained in a cell-free system. Given this constraint, a systematic examination of in vivo C-P lyase activity has been conducted to develop insight into the C-P cleavage reaction. Six bacterial strains were obtained by enrichment culture, identified, and characterized with respect to their phosphonic acid substrate specificity. One isolate, Agrobacterium radiobacter, was shown to cleave the carbon-phosphorus bond of a wide range of substrates, including fosfomycin, glyphosate, and dialkyl phosphinic acids. Furthermore, this organism processed vinyl-, propenyl-, and propynylphosphonic acids, a previously uninvestigated group, to ethylene, propene, and propyne, respectively. A determination of product stoichiometries revealed that both C-P bonds of dimethylphosphinic acid are cleaved quantitatively to methane and, furthermore, that the extent of C-P bond cleavage correlated linearly with the specific growth rate for a range of substrates. The broad substrate specificity of Agrobacterium C-P lyase and the comprehensive characterization of the in vivo activity make this an attractive system for further biochemical and mechanistic experiments. In addition, the failure to observe the activity in a group of gram-positive bacteria holds open the possibility that a periplasmic component may be required for in vivo expression of C-P lyase activity.

Bacteria↗
PubMed1999

Insecticidal properties of 3-aminopropyl(methyl)phosphinic acid and its effect on K(+)-evoked release of acetylcholine from cockroach synaptosomes.

3-Aminopropyl(methyl)phosphinic acid (APMP), a potent agonist of mammalian GABAB receptors, caused prostration in houseflies (Musca domestica L.) on injection into their thoraces, with an ED50 value of 0.42 microgram/fly. The 48-h LD50 values of APMP were estimated to be 0.45 and 5.6 micrograms/fly in the presence and absence of piperonyl butoxide, a mixed-function oxidase inhibitor, respectively. Analogues of APMP, bearing a longer or shorter side chain by a CH2 unit, or a phenyl group in the place of the methyl group, were without effects. In perfusion assays with synaptosomes prepared from the thoracic/abdominal nerve cords of cockroaches (Periplaneta americana L.), 1 mM APMP reduced K(+)-evoked acetylcholine release to 10.4% of the control. These findings indicate that the--physiologically important site of action of APMP, which might be implicated in neurotransmitter release, is present in insect neurons.

Acetylcholine↗
PubMed2004

Sulfone and phosphinic acid analogs of decaprenolphosphoarabinose as potential anti-tuberculosis agents.

Mycobacteria biosynthesize a cell wall structure that is rich in polysaccharides containing arabinofuranose residues. The source of these arabinofuranose residues is decaprenolphosphoarabinose (1), the donor substrate for mycobacterial arabinosyltransferases. We have previously demonstrated that an analog of 1, C-phosphonate 7, prevented the growth of mycobacteria and this compound is currently undergoing testing for efficacy in tuberculosis-infected mice. We describe here the synthesis and testing of additional analogs of 1 that contain either a sulfone (8-14) or phosphinic acid (15-19) moiety in place of the phosphodiester functionality. Screening of these compounds in vitro against Mycobacterium tuberculosis strain H(37)Rv revealed that while some of these compounds possessed low to modest activity, none was as potent as 7.

Antitubercular Agents↗
PubMed1984

Excitatory amino acid receptor interactions of a novel alpha-phosphinic acid analogue of alpha-methylaspartic acid.

An alpha-phosphino analogue of alpha-methylaspartate has been synthesized. The compound may not interact with excitatory amino acid receptors directly, as assessed by direct in vitro radioreceptor binding methods; however, it possesses weak anticonvulsant activity and exhibits an excitant action in vitro that is apparently not mediated by a N-methyl-D-aspartate receptor.

Acetylcholine↗
PubMed2004

Environmentally benign synthesis of h-phosphinic acids using a water-tolerant, recyclable polymer-supported catalyst.

[reaction: see text] A reusable polymer-supported hydrophosphinylation catalyst is described for the preparation of H-phosphinic acids. The polystyrene-based ligand is prepared in one step from commercially available compounds. The polymeric catalyst generally gives good yields for a variety of substrates and is water- and air-tolerant, although the scope of alkenes and alkynes which can be employed is somewhat narrower than with our original xantphos/Pd(2)dba(3) catalyst.

Journal Article↗