Hydrogen Phosphonate Research Articles

Study of the reactions of dimethyl hydrogen phosphonate with urethane and acetanilide

Study of the reactions of dimethyl hydrogen phosphonate with urethane and acetanilide

Formation of anomeric phosphodiester linkages using H-phosphonate acceptors

A new way of constructing anomeric glycosyl phosphodiester linkages has been explored. Non-anomeric monosaccharide hydrogen phosphonate monoesters ( 5 and 9) have been used as acceptors in couplings using various benzylated galactosyl donors (trichloroacetimidate, thioglycoside, bromo and chloro sugars, 1–4, 7 and 8) and promoters to give, after oxidation, good yields of phosphodiester linked “disaccharides” ( 6 and 10), products usually obtained by using an anomeric hydrogen monophosphonate, a hydroxyl acceptor and pivaloyl chloride as coupling reagent.

Antiviral Activity and Resistance Profile of Phosphazid - A Novel Prodrug of AZT

Both AZT and its novel 5′-hydrogen phosphonate derivative, Phosphazid, possess similar in vitro activity and resistance profiles. Experiments involving AZT-resistant virus isolates revealed a strong correlation between resistance to AZT and cross-resistance to Phosphazid. In vitro selection for resistance to Phosphazid yielded viruses that were about 15-fold less sensitive than wild-type virus to this drug. Sequencing of the reverse transcriptase region of seven Phosphazid-selected viruses revealed a single codon mutation, D67N, that is associated with resistance to AZT.

New lead triphosphonates: synthesis, properties and crystal structures

Two new lead nitrilotris(methylene)triphosphonates, Pb[(H 2 O 3 PCH 2 )N(CH 2 PO 3 H) 2 ] I and Pb 2 [(O 3 PCH 2 )N(CH 2 PO 3 H) 2 ]·H 2 O II, have been synthesised. I is triclinic, space group P1, a=8.5077(2), b=11.2363(3), c=5.9484(2) A, α=98.802(2), β=104.955(1), γ=80.911(2)°, Z=2. II is monoclinic, space group Pn, a=7.3614(2), b=11.3889(2), c=7.2541(2) A, β=100.389(2)° and Z=2. Their structures have been solved from laboratory X-ray data by using ab initio powder diffraction methodology. The reliability factors were R wP =9.28%, R P =7.20% and R F =2.67%, for I, and R wP =12.51%, R P =9.38% and R F =4.45%, for II. I shows a new layered structure which has small cavities, inside an inorganic layer, in which the hydrogen phosphonate and the dihydrogen phosphonate groups are located. II is also layered with the water molecule situated in the interlamellar space. Thermal data, IR data and ion-exchange properties are also reported and discussed. II dehydrates to yield orthorhombic Pb 2 [(O 3 PCH 2 )N(CH 2 PO 3 H) 2 ] III. Hydrolysis of I leads to II.

Synthesis and hybridization property of an oligonucleotide analog containing A 1′,3′-DI- O-methylene-α- D-fructose backbone

Hydrogen phosphonate monomers of T (thymine) and C m (5-methylcytosine) bearing a 1′,3′-di- O-methylene-α- D-fructose sugar moiety were synthesized and incorporated into an oligonucleotide. Hybridization studies by thermal denaturation experiment indicated that this oligonucleotide did not form a duplex with the complementary RNA target.

High yield protection of purine ribonucleosides for H-phosphonate RNA synthesis

We report a new method for protecting nucleosides for hydrogen phosphonate RNA synthesis that gives very high yields for the purines. This method is based on our finding that, for adenosine and guanosine, silylation of a mixture of 2′ and 3′ H-phosphonates in the presence of DBU is highly selective for the 2′ hydroxyl.

Synthesis and hybridization study of a boranophosphate-linked oligothymidine deoxynucleotide

A T 15 oligodeoxynucleotide (ODN) fully substituted with a diastereomeric mixture of boranophosphate linkages was synthesized through silylation of its hydrogen phosphonate precursor on solid support followed by reaction with borane. The hybridization properties of this ODN with complementary RNA and DNA were determined by T m analysis. This analog does not hybridize to any significant extent under the conditions tested.

Ultrafast Cleavage and Deprotection of Oligonucleotides Synthesis and Use of CAc Derivatives

We have investigated the use of alkylamines as fast cleavage and deprotection reagents for the solid phase synthesis of oligonucleotides and found methylamine/ammonium hydroxide (or methylamine) as an efficient reagent. The transamination side product formed with the commonly used dCbz has been eliminated by the use of dCAc phosphoramidite. This system has successfully been used in the synthesis of oligonucleotides and oligonucleoside phosphorothioates. DMT dCAc hydrogen phosphonate and DMT ribo CAc-2′-O Me phosphoramidite also have been prepared and used in the synthesis of oligonucleotides.

SUR QUELQUES DÉRIVÉS PHOSPHORES DE LA SPERMINE

Abstract The reaction of spermine with aromatic aldehyde leads to an equilibrated system between the bis imine form 1' and the hexahydropyrimidine form 1. In contrary the formaldehyde adduct of spermine exist only on the hexahydropyrimidine form 9. 1–1' is readily hydrolyzed by HCl with regeneration of the aldehyde and spermine. The NaBH4, reduction of 1–1' leads to the dibenzyl spermine 8 and the phosphonate adducts 2 or 6 are obtained from 1–1' and a hydrogen phosphonate. These last two reactions failed with 9. Inversely 9 and 1–1' reacts equably well with tetramethyl chloro dioxaphospholane with formation of cyclic phosphinamidates 10 and 5. In the second case a kinetic intermediate 3 can be observed by 31P NMR.

Preferential phosphorylation at the primary alcohol of non-protected thymidine or carbohydrates

A preferential phosphorylation at the primary alcohol of non-protected thymidine or carbohydrates by the hydrogen phosphonate method is described. Thus, 6-(mannopyrannosyl), 6-(glucopyrannosyl) or 5′-(thymidinyl) phosphodiesters were obtained in 35% to 80% yields.

Synthesis of double-tailed (perfluoroalkyl)alkyl phosphosugars: new components for drug-carrying and -targeting systems

Double-tailed d-glycose 3- and 6-[sodium (perfluoroalkyl)alkyl phosphates] were synthesized via the hydrogen phosphonate approach. Stable double-tailed (perfluoroalkyl)alkyl hydrogenphosphonates, prepared from double-tailed (perfluoroalkyl)alkanols and PCl 3-imidazole, reacted with 1,2:3,4-di- O-isopropylidene-α- d-galactopyranose or with 1,2:5,6 -di- O-isopropylidene-α- d-glucofuranose in the presence of Me 3CCOCl as the condensing agent to give, after oxidation with aqueous iodine, the corresponding O-protected glycose phosphate diesters. O-Deisopropylidenation of the latter by aqueous trifluoroacetic acid afforded the target compound in 70% yield, based on the protected glycosides. Condensation of 1,2,3,4-tetra- O-acetyl-β- d-glucopyranose or -mannopyranose with double-tailed (perfluoroalkyl)alkyl hydrogenphosphonates or 10-eicosyl hydrogenphosphonate, via the coupling and oxidation steps described above, afforded per- O-acetylglycose phosphodiesters. O-Deacetylation with MeONa-MeOH was achieved in 65% yield based on the protected sugar. All the compounds were characterized by 19F, 1H, 13C, and 31P NMR data. Preliminary biocompatibility assays indicate a reduction of hemolytic activity when fluorinated chains are present and maximum tolerated doses of ca. 125 mg/kg body weight in mice.

Alkyl Hydrogen Phosphonate Derivatives of the anti-HIV Agent AZT may be Less Toxic than the Parent Nucleoside Analogue

Novel alkyl hydrogen phosphonate derivatives of the anti-HIV nucleoside analogue AZT have been prepared by phosphorochloridite chemistry. These materials are designed to act as labile membrane-soluble prodrugs of the bioactive free nucleotides. In vitro evaluation has revealed the compounds to have a pronounced and selective antiviral action. Short-chain (C1-C7) alkyl derivatives are more potent than the parent hydrogen phosphonate, whilst one long-chain (C18) compound is less active. In an assay that demonstrates the toxicity of the parent drug AZT, the alkyl H-phosphonates appear to be less cytotoxic, whilst retaining full antiviral activity. Lastly, the compounds are all poorly active in a cell line (JM) that is poorly responsive to AZT, indicating that they act as depot forms of the nucleoside rather than of the free nucleotide.

Synthese und Eigenschaften von N4‐Hexadecyl‐2′‐desoxycytidylyl‐(3′‐5′)‐5‐ethyl‐2′‐desoxyuridin und 2′‐Desoxythymidylyl‐(3′‐5′)‐N4‐hexadecyl‐1‐β‐D‐arabinofuranosylcytosin, zwei Vertreter einer neuen Prodrug‐Gruppe

Synthesis and Properties of N4‐Hexadecyl‐2′‐deoxycytidylyl‐(3′‐5′)‐5‐ethyl‐2′‐deoxyuridine and 2′‐Deoxythymidylyl‐(3′‐5′)‐N4‐hexadecyl‐1‐β‐D‐arabinofuranosylcytosine, Two Representatives of a New Kind of ProdrugsThe gram‐scale condensation of N4‐hexadecyl‐2′‐deoxycytidine with the antiviral 5‐ethyl‐2′‐deoxyuridine and of 2′‐deoxythymidine with the antineoplastic N4‐hexadecyl‐1‐β‐D‐arabinofuranosylcytosine via a 3′‐5′‐phosphodiester linkage using the hydrogen phosphonate method is described. The purity and the structure of the synthetic products were determined chromatographically (TLC, HPLC) and spectroscopically (MS‐MS, 2D‐NMR). The resulting amphiphilic dinucleoside phosphates represent two examples of a new kind of prodrugs in which lipophilic or hydrophilic nucleoside residues are applied for the masking of 5′‐phosphorylated nucleoside analogues which are known as chemotherapeutics. The prodrugs are soluble in water and can also be incorporated together with matrix lipids into stable liposome dispersions. magnified image

Synthesis of the phosphodiester of 3β(7β-hydroxycholesterol) and of 5′(3′deoxy, 3′azido-thymidine).

In order to enhance the therapeutic efficacy of azido-thymidine (AZT) by improving its pharmacokinetic properties and to try to target its action to the lymphocytes, the phosphodiester of 3β(7β-hydroxycholesterol) and of 5′(3′deoxy, 3′azido-thymidine) 1 was synthesized using two different techniques of phosphorylation : the phosphoramidite and the hydrogen phosphonate methodologies. Preliminary results show an in vitro anti-HIV activity.

The 5′-Hydrogen Phosphonate Analog as a Potential Prodrug of 3′-Azido-2′,3′-dideoxythymidine (AZT)

Abstract A novel synthesis of AZT-5′-H-phosphonate 2, involving decarboxylation of the phosphonoformate intermediate 7, is reported herein. Studies of the metabolism of 2 in U937 cells indicate that 2 is readily converted to AZT-5′-monophosphate.

Detection of specific base sequences in solution using DNA probes labeled with d- and/or 15N-substituted spin-labels.

In order to enhance the sensitivity and the accuracy of the detection by the DNA probe method in which spin-labeled oligonucleotides are used as probes, 4-amino-2,2,6,6-tetramethylpiperidine-15N-oxyl-d16 (4-amino-TEMPO-15N-d16) and 4-amino-2,2,6,6-tetramethylpiperidine-14N-oxyl-d16 (4-amino-TEMPO-14N-d16) were incorporated into the phosphate linkage of oligonucleotides by the hydrogen phosphonate method and these DNA probes were used for the detection of target DNAs in solution. The intensities of the electron paramagnetic resonance (EPR) signals of the oligonucleotides labeled with 4-amino-TEMPO-14N-d16 and 4-amino-TEMPO-15N-d16 were 3-fold and 4-fold larger than that of the oligonucleotide labeled with 4-amino-TEMPO-14N, respectively. Also, the EPR lines of these labeled oligonucleotides do not overlap each other, allowing the detection of two different regions in the same target DNA by the single EPR measurement.

New developments in the synthesis of phosphopolyprenols and their glycosyl esters.

Efficient methods were developed in our group in recent years for chemical synthesis of polyprenyl phosphates, polyprenyl monophosphate sugars, and polyprenyl diphosphate sugars, which were known to serve as important intermediates in biosynthesis of complex carbohydrates. A simple procedure was developed involving the phosphorylation of aliphatic alcohols with tetra-n-butylammonium dihydrogen phosphate and trichloroacetonitrile. Monophosphates of various natural and modified dolichols and polyprenols, as well as the derivatives of retinol, cholesterol, and nonacosanol, were prepared in high yields. First syntheses of dolichyl thiophosphate and dolichyl hydrogen phosphonate were developed, and these derivatives were of interest as analogs of dolichyl phosphate. Polyprenyl monophosphate sugars, including derivatives of alpha- and beta-anomers of D-glucopyranose, D-galactopyranose, D-mannopyranose, and 2-acetamido-2-deoxy-D-glucopyranose, were obtained smoothly from moraprenyl trichloroacetimidate and acylated glycosyl phosphates after deprotection. A method for the synthesis of polyprenyl diphosphate sugars from polyprenyl phosphoroimidazolidate and unprotected glycosyl phosphates was shown to be applicable for a wide range of the monosaccharide derivatives including hexoses, deoxyhexoses, 2-acetamido-2-deoxyhexoses, and uronic acids. A series of the oligosaccharide derivatives was also prepared by this method.

THE REACTION OF DIMETHYL HYDROGEN PHOSPHONATE AND AMINOALCOHOLS

Abstract The interaction between dimethyl hydrogen phosphonate (DMHP) and aminoalcohols was examined. It was found that at the temperature of 80°C the basic reaction is that of alkylation of the aminoalcohols. The structure of the end products was proved by the aid of 1H- and 31P-NMR spectroscopy.

Hydrolysis of phosphonoformate esters: product distribution and reactivity patterns

Phosphonoformate triesters are hydrolysed to mixtures of hydrogen phosphonate and phosphonoformate esters and free acids; the rates and product distribution are dependent on pH and ester leaving group abilities.

Fluorescent-labeled oligonucleotide probes: detection of hybrid formation in solution by fluorescence polarization spectroscopy

Fluorescein-labeled oligonucleotides as DNA-probes were synthesized and used to monitor hybrid formation, namely to detect DNA or oligonucleotide sequence in solution. The introduction of fluorescein to oligonucleotides was carried out by oxidation of a hydrogen phosphonate linkage with ethylenediamine or hexamethylenediamine as a tether and by a subsequent labeling of the primary amine moiety by FITC. Fluorescence anisotropy, r, was adopted as an index to monitor the behavior of F-probe in solution. An increase in the anisotropy was observed upon an increase in the chain-length of F-probe. When F-Probe formed a hybrid with its complementary oligonucleotide in solution, the r value increased compared to that of F-Probe itself. These observations clearly indicate that measurements of r in solution will readily lead to the monitoring of the presence of a hybrid in solution. Consequently, it is promising to detect a certain nucleic acid sequence in solution using fluorescent-labeled oligonucleotides.