Janina Baraniak

Limited usefulness of the PFA-100 for the monitoring of ADP receptor antagonists--in vitro experience.

Abstract We have evaluated the usefulness of the PFA-100™ system (collagen/ADP and collagen/epinephrine cartridges) to assess the in vitro effects of a few platelet function inhibitors: Aspisol® (60 μg/ml), 4-[4-[4-(aminoiminomethyl]-1-piperazinyl]-1-piperidineactetic acid, hydrochloride trihydrate (GR144053F, fibrinogen receptor antagonist, 100 nM), adenosine-3′,5′-diphosphate (A3P5P, P2Y1 ADP receptor antagonist, 500 μM) and Bis[(adenosine-5′-O-phosphorodithioyl) methylene]-phosphinic acid (APTMPA, P2Y12 ADP receptor antagonist, 500 μM) on platelet function, as compared with the other commonly used diagnostic technique, a whole blood electrical aggregometry (20 μM ADP-or 0.5 mM arachidonic acid). The in vitro studies were carried out on a group of 38 subjects. Whereas all the examined platelet antagonists and inhibitors almost completely blocked the 20 mM ADP-or 0.5 mM arachidonic acid-induced (in the case of acetylsalicylic acid) whole blood aggregation, only two inhibitors (Aspisol® and GR144053F) remained effective in a significant prolongation of the PFA-100™ occlusion time. Otherwise, using the PFA-100™ system we were not able to detect the inhibitory actions of ADP receptor antagonists–P2Y1 and P2Y12. Our findings point to a limited usefulness of the PFA-100™ system for the monitoring of the effectiveness of ADP receptor antagonists. The outcomes of this study show that platelet aggregometry in whole blood is characterised by the highest sensitivity in the monitoring of the investigated blood platelet inhibitors.

Stereospecific synthesis of adenosine 3′,5′-(SP)- and -(RP)-cyclic phosphorothioates (cAMPS)

NNO 2 ′-Tribenzoyladenosine 3′,5′-cyclic phosphate (3) was converted into a diastereoisomeric mixture of NNO2′-tribenzoyladenosine 3′,5′-cyclic phosphoranilidates (4); after separation of these diastereoisomers, the corresponding adenosine 3′,5′-cyclic phosphorothioates (1, cAMPS) were obtained and the absolute configuration at the P atom in the diastereoisomers of (4) and (1) was established by 31P n.m.r. spectroscopy.

Ribonucleoside cyclic 3′,5′-phosphoramidates: synthesis, stereochemistry, and conversion into ribonucleoside cyclic 3′,5′-phosphorothioates and -[18O]phosphates

Base- and O2′-protected nucleoside cyclic 3′,5′-phosphates (1) react with aniline in the presence of triphenylphosphine–carbon tetrachloride to give the nucleoside cyclic 3′,5′-phosphoranilidates (2), which after separation into individual diastereoisomers are converted in stereoretentive manner into the corresponding nucleoside cyclic 3′,5′-phosphorothioates (3). Isotopomers of adenosine cyclic 3′,5′-[18O] phosphates (9a) are prepared via two independent routes: (a) reaction of adenosine cyclic 3′,5′-phosphoranilidates (2a) with sodium hydride–[18O]benzaldehyde (retention) or (b) acid-catalysed hydrolysis of adenosine cyclic 3′,5′-N,N-dimethylphosphoramidates (10a)(inversion).Adenosine cyclic 3′,5′-phosphoranilidothioates (Sp)-(23) and (Rp)-(23), prepared via cyclisation of the corresponding 5′-[O-(4-nitrophenyl)phosphoranilidothioates](22), have been converted into P-achiral adenosine cyclic 3′,5′-phosphorodithioate (26).

Diadenylated polyols as new non-isopolar analogues of diadenosine tri- and tetraphosphates

Abstract A series of diadenosine polyphosphate-mimics were prepared based upon phosphorothioylation of the hydroxyl functions of polyols 1 and 1,3,2-oxathiaphospholane ring-opening condensation methodology.

Tetra-Thymidine Phosphorofluoridates via Tetra-Thymidine Phosphoro-selenoates: Synthesis and Stability

Abstract Tetra-thymidine phosphoroselenoates obtained via phosphoramidite methodology with bis(di-O,O-isopropyl phosphinothioyl)diselenide as oxidising reagent, under treatment with iodine and triethylamine tris(hydrofluoride) (TAF) provide a diastereomeric mixture of tetra-thymidine phosphorofluoridates whose hydrotytic stability was studied by HPLC.

Inhibition of ADP-triggered blood platelet aggregation by diadenosine polyphosphate analogues.

The synthesis and biological evaluation of new diadenosine polyphosphate analogues on blood platelet aggregation are reported. The most active are compounds with a sulfur atom replacing one or both non-bridging oxygens at phosphorus bound to adenosyl residues and hydroxymethyl groups of bis(hydroxymethyl)phosphinic acid.

Conjugation of amino acid O-methyl esters with AZT-5′-O-phosphorothioate and phosphorodithioate

Abstract Based upon 1,3,2-oxathia(-dithia)phospholane chemistry, 5′- O -derivatisation of AZT with the O -methyl esters of l -phenylalanine and l -tryptophan was performed and the corresponding 5′-aminoacidophosphoramidothioates or phosphoramidodithioates of AZT were obtained in satisfactory yield.

X-ray and high resolution selenium-77 solid state NMR spectroscopy as complementary probes to structural studies of organophosphorus diselenides

77Se high resolution solid state NMR spectroscopy was employed to study structural properties of bis(diisopropoxyphosphorothioyl) diselenide 1 and bis(dineopentoxyphosphorothioyl) diselenide 2. The principal elements Tii of 77Se effective dipolar/chemical shift tensor were calculated from spinning sideband intensities employing the WIN-MAS program. The values of anisotropy and asymmetry parameters reflect the distortion of the selenium environment. It was found that the T33 component mostly contributes to changes in the isotropic chemical shifts. 77Se CP/MAS experiments were used to decide the assignment of space group by counting the number of crystallographically unique selenium centers in the unit cell. Crystals of diselenide 1 are triclinic, space group P1 with a = 8.485(3) A, b = 8.508(1) A, c = 8.511(2) A, alpha = 98.835(15) degrees, beta = 111.653(24) degrees, gamma = 93.524(21) degrees, V = 559.5(3) A3, Dc = 1.544(2) g/cm3 and Z = 1. Refinement using 2222 reflections for 157 variables gives R = 0.037. Crystals of diselenide 2 are triclinic, space group P1 with a = 9.1418(8) A, b = 9.1465(8) A, c = 9.9200(9) A, alpha = 74.751(8) degrees, beta = 74.629(7) degrees, gamma = 82.216(7) degrees, V = 769.7(1) A3, Dc = 1.365(2) g/cm3 and Z = 1. Refinement using 3316 reflections for 297 variables gives R = 0.0272.

N-benzoyl O,O-dialkyl phosphoranilidates: reaction with O- and N-nucleophiles

Abstract Solvolysis of mixed phosphoric-carboxylic N-phenylimides occurs with exclusive attack of nucleophilies at the carbonyl carbon centre and is accompanied by phosphoryl N->O migration.

Electrophilic catalysis of N-- > 0 phosphyl migration

Abstract 2-N-Benzoyl-N-phenylamino-2-oxo-5,5-dimethyl-1,3,2-dioxaphosphorinane ( 3a ) undergoes rearrangement to (2-oxo-5,5-dimethyl-1,3,2-dioxaphosphorinanyl) (N-phenyliminobenzoyl)oxide ( 4a ). This transformation is shown to be catalysed by electrophilic reagents such as benzoyl chloride, trimethylsilyl chloride, p-toluenesulphonyl chloride.