Arylazoamidoximes and related compounds as NO-modulators.

Three amidinoarylhydrazines 1, three arylazoamidines 2, and nine arylazoamidoximes 3 have been synthesized and investigated for their potential to function as nitric oxide (NO) modulators. In-vitro studies demonstrated that 2 and 3 inhibited platelet aggregation (2c, IC(50 )= 3 microM) which could also be shown in vivo by inhibition of thrombus formation in arterioles (3a, 22%). Moreover, for all compounds antihypertensive effects were examined in vivo with SHR rats, with 2a being the most potent candidate by lowering blood pressure by 19%.

New 1H-pyrazole-4-carboxamides with antiplatelet activity.

Nine title compounds were synthesized and investigated in the Born test for their antiplatelet activities against collagen, ADP, adrenaline, and platelet activating factor (PAF) as inducers of the aggregation. Using collagen three compounds with IC50 values below 100 microM were found (3b, 3e, 3i). Activities in nanomolar concentrations were observed against ADP (3b, IC50 = 9.

New 2-amino-thiazole-4-acetamides with antiplatelet activity.

In the Born test, 23 title compounds were synthesized and investigated for their antiplatelet activities against collagen, ADP, adrenaline, and platelet-activating factor (PAF) as inducers of the aggregation. Using collagen, three compounds with IC(50) values below 10 microM were found (3a, 3b, 3c) and 15 compounds with IC(50) values between 10 and 100 microM were determined. In general, a cyclohexylamino rest on an 4-carboxamide moiety is a pre-requisite for this pharmacological activity.

New purines with antiplatelet activity.

Four purine-2,6-diamines, 4a, b, 5a, b, nineteen N-(purin-2-yl)benzenecarboxamides 6a-q, 7b, and one N-(purin-2-yl)-2-furanecarboxamide 8 were prepared for the first time and tested for their inhibition of blood platelet aggregation. Six compounds, 6a, b, h, m, o, p, inhibited the platelet aggregation induced by collagen with IC(50 )values between 3 and 10 micromol/L in the Born test. ADP, PAF, and adrenaline were used as specific aggregation inducers to examine the mechanism of the anti-aggregating activity.

New pyrimido[5,4-c]cinnolines with antiplatelet activities.

Twenty one new pyrimido[5,4-c]cinnolines containing different lipophilic moieties (viz. phenyl, 4-methoxyphenyl, 2-furanyl, 2-thienyl) in position 2 and additional basic groups (e.g.

Synthesis and antiplatelet activity of new imidazole-4-carboxylic acid derivatives.

1-Arylalkyl-5-phenylsulfonamino-imidazole-4-carboxylic acid esters and their carboxamides with an additional secondary amino group were synthesized and identified as antiplatelet agents in a low micromolar range (Born-test, inducer collagen). To describe the mechanism of action more precisely the Born-test was carried out as well with ADP, adrenaline or PAF, respectively. In addition, two compounds were investigated for their COX-1 inhibitory activities.

New oxadiazole derivatives showing partly antiplatelet, antithrombotic and serotonin antagonistic properties.

Ten new 1, 2, 4-oxadiazole- and six new 1, 3, 4-oxadiazole-carboxamides containing different lipophilic moieties (i.e. 4-biphenyl-, 1-naphthyl, phenylpropyl- and n-hexyl substituents) and additional basic groups which are mainly alkyl- and dialkylaminoalkyl residues have been synthesized and tested for antiplatelet effects in vitro (Born-test) and antithrombotic properties in vivo (laser thrombosis model).

Antiaggregating and antithrombotic activities of new 1, 2, 3-triazolecarboxamides.

Twenty five new triazolecarboxamides related to YC-1 were prepared and tested for their antiplatelet (in vitro) and antithrombotic (in vivo) activities. Five of them inhibited the aggregation of blood platelets (Born test, inducer collagen) with IC50 values between 90 and 130 microM. Nine compounds exhibited significant antithrombotic properties with an inhibition of thrombus formation between 11 and 7%.

New antithrombotic 1-phthalazinamines with serotonin antagonistic properties.

We report nineteen 4-aryl- and 4-arylalkyl-1-phthalazinamines (5-8) which we prepared and tested for antithrombotic properties. All compounds were assayed for their antiplatelet activity in the "Born test" with collagen as inducer of the aggregation. N-[4-(1H-1, 2, 4-triazol-1-yl)butyl]-4-phenyl-1-phthalazin-amine (7 c) was the most potent compound, having an IC(50) of 8 microM.

Role of nitric oxide in zymosan induced paw inflammation and thermal hyperalgesia.

Objective: To assess the involvement of spinal inducible nitric oxide synthase (iNOS) in inflammation and nociception.

Materials And Methods: The time course of iNOS mRNA expression in rat spinal cord and inflamed paw was assessed by means of quantitative real time RT-PCR. In addition, the effects of the iNOS inhibitor L-NIL on inflammatory paw edema and thermal hyperalgesia were studied in comparison to those of the NO-donor RE-2047.

Suppressed injury-induced rise in spinal prostaglandin E2 production and reduced early thermal hyperalgesia in iNOS-deficient mice.

It is widely accepted that peripheral injury increases spinal inducible cyclooxygenase (COX-2) expression and prostaglandin E(2) (PGE(2)) formation as key mediators of nociceptive sensitization. Here, we used inducible nitric oxide synthase (iNOS) gene-deficient (iNOS-/-) mice to determine the contribution of iNOS-derived nitric oxide (NO) to this process. iNOS-/- mice exhibited reduced thermal hyperalgesia after zymosan injection.

New NO donors with antithrombotic and vasodilating activities, Part 27. Azide oximes and 1-hydroxytetrazoles.

Eleven azide oximes were prepared and tested for their antiplatelet (in vitro), antithrombotic, and blood pressure lowering activities. Nine of them inhibited the aggregation of blood platelets (Born test, inducer collagen) with IC50 values between 10 and 50 microM. The most active compounds i.

New NO donors with antithrombotic and vasodilating activities, Part 29. N-(1-cyanocyclohexyl)-C-phenylnitrones and glyoxaldinitrones.

Six N-(1-cyanocyclohexyl)-C-phenylnitrones 4a-f (4b-f for the first time) and 22 glyoxaldinitrones 7a-v were prepared and tested for antithrombotic (p.o. administration to rats, 60 mg/kg) effects.

New NO donors with antithrombotic and vasodilating activities, Part 28. N-(1-cyanoalkyl)-N-hydroxyureas.

Nineteen N-(1-cyanoalkyl)-N-hydroxyureas comprising aliphatic (3a-i, 4a, b, and 5a) and aromatic (3j-n, 4c, 5b) compounds were prepared, fourteen of them for the first time, and tested for antithrombotic (p.o. administration to rats, 60 mg/kg) effects.

New NO donors with antithrombotic and vasodilating activities. Part 22. Nitrosation products of hexamethylenetetramine.

Two nitrosation products of hexamethylenetetramine, namely 1,3,5-trinitrosohexahydro-1,3,5-triazine (1) and 3,7-dinitroso- 1,3,5,7-tetrazabicyclo[3.3.1]nonane (2), were synthesized.

Interaction of Viagra with the NO donors molsidomine and RE 2047 with regard to antithrombotic and blood pressure lowering activities.

After p.o. administration to rats in doses up to 30 mg/kg, Viagra showed no antithrombotic effect.

Bromelain proteases reduce human platelet aggregation in vitro, adhesion to bovine endothelial cells and thrombus formation in rat vessels in vivo.

The thiol protease, bromelain, an extract from pineapple stem, was suggested to have antithrombotic and anticoagulant activities in vivo. We studied the effects of bromelain on cell size distribution of isolated human platelets in vitro by Coulter Counter measurements. Preincubation of platelets with bromelain (10 micrograms/mL) completely prevented the thrombin (0.

New NO donors with antithrombotic and vasodilating activities, Part 26. Amidoximes and their prodrugs.

Seventeen amidoximes (2a-q) comprising aliphatic (2a-d), aromatic (2e-n), and bis compounds (2o-q) have been synthesized. In the Born test 4-chlorophenylethenecarboxamidoxime (21) was most active and inhibited the blood platelet aggregation induced by collagen with an IC50 = 3 microM. After oral administration to rats (60 mg/kg) fourteen compounds significantly inhibited the formation of thrombi in arterioles and venules.

New NO donors with antithrombotic and vasodilating activities, part 25. Hydroxylamine derivatives.

Twelve ethoxycarbonyl or phenylsulfonyl derivatives as prodrugs of hydroxylamine or phenylhydroxylamine were prepared and tested for antiplatelet (in vitro, Born test) antithrombotic (in vivo thrombosis model), and antihypertensive (in vivo, SHR rats) effects. In the Born test N,N-bisphenylsulfonylhydroxylamine (10) was most active (IC50 = 11 mumol/L). The N-ethoxycarbonyl-phenylhydroxylamine (7) was the most potent antithrombotic compound.

2-Nitrosoimino-3,6-dihydro-2H-1,3,4-thiadiazines with antiplatelet and antithrombotic properties.

The successful synthesis of 17 nitrosimines of 2 H-1,3,4-thiadiazines is reported. They are best characterized by their electronic spectra (lambda max = 504-522 nm). Some of the compounds were able to inhibit the aggregation of blood platelets in the Born-test (inducer collagen).

New NO donors with antithrombotic and vasodilating activities, Part 24. Hydrazine derivatives.

Suitable hydrazines like phenylhydrazine (1), N,N-dimethyl hydrazine (4), and N,N-diphenyl hydrazine (5) can be oxidized by hydrogen peroxide at pH 7.4 and 37 degrees C to nitrosohydrogen and further to nitrite and nitrate. The extent of this property is correlated with platelet aggregation inhibiting and antithrombotic effects of these compounds, suggesting that an NO mediated mechanism might be involved.

NO donors with antithrombotic and vasodilating activities, Part 23. Organic azides.

Twenty eight organic azides were synthesized and tested for their antithrombotic and blood pressure lowering activities in rats (60 mg/kg, p.o.).

New NO-donors with antithrombotic and vasodilating activities, Part 21. Pseudonitrosites and other azodioxides with vicinal electron acceptors.

Twelve vicinally substituted nitro-nitroso compounds (pseudonitrosites) were synthesized, nine of them for the first time. In the solid state the dimeric azodioxides are present. In the class of the pseudonitrosites 2a-h, all compounds exhibited comparatively strong antiplatelet activity in vitro (Born test, collagen).

New NO-donors with antithrombotic and vasodilating activities, Part 20. Azodioxides activated by electron acceptors in geminal or vicinal position.

Twenty-two nitroso compounds with cyano, acyloxy, or carbonyl groups in geminal position were prepared, eight of them for the first time. In the solid state these compounds dimerize to colorless azodioxides. Exceptions are the 4-nitrobenzoyloxynitroso compounds 7b, f, and g which form bright blue crystals.