2-Substituted 4-, 5-, and 6-[(1E)-3-oxo-3-phenylprop-1-en-1-yl]pyridazin-3(2H)-ones and 2-substituted 4,5-bis[(1E)-3-oxo-3-phenylprop-1-en-1-yl]pyridazin-3(2H)-ones as potent platelet aggregation inhibitors: design, synthesis, and SAR studies

A set of regioisomeric 2-substituted pyridazin-3(2H)-ones containing a 3-oxo-3-phenylprop-1-en-1-yl fragment at either position 4, 5 or 6 and 2-substituted pyridazin-3(2H)-ones containing the same fragment both at positions 4 and 5 have been synthesized and evaluated as antiplatelet agents. The study allows the identification of a new highly potent platelet aggregation inhibitor (4c).     

Synthesis of new 1-phenyl-3-{4-[(2E)-3-phenylprop-2-enoyl]phenyl}-thiourea and urea derivatives with anti-nociceptive activity

Chalcones or 1,3-diaryl-2-propen-1-ones are known to be useful for treating pain, inflammation, and certain diseases although their uses have not been scientifically verified. Due to the limitations of opioid and NSAID therapy, there is a continuing search for new analgesics. A series of novel new 1-phenyl-3-{4-[(2E)-3-phenylprop-2-enoyl]phenyl}-thiourea and urea derivatives were synthesized and evaluated against writhing test in mice, following the aromatic substitution pattern proposed by Topliss. The results of the preliminary bioassays indicate that compound 3 presents promising anti-nociceptive activity in acetic acid-, formalin-, and glutamate-induced pain in mice, compared with some well-known non-steroidal anti-inflammatory and analgesic drugs.     

Atropisomeric property of 1-(2,6-difluorobenzyl)-3-[(2R)-amino-2-phenethyl]-5-(2-fluoro-3-methoxyphenyl)-6-methyluracil

1-(2,6-Difluorobenzyl)-3-[(2R)-amino-2-phenethyl]-5-(2-fluoro-3-methoxyphenyl)-6-methyluracil (6), a potent and orally active antagonist of the human gonadotropin-releasing hormone receptor, exists as a pair of atropisomers in solution, which was detected by NMR spectroscopy, and separable by HPLC. In addition to a (R)-configured benzylamine, there is a second stereogenic element due to the presence of a chiral axis between the substituted 5-phenyl group and the uracil core. The rate constant of the interconversion (k = 5.07 x 10(-5) s(-1)) of these two atropisomers was determined by proton NMR analysis of a diastereoisomer-enriched sample in aqueous solution at 25 degrees C, and the corresponding Gibbs free energy DeltaG(#) of rotation barrier (97.4 kJ mol(-1)) was calculated using the Eyring equation. The diastereoisomer half-life at physiological temperature (37 degrees C) in aqueous media was estimated to be about 46 min.     

1-(2-Aminoethyl)-3-(arylsulfonyl)-1H-indoles as novel 5-HT6 receptor ligands

Novel 1-(2-aminoethyl)-3-(arylsulfonyl)-1H-indoles were prepared. Binding assays indicated they are 5-HT(6) receptor ligands, among which N,N-dimethyl-N-(2-[3-(1-naphthylsulfonyl)-1H-indol-1-yl]ethyl)amine 8t and N-methyl-N-(2-[3-(1-naphthylsulfonyl)-1H-indol-1-yl]ethyl)amine 8u showed high affinity for 5-HT(6) receptors with K(i)=3.7 and 5.7 nM, respectively.     

Synthesis, antimicrobial, and anti-HIV-1 activity of certain 5-(1-adamantyl)-2-substituted thio-1,3,4-oxadiazoles and 5-(1-adamantyl)-3-substituted aminomethyl-1,3,4-oxadiazoline-2-thiones

The reaction of 5-(1-adamantyl)-1,3,4-oxadiazoline-2-thione 2 with iodoethane, 2-dimethylaminoethyl chloride hydrochloride or 2-piperidinoethyl chloride hydrochloride in ethanolic potassium hydroxide yielded the corresponding 5-(1-adamantyl)-2-ethyl or substituted ethylthio-1,3,4-oxadiazoles 3a-c. Interaction of 2 with formaldehyde solution and primary aromatic amines or 1-substituted piperazines, in ethanol at room temperature yielded the corresponding 5-(1-adamantyl)-3-arylaminomethyl-1,3,4-oxadiazoline-2-thiones 4a-m or 5-(1-adamantyl)-3-(4-substituted-1-piperazinylmethyl)-1,3,4-oxadiazoline-2-thiones 5a-h, respectively. All the synthesized compounds were tested for in vitro activities against certain strains of Gram-positive and Gram-negative bacteria and the yeast-like pathogenic fungus Candida albicans. Compounds 2, 5a, and 5e were found as the most active derivatives, particularly against the Gram-positive bacteria. In addition, the antiviral activity of compounds 2, 4a-m, and 5a-h against HIV-1 using the XTT assay was carried out. Compound 2 produced 100%, 43%, and 37% reduction of viral replication at 50, 10, and 2microg/mL concentrations, respectively.     

3-(4-Piperidinyl)- and 3-(8-aza-bicyclo[3.2.1]oct-3-yl)-2-phenyl-1H-indoles as bioavailable h5-HT2A antagonists

A series of 3-(4-piperidinyl)- and 3-(8-aza-bicyclo[3.2.l]oct-3-yl)-2-phenyl-1H-indoles have been prepared and evaluated as ligands for the h5-HT_2A receptor. 3-(8-Phenethyl-8-aza-bicyclo[3.2.l]oct-3-yI)-2-phenyl-1H-indole is a high-affinity (1.2 nM), selective (>800 fold over h5-HT_2C and hD₂ receptors) antagonist at the h5-HT_2A receptor with oral bioavailability in rats.     

Antiviral activity of the 3''-amino derivative of (E)-5-(2-bromovinyl)-2''-deoxyuridine.

3'-NH2-BV-dUrd, the 3'-amino derivative of (E)-5-(2-bromovinyl)-2'-deoxyuridine, was found to be a potent and selective inhibitor of herpes simplex virus type 1 (HSV-1) and varicella-zoster virus (VZV) replication. 3'-NH2-BV-dUrd was about 4-12 times less potent but equally selective in its anti-herpes activity as BV-dUrd. Akin to BV-dUrd, 3'-NH2-BV-dUrd was much less inhibitory to herpes simplex virus type 2 than type 1. It was totally inactive against a thymidine kinase-deficient mutant of HSV-1. The 5'-triphosphate of 3'-NH2-BV-dUrd (3'-NH2-BV-dUTP) was evaluated for its inhibitory effects on purified herpes viral and cellular DNA polymerases. Among the DNA polymerases tested, HSV-1 DNA polymerase and DNA polymerase alpha were the most sensitive to inhibition by 3'-NH2-BV-dUTP (Ki values 0.13 and 0.10 microM, respectively). The Km/Ki ratio for DNA polymerase alpha was 47, as compared with 4.6 for HSV-1 DNA polymerase. Thus, the selectivity of 3'-NH2-BV-dUrd as an anti-herpes agent cannot be ascribed to a discriminative effect of its 5'-triphosphate at the DNA polymerase level. This selectivity most probably resides at the thymidine kinase level. 3'-NH2-BV-dUrd would be phosphorylated preferentially by the HSV-1-induced thymidine kinase (Ki 1.9 microM, as compared with greater than 200 microM for the cellular thymidine kinase), and this preferential phosphorylation would confine the further action of the compound to the virus-infected cell.     

Bivalent ligand approach on 4-[2-(3-methoxyphenyl)ethyl]-1-(2-methoxyphenyl)piperazine: synthesis and binding affinities for 5-HT(7) and 5-HT(1A) receptors

We here report on the synthesis and binding properties at 5-HT(7) and 5-HT(1A) receptors of ligands 3-12, that were designed according to the 'bivalent ligand' approach. Two moieties of the 5-HT(7)/5-HT(1A) ligand 4-[2-(3-methoxyphenyl)ethyl]-1-(2-methoxyphenyl)piperazine (1) were linked through their 3-methoxy substituent by polymethylene chains of variable length, with the aim to increase the affinity for 5-HT(7) receptor and the selectivity over 5-HT(1A) receptors. In the best cases, the dimers showed affinities for 5-HT(7) receptors as high as the monomer with no improvement in selectivity. Some dimers displayed 5-HT(1A) receptor affinities slightly higher than monomer 1.     

Solution conformation of asparagine-linked oligosaccharides: alpha(1-2)-, alpha(1-3)-, beta(1-2)-, and beta(1-4)-linked units

The solution conformation is presented for representatives of each of the major classes of asparaginyl oligosaccharides. In this report the conformation of alpha(1-3)-, alpha(1-2)-, beta(1-2)-, and beta(1-4)-linked units is described. The conformational properties of these glycopeptides were determined by high-resolution 1H nuclear magnetic resonance in conjunction with potential energy calculations. The NMR parameters that were used in this analysis were chemical shifts and nuclear Overhauser enhancements. Potential energy calculations were used to evaluate the preferred conformers available for the different linkages in glycopeptides and to draw conclusions about the behavior in solution of these molecules. It was found that the linkage conformation of the Man alpha 1-3 residues was not affected by substitution either at the 2-position by alpha Man or beta GlcNAc or at the 4-position by beta GlcNAc or by the presence of a bisecting GlcNAc on the adjacent beta Man residue.     

3-(2-pyrrolidin-1-ylethyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole derivatives as high affinity human 5-HT(1B/1D) ligands

A series of 3-(2-pyrrolidin-1-ylethyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole derivatives (2) has been prepared using parallel synthesis techniques, and their structure-activity relationships studied. High affinity human 5-HT(1B/1D) (h5-HT(1B/1D)) ligands have been identified.     

Structure--activity relationships of 1beta-methyl-2-(5-phenylpyrrolidin-3-ylthio)carbapenems

Structure--activity relationship studies of 1beta-methyl-2-[(3S,5R)-5-(4-aminomethylphenyl)pyrrolidin-3-ylthio]carbapenems, especially those pertaining to the relationship between antibacterial activity and side-chain structure were conducted. These studies suggested that the trans-(3S,5R)-5-phenylpyrrolidin-3-ylthio side-chain and the aminomethyl group at the 4-position of the phenyl ring play a key role in enhancing the antibacterial activity against the MRSA and Pseudomonas aeruginosa strains. In particular, the basicity of a substituent at the 4-position of the phenyl ring were shown to greatly contribute to the antibacterial activity against MRSA and methicillin-resistant Staphyloccocus epidermidis strains. In contrast, the amidine group was shown to lead to potent antibacterial activity against P. aeruginosa strains comparable to that of imipenem, however, a good correlation between the basicity of the 4-substituent and antipseudomonal activity was not observed. In conclusion, the 4-aminomethyl or methylaminomethyl group on the phenyl ring was the best substituent for antipseudomonal activity.     

Synthesis and Fungicidal Activity of 5-Aryl-1-(aryloxyacetyl)-3-(tert-butyl or phenyl)-4-(1H-1,2,4-triazol-1-yl)-4,5-Dihydropyrazole

A series of novel 5-aryl-1-(aryloxyacetyl)-3-(tert-butyl or phenyl)-4-(1H-1,2,4-triazol-1-yl)-4,5-dihydropyrazole 3a-3n were synthesized by the annulation of 2-aryloxyacetohydrazides with 3-aryl-1-t-butyl(or phenyl)-2-(1H-1,2,4-triazol-1-yl)prop-2-en-1-ones(1)in the presence of a catalytic amount of acetic acid.Compounds 2 were obtained by the Knoevenagel reactions of 1-t-butyl(or phenyl)-2-(1H-1,2,4-triazol-1-yl)ethanone(2)with aromatic aldehydes in the presence of piperidine.Their structures were confirmed by IR,1H-NMR,ESIMS,and elemental analyses.The preliminary bioassay indicated that some compounds displayed moderate to excellent fungicidal activity.For example,compounds 31,3m,and 3n possessed100%inhibition against Cercospora arachidicola Hori at the concentration of 50 mg/L.     

Synthesis and antimicrobial activity of new 3-(1-R-3(5)-methyl-4-nitroso-1H-5(3)-pyrazolyl)-5-methylisoxazoles

A number of new 3-(1-R-3(5)-methyl-4-nitroso-1H-5(3)-pyrazolyl)-5-methylisoxazoles 6a–g (7b–f) were synthesized and tested for antibacterial and antifungal activity. Some of these compounds displayed antifungal activity at non-cytotoxic concentrations. Derivative 6c was 9 times more potent in vitro than miconazole and 20 times more selective against C. neoformans. 6c was also 8- and 125-fold more potent than amphotericin B and fluconazole, respectively. None of the compounds was active against bacteria. Preliminary structure–activity relationship (SAR) studies showed that the NO group at position 4 of the pyrazole ring is essential for the activity. Lipophilicity of the pyrazole moiety, N-alkyl chain length and planarity of the two heterocyclic rings appear to play a decisive role in modulating cytotoxicity and antifungal activity.     

Studies on tetrahydrofuranyl-5-fluorouracils. 2. NMR studies of 1-(tetrahydro-2-furanyl)-, 3-(tetrahydro-2-furanyl)-, and 1,3-bis(tetrahydro-2-furanyl)-5-fluorouracils.

Measurements of the 1H NMR spectra of the diastereoisomers of 1-(tetrahydro-2-furanyl)-5-fluorouracil, 3-(tetrahydro-2-furanyl)-5-fluorouracil, and 1,3-bis(tetrahydro-2-furanyl)-5-fluorouracil in the presence of tris[3-(2,2,2-trifluoro-1-hydroxyethylidene)-d-camphorato]europium(Eu(TFC)3) as a chiral shift reagent showed differences between the isomers in the chemical shift changes of the protons of C2'-H and C6-H etc.     

5-{2-[4-(2-methyl-5-quinolinyl)-1-piperazinyl]ethyl}-2(1H)-quinolinones and 3,4-dihydro-2(1H)-quinolinones: dual-acting 5-HT1 receptor antagonists and serotonin reuptake inhibitors. Part 3

5-{2-[4-(2-Methyl-5-quinolinyl)-1-piperazinyl]ethyl}-2(1H)-quinolinones and 3,4-dihydro-2(1H)-quinolinones have been identified with different combinations of 5-HT(1) autoreceptor antagonist and hSerT potencies and excellent rat PK profiles. The availability of tool compounds with a range of profiles at targets known to play a key role in the control of synaptic 5-HT levels will allow exploration of different pharmacological profiles in a range of animal behavioral and disease models.     

(R)-3-(N-methylpyrrolidin-2-ylmethyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole derivatives as high affinity h5-HT1B/1D ligands

A series of (R)-3-(N-methylpyrrolidin-2-ylmethyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole derivatives (2) have been prepared using parallel synthesis, and their structure-activity relationship studied. High affinity human 5-HT(1B/1D) (h5-HT(1B/1D)) ligands have been identified.     

Retinoic acid metabolism inhibition by 3-azolylmethyl-1H-indoles and 2, 3 or 5-(alpha-azolylbenzyl)-1H-indoles

Among a library of 70 azoles, 8 indole derivatives substituted in the 2-, 3- or 5- position with an azolylmethyl or alpha-azolylbenzyl chain were evaluated for retinoic acid (RA) metabolism inhibitory activity. The most active inhibitors identified in this study were 5-bromo-1-ethyl-3-methyl-2-[(phenyl)(1H-1,2,4-triazol-1-yl)methyl]-1H-indole (3) (68.9% inhibition) and 5-bromo-1-ethyl-2-[(4-fluorophenyl) (1H-1,2,4-triazol-1-yl)methyl]-3-methyl-1H-indole (6) (60.4% inhibition). At the same concentration (100 microM) ketoconazole exerted similar inhibitory effect (70% inhibition).     

1-(2-Aminoethyl)-3-(arylsulfonyl)-1H-pyrrolopyridines are 5-HT6 receptor ligands

1-(2-Aminoethyl)-3-(arylsulfonyl)-1H-pyrrolopyridines were prepared. Binding assays indicated they are 5-HT₆ receptor ligands, among which 6f and 6g showed high affinity for 5-HT₆ receptors with K_i = 3.9 and 1.7 nM, respectively.     

3-(4-Piperidinyl)- and 3-(8-aza-bicyclo[3.2.1]oct-3-yl)-2-phenyl-1H-indoles as bioavailable h5-HT2A antagonists

A series of 3-(4-piperidinyl)- and 3-(8-aza-bicyclo[3.2.l]oct-3-yl)-2-phenyl-1H-indoles have been prepared and evaluated as ligands for the h5-HT_2A receptor. 3-(8-Phenethyl-8-aza-bicyclo[3.2.l]oct-3-yI)-2-phenyl-1H-indole is a high-affinity (1.2 nM), selective (>800 fold over h5-HT_2C and hD₂ receptors) antagonist at the h5-HT_2A receptor with oral bioavailability in rats.