Effect of subinhibitory concentration of some established and experimental antifungal compounds on the germ tube formation in Candida albicans

The influence of subinhibitory concentrations of six established and 19 newly synthesized antifungal compounds on the dimorphic transition of three C. albicans strains was evaluated in the filamentation-inducing medium. Amphotericin B was found to produce almost complete inhibition in the germination at a concentration of 1/10 of the corresponding MIC and partial inhibition at a concentration as low as MIC/50. Flucytosine and four azole derivatives were proven ineffective. From the newly synthesized drugs, the incrustoporin derivative LNO6-22, two phenylguanidine derivatives (PG15, PG45), and four thiosalicylanilide derivatives, in particular, showed results comparable to those of amphotericin B, with a high inhibition of germ tube formation at concentrations of MIC/10. In general, concentrations of MIC/50 had no visible effect.

Regioselective Synthesis of 5-Alkylsalicylates, 5-Alkyl-2-hydroxy-acetophenones, and 5-Alkyl-2-hydroxy-benzophenones by [3 + 3] Cyclization of 1,3-Bis(silyl enol ethers) with 2-Alkyl-1,1,3,3-tetraethoxypropanes

A variety of 5-alkylsalicylates, 5-alkyl-2-hydroxy-acetophenones, and 5-alkyl-2-hydroxy-benzophenones was regioselectively prepared by TiCl4 mediated formal [3 + 3] cyclization of 1,3-bis(silyl enol ethers) with 2-alkyl-1,1,3,3-tetraethoxypropanes.

Thiosemicarbazones of Formyl Benzoic Acids as Novel Potent Inhibitors of Estrone Sulfatase

Thiosemicarbazones of the microbial metabolite madurahydroxylactone, a polysubstituted benzo[a]naphthacenequinone, have been previously reported by us as potent nonsteroidal inhibitors of the enzyme estrone sulfatase (cyclohexylthiosemicarbazone 1, IC50 0.46 microM). The active pharmacophore of 1 has now been identified to be 2-formyl-6-hydroxybenzoic acid cyclohexylthiosemicarbazone (25, IC50 4.2 microM). The active partial structure was derivatized in the search for novel agents against hormone-dependent breast cancer. Further substantial increases in activity were achieved by reversal of functional groups leading to the cyclohexylthiosemicarbazones of 5-formylsalicylic acid (35, IC50 0.05 microM) and 3-formylsalicylic acid (34, IC50 0.15 microM) as the most potent analogues identified to date. Both compounds were shown to be noncompetitive inhibitors of estrone sulfatase with Ki values of 0.13 microM and 0.12 microM, respectively. The compounds showed low acute toxicity in the hen's fertile egg screening test.

Methylenedisalicylic acid derivatives: New PTP1B inhibitors that confer resistance to diet-induced obesity

Methylenedisalicylic acid derivatives were synthesized and their inhibitory activities against protein tyrosine phosphatases (PTPases) examined. Two of the compounds, 8 and 9, showed K(i) values of 9.4 and 6.3microM against PTP1B, 4- and 7-fold lower values compared to those against TC-PTP. They were reversible and slow-binding inhibitors against PTP1B. When compound 8 was fed to a mouse model, the weight gain and adipocyte fat storage induced by a high-fat-diet were significantly suppressed.

[Synthesis and bioactivies of salicylic acid-g-chitosan derivatives]

To prepare the derivatives of salicylic acid-g-chitosan and study their synergistic and complementary actions, the synergism of anti-inflammatory action of the derivatives was investigated with the experiments of xylene-induces mice ear edema, the analgesic activities by the tartaric emetic-induced mice twist test and the hot-plate test, and the complementary effects between salicylic acid and chitosan through morphological changes of stomach mucous membrane of rat, separately. The anti-inflammatory activities of salicylic acid-g-chitosan derivatives for anti-inflammatory activities were more potent than that of salicylic acid and chitosan and dexamethasone cream in external use, and more potent than that of aspirin orally. However, immediate analgesic activity of the derivatives was lower than that of aspirin and persistent activity was similar as that of aspirin. And the stomach mucous membrane morphology change of the derivatives was much milder than that of aspirin. The salicylic acid grafted chitosan derivatives showed synergistic and complementary effect on the anti-inflammatory and analgesic activities and so on.

Development of molecular probes for second-site screening and design of protein tyrosine phosphatase inhibitors

We report on the design, synthesis, and evaluation of a series of furanyl-salicyl-nitroxide derivatives as effective chemical probes for second-site screening against phosphotyrosine phosphatases (PTPs) using NMR-based techniques. The compounds have been tested against a panel of PTPs to assess their ability to inhibit a broad spectrum of these phosphatases. The utility of the derived compounds is illustrated with the phosphatase YopH, a bacterial toxin from Yersinia pestis. Novel chemical fragments were identified during an NMR-based screen for compounds that are capable of binding on the surface of YopH in regions adjacent the catalytic site in the presence of the spin-labeled compounds. Our data demonstrate the value of the derived chemical probes for NMR-based second-site screening in PTPs.

Queen sex pheromone of the slave-making ant, Polyergus breviceps

Workers of the slave-making ant, Polyergus breviceps, raid nests of Formica ants and return with Formica pupae that mature into worker ants in the slave-makers' colony. These Formica workers then tend the Polyergus brood, workers, and reproductives. During raids in the mating season, winged virgin Polyergus queens accompany the workers in the raiding columns. During the raid, the virgin queens release a pheromone that attracts males that quickly mate with the queens. We report the identification, synthesis, and bioassay of the sex attractant pheromone of the queens as an approximately 1:6 ratio of (R)-3-ethyl-4-methylpentan-1-ol and methyl 6-methylsalicylate. The ants produce exclusively the (R)-enantiomer of the alcohol, and the (S)-enantiomer has no biological activity, neither inhibiting nor increasing attraction to blends of methyl 6-methylsalicylate with the (R)-enantiomer.

2-(4-Chlorobenzyl)-3-hydroxy-7,8,9,10-tetrahydrobenzo[H]quinoline-4-carboxylic Acid (PSI-697): Identification of a Clinical Candidate from the Quinoline Salicylic Acid Series of P-Selectin Antagonists

P-selectin-PSGL-1 interaction causes rolling of leukocytes on the endothelial cell surface, which subsequently leads to firm adherence and leukocyte transmigration through the vessel wall into the surrounding tissues. P-selectin is upregulated on the surface of both platelets and endothelium in a variety of atherosclerosis-associated conditions. Consequently, inhibition of this interaction by means of a small molecule P-selectin antagonist is an attractive strategy for the treatment of atherosclerosis. High-throughput screening and subsequent analoging had led to the identification of compound 1 as the lead candidate. Herein, we report the continuation of this work and the discovery of a second-generation series, the tetrahydrobenzoquinoline salicylic acids. These compounds have improved pharmacokinetic properties, and a number of them have shown oral efficacy in mouse and rat models of atherogenesis and vascular injury. The lead 31 (PSI-697), is currently in clinical development for the treatment of atherothrombotic vascular events.

Synthesis and Biological Evaluation of Quinoline Salicylic Acids As P-Selectin Antagonists

Leukocyte recruitment of sites of inflammation and tissue injury involves leukocyte rolling along the endothelial wall, followed by firm adherence of the leukocyte, and finally transmigration of the leukocyte across cell junctions into the underlying tissue. The initial rolling step is mediated by the interaction of leukocyte glycoproteins containing active moieties such as sialyl Lewisx (sLex) with P-selectin expressed on endothelial cells. Consequently, inhibition of this interaction by means of a small molecule P-selectin antagonist is an attractive strategy for the treatment of inflammatory diseases such as arthritis. High-throughput screening of the Wyeth chemical library identified the quinoline salicylic acid class of compounds (1) as antagonists of P-selectin, with potency in in vitro and cell-based assays far superior to that of sLex. Through iterative medicinal chemistry, we identified analogues with improved P-selectin activity, decreased inhibition of dihydrooratate dehydrogenase, and acceptable CYP profiles. Lead compound 36 was efficacious in the rat AIA model of rheumatoid arthritis.

Novel inhibitors of the trypanosome alternative oxidase inhibit Trypanosoma brucei brucei growth and respiration

African trypanosomiasis is a deadly disease for which few chemotherapeutic options are available. The causative agents, Trypanosoma brucei rhodesiense and T. b. gambiense, utilize a non-cytochrome, alternative oxidase (AOX) for their cellular respiration. The absence of this enzyme in mammalian cells makes it a logical target for therapeutic agents. We designed three novel compounds, ACB41, ACD15, and ACD16, and investigated their effects on trypanosome alternative oxidase (TAO) enzymatic activity, parasite respiration, and parasite growth in vitro. All three compounds contain a 2-hydroxybenzoic acid moiety, analogous to that present in SHAM, and a prenyl side chain similar to that found in ubiquinol. ACD15 and ACD16 are further differentiated by the presence of a solubility-enhancing carbohydrate moiety. Kinetic studies with purified TAO show that all three compounds competitively inhibit TAO, and two compounds, ACB41 and ACD15, have inhibition constants five- and three-fold more potent than SHAM, respectively. All three compounds inhibited the respiration and growth of continuously cultured T. b. brucei bloodstream cells in a dose-dependent manner. None of the compounds interfered with respiration of rat liver mitochondria, nor did they inhibit the growth of a continuously cultured mammalian cell line. Collectively, the results suggest we have identified a new class of compounds that are inhibitors of TAO, have trypanocidal properties in vitro, and warrant further investigation in vivo.

Novel chemically synthesized salicylate derivative as an effective elicitor for inducing the biosynthesis of plant secondary metabolites

Trifluoroethyl salicylate (TFESA), a novel salicylate derivative, was chemically synthesized and evaluated by bioassay as a potential elicitor for inducing the biosynthesis of plant secondary metabolites. A cell line of Taxus chinensis, which stably produced a high level of bioactive taxuyunnanine C (Tc), was taken as a model plant cell system. The application of TFESA to the cell cultures could significantly induce Tc biosynthesis, although the cell growth was slightly inhibited. More interestingly, Tc production was enhanced more in the presence of TFESA compared with a structure-similar well-known elicitor, salicylic acid (SA). For example, addition of 100 microM TFESA on day 7 led to a high Tc content of 21.9 +/- 0.1 mg g(-1) (at day 21), whereas the Tc content was 14.0 +/- 0.2 and 16.7 +/- 0.3 mg g(-1) for the control and that with addition of 100 microM SA, respectively. The results indicate that the newly synthesized TFESA can act as a powerful elicitor for secondary metabolism induction in plant cell cultures.

[Structure-activity relationships of salicylic acid and its analogs in the inhibitory action on beta-lactamase]

AIM

Nineteen compounds related to salicylic acid were evaluated for their in vitro activity of inhibiting beta-lactamase isolated from a resistant strain of Pseudomonas aeruginosa, and their structure-activity relationships were examined.

METHODS

Nitrocefin method was used.

RESULTS

The 50% inhibitory concentration (IC50) of salicylic acid inhibiting beta-lactamase was 22 mmol x L(-1); four analogs had IC50 lower than that of salicylic acid; fifteen analogs had IC50 higher than that of salicylic acid.

CONCLUSION

Examination of the structure-activity relationships of the compounds revealed that carboxyl group and adjoining hydroxyl group were active group, and replacement of adjoining hydroxyl by carboxyl increased activity nearly 4-fold. Moreover, addition of a sulfonic group at C-5 and nitro group at C-3, 5 of benzenoic ring of salicylic acid resulted in a 2-fold to 3-fold increase in activity, addition of a amino group at C-5 of benzenoic ring of salicylic acid decreased activity, add addition of -Cl or -F at C-2,4 position of benzenoic ring of benzoic acid did not show activity.

Directed Ortho-Metalation of Unprotected Benzoic Acids. Methodology and Regioselective Synthesis of Useful Contiguously 3- and 6-Substituted 2-Methoxybenzoic Acid Building Blocks

[reaction: see text] By treatment with s-BuLi/TMEDA at -78 degrees C, unprotected 2-methoxybenzoic acid is deprotonated exclusively in the position ortho to the carboxylate. A reversal of regioselectivity is observed when the acid is treated with n-BuLi/t-BuOK. These results are of general utility for the one-pot preparation of a variety of very simple 3- and 6-substituted 2-methoxybenzoic acids that are not easily accessible by conventional means. The potential usefulness of the method is demonstrated by the expedient synthesis of lunularic acid.

Synthesis and anti-inflammatory testing of some new compounds incorporating 5-aminosalicylic acid (5-ASA) as potential prodrugs

This work includes the synthesis of 15 final compounds (6a-h and 7b-h) as prodrugs of 5-ASA in the form of the acid itself, esters and amides linked by an amide linkage through a spacer to the endocyclic ring N of nicotinamide. Also, 15 new intermediate compounds were prepared. The target compounds (6b, 6f, 7b, and 7e-h) revealed potent analgesic and anti-inflammatory activities in comparison to sulfasalazine and 5-ASA. In addition, ulcerogenicity, LD50, in vivo and in vitro metabolism of compound 7f were determined.

Synthesis of Photoactivatable Acyclic Analogues of the Lobatamides

[structure: see text] The lobatamides and related salicylate enamide natural products are potent mammalian V-ATPase inhibitors. To probe details of binding of the lobatamides to mammalian V-ATPase, three photoactivatable analogues bearing benzophenone photoaffinity labels have been prepared. The analogues were designed on the basis of a simplified acyclic analogue 2. Late-stage installation of the enamide side chain and tandem deallylation/amidation were employed in synthetic routes to these derivatives. Simplified analogue 2 showed strong inhibition against bovine clathrin-coated vesicle V-ATPase (10 nM). Analogues 3-5 were also evaluated for inhibition of bovine V-ATPase in order to select a suitable candidate for future photoaffinity labeling studies.

catena-Poly[[bis(1H-benzimidazole-kappaN3)(salicylato-kappaO)copper(II)]-mu-salicylato-O,O':O'']

The title compound, [Cu(C7H5O3)2(C7H6N2)2]n, is a one-dimensional polymeric complex bridged by salicylate anions. The Cu(II) atom is surrounded by three salicylate and two benzimidazole ligands, with a tetragonally elongated octahedral coordination geometry. The Cu-O bond distances in the axial directions are 2.6092 (16) and 2.6834 (17) A. pi-pi stacking interactions exist between the benzimidazole rings of neighboring polymeric complex chains.

Crystal structure and characterization of the dinuclear Cd(II) complex [Cd(H2O)2(o-HOC6H4COO)2]2

The structure of a new binuclear cadmium (II) complex, [Cd(H2O)2(Sal)2]2 (Sal= salicylate), has been determined by X-ray crystallography. It was also characterized by elemental analysis, its IR spectrum and thermogravimetric-differential scanning calorimetry (TG-DSC). It crystallizes in the monoclinic system, space group P2(1)/c, with lattice parameters a = 15.742(3) A, b = 12.451(3) A, c = 7.7225(15) A, beta = 96.07(3)degrees and Z = 4. Two cadmium (II) ions are bridged by two mu(2)-carboxy oxygen atoms. Each cadmium atom lies in a distorted capped octahedron coordination geometry. The thermal gravimetry (TG) data indicate that there are four discrete decomposition steps with two endothermic peaks and one exothermic peak. The final thermal decomposition product is CdO.

Potential antipsoriatic avarol derivatives as antioxidants and inhibitors of PGE(2) generation and proliferation in the HaCaT cell line

The synthesis and structure-activity relationships for a series of 14 new avarol derivatives as antioxidants and inhibitors of cell proliferation and PGE(2) generation in human keratinocytes are described. Compound 6 (thiosalicylic derivative) was the most potent inhibitor of superoxide generation in human neutrophils and also potently inhibited PGE(2) generation in the human keratinocyte HaCaT cell line. Compound 7(3'-methylaminoavarone) presented the best antiproliferative profile, by the inhibition of (3)H-thymidine incorporation in HaCaT cells, with potency similar to the reference compound anthralin. None of the avarol derivatives showed any sign of cytotoxicity measured as LDH release in treated keratinocytes. The potency and pharmacological profile of derivatives are also discussed.

[Influence of 2-aryl-3-halogen/3-hydroxy-1,4-naphthoquinones with salicylic and cinnamic acid partial structures on the arachidonic acid cascade]

Searching for more potent 5-lipoxygenase (LO) inhibitors one tert-butyl group of the selective 5-LO-inhibitor 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-3-hydroxy-1,4-naphthoquinone (1) was substituted by polar functions (-CHO, -COOH, -CH=CH-COOR, -CH2-CH2-COOR). At the same time the 5-LO selectivity of the new compounds within the arachidonic acid cascade was investigated. For this 12-LO- and COX-1-assays with activated human platelets were used. Screening the test compounds new selective 5-LO-inhibitors (4, 9 and 16) and a COX-1-inhibitor (10) as well as dual 5-LO/COX-1- (23) and 12-LO/COX-1- (12) inhibiting compounds were found. Obviously in this class of compounds 5-LO and 12-LO inhibition are mutually excluded for a structural reason. In addition to the well known 3-chloro- (19) and 3-bromo- (20) analogues of 1 the 3-fluoro- (22), 3-iodo- (23) and the 3-carbonitrile- (24) derivatives were synthesized. All 3-halogen compounds, except 23 and the nitrile, are potent non selective inhibitors of all three enzymes. Causative for this unselectivity is the inhibition of the arachidonic acid release by inhibition of the cytosolic phospholipase A2 (cPLA2) with the exception of 24.

Divergent and Stereocontrolled Synthesis of the Enamide Side Chains of Oximidines I/II/III, Salicylihalamides A/B, Lobatamides A/D, and CJ-12,950

[reaction: see text] A unified strategy for the divergent and stereocontrolled introduction of the (E)- and (Z)-enamide side-chains of oximidines I, II, and III, salicylihalamides A and B, lobatamides A and D, and CJ-12,950 is detailed. The synthesis relied on the copper-promoted C-N coupling of (E)- and (Z)-vinyl iodides with a protected maleimide hemiaminal followed by deprotection and reaction of the resulting (E)- or (Z)-enelactam hemiaminals with O-methylhydroxylamine or propylidenetriphenylphosphorane.

Selective protein tyrosine phosphatase 1B inhibitors: targeting the second phosphotyrosine binding site with non-carboxylic acid-containing ligands

Protein tyrosine phosphatase (PTPase) 1B (PTP1B) has been implicated as a key negative regulator of both insulin and leptin signaling cascades. We identified several salicylic acid-based ligands for the second phosphotyrosine binding site of PTP1B using a NMR-based screening. Structure-based linking with a catalytic site-directed oxalylarylaminobenzoic acid-based pharmacophore led to the identification of a novel series of potent PTP1B inhibitors exhibiting 6-fold selectivity over the highly homologous T-cell PTPase (TCPTP) and high selectivity over other phosphatases.

Lobatamide C: total synthesis, stereochemical assignment, preparation of simplified analogues, and V-ATPase inhibition studies

The total synthesis and stereochemical assignment of the potent antitumor macrolide lobatamide C, as well as synthesis of simplified lobatamide analogues, is reported. Cu(I)-mediated enamide formation methodology has been developed to prepare the highly unsaturated enamide side chain of the natural product and analogues. A key fragment coupling employs base-mediated esterification of a beta-hydroxy acid and a salicylate cyanomethyl ester. Three additional stereoisomers of lobatamide C have been prepared using related synthetic routes. The stereochemistry at C8, C11, and C15 of lobatamide C was assigned by comparison of stereoisomers and X-ray analysis of a crystalline derivative. Synthetic lobatamide C, stereoisomers, and simplified analogues have been evaluated for inhibition of bovine chromaffin granule membrane V-ATPase. The salicylate phenol, enamide NH, and ortho-substitution of the salicylate ester have been shown to be important for V-ATPase inhibitory activity.