Cytotoxic activity of platinum (II) complexes with tri-n-butylphosphine. Crystal structure of the dinuclear hydrazine-bridged complex, cis,cis-[PtCl(PBu3n)2(mu-N2H4)PtCl(PBu3n) 2] (ClO4)2.2CHCl3.

A series of platinum(II) tri-n-butylphosphine complexes having the formulas cis-[PtCl2L2], NEt4[PtCl3L], [PtCl(en)L]Cl, [Pt(en)L2](ClO4)2, sym-trans-[Pt2Cl4L2], [Pt2Cl2L4](ClO4)2, trans,trans-[PtCl2L(mu-N2H4)PtCl2L] trans,trans-[PtCl2L(mu-en)PtCl2L], and cis,cis-[PtClL2(mu-N2H4)PtClL2](ClO4)2 (L = tri-n-butylphosphine; en = ethylenediamine) have been synthesized and their cytotoxic activity in vitro and in vivo has been studied. The solution behavior of the novel dinuclear diamine-bridged platinum(II) complexes has been investigated by means of UV and 31P NMR spectroscopy. For the ionic hydrazine compound cis,cis-[PtClL2(mu-N2H4)PtClL2](ClO4)2, an x-ray structure determination is reported. Crystal data: space group P2(1)/a, a = 17.803(1), b = 18.888(3), c = 12.506(3) A, beta = 107.97(2) degrees, Z = 2, R = 0.052, RW = 0.058. The platinum coordination is approximately square-planar, with the bond lengths Pt-Cl = 2.358(5), Pt-N = 2.15(1), Pt-P(trans to Cl) = 2.260(5), and Pt-P(trans to N) = 2.262(6) A. All investigated compounds were cytotoxic in vitro against L1210 cells and showed no cross-resistance to cisplatin. On the other hand, no antitumor activity was observed vs L1210 leucemia in DBA2 mice.     

3-(4-Methyl-3-pentenyl)-2(5H)-furanone, alpha,alpha-acariolide and 4-(4-methyl-3-pentenyl)-2(5H)-furanone, alpha,beta-acariolide: new monoterpene lactones from the astigmatid mites, Schwiebea araujoae and Rhizoglyphus sp. (Astigmata: Acaridae)

A new monoterpene lactone from the acarid mite, Schwiebea araujoae, was elucidated without its isolation by GC/FT-IR and GC/MS analyses to be 3-(4-methyl-3-pentenyl)-2(5H)-furanone (1) and tentatively named as alpha,alpha-acariolide. The structure of 1 was identified by its synthesis from alpha-bromo-gamma-butyrolactone via 4 reaction steps. The synthesized compound gave the same GC/MS and GC/FT-IR spectra as those of the natural product. The other monoterpene lactone was likewise elucidated from the unidentified Rhizoglyphus mite to be 4-(4-methyl-3-pentenyl)-2(5H)-furanone (2) and named as alpha,beta-acariolide; it was also identified by its synthesis in 5 reaction steps from the same butyrolactone as the starting material. GC/MS and GC/FT-IR spectra of the preparation were identical to those of the natural product.     

2-Alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)carboxylic acids and amides: synthesis,molecular docking,antimicrobial and anticancer properties

In this study, a series of novel 2-alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)carboxylic acids and amides were synthesized and evaluated for antimicrobial and anticancer activities. Their structure was confirmed by elemental analysis and spectral data (FT-IR, LC-MS, ¹H-NMR). Antimicrobial activity was tested in vitro against Staphylococcus aureus, Enterococcus faecalis, Enterobacter aerogenes, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Candida albicans and NCI in vitro preliminary anticancer activity against nine different cancer types. The most active antibacterial and antifungal compounds were: 2.1, 2.2 and 2.4. The introduction of the carboxylic acid or amide residue into the fourth position of quinazolin-4(3H)-thione resulted in the absence of antimicrobial activity. Substance 3.8 inhibited renal cancer UO-31 line and 2.18 – leukemia CCRF-CEM. The results of in silico molecular docking for DHFR and CK2 kinase had no correlation with in vitro properties, proposing the presence of other biological activity pathways.     

Synthesis of N4-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine analogues. n-Butyramide, 3-chloropropionamide, 3-aminopropionamide, and isovaleramide analogues

The syntheses of four analogues of N4-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine are described. Activated carboxylic acids were reacted with 2-acetamido-2-deoxy-beta-D-glucopyranosylamine. n-Butyric anhydride gave N-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-n-butyramide. 3-Chloropropionic anhydride was synthesized from 3-chloropropionic acid and gave N-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-3-chloropropionamide. Equilibration of the latter with ammonium bicarbonate gave N1-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-3-aminopropionamide. Succinimidyl isovalerate was synthesized and gave N-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-isovaleramide.     

Optical activity of dimolybdenum complex induced by chiral,chelating diamine ligand; syntheses and structures of [Mo2(O2CCF3)2(S,S-dach)2(CH3CN)2][BF4]2 and [Mo2(O2CCF3)2(R,R-dach)2(CH3CN)2][BF4]2 (dach=1,2-diaminocyclohexane)

The first structurally characterized, quadruply bonded complexes containing chiral diamine ligands, [Mo₂(O₂CCF₃)₂(S,S-dach)₂(CH₃CN)₂][BF₄]₂ (1), and [Mo₂(O₂CCF₃)₂(R,R-dach)₂(CH₃CN)₂][BF₄]₂ (2); (dach=1,2-diaminocyclohexane) were prepared by reactions of [Mo₂(O₂CCF₃)₂(CH₃CN)₆][BF₄]₂ with S,S-dach and R,R-dach, respectively, in CH₃CN. Their UV–Vis and circular dichroism (CD) spectra have been recorded and their structures determined by X-ray crystallography. Crystals of complexes 1 and 2 conform to the space groups P2 with two independent half molecules in the asymmetric unit. The two molecules have a similar structure consisting of a Mo₂ unit bridged by two cis-trifluoroacetate ligands and chelated by two dach ligands. Two acetonitrile molecules are coordinated to the Mo centers along the MoMo bond. The absorption wavelength at 507 nm for both 1 and 2 can be assigned to δ_xy→δ_xy* transitions. The solution CD spectra of these two complexes show two prominent bands at 525 and 385 nm and form mirror images of each other. The solid CD spectra of complexes 1 and 2 show marked red-shift in the absorption energies as compared with those measured in solution. The one-electron static coupling mechanism was invoked to explain the CD spectra for these complexes and the second lowest energy bands were assigned to be δ_xy→δ_x²−y² transitions.     

Inhibition of ADAMTS4 (aggrecanase-1) by tissue inhibitors of metalloproteinases (TIMP-1, 2, 3 and 4)

ADAMTS4 (aggrecanase-1) is considered to play a key role in the degradation of aggrecan in arthritides. The inhibitory activity of tissue inhibitors of metalloproteinases (TIMPs) to ADAMTS4 was examined in an assay using aggrecan substrate. Among the four TIMPs, TIMP-3 inhibited the activity most efficiently with an IC(50) value of 7.9 nM, which was at least 44-fold lower than that of TIMP-1 (350 nM) and TIMP-2 (420 nM) and >250-fold less than that of TIMP-4 (2 microM for 35% inhibition). These results suggest that TIMP-3 is a potent inhibitor against the aggrecanase activity of ADAMTS4 in vivo.     

Mechanistic studies on metal-pyrophosphate hydrolysis. Structure of tetraammine(chloroaquo)cobalt (III) dichloride ([Co(NH3)4ClH2O]2+.2Cl-), an acid hydrolysis product of Co(NH3)4HP2O7 and Co(NH3)4PO4

The octahedral complex tetraammine(chloroaquo)cobalt(III) dichloride is shown to be the HCl hydrolysis product of both P1,2-bidentate tetraammine(pyrophosphato)cobalt(III) [Co(NH3)4HP2O7 or CoPP] and bidentate tetraammine(phosphato)cobalt(III) [Co(NH3)4PO4 or CoP]. The complex crystallizes in the orthorhombic space group Pna21 with cell dimensions a = 13.033(2)A, b = 6.710(1)A, and c = 10.318(2)A; the crystal structure was refined to a final disagreement index of 0.033. The average of the four Co-N distances is 1.944 +/- 6A. The Co-Cl distance is 2.257(2)A and the Co-O(W) distance is 1.971(4)A. Both protons of the coordinated water molecule are engaged in strong hydrogen bonds to the two nonbonded chloride counterions with O(W)-Cl distances of 3.087(6)A and 3.123(6)A. Each nonbonded chloride is engaged in seven hydrogen bonding interactions resulting from the high ratio of hydrogen bond donors to acceptors in the CoP structure. Cobalt bisphosphate (CoP2) is the final enzyme hydrolysis product when CoPP is used as substrate in the yeast inorganic pyrophosphatase reaction. The bridge oxygen atom is the site of initial CoPP cleavage both for HCl catalyzed hydrolysis as well as for enzyme catalyzed hydrolysis.     

Synthesis of novel 2-phenylsulfonylhydrazono-3-(2',3',4',6'-tetra-O-acetyl-beta-d-glucopyranosyl)thiazolidine-4-ones from thiosemicarbazide precursors

To develop novel biologically active organic compounds possessing a sugar moiety, a series of 2-phenylsulfonylhydrazono-3-(2',3',4',6'-tetra-O-acetyl-beta-d-glucopyranosyl)thiazolidine-4-one were synthesized via reaction of the thiosemicarbazide with ethyl bromoacetate. Their chemical structures were characterized by (1)H and (13)C NMR spectroscopy, elemental analysis and MS. The bioassay results indicated that some of these compound exhibit moderate fungicidal and herbicidal activities. Furthermore, the effect of various solvents at reflux temperature on the reactions of ethyl bromoacetate with the related thiosemicarbazides was investigated.     

Conformational analysis of m4(2)C-m4(2)C-m6(2)A: a chemically modified 3'-acceptor end of tRNA, studied by NMR and CD methods.

A study on the conformation of the title compound, C-C-A, and on its constituent dinucleotides is presented. 1H-NMR spectra at 360 and 500 MHz were completely assigned by decoupling experiments. Computer simulation of the spectra yielded precise proton-proton and proton-phosphorus coupling constant values. The coupling constants are analyzed in terms of torsion angles and of N- and S-type sugar pucker. 31P-NMR spectra gave some information about P-O backbone torsion angles alpha and zeta. CD spectroscopy was used to obtain insight in the base-base interaction. The C(1) and C(2) unit in C-C-A show normal preference for N-type conformation of the sugar ring, whereas the A(3) residue appears rather biased towards the S-conformation. The zeta and alpha backbone torsion angles in the C-C phosphodiester linkage in C-C-A appear to assume normal g-, g- conformation, the zeta, alpha combination in the C-A linkage is proposed to have a g+, t conformation. In the C-C fragment in C-C-A a regular stack is indicated; it is suggested that the C-A part adopts an unusual antiparallel base stack.     

The discovery of rofecoxib, [MK 966, Vioxx, 4-(4'-methylsulfonylphenyl)-3-phenyl-2(5H)-furanone], an orally active cyclooxygenase-2-inhibitor.

The development of a COX-2 inhibitor rofecoxib (MK 966, Vioxx) is described. It is essentially equipotent to indomethacin both in vitro and in vivo but without the ulcerogenic side effect due to COX-1 inhibition.     

Derivatives of (2R,3R,4S)-2-aminomethylpyrrolidine-3,4-diol are selective alpha-mannosidase inhibitors.

A collection of (2R,3R,4S)-3,4-dihydroxypyrrolidin-2-yl derivatives have been tested for their inhibitory activities toward 25 glycosidases. Competitive (K(i)=7.4 microM) and selective inhibition of alpha-mannosidase from jack bean has been found for (2R,3R,4S)-2-[(benzylamino)methyl]pyrrolidine-3,4-diol and other derivatives.     

Resistance profiles of (+)2'-deoxy-3'-oxa-4'-thiocytidine and (-)2'-deoxy-3'-oxa-4'-thio-5-fluorocytidine.

Resistant variants were selected in vitro against two novel nucleoside analogues, (+) dOTC and (-) dOTFC using the HIV-1 molecular clone HXB2D. The variants obtained displayed 6.5-fold and 10-fold resistance to these compounds, respectively. Cloning and sequencing of the RT genes of the selected viruses identified two mutations, M184I for (+) dOTC and M184V for (-) dOTFC. Results with mutated recombinant clones of HXB2D confirmed the importance of these mutations in MT-4 cells. The resistance profiles of clinical samples with wild-type or 3TC-resistant phenotypes were also studied; low to moderate levels of cross-resistance were observed against the novel compounds.     

2-(2'-phosphoryloxyphenyl)-4(3H)-quinazolinone derivatives as fluorogenic precipitating substrates of phosphatases.

Characterization of 2-(2'-phosphoryloxyphenyl)-4(3H)-quinazolinone (PPQ) derivatives as fluorogenic precipitating substrates of phosphatases is reported in this work. Soluble and colorless PPQ derivatives can be specifically hydrolyzed by acid and alkaline phosphatases into insoluble products, 2-(2'-hydroxyphenyl)-4(3H)-quinazolinone (HPQ) derivatives which appear as fluorescent precipitates in water. The fluorescence and precipitation of HPQ depend on the concentration of its neutral phenolic form and therefore are related to the aqueous pH and PPQ concentration converted. Since HPQ formed from corresponding PPQ hydrolysis by phosphatases instantly precipitates and simultaneously fluoresces with a high photostability and large Stokes shift in water, PPQ can serve as a novel class of substrate dyes for detecting any immobilized phosphatase activities in situ, especially for applications of sensitive fluorescence histochemistry and cytochemistry. This is demonstrated by the alkaline phosphatase-aided visualization of static concanavalin A (Con A) receptors. By a linkage-amplification technique involving biotinylated Con A, streptavidin-alkaline phosphatase conjugate, and a PPQ substrate, the Con A receptors on the membrane of fixed NIH 3T3 cell were specifically viewed as dense, contrasting, durable, and cytologically resolved fluorescent stains under a conventional fluorescent microscope.     

Short and efficient synthesis of (2S,3R,4R,5R) and (2S,3R,4R,5S)-tetrahydroxyazepanes via the Henry reaction

The Henry reaction with the easily available alpha-d-xylo-pentodialdose afforded a diastereomeric mixture of nitroaldoses with the alpha-d-gluco- and beta-l-ido-configuration, respectively, in good yield. When n-BuLi was used as the base, the reaction afforded the alpha-d-gluco-nitroaldose as the only product. The reduction of the nitro group in the alpha-d-gluco- and beta-l-ido-nitroaldoses, removal of the protecting groups and intramolecular reductive cyclo-amination afforded the corresponding (2S,3R,4R,5R) and (2S,3R,4R,5S) tetrahydroxyazepanes.     

Preparation,structure and properties of dicyano silver complexes of the M(en)3Ag2(CN)4 and M(en)2Ag2(CN)4 type

Complexes of the M(en)₃Ag₂(CN)₄ (M = Ni, Zn, Cd) and M(en)₂Ag₂(CN)₄ (M = Ni, Cu, Zn, Cd) type were prepared and identified by elemental analysis, infrared spectroscopy, measurement of magnetic susceptibility, and X-ray powder diffractometry. The crystal structures of Ni(en)₃Ag₂(CN)₄ (I) and Zn(en)₂Ag₂(CN)₄ (II) were determined by the method of monocrystal structure analysis. Complex I crystallizes in the space group C2/c, a = 1.2639(5), b = 1.3739(4), c = 1.2494(4) nm, β = 113.25(4)°, D_m = 1.86(1), D_c = 1.86 gcm⁻³ Z = 4, R = 0.0429. The crystal structure of I consists of complex cations [Ni(en)₃]²⁺ and complex anions [Ag(CN)₂]⁻. Complex II crystallizes in the space group I2/m, a = 0.9150(3), b = 1.3308(4), c = 0.6442(2) nm, β = 95.80(3)°, D_m = 2.14(1), D_c = 2.15 gcm⁻³, Z = 2, R = 0.0334. Its crystal structure consists of infinite, positively charged chains of the [-NCAgCNZn- (en)₂]_nⁿ⁺ type and isolated [Ag(CN)₂]⁻ anions. The atoms of Ag are positioned parallely to the z axis and the AgAg distance is equal to 0.3221(2) nm.     

Synthesis of the isomeric trisaccharides, methyl O-alpha-L-fucopyranosyl- (1----3, 4, and 6)-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----3)-beta- D-galactopyranoside

Benzylation of methyl 3-O-(2-acetamido-4,6-O-benzylidene-2-deoxy-beta-D- glucopyranosyl)-2,4,6-tri-O-benzyl-beta-D-galactopyranoside with benzyl bromide in N,N-dimethylformamide in the presence of sodium hydride afforded methyl 3-O- (2-acetamido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-beta-D-glucopyranosyl) -2,4,6- tri-O-benzyl-beta-D-galactopyranoside (3). Reductive ring-opening of the benzylidene group of 3 gave methyl 3-O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D- glucopyranosyl)- 2,4,6-tri-O-benzyl-beta-D-galactopyranoside (4). Cleavage of the 4,6-acetal group of 3 with hot, 80% aqueous acetic acid afforded the diol (5). Compounds 3, 4, and 5 were each subjected to halide ion-catalyzed glycosylation with 2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl bromide to produce the corresponding trisaccharide derivatives, which, on catalytic hydrogenation, furnished the title trisaccharides, respectively.     

Synthesis of 2',3'-dideoxy-3'-C-(hydroxymethyl)-4'-thiopentofuranosyl nucleosides as potential antiviral agent.

1-O-Acetyl-2,3-dideoxy-3-C-(hydroxymethyl)-4-thiofuranose derivative was synthesized from (S,S)-1,4-bis(benzyloxy)-2,3-epoxybutane derived from (+)-diethyl L-tartrate and the enantiomerically pure (E)-5-(2-bromovinyl)-1-[2',3'-dideoxy-3'-C-(hydroxymethyl)-beta-D-4'- thiopentofuranosyl]uracil 4 was obtained via coupling of silylated uracil followed by palladium-mediated coupling of methyl acrylate.