In vitro Characterization of Enzymes Involved in the Synthesis of Nonproteinogenic Residue (2S,3S)‐β‐Methylphenylalanine in Glycopeptide Antibiotic Mannopeptimycin

Mannopeptimycin, a potent drug lead, has superior activity against difficult‐to‐treat multidrug‐resistant Gram‐positive pathogens such as methicillin‐resistant Staphylococcus aureus (MRSA). (2S,3S)‐β‐Methylphenylalanine is a residue in the cyclic hexapeptide core of mannopeptimycin, but the synthesis of this residue is far from clear. We report here on the reaction order and the stereochemical course of reaction in the formation of (2S,3S)‐β‐methylphenylalanine. The reaction is executed by the enzymes MppJ and TyrB, an S‐adenosyl methionine (SAM)‐dependent methyltransferase and an (S)‐aromatic‐amino‐acid aminotransferase, respectively. Phenylpyruvic acid is methylated by MppJ at its benzylic position at the expense of one equivalent of SAM. The resulting β‐methyl phenylpyruvic acid is then converted to (2S,3S)‐β‐methylphenylalanine by TyrB. MppJ was further determined to be regioselective and stereoselective in its catalysis of the formation of (3S)‐β‐methylphenylpyruvic acid. The binding constant (K_D) of MppJ versus SAM is 26 μM . The kinetic constants with respect to k_{cat Ppy} and K_{M Ppy}, and k_{cat SAM} and K_{M SAM} are 0.8 s^?1 and 2.5 mM , and 8.15 s^?1 and 0.014 mM , respectively. These results suggest SAM has higher binding affinity for MppJ than Ppy, and the C? C bond formation in βmPpy might be the rate‐limiting step, as opposed to the C? S bond breakage in SAM.     

Treatment of paper and pulp wastewater and removal of odorous compounds by a Fenton‐like process at the pilot scale

A Fenton‐like process, involving oxidation and coagulation, was evaluated for the removal of odorous compounds and treatment of a pulp and paper wastewater. The main parameters that govern the complex reactive system [pH and Fe(III) and hydrogen peroxide concentrations] were studied. Concentrations of Fe(III) between 100 and 1000 mg L^?1 and of H₂O₂ between 0 and 2000 mg L^?1 were chosen. The main mechanism for color removal was coagulation. The maximum COD, color and aromatic compound removals were 75, 98 and 95%, respectively, under optimal operating conditions ([Fe(III)] = 400 mg L^?1; [H₂O₂] = 500–1000 mg L^?1; pH = 2.5; followed by coagulation at pH 5.0). The biodegradability of the wastewater treated increased from 0.4 to 0.7 under optimal conditions and no residual hydrogen peroxide was found after treatment. However, partially or non‐oxidized compounds present in the treated wastewater presented higher acute toxicity to Artemia salina than the untreated wastewater. Based on the optimum conditions, pilot‐scale experiments were conducted and revealed a high efficiency in relation to the mineralization of organic compounds. Terpenes [(1S)‐α‐pinene, β‐pinene, (1R)‐α‐pinene and limonene] were identified in the wastewater and were completely eliminated by the Fenton‐like treatment. Copyright © 2006 Society of Chemical Industry     

Novel Antitumor L‐Arabinose Derivative of Indolocarbazole with High Affinity to DNA

Novel indolocarbazole derivative 12‐(α‐L ‐arabinopyranosyl)indolo[2,3‐α]pyrrolo[3,4‐c]carbazole‐5,7‐dione (AIC) demonstrated high potency (at submicromolar concentrations) against the NCI panel of human tumor cell lines and transplanted tumors in vivo. In search of tentative targets for AIC, we found that the drug formed high affinity intercalative complexes with d(AT)₂₀, d(GC)₂₀ and calf thymus DNA (binding constants (1.6×10⁶) M ^?1≤K_a≤(3.3×10⁶) M ^?1). The drug intercalated preferentially into GC pairs of the duplex. Importantly, the concentrations at which AIC formed the intercalative complexes with DNA (C≤1 μM ) were identical to the concentrations that triggered p53‐dependent gene reporter transactivation, the replication block, the inhibition of topoisomerase I‐mediated DNA relaxation and death of HCT116 human colon carcinoma cells. We conclude that the formation of high affinity intercalative complexes with DNA is an important factor for anticancer efficacy of AIC.     

Discovery and characterization of atropisomer PH-797804, a p38 MAP kinase inhibitor, as a clinical drug candidate

PH‐797804 ((aS)‐3‐{3‐bromo‐4‐[(2,4‐difluorobenzyl)oxy]‐6‐methyl‐2‐oxopyridin‐1(2H)‐yl}‐N,4‐dimethylbenzamde) is a diarylpyridinone inhibitor of p38 mitogen‐activated protein (MAP) kinase derived from a racemic mixture as the more potent atropisomer (aS), first proposed by molecular modeling and subsequently confirmed by experiments. Due to steric constraints imposed by the pyridinone carbonyl group and the 6‐ and 6′‐methyl substituents of PH‐797804, rotation around the connecting bond of the pyridinone and the N‐phenyl ring is restricted. Density functional theory predicts a remarkably high rotational energy barrier of >30 kcal mol^?1, corresponding to a half‐life of more than one hundred years at room temperature. This gives rise to discrete conformational spaces for the N‐phenylpyridinone group, and as a result, two atropic isomers that do not interconvert under ambient conditions. Molecular modeling studies predict that the two isomers should differ in their binding affinity for p38α kinase; whereas the atropic S (aS) isomer binds favorably, the opposite aR isomer incurs significant steric interference with p38α kinase. The two isomers were subsequently identified and separated by chiral chromatography. IC₅₀ values from p38α kinase assays confirm that one atropisomer is >100‐fold more potent than the other. It was ultimately confirmed by small‐molecule X‐ray diffraction that the more potent atropisomer, PH‐797804, is the aS isomer of the racemic pair. Extensive pharmacological characterization supports that PH‐797804 carries most activity both in vitro and in vivo, and it has a stability profile compatible with oral formulation and delivery options.     

Semisynthetic Ursolic Acid Fluorolactone Derivatives Inhibit Growth with Induction of p21(waf1) and Induce Apoptosis with Upregulation of NOXA and Downregulation of c-FLIP in Cancer Cells

A series of ursolic acid ((1S,2R,4aS,6aR,6aS,6bR,8aR,10S,12aR,14bS)‐10‐hydroxy‐1,2,6a,6b,9,9,12a‐heptamethyl‐2,3,4,5,6,6a,7,8,8a,10,11,12,13,14b‐tetradecahydro‐1H‐picene‐4a‐carboxylic acid) derivatives with a 12‐fluoro‐13,28β‐lactone moiety were synthesized using the electrophilic fluorination reagent Selectfluor. The antiproliferative effects of these novel compounds were evaluated in AsPC‐1 pancreatic cancer cells, and the structure–activity relationships (SARs) were evaluated. Of the compounds synthesized, ursolic acid derivatives carrying a heterocyclic ring, such as imidazole or methylimidazole, and cyanoenones were among the more potent inhibitors of AsPC‐1 pancreatic cancer cell growth. 2‐Cyano‐3‐oxo‐12α‐fluoro‐urs‐1‐en‐13,28β‐olide, compound 20 , was the most effective inhibitor with IC₅₀ values of 0.7, 0.9 and 1.8 μM in pancreatic cancer cell lines AsPC‐1, MIA PaCa‐2 and PANC‐1, respectively. This compound also exhibited better antiproliferative activities against breast (MCF7), prostate (PC‐3), hepatocellular (Hep G2) and lung (A549) cancer cell lines, with IC₅₀ values lower than 1 μM . The mechanism of action by which these compounds exert their biological effect was evaluated in AsPC‐1 cells using the most potent inhibitor synthesized, compound 20 . At 1 μM , the cell cycle arrested at the G1 phase with upregulation of p21^waf1. Apoptosis was induced at an inhibitor concentration of 8 μM with upregulation of NOXA and downregulation of c‐FLIP. These data indicate that fluorolactone derivatives of ursolic acid have improved antiproliferative activity, acting through arrest of the cell cycle and induction of apoptosis.     

E‐64c‐Hydrazide: A Lead Structure for the Development of Irreversible Cathepsin C Inhibitors

Cathepsin C is a papain‐like cysteine protease with dipeptidyl aminopeptidase activity that is thought to activate various granule‐associated serine proteases. Its exopeptidase activity is structurally explained by the so‐called exclusion domain, which blocks the active‐site cleft beyond the S2 site and, with its Asp 1 residue, provides an anchoring point for the N terminus of peptide and protein substrates. Here, the hydrazide of (2S,3S)‐trans‐epoxysuccinyl‐L ‐leucylamido‐3‐methylbutane (E‐64c) (k₂/K_i=140±5 M ^?1 s^?1) is demonstrated to be a lead structure for the development of irreversible cathepsin C inhibitors. The distal amino group of the hydrazide moiety addresses the acidic Asp 1 residue at the entrance of the S2 pocket by hydrogen bonding while also occupying the flat hydrophobic S1′–S2′ area with its leucine‐isoamylamide moiety. Furthermore, structure–activity relationship studies revealed that functionalization of this distal amino group with alkyl residues can be used to occupy the conserved hydrophobic S2 pocket. In particular, the n‐butyl derivative was identified as the most potent inhibitor of the series (k₂/K_i=56 000±1700 M ^?1 s^?1).     

Reactive extraction of succinic acid using supercritical carbon dioxide

Reactive extraction using supercritical carbon dioxide (scCO₂) and tri-n-octylamine (TOA) was evaluated as a separation method of succinic acid from an aqueous solution. The reactive extraction of succinic acid was performed at varying initial acid concentrations in aqueous solution (0.07–0.45 mol?dm^?3), temperature (35–65°C) and pressure (8–16 MPa). The succinic acid separation was conducted in both batch mode and semi-continuous mode. The highest reactive extraction efficiency of approx. 62% was obtained for the process conducted in semi-continuous mode at 35°C and 16 MPa for the initial acid concentrations in aqueous phase of 0.39 mol?dm^?3.     

A new process for Al2O3 production from low‐grade diasporic bauxite based on reactive silica dissolution and stabilization in NaOH‐NaAl(OH)4 media

A new process of Al₂O₃ production from low‐grade diasporic bauxite based on the reactive silica dissolution and stabilization in concentrated NaOH‐NaAl(OH)₄ solutions is proposed and proved feasible. NaOH and Al₂O₃ concentrations and leaching temperature were found to be the main factors affecting the leaching process of reactive silica. The A/S (mass ratio of Al₂O₃/SiO₂) of diasporic bauxite was enhanced from 5.4 to 15 by reactive silica removal under the optimum operation conditions. Two obvious steps control the whole leaching process of reactive silica in NaOH‐NaAl(OH)₄ media: reactive silica dissolution and desilication products (DSPs) precipitation. The kinetics data of two controlling steps fit a shrinking core model based on the calculation of OH^? activity with the aid of OLI platform and an empirical kinetic model well, respectively. Apparent activation energies of reactive silica leaching in the temperature range from 80 to 110 °C are 101.91 and 58.65 kJ mol^?1 for the two steps, respectively. The stabilization mechanism of reactive silica in concentrated NaOH‐NaAl(OH)₄ solution was also elucidated based on the complexation of aluminum‐bearing species and the calculation of supersaturation to DSP. It was found that the concentration of OH^? sharply decreases due to the formation of Al(OH) species with increasing aluminum concentration, suppressing greatly DSP precipitation. This proposed process paves the way for Al₂O₃ production from low‐grade diasporic bauxite with high‐reactive silica content. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Development of Rhodesain Inhibitors with a 3‐Bromoisoxazoline Warhead

Novel rhodesain inhibitors were obtained by combining an enantiomerically pure 3‐bromoisoxazoline warhead with a specific peptidomimetic recognition moiety. All derivatives behaved as inhibitors of rhodesain, with low micromolar K_i values. Their activity against the enzyme was found to be paralleled by an in vitro antitrypanosomal activity, with IC₅₀ values in the mid‐micromolar range. Notably, a preference for parasitic over human proteases, specifically cathepsins B and L, was observed.     

Physicochemical studies of globular proteins—Bovine serum albumin,egg albumin,and lysozyme—In some aqueous iodide salts solutions of IA group and cetyltrimethyl ammonium bromide systems

Densities (ρ, kg m^?3), and viscosities (η, 0.1 kg m^?1 s^?1) of Bovine Serum Albumin (BSA), Egg Albumin, and Lysozyme in aqueous iodide salts of lithium, sodium, and potassium, along with cationic surfactant‐cetyltrimethyl ammonium bromide (CTAB) were measured at a temperature of 303.15 K. The 0.0010–0.0018 g %, w/v of each protein at an interval of 0.0002 mol L^?1 in 0.2, 0.4, and 0.8 millimol L^?1 of salt and CTAB are studied. Data are used for apparent molar volumes (V_?, 10^?6 m³ mol^?1) and intrinsic viscosities ([η], dL kg^?1), respectively. Data are regressed and extrapolated to zero concentrations for ρ⁰, η⁰, and limiting values and S_d, S_η and S_V corresponding slopes for protein–salt structural interactions. With size of cations, the densities decrease as CTAB > LiI > NaI > KI and increase with salts concentrations, with salts the densities are as Lysozyme > BSA > Egg Albumin, viscosities and V_? as BSA > Egg–Albumin > Lysozyme. The ρ and η values with CTAB higher and [η] are lower and converse at around 0.4 mmol L^?1 salt and is effective for greater stability of proteins. The [η] in CTAB are higher than other salts and decreases with size of cations with stronger intermolecular forces. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

A Bisbenzamidine Phosphonate as a Janus‐faced Inhibitor for Trypsin‐like Serine Proteases

A hybrid approach was applied for the design of an inhibitor of trypsin‐like serine proteases. Compound 16 [(R,R)‐ and (R,S)‐diphenyl (4‐(1‐(4‐amidinobenzylamino)‐1‐oxo‐3‐phenylpropan‐2‐ylcarbamoyl)phenylamino)(4‐amidinophenyl)methylphosphonate hydrochloride], prepared in a convergent synthetic procedure, possesses a phosphonate warhead prone to react with the active site serine residue in a covalent, irreversible manner. Each of the two benzamidine moieties of 16 can potentially be accommodated in the S1 pocket of the target enzyme, but only the benzamidine close to the phosphonate group would then promote an irreversible interaction. The Janus‐faced inhibitor 16 was evaluated against several serine proteases and caused a pronounced inactivation of human thrombin with a second‐order rate constant (k_inac/K_i) of 59 500 M ^?1 s^?1. With human matriptase, 16 showed preference for a reversible mode of inhibition (IC₅₀=2.6 μM ) as indicated by linear progress curves and enzyme reactivation.     

Crystal Structure of HydG from Carboxydothermus hydrogenoformans: A Trifunctional [FeFe]‐Hydrogenase Maturase

The structure of the radical S‐adenosyl‐L ‐methionine (SAM) [FeFe]‐hydrogenase maturase HydG involved in CN^?/CO synthesis is characterized by two internal tunnels connecting its tyrosine‐binding pocket with the external medium and the C‐terminal Fe₄S₄ cluster‐containing region. A comparison with a tryptophan‐bound NosL structure suggests that substrate binding causes the closing of the first tunnel and, along with mutagenesis studies, that tyrosine binds to HydG with its amino group well positioned for H‐abstraction by SAM. In this orientation the dehydroglycine (DHG) fragment caused by tyrosine Cα?Cβ bond scission can readily migrate through the second tunnel towards the C‐terminal domain where both CN^? and CO are synthesized. Our HydG structure appears to be in a relaxed state with its C‐terminal cluster CysX₂CysX₂₂Cys motif exposed to solvent. A rotation of this domain coupled to Fe₄S₄ cluster assembly would bury its putatively reactive unique Fe ion thereby allowing it to interact with DHG.     

Studies on Micellar Behavior of PEO‐PBO or PEO‐PBO‐PEO Copolymers,or Surface Active Amphiphilic Ionic Liquids in Aqueous Media and Exploration of the Micellar Solutions for Solubilization of Dexamethasone and its Delayed Release

The aggregation behavior of a di‐ and tri‐block copolymers of type PEO‐PBO, PEO‐PBO‐PEO, surface‐active ionic liquid (SAIL) of type 4‐dodecyl‐4‐methylmorpholinium chloride [C₁₂mmor][Cl], and 1‐dodecyl‐1‐methylpyrrolidinium chloride [C₁₂mpyrr][Cl]) in water as well as in 10 mM of a poorly water soluble dexamethasone (dex) aqueous solution was studied by determining the critical micelle concentrations using drug solubilization, surface tension, and isothermal titration calorimetry (ITC) methods. ITC measurements were also made on solutions prepared by mixing the micellar aqueous solutions of copolymers and simple aqueous solutions of SAIL across the mole fractions at three different temperatures (298.15, 308.15, and 318.15 K). The thermodynamic parameters, namely Gibbs free energy (ΔG_m), enthalpy (ΔH_m), and entropy (ΔS_m), of micellization were calculated, and it was observed that the negative ΔG_m and positive ΔS_m for the mixture solutions increase with the increase in mole fraction of SAIL. Otherwise, the micellization is reported to be a spontaneous and highly entropy‐driven process. The dex‐solubilized micellar solutions were mixed with agar to obtain standing gels. The gel samples were dry‐cast into thin films, and the release of dex from films by simple dilution was monitored by UV measurements. The drug release data was fitted to several mechanistic models, and it was inferred that the release mechanism for dex from thin films is non‐Fickian for mixtures and Fickian in copolymer or SAIL micellar aqueous solutions. The transport of dex is diffusion‐controlled with diffusivities of 5.8–12 × 10^?11 m² s^?1 for copolymer micelles, 5–11 × 10^?11 m² s^?1 for micelles of SAIL, and 3–14 × 10^?11 m² s^?1 for the mixed micelles of copolymer and SAIL in aqueous media.     

New cis-configured aziridine-2-carboxylates as aspartic acid protease inhibitors

A series of 52 cis‐configured 1‐alkyl‐3‐phenylaziridine‐2‐carboxylates were synthesized as new pseudo‐irreversible inhibitors of Candida albicans secreted aspartic acid protease 1 (SAP1), SAP2, SAP3, and SAP8. Some of the compounds, which were obtained as diastereomers with S,S‐ and R,R‐configured aziridine rings by Cromwell synthesis of racemic (2R,3S+2S,3R)‐dibromophenylpropionic acid ester with amines, followed by ester hydrolysis and coupling to hydrophobic amino acid esters, were separated by preparative HPLC. The absolute configuration of the aziridine ring was assigned by a combination of experimental circular dichroism (CD) investigations and quantum chemical CD calculations. In agreement with previous docking studies, the diastereomers all exhibit similar activity. The compounds were found to be more active against the related mammalian enzyme cathepsin D, presumably due to productive interactions of the N‐alkyl substituent with the highly lipophilic S2 pocket. The most active inhibitors ( 5 , 9 , 10 , 21 , and 28 ), characterized by benzyl, cyclohexylmethyl, tert‐butyl, or 1,4‐dimethylpentyl moieties at the aziridine nitrogen atom, exhibit k_2nd values between 500 and 900×10³ M ^?1 min^?1 and K_i values near or below 1 μM for cathepsin D.     

Fermentative production of fumaric acid from Eucalyptus globulus wood hydrolyzates

Fumaric acid (FA) was produced from Eucalyptus globulus wood by successive steps of hydrothermal processing (to solubilize hemicelluloses and to increase the susceptibility of solids to enzymatic hydrolysis), enzymatic hydrolysis and fermentation with Rhizopus arrhizus DSM 5772. For comparative purposes, additional fermentations were carried out using synthetic media. Single stage fermentation of synthetic media led to a medium containing 11.8 g FA L^?1 (Y_P/S = 0.60 g g^?1). Operating in fed batch mode, the fourth stage increased the FA concentration from 19.7 up to 43.6 g L^?1 (Y_P/S = 0.71 g g^?1). Hydrolyzate fermentation in a single stage resulted in lower fumaric acid concentration (9.65 g L^?1) and yield (0.35 g g^?1). Additional fermentations were carried out in media made with hydrolyzates subjected to membrane processing, adsorption or ion exchange. The highest yield (Y_P/S = 0.44 g g^?1) was reached in media made up of ion‐exchange treated hydrolyzates and a commercial glucose solution in proportion 85/15 w/w. Copyright © 2011 Society of Chemical Industry     

Structure and Binding of Peptide‐Dendrimer Ligands to Vitamin B12

The third‐generation peptide‐dendrimer B1 (AcES)₈(BEA)₄(K‐Amb‐Y)₂BCD‐NH₂ (B=branching (S)‐2,3‐diaminopropanoic acid, K=branching lysine, Amb=4‐aminomethyl‐benzoic acid) is the first synthetic model for cobalamin‐binding proteins and binds cobalamin strongly (K_a=5.0×10⁶ M ^?1) and rapidly (k₂=346 M ^?1 s^?1) by coordination of cobalt to the cysteine residue at the dendrimer core. A structure–activity relationship study is reported concerning the role of negative charges in binding. Substituting glutamates (E) for glutamines (Q) in the outer branches of B1 to form N3 (AcQS)₈(BQA)₄(B‐Amb‐Y)₂BCD‐NH₂ leads to stronger (K_a=12.0×10⁶ M ^?1) but slower (k₂=67 M ^?1 s^?1) cobalamin binding. CD and FTIR spectra show that the dendrimers and their cobalamin complexes exist as random‐coil structures without aggregation in solution. The hydrodynamic radii of the dendrimers determined by diffusion NMR either remains constant or slightly decreases upon binding to cobalamin; this indicates the formation of compact, presumably hydrophobically collapsed complexes.     

Self‐organization of amphiphilic poly[2‐(methacryloyloxy)ethyl phosphorylcholine] carrying tocopheryl moieties as terminal groups

Poly[2‐(methacryloyloxy)ethyl phosphorylcholine](PMPC) with one pendant tocopheryl moiety at the polymer terminus (PMPC‐Toco) was prepared by the radical polymerization of 2‐(methacryloyloxy)ethyl phosphorylcholine (MPC) initiated with 4,4′‐azobis[(3‐tocopheryl)‐4‐cyanopentanoate] in the presence of 2‐mercaptoethanol as a chain transfer reagent. The self‐organization of PMPC‐Toco was analyzed with fluorescence and ¹H‐NMR measurements. The critical micelle concentrations of PMPC‐Toco with [η] = 0.25, 0.13, 0.10, and 0.05 dL g^?1 were found to be 200, 100, 100, and 90 mg L^?1, respectively. The blood compatibility of PMPC‐Toco was evaluated from the Michaelis constant (K_m) for the enzymatic reaction of thrombin and a synthetic substrate, S‐2238, in the presence of PMPC‐Toco. The K_m values were 0.21, 0.23, 0.36, and 0.21 for PMPC‐Toco‐1, 2, 3, and PMPC ([η] = 0.56 dL g^?1), respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Gas‐Liquid Mass Transfer in a Slurry Bubble Column at High Slurry Concentrations and High Gas Velocities

The volumetric mass transfer coefficient k_La in a 0.1 m‐diameter bubble column was studied for an air‐slurry system. A C₉‐C₁₁ n‐paraffin oil was employed as the liquid phase with fine alumina catalyst carrier particles used as the solid phase. The n‐paraffin oil had properties similar to those of the liquid phase in a commercial Fischer‐Tropsch reactor under reaction conditions. The superficial gas velocity U_G was varied in the range of 0.01 to 0.8 m/s, spanning both the homogeneous and heterogeneous flow regimes. The slurry concentration ?_S ranged from 0 to 0.5. The experimental results obtained show that the gas hold‐up ?_G decreases with an increase in slurry concentration, with this decrease being most significant when ?_S < 0.2. k_La/?_G was found to be practically independent of the superficial gas velocity when U_G > 0.1 m/s is taking on values predominantly between 0.4 and 0.6 s^–1 when ?_S = 0.1 to 0.4, and 0.29 s^–1, when ?_S = 0.5. This study provides a practical means for estimating the volumetric mass transfer coefficient k_La in an industrial‐size bubble column slurry reactor, with a particular focus on the Fischer‐Tropsch process as well as high gas velocities and high slurry concentrations.     

Synthesis and Biological Evaluation of N‐Substituted Sophocarpinic Acid Derivatives as Coxsackievirus B3 Inhibitors

A series of novel N‐substituted sophocarpinic acid derivatives was designed, synthesized, and evaluated for their anti‐enteroviral activities against coxsackievirus type B3 (CVB3) and coxsackievirus type B6 (CVB6) in Vero cells. Structure–activity relationship analysis revealed that the introduction of a benzenesulfonyl moiety on the 12‐nitrogen atom in (E)‐β,γ‐sophocarpinic acid might significantly enhance anti‐CVB3 activity. Among the derivatives, (E)‐12‐N‐(m‐cyanobenzenesulfonyl)‐β,γ‐sophocarpinic acid ( 11 m ), possessing a meta‐cyanobenzenesulfonyl group, exhibited potent activity against CVB3 with a selectivity index (SI) of 107. Furthermore, compound 11 m also showed a good oral pharmacokinetic profile, with an AUC value of 7.29 μM h^?1 in rats, and good safety through the oral route in mice, with an LD₅₀ value of >1000 mg kg^?1; these values suggest a druggable characteristic. Therefore, compound 11 m was selected for further investigation as a promising CVB3 inhibitor. We consider (E)‐β,γ‐N‐(benzenesulfonyl)sophocarpinic acids to be a novel class of anti‐CVB3 agents.     

Synthesis and biological activity of phthalimide‐based polymers containing 5‐fluorouracil

The attachment of anticancer agents to polymers is a promising approach towards reducing the toxic side‐effects and retaining the potent antitumour activity of these agents. A new tetrahydrophthalimido monomer containing 5‐fluorouracil (ETPFU) and its homopolymer and copolymers with acrylic acid (AA) and with vinyl acetate (VAc) have been synthesized and spectroscopically characterized. The ETPFU contents in poly(ETPFU‐co‐AA) and poly(ETPFU‐co‐VAc) obtained by elemental analysis were 21 mol% and 20 mol%, respectively. The average molecular weights of the polymers determined by gel permeation chromatography were as follows: M_n = 8900 g mol^?1, M_w = 13 300 g mol^?1, M_w/M_n = 1.5 for poly(ETPFU); M_n = 13 500 g mol^?1, M_w = 16 600 g mol^?1, M_w/M_n = 1.2 for poly(ETPFU‐co‐AA); M_n = 8300 g mol^?1, M_w = 11 600 g mol^?1, M_w/M_n = 1.4 poly(ETPFU‐co‐VAc). The in vitro cytotoxicity of the compounds against FM3A and U937 cancer cell lines increased in the following order: ETPFU > 5‐FU > poly(ETPFU) > poly(ETPFU‐co‐AA) > poly(ETPFU‐co‐VAc). The in vivo antitumour activities of all the polymers in Balb/C mice bearing the sarcoma 180 tumour cell line were greater than those of 5‐FU and monomer at the highest dose (800 mg kg^?1). © 2002 Society of Chemical Industry