Novel acyclic nucleoside phosphonate analogues with potent anti-hepatitis B virus activities

Novel acyclic nucleoside phosphonates with a pyrimidine base preferentially containing an amino group at C-2 and C-4 and a 2-(phosphonomethoxy)ethoxy or (R)-2-(phosphonomethoxy)propoxy group at C-6 selectively inhibit the replication of wild-type and lamivudine-resistant hepatitis B viruses. The activity of the most potent compounds was comparable to that of adefovir.     

Novel chalcone derivatives containing a 1,2,4-triazine moiety: design,synthesis, antibacterial and antiviral activities

A series of novel chalcone derivatives containing the 1,2,4-triazine moiety were synthesized and their structures were confirmed by ¹H NMR, ¹³C NMR and elemental analyses. Antiviral bioassays revealed that most of the compounds exhibited good antiviral activity against tobacco mosaic virus (TMV) at a concentration of 500 μg mL⁻¹. The designated compound 4l was 50% effective in terms of curative and protective activities against TMV with 50% effective concentrations (EC₅₀) of 10.9 and 79.4 μg mL⁻¹, which were better than those of ningnanmycin (81.4 and 82.2 μg mL⁻¹). Microscale thermophoresis (MST) also showed that the binding of compound 4l to coat protein (TMV-CP) yielded a K_d value of 0.275 ± 0.160 μmol L⁻¹, which was better than that of ningnanmycin (0.523 ± 0.250 μmol L⁻¹). At the same time, molecular docking studies for 4l with TMV-CP (PDB code:1EI7) showed that the compound was embedded well in the pocket between the two subunits of TMV-CP. Meanwhile, compound 4a demonstrated excellent antibacterial activities against Ralstonia solanacearum (R. solanacearum), with an EC₅₀ value of 0.1 μg mL⁻¹, which was better than that of thiodiazole-copper (36.1 μg mL⁻¹) and bismerthiazol (49.5 μg mL⁻¹). The compounds act by causing folding and deformation of the bacterial cell membrane as observed using scanning electron microscopy (SEM). The chalcone derivatives thus synthesized could become potential alternative templates for novel antiviral and antibacterial agents.

A series of novel chalcone derivatives containing the 1,2,4-triazine moiety were synthesized and their structures were confirmed by ¹H NMR, ¹³C NMR and elemental analyses.     

In vitro antiviral activity of penciclovir, a novel purine nucleoside, against duck hepatitis B virus.

The in vitro antihepadnavirus activities of the purine nucleoside analogs ganciclovir (9-[2-hydroxy-1-(hydroxymethyl)ethoxymethyl]guanine) and penciclovir [9-(4-hydroxy-3-hydroxymethylbut-1-yl)guanine; BRL 39123] were compared in primary duck hepatocyte cultures congenitally infected with the duck hepatitis B virus (DHBV). Both compounds inhibited DHBV DNA replication to a comparable extent during continuous short-term treatment of the cultures. However penciclovir was more active both during longer-term continuous treatment (50% inhibitory concentrations: penciclovir, 0.7 +/- 0.1 microM; ganciclovir, 4.0 +/- 0.2 microM) and in washout experiments (50% inhibitory concentrations: penciclovir, 3.0 +/- 0.4 microM; ganciclovir, 46 +/- 1.5 microM) designed to compare the persistence of inhibitory activity after removal of the extracellular compound. The effects on viral protein synthesis were similar to the effects on viral DNA replication. These data suggest that penciclovir or its oral form, famciclovir, may have clinical utility in the treatment of chronic hepatitis B virus infection.     

N4-acyl-modified D-2',3'-dideoxy-5-fluorocytidine nucleoside analogues with improved antiviral activity

A series of 2',3'-dideoxy (D2) and 2',3'-didehydro-2',3'-dideoxy (D4) 5-fluorocytosine nucleosides modified with substituted benzoyl, heteroaromatic carbonyl, cycloalkylcarbonyl and alkanoyl at the N4-position were synthesized and evaluated for anti-human immunodeficiency virus type 1 (HIV-1) and anti-hepatitis B virus (HBV) activity in vitro. For most D2-nucleosides, N4-substitutions improved the anti-HIV-1 activity markedly without increasing the cytotoxicity. In the D4-nucleosides series, some of the substituents at the N4-position enhanced the anti-HIV-1 activity with a modest increase in the cytotoxicity. The most potent and selective N4-modified nucleoside for the D2-series was N4-p-iodobenzoyl-D2FC, which had a 46-fold increase in anti-HIV-1 potency in MT-2 cells compared to the parent nucleoside D-D2FC. In the D4-series, N4-p-bromobenzoyl-D4FC was 12-fold more potent in MT-2 cells compared to the parent nucleoside D-D4FC. All eight N4-p-halobenzoyl-substituted D2- and D4-nucleosides evaluated against HBV in HepAD38 cells demonstrated equal or greater potency than the two parental compounds, D-D2FC and D-D4FC. The N4-modification especially in the D2-nucleoside series containing the N4-nicotinoyl, o-nitrobenzoyl and n-butyryl showed a significant reduction in mitochondrial toxicity relative to the parent nucleoside analogue. Although the 5'-triphosphate of the parent compound (D-D4FC-TP) was formed from the N4-acyl-D4FC analogues in different cells, the levels of the 5'-triphosphate nucleotide did not correlate with the cell-derived 90% effective antiviral concentrations (EC90), suggesting that a direct interaction of the triphosphates of these N4-acyl nucleosides was involved in the antiviral activity.     

Novel pyrazolo[3,4-d]pyrimidine nucleoside analog with broad-spectrum antiviral activity.

A novel nucleoside analog, 4(5H)-oxo-1-beta-D- ribofuranosylpyrazolo[3,4-d]pyrimidine-3-thiocarboxamide (N10169), was evaluated in cell culture and in animals for antiviral activity against DNA and RNA viruses. The compound was highly active against strains of adeno-, vaccinia, influenza B, paramyxo-, picorna-, and reoviruses, with 50% inhibition of virus-induced cytopathology at 1 to 10 microM. Lesser or no antiviral effects were observed against herpes simplex, cytomegalo-, corona-, influenza A, vesicular stomatitis, and visna viruses. Drug potency against certain viruses was highly cell line dependent (N10169 was highly active in HeLa cells but was much less potent in Vero cells). This was correlated, in part, to differences in levels of adenosine kinase activity in these cell lines, since adenosine kinase appears to phosphorylate N10169 to its active form. N10169 was inhibitory to proliferating cells at antiviral concentrations, whereas stationary-phase monolayers tolerated higher concentrations (less than or equal to 100 microM). Exogenous uridine was able to reverse the virus-inhibitory effects of the compound, leading to the discovery that N10169 5'-monophosphate is a potent inhibitor of cellular orotidylate decarboxylase. N10169 was evaluated in mice that were infected intraperitoneally with banzi virus or inoculated intranasally with influenza B virus, and in hamsters that were infected intranasally with vaccinia virus. In each model, intraperitoneal injection of N10169 (100 to 300 mg/kg per day for 7 days) twice daily was ineffective, whereas intraperitoneal injection of ribavirin showed some benefit in the influenza B and banzi virus infection models.     

强效核苷类似物抗病毒过程中血清HBV DNA变化和HBeAg血清学转换分析

目的:探讨恩替卡韦及替比夫定治疗慢性乙型肝炎(慢乙肝)过程中血清HBV DNA水平变化和HBeAg血清学阴转率的差异.方法:选择初治慢乙肝患者126例,按其治疗方案分为恩替卡韦0.5 mg/d治疗组(恩替卡韦组)83例和替比夫定600 mg/d治疗组(替比夫定组)43例,观察两组慢乙肝患者治疗前及治疗4、8、12、24、48周时血清HBV DNA水平、阴转率及其下降模式,比较治疗48周时HBeAg血清学阴转率.结果:治疗4周时思替卡韦组和替比夫定组HBeAg阳性患者HBV DNA水平分别为(5.57±1.30)lg copies/L、(5.76±1.34)lg copies/L,两组HBeAg阴性患者则分别为(5.75±1.01)lg copies/L、(6.03±1.86)lg copies/L,两组HBV DNA水平与治疗前比较差异均有统计学意义(P均<0.05),但两组组间比较差异无统计学意义(P>0.05).两组HBeAg阳性患者各个时间点HBV DNA阴转率比较差异均无统计学意义(P>0.05);恩替卡韦组HBeAg阴性患者除24周外的HBV DNA阴转率均明显高于替比夫定组HBeAg阴性患者(P均<0.05).无论是HBeAg阳性患者还是HBeAg阴性患者,两组的病毒下降模式比较差异无统计学意义(P>0.05).两组治疗48周HBeAg阴转率比较差异无统计学意义(P>0.05).结论:两种核苷类似物均能快速、强效抑制HBV DNA;对于HBeAg阴性患者,恩替卡韦治疗较替比夫定治疗可获得更高的HBV DNA阴转率.     

Synthesis and antibacterial and antiviral activities of myricetin derivatives containing a 1,2,4-triazole Schiff base

A series of novel myricetin derivatives containing a 1,2,4-triazole Schiff base were designed and synthesized. Their structures were systematically characterized using ¹H NMR, ¹³C NMR, and HRMS. During antibacterial bioassays, 6f, 6i, and 6q demonstrated a good inhibitory effect against Xanthomonas axonopodis pv. citri (Xac), with half-maximal effective concentration (EC₅₀) values of 10.0, 9.4, and 8.8 μg mL⁻¹, respectively, which were better than those of bismerthiazol (54.9 μg mL⁻¹) and thiodiazole copper (61.1 μg mL⁻¹). Note that 6w demonstrated a good inhibitory effect against Ralstonia solanacearum (Rs) with and EC₅₀ value of 15.5 μg mL⁻¹, which was better than those of bismerthiazol (55.2 μg mL⁻¹) and thiodiazole copper (127.9 μg mL⁻¹). Similarly, 6a, 6d, and 6e demonstrated a good inhibitory effect against Xanthomonas oryzae pv. oryzae (Xoo) with EC₅₀ values of 47.1, 61.2, and 61.0 μg mL⁻¹, respectively, which were better than those of bismerthiazol (148.2 μg mL⁻¹) and thiodiazole copper (175.5 μg mL⁻¹). Furthermore, we used scanning electron microscopy (SEM) to study the possible sterilization process of the target compound 6q against Xac. The results indicated the possibility of destroying the bacterial cell membrane structure, resulting in an incomplete bacterial structure, and thus achieving inhibition. Furthermore, antiviral bioassays revealed that most compounds exhibited excellent antiviral activity against tobacco mosaic virus (TMV) at a concentration of 500 μg mL⁻¹. The results of the molecular docking studies for 6g with TMV-CP (PDB code: 1EI7) showed that compound 6g had partially interacted with TMV-CP. Therefore, mechanistic studies of the action of compound 6g could be further studied based on that.

The myricetin derivatives containing a 1,2,4-triazole Schiff base were designed and synthesized. Antibacterial mechanism was investigated through SEM.     

New chalcone derivatives: synthesis,antiviral activity and mechanism of action

In this work, twenty-eight chalcone derivatives containing a purine (sulfur) ether moiety were synthesized and their antiviral activities were evaluated. Biological results showed that compound 5d exhibited outstanding inactive activity against tobacco mosaic virus (TMV) in vivo (EC₅₀ = 65.8 μg mL⁻¹), which is significantly superior to that of ribavirin (EC₅₀ = 154.3 μg mL⁻¹). Transmission electron microscopy indicated that compound 5d can break the integrity of TMV particles. The results of microscale thermophoresis, fluorescence titration and molecular docking showed that compound 5d had stronger combining affinity (K_a = 1.02 ×10⁵ L mol⁻¹, K_d = 13.4 μmol L⁻¹) with TMV coat protein (TMV-CP), which is due to the formation of five hydrogen bonds between compound 5d and the amino-acid residues of TMV-CP. These findings revealed that compound 5d can effectively inhibit the infective ability of TMV. This work provides inspiration and reference for the discovery of new antiviral agents.

The chalcone derivatives containing a purine (sulfur) ether moiety were synthesized. The antiviral mechanism suggested that the antiviral activity of compound 5d may depend on its stronger binding affinity with TMV-CP.     

Erythrocyte adenosine deaminase, purine nucleoside phosphorylase and phosphoribosyltransferase activity in patients with Down's syndrome

The erythrocyte adenosine deaminase, nucleoside phosphorylase, hypoxanthineguanine phosphoribosyltransferase and adenine phosphoribosyltransferase activities and plasma urate concentrations were measured in 20 cases of Down's syndrome and in 20 age- and sex-matched control subjects. The mean erythrocyte adenosine deaminase and adenine phosphoribosyltransferase activities and plasma urate concentrations were significantly higher in Down's syndrome subjects than in controls (p less than 0.001, p less than 0.01 and p less than 0.001, respectively). In all subjects studied there was a positive correlation between the erythrocyte adenosine deaminase activity and plasma urate concentration (r = 0.488, p less than 0.005). The concentrations of the erythrocyte adenine nucleotides, AMP, ADP and ATP, did not differ in Down's syndrome (n = 10) from those of control subjects (n = 10). The results suggest that the increase of plasma urate concentrations is a consequence of the increase in adenosine deaminase activity in Down's syndrome patients.     

Thienothiadiazine 2,2-dioxide acyclonucleosides: synthesis and antiviral activity

The synthesis of acyclonucleosides derived from thieno[3,2-c] and thieno[2,3-c][1,2,6]thiadiazine 2,2-dioxides was achieved following the silylation method. Lipase-mediated methodology was employed for deprotection of the acyclic moieties. The antiviral effects were determined against a broad spectrum of viruses, including cytomegalovirus (CMV) and varicella zoster virus (VZV). Only minor antiviral activity against VZV was observed for those acyclonucleosides carrying a benzyl group.     

Design and synthesis of purine nucleoside analogues for the formation of stable anti-parallel-type triplex DNA with duplex DNA bearing the 5mCG base pair

We herein demonstrated for the first time the direct recognition of duplex DNA bearing the 5-methyl-2′-deoxycytosine and 2′-deoxyguanosine base pair by triplex DNA formation. Triplex-forming oligonucleotides contained the novel artificial nucleoside analogues 2-amino-2′-deoxy-nebularine derivatives, and their molecular design, synthesis, and functional evaluation are described.

We herein demonstrated for the first time the direct recognition of duplex DNA bearing the 5-methyl-2′-deoxycytosine and 2′-deoxyguanosine base pair by triplex DNA formation.     

In vivo antiherpesvirus activity of N-7-substituted acyclic nucleoside analog 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine.

The efficacy of 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine (S2242) was evaluated in several animal models for herpesvirus infections. Compound S2242 was more effective than acyclovir (i) when administered subcutaneously in a model for herpes simplex virus type 1 (HSV-1)-induced mortality in immunocompetent mice and (ii) when applied topically to hairless (hr/hr) mice that had been infected intracutaneously with HSV-2. In SCID (severe combined immune deficient) mice that had been infected with a thymidine kinase-deficient HSV-1 strain, S2242 (administered subcutaneously at a dosage of 50 mg/kg/day) completely protected against virus-induced mortality whereas foscarnet was less effective and acyclovir had no or little protective effect. Compound S2242 was far more effective than ganciclovir in preventing or delaying murine cytomegalovirus-induced mortality in immunocompetent and SCID mice. The compound was more effective when a given dose was fractionated and administered on subsequent days than when this dose was administered in one single injection. A 5-day treatment course with S2242 (10 and 50 mg/kg/day) for newborn mice that had been infected with a lethal dose of murine cytomegalovirus suppressed virus-induced mortality. Compound S2242 had no inhibitory effect on the growth of weanling (at 50 mg/kg for 5 days) and 3- to 4-week-old mice (at doses of 50 to 200 mg/kg for 6 weeks). However, akin to ganciclovir, compound S2242 significantly reduced testicle weight, testicle morphology, and spermatogenesis.     

Substrate specificity and phosphorylation of antiviral and anticancer nucleoside analogues by human deoxyribonucleoside kinases and ribonucleoside kinases

Structural analogues of nucleosides, nucleoside analogues (NA), are used in the treatment of cancer and viral infections. Antiviral NAs inhibit replication of the viral genome, whereas anticancer NAs inhibit cellular DNA replication and repair. NAs are inactive prodrugs that are dependent on intracellular phosphorylation to their pharmacologically active triphosphate form. The deoxyribonucleoside kinases (dNK) and ribonucleoside kinases (rNK) catalyze the first phosphorylation step, converting deoxyribonucleosides and ribonucleosides to their corresponding monophosphate form. The dNKs have been studied intensively, whereas the rNKs have not been as thoroughly investigated. This overview is focused on the substrate specificity, tissue distribution, and subcellular location of the mammalian dNKs and rNKs and their role in the activation of NAs.     

Effects of antiviral nucleoside analogs on human DNA polymerases and mitochondrial DNA synthesis.

Inhibition constants were determined for 16 nucleoside analog triphosphates against human DNA polymerases alpha, beta, gamma, and epsilon, and 7 nucleoside analogs were examined as inhibitors of mitochondrial DNA synthesis in human Molt-4 cells in culture. The results demonstrate no clear quantitative or qualitative correlation between inhibition of DNA polymerases, particularly mitochondrial DNA polymerase gamma, and the inhibition of mitochondrial DNA synthesis in Molt-4 cell culture. Furthermore, the data indicate that inhibition of isolated DNA polymerases may not be predictive of in vitro or in vivo toxicity. Finally, it is not clear whether inhibition of mitochondrial DNA synthesis will be an accurate predictor of the potential in vivo toxicity of antiviral nucleoside analogs.     

Polymorphism,phase transformation and energetic properties of 3-nitro-1,2,4-triazole

We report the preparation, analysis, and phase transformation behavior of polymorphs of 3-nitro-1,2,4-triazole. The compound crystallizes in two different polymorphic forms, Form I (tetragonal, P4₁2₁2) and Form II (monoclinic, P2₁/c). Analysis of the polymorphs has been investigated using microscopy, differential scanning calorimetry, in situ variable-temperature powder X-ray diffraction, and single-crystal X-ray diffraction. On heating, Form II converts into Form I irreversibly, and on further heating, decomposition is observed. In situ powder X-ray diffraction studies revealed that Form II transforms to Form I above 98 °C, indicating that Form I is more stable than Form II at high temperature. Form II of 3-nitro-1,2,4-triazole has good detonation properties (V_det = 8213 m s⁻¹, P_C–J = 27.45 GPa), and low sensitivity (IS > 40 J, FS = 360 N, ESD = 29 J), which make it a competitive candidate for use as a new insensitive explosive.

On heating, Form II converts into Form I irreversibly, which indicates Form I is more stable at higher temperatures.     

Novel catenated N6 energetic compounds based on substituted 1,2,4-triazoles: synthesis,structures and properties

1-Amino-3,5-dinitro-1,2,4-triazole (ADNT) was prepared using an efficient N-amination process. Three novel catenated N₆ energetic derivatives of ADNT, which contain 1,1′-azobis(3,5-dinitro-1,2,4-triazole) (ABDNT), 1,1′-azobis(3-chloro-5-nitro-1,2,4-triazole) (ABCNT) and 1,1′-azobis(3,5-diazido-1,2,4-triazole) (ABDAT), were synthesized from N-amino oxidative-coupling reactions of ADNT. All compounds were fully characterized by ¹H and ¹³C nuclear magnetic resonance spectroscopies, infrared spectroscopy, elemental analysis, mass spectrum, as well as differential scanning calorimetry (DSC). The crystal structure of compound ABCNT was confirmed by single-crystal X-ray diffraction showing an extensive conjugated structure. The densities of energetic derivatives ranged from 1.71 to 1.93 g cm⁻³, and all compounds have positive heats of formation in the range of 774.8 to 2150.8 kJ mol⁻¹. Based on the measured densities and calculated heats of formation, theoretical performance calculations, including detonation pressures (29.6–42.4 GPa) and detonation velocities (8.22–9.49 km s⁻¹) were carried out using the Gaussian 09 program and Kamlet–Jacobs equations, and they compared favorably with those of TNT and RDX. These properties make them potentially competitive as new high energy-density compounds.

Novel catenated N₆ energetic compounds based on substituted 1,2,4-triazoles were synthesized, which can be used as new high energy-density materials.     

Enzymatic synthesis of nucleoside analogues from uridines and vinyl esters in a continuous-flow microreactor

We achieved the effective controllable regioselective acylation of the primary hydroxyl group of uridine derivatives catalyzed by Lipase TL IM from Thermomyces lanuginosus with excellent conversion and regioselectivity. Various reaction parameters were studied. These regioselective acylations performed in continuous flow microreactors are a proof-of-concept opening the use of enzymatic microreactors in uridine derivative biotransformations.

We achieved the effective controllable regioselective acylation of the primary hydroxyl group of uridine derivatives catalyzed by Lipase TL IM from Thermomyces lanuginosus with excellent conversion and regioselectivity.

Continuous-flow processes form the basis of the petrochemical and bulk chemicals industry, where strong competition, stringent environmental and safety regulations, and low profit margins drive the need for high-performing, cost effective, safe, and atom-efficient chemical operations. Continuous flow microreactor technology (MRT)^1–4 has become increasingly popular as alternative to conventional batch chemistry synthesis due to significant advantages stemming mostly from the ideal heat transfer in such reactors and the high process stability that can be reached.^5–7 Providing a precise control over different reaction parameters, MRT allows for simple screening and optimization of reaction conditions. Scale-up^8–10 is also easy by increasing the column size or number of columns (numbering-up). Moreover, unique reactivities and selectivities are sometimes observed under continuous-flow conditions.^11,12 As a result of the outflow of products, overreactions are avoided, and catalyst/substrate conditions in continuous-flow systems can increase the reactivity and selectivity. The separation of catalysts and products is very easy when heterogeneous catalysts are packed in continuous-flow columns.^13,14Nucleoside analogues, such as azidothymidine, telbivudine and doxifluridine, have shown high effectiveness as antiviral¹⁵ and antitumor¹⁶ agents (Fig. 1). However, their efficiency is sometimes reduced by the appearance of resistance mechanisms.¹⁷ Therefore, the search for new nucleoside derivatives has attracted more and more attention from chemists. Many works on the modification on the sugar moiety of nucleosides to add more and better biological traits to existing candidates have been reported.^18–20 The most common introduced substituents on sugar moiety of nucleosides include halogen, N₃, CF₃, CN, alkyl, alkenyl, alkynyl, aryl, thio and seleno groups. Regioselective acylation of sugar moiety of nucleosides is another way to get nucleoside analogues.^21–25 But as we can see, the sugar moiety of nucleosides contains at least three hydroxyl groups, which make regioselective acylation of nucleosides more difficult, traditional chemical synthesis routes often require complex protection–unprotection procedures and harsh conditions.^20,26–28 Therefore, it is important to find a new, simple and environmentally friendly method for the preparation of nucleosides analogues.Open in a separate windowFig. 1Examples of nucleoside analogues.Enzymes are the most proficient catalysts, offering much more competitive processes compared to chemical catalysts, such as mild reaction conditions, high efficiency and selectivity. In the past few years, several works about the enzyme-catalyzed synthesis of uridine esters were reported.^29–36 Some lipase such as CAL-B²² and pseudomonas cepacia lipase²⁹ have been applied to the synthesis of uridine esters, but it requires a longer reaction time (24 h) to achieve the desired result. Flow chemistry especially catalyst/substrate conditions in continuous-flow systems can increase the reactivity and selectivity.^37,38 In the interest of developing highly efficient method for the synthesis of uridine esters, we envisaged modifying our procedure to achieve a continuous flow microreactor protocol for the synthesis of uridine esters. Specifically, we directed our attention towards the development of an enzymatic microreactor strategy involving lipase TL IM from Thermomyces lanuginosus as catalysts (Scheme 1). The aim of this paper is to investigate, under a continuous flow microreactor, the effect of various reaction parameters on the reaction yield. What''s more, we want to quickly build the related compound library through the new synthesis method for the next drug screening.Open in a separate windowScheme 1Enzymatic synthesis of uridine esters from uridine derivatives and vinyl esters in continuous flow microreactors.The enzymatic synthesis of uridine esters from uridine derivatives and vinyl esters in a continuous-flow microreactor is described in Fig. 2. We first examined whether the reaction can be performed in continuous flow microreactors. The device was composed of a syringe pump, coil reactor and Y-shaped mixer (φ = 1.8 mm; M). A syringe pump (Harvard Apparatus PHD 2000) was used to introduce two separate feed streams to a 3.1 mL PFA coil reactor (2.0 mm I. D.). Reagent feed 1 (10 mL) with the uridine dissolved in DMSO and tert-amyl alcohol mixed solvent, reagent feed 2 (10 mL) with the vinyl esters dissolved in tert-amyl alcohol. Two feed streams were mixed into a single PFA tubing and fed a Y-shaped mixer. The coil reactor was filled with lipozyme TL IM (catalyst reactivity: 250 IUN g⁻¹) and submerged into a thermostatic water bath to control the temperature. After initial optimization, it was found that the target uridine esters (3a–3l) could be obtained, after a thirty minutes residence time, in excellent yield (80–99%) after separation and purification (Open in a separate windowFig. 2Experimental setup for the enzymatic synthesis of uridine esters catalyzed by lipozyme TL IM.Shaker and continuous flow synthesis of uridine esters catalyzed by lipozyme TL IM

Highly functionalized pyrrolidine analogues: stereoselective synthesis and caspase-dependent apoptotic activity

Novel spiropyrrolidine heterocyclic hybrids were synthesized for the first time in a sustainable fashion employing a 1,3-dipolar cycloaddition strategy to form a new class of azomethine ylides generated from tyrosine and acenaphthenequinone. Following their synthesis and characterization, these heterocyclic hybrids were tested for their anticancer activities by incubation at different concentrations and durations with different cancer and non-cancer cell cultures, and the results indicated a potential therapeutic activity. Further analysis of cancer cell death revealed that it occurred through a caspase-related apoptotic pathway, specifically mediated by caspase-3. These results demonstrated that the obtained spiropyrrolidine heterocyclic hybrids may be good hit compounds for the development of potential therapeutic agents for the treatment of malignant tumors.

Spiropyrrolidines were synthesized employing a new class of azomethine ylide for the first time and were tested for their anticancer activity, where the cell death mechanism revealed that it is occurring through the caspase-3 dependent pathway.