Synthesis, antitumor and antimicrobial activities of 4-(4-chlorophenyl)-3-cyano-2-(β-O-glycosyloxy)-6-(thien-2-yl)-nicotinonitrile

4-(4-Chlorophenyl)-3-cyano-6-(thien-2-yl)-1H-pyridin-2-one (2) was obtained by reaction of 2-acetyl thiophene with 4-chlorobenzaldehyde and ethyl cyanoacetate in presence of ammonium acetate or by the reaction of α,β-unsaturated compound 1 with ethyl cyanoacetate in the presence of ammonium acetate. 4-(4-Chlorophenyl)-2-(2′,3′,4′,6′-tetra-O-acetyl-β-d-gluco/galactopyranosyloxy)-6-(thien-2-yl)nicotinonitrile (5a and 5b), riboside 11, xyloside 12 and lactoside 16 were prepared by the reaction of 2 with glycosyl/galactosyl/xylosyl/lactosyl bromide and peracetylated xylose/ribose under the conventional and microwave irradiation methods. The reaction has regioselectively gave the O-glycosides and not the N-glycosides. The glycosides 5a,b, riboside 11, xyloside 12 and lactoside 16 were deacetylated in the presence of Et₃N/MeOH and few drops of water to give 7a,b, 13, 14 and 17. The structure of the new synthesized compounds was confirmed by using IR, ¹H, ¹³C NMR spectra and microanalysis. Selected members of these compounds were screened for antitumor and antibacterial activity.     

Synthesis, antiproliferative activity, and mechanism of action of a series of 2-{[(2E)-3-phenylprop-2-enoyl]amino}benzamides

Several new 2-{[(2E)-3-phenylprop-2-enoyl]amino}benzamides 12a-s and 17t-v were synthesized by stirring in pyridine the (E)-3-(2-R1-3-R2-4-R3-phenyl)acrylic acid chlorides 11c-k and 11t-v with the appropriate anthranilamide derivatives 10a-c or the 5-iodoanthranilic acid 13. Some of the synthesized compounds were evaluated for their in vitro antiproliferative activity against the full NCI tumor cell line panel derived from nine clinically isolated cancer types (leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate and breast). COMPARE analysis, effects on tubulin polymerization in cells and with purified tubulin, and effects on cell cycle distribution for 17t, the most active of the series, indicate that these new antiproliferative compounds act as antitubulin agents.     

Synthesis of 4H-chromene, coumarin, 12H-chromeno[2,3-d]pyrimidine derivatives and some of their antimicrobial and cytotoxicity activities

Condensation of 3-N,N-diethylaminophenol (1) with α-cyanocinnamonitriles (2a-c) and ethyl α-cyanocinnamates (2d-f) provided compounds 3a-f and 4a-c. 12H-Chromeno[2,3-d]pyrimidine derivatives 6, 11-13 and 16 were obtained by treatment of 4H-chromene compounds (3) with different electrophiles followed by nucleophilic reagents. Structures of these compounds were established on the basis of IR, UV, ¹H NMR, ¹³C NMR and MS data. Some of the new compounds were evaluated for antimicrobial and cytotoxicity activities.     

Synthesis, biopharmaceutical characterization, antimicrobial and antioxidant activities of 1-(4'-O-β-D-glucopyranosyloxy-2'-hydroxyphenyl)-3-aryl-propane-1,3-diones

This research communication is toward the investigation of the antibacterial, antifungal and antioxidant activities of the synthesized compounds 1-(4′-O-β-d-glucopyranosyloxy-2′-hydroxyphenyl)-3-aryl-propane-1,3-diones (5a)-(5h). These compounds have been obtained by the interaction of α-acetobromoglucose with 1-(2′,4′-dihydroxyphenyl)-3-aryl-propane-1,3-diones (3a)-(3h) under anhydrous condition and at lower temperature. The structures of these newly synthesized O-β-d-glucopyranosides were established on the basis of chemical, elemental, and spectral analyses. Further, the compounds (5b), (5c), (5d) and (5g) showed potent antibacterial and antifungal activity. A good correlation was obtained between the theoretical predictions of bioavailability using Lipinski’s rule-of-five and experimental verification.     

Conjugates of 3α-methoxyserrat-14-en-21β-ol (PJ-1) and 3β-methoxyserrat-14-en-21β-ol (PJ-2) as cancer chemopreventive agents

3α-Methoxyserrat-14-en-21β-ol (PJ-1) and 3β-methoxyserrat-14-en-21β-ol (PJ-2) were conjugated with well-known phenolic compounds, narigenin, hesperetin, genistein, and daidzein (1-8). Other conjugates of PJ-2-3,5-dihydroxy-4-methoxybenzoic acid (9), PJ-2-pyrogallol (10), and derivatives of PJ-1, PJ-2-3,3-dimethyl-succinates (11, 12), PJ-1, PJ-2-succinates (13, 14), PJ-2-glycine (15), PJ-2-piperidine acetic acid (16), and PJ-1 epoxy-3,3-dimethyl-succinate (17) were tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). The inhibitory effects of 11 (IC₅₀ = 251), 12 (IC₅₀ = 248), and 17 (IC₅₀ = 230 mol ratio/32 pmol/TPA), were 2-fold stronger than those of the other compounds such as oleanolic acid (IC₅₀ = 449). Compounds 10, 11, and 17 inhibited mouse skin tumor promotion in an in vivo two-stage carcinogenesis model. The in vivo two-stage mouse-skin carcinogenesis test employed 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA as a promoter.     

Cytotoxic and protective DNA damage of three new diterpenoids from the brown alga Dictoyota dichotoma

Three new diterpenes Amijiol acetate (3), dolabellane, Dolabellatrienol (4), and dolastane, Amijiol-7, 10-diacetate (9) were isolated together with the previously described Pachydictyol A (1), Isopachydictyol A (2), 8β-hydroxypachydictyol A (5), Amijiol (6), Isodictyohemiacetal (7) and Dictyol C (8) from the Red Sea brown alga Dictyota dichotoma var. implexa. The structures and relative stereochemistry of the new diterpenoids were proposed on the basis of their spectral data. Compounds 3 and 9 have potent activity against DNA damage, cytotoxicity against WI-38, HepG2, and MCF-7 cell lines, and antioxidant using ABTS and erythrocytes hemolysis.     

Industrially viable processes for synthesis of biologically active hydroxycarotenoids commonly found in fruits and vegetables

Human plasma and tissues contain in excess of 12 dietary carotenoids and several metabolites that originate from consumption of fruits and vegetables. The major hydroxycarotenoids absorbed by humans are: (3R,3′R,6′R)-lutein (1), (3R,3′R)-zeaxanthin (2), (3R,6′R)-α-cryptoxanthin (3), and (3R)-β-cryptoxanthin (4) and their E/Z-stereoisomers. In addition, several hydroxycarotenoids that result from metabolic transformation of 1 have also been identified in human plasma and ocular tissues. Epidemiological and experimental evidence to date suggest hydroxycarotenoids may protect against chronic diseases such as cancer, cardiovascular disease and age-related macular degeneration (AMD). Therefore, supplementation with these carotenoids in individuals with a low dietary intake of fruits and vegetables is essential. However, with the exception of 1 and 2, industrial production of 3 and 4 have not yet materialized. A relatively straightforward semisynthetic process has been developed that transform 1 into a mixture of 3 (12%) and 4 (80%). Hydroxycarotenoid 3 can also be directly prepared from allylic deoxygenation of 1 in a single step in an excellent yield. These two processes provide an easy access to optically active 3 and 4 that are normally prepared by numerous synthetic steps.     

Synthesis and biological evaluation of unsaturated keto and exomethylene D-arabinopyranonucleoside analogs: novel 5-fluorouracil analogs that target thymidylate synthase

The synthesis of pyrimidine unsaturated keto and exomethylene arabinopyranonucleoside analogs as potential antitumor and antiviral agents is described. Commercially available 1,2,3,4-tetra-O-acetyl-d-arabinopyranose (1) was condensed with silylated thymine, uracil, 5-fluorouracil, N⁴-benzoyl cytosine and 5-(trifluoromethyl)uracil, respectively, deacetylated and acetylated to afford 1-(3,4-O-isopropylidene-α-d-arabinopyranosyl)pyrimidine analogs 4. Two different synthetic routes were investigated for the conversion of compounds 4 into the new 1-(2,3,4-trideoxy-2-methylene-α-pent-3-enopyranosyl)nucleoside derivatives of thymine (10a), uracil (10b), 5-fluorouracil (10c) and N⁴-benzoyl cytosine (10d). Only the first approach could afford derivative 10d. Debenzoylation of 10d afforded 1-(2,3,4-trideoxy-2-methylene-α-pent-3-enopyranosyl)cytosine (10f). The first approach resulted also to the 2-keto-3,4-unsaturated analogs 9. The new analogs did not show inhibition of DNA and RNA virus replication in cell culture. The 2′-ketonucleoside derivatives 9 were found to be more cytostatic than the corresponding 2′-exomethylene nucleosides 10. The 5-fluorouracil unsaturated keto derivative 9c and the exomethylene derivatives 10c and 13c showed antiproliferative activity in the lower micromolar range. Experimental evidence revealed that 9c, 10c and 13c may act as novel types of 5-fluorouracil releasing prodrugs, and points to thymidylate synthase as target for their cytostatic action.     

One-pot microwave assisted synthesis under green chemistry conditions, antioxidant screening, and cytotoxicity assessments of benzimidazole Schiff bases and pyrimido[1,2-a]benzimidazol-3(4H)-ones

The synthesis of a number of benzimidazole Schiff bases 3 and 3-oxo-pyrimido[1,2-a]benzimidazoles 4 in excellent yields by a one-step sequence from the reaction of 2-aminobenzimidazole under green chemistry conditions is described. Structural assignments of the new compounds as well as complete assignment of ¹H and ¹³C NMR signals have been unambiguously achieved based on the analysis of their ¹H and ¹³C NMR (1D and 2D), IR, MS and elemental analysis data. To the synthesized Schiff bases the E-configuration was assigned on the basis of comparison of experimental and calculated (DFT) ¹³C NMR chemical shifts. Compounds 3 and 4 were evaluated as inhibitors of lipoxygenase (LOX) and of lipid peroxidation (LPO). All the tested derivatives showed inhibition of lipid peroxidation, whereas most of them were found to have higher activation than the reference compound trolox; The Schiff bases 3e, 3h, and 3i, and the pyrimidobenzimidazoles 4a, 4e and 4f were found to be the most potent. The most potent LOX inhibitor within the subset of Schiff bases was found compound 3i, followed by 3f, whereas compounds 4a and 4g were found the most potent of the 3-oxo-pyrimido[1,2-a]benzimidazole group. Moreover, some cytotoxicity assessments were undertaken, whereupon it was found that Schiff base 3i and pyrimidobenzimidazoles 4e and 4f did not exhibit cytotoxicity at similar concentrations resembling thus the inhibitory activity of lipid peroxidation. The most cytotoxic Schiff base and pyrimidobenzimidazole were found to be 3d and 4c, respectively.     

Synthesis, characterization and pharmacological activity of 4-{[1-substituted aminomethyl-4-arylideneamino-5-sulfanyl-4,5-dihydro-1H-1,2,4-triazol-3-yl]methyl}-2H-1,4-benzothiazin-3(4H)-ones

A new series of Schiff and Mannich bases derivatives (6) of 4-[(4-amino-5-sulfanyl-4H-1,2,4-triazol-3-yl)methyl]-2H-1,4-benzothiazin-3(4H)-one (4), derived from (3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl)acetic acid (3) were synthesized. The structures of all newly synthesized compounds were elucidated by elemental analysis, IR, ¹H NMR and mass spectral data. Synthesized compounds were evaluated for their anti-inflammatory and analgesic activity. Among the tested compounds, the (3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl)acetic acid (3) possess analgesic activity comparable to that of pentazocine; activity decreased on derivatization of the carboxylic acid group. However the anti-inflammatory activity of (3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl)acetic acid (3) increased by derivatization of the carboxylic acid group and some of the compounds showed anti-inflammatory activity comparable to that of indomethacin.     

3-benzylamino-β-carboline derivatives induce apoptosis through G2/M arrest in human carcinoma cells HeLa S-3

β-Carboline derivatives are known as the lead compounds for anti-tumor agents. To examine an optimal structure for anti-tumor activity, we synthesized a variety of β-carboline derivatives, possessing a variety of substituents on the nitrogen atom of the amino group of 3-amino-β-carboline, and evaluated their anti-tumor activity for HeLa S-3 cell line. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that an optimal structure for anti-tumor activity was 3-cyclohexylmethylamino (1e) or 3-benzylamino-β-carboline (1f). An optimal counter anion of 2-methyl-3-benzylamino- β-carbolinium salts was a triflate anion 2c. In addition, the introduction of a hydroxyl group on the meta-position of the benzyl group of 3-benzylamino-β-carboline (3e) enhanced its anti-tumor activity. Hoechst 33342 staining and DNA fragmentation assay suggested that 1f, 2c and 3e induced cell death by apoptosis unlike 1e. Flow cytometry analysis showed that 1f, 2c and 3e induced cell apoptosis through arrest of the cell cycle in the G₂/M phase.     

Synthesis and evaluation of monoamidoxime derivatives: toward new antileishmanial compounds

A new series of monoamidoxime derivatives was synthesized using manganese(III) acetate by microwave irradiation. Several amidoximes (27-31, 33, 38) showed valuable in vitro activities toward Leishmania donovani promastigotes, exhibiting IC₅₀ values between 5.21 and 7.89 μM. In parallel, the cytotoxicity of these compounds was evaluated on murine J774A.1 cells, revealing the corresponding selectivity index (SI). Among the 13 tested compounds, 4 monoamidoximes (27-30) exhibited an SI more than 20 times better than pentamidine. Moreover, monoamidoxime 28 (4-[5-Benzyl-3-(4-fluorophenylsulfonyl)-5-methyl-4,5-dihydrofuran-2-yl]-N′-hydroxybenzimidamide) is 40 times more selective than pentamidine, and 1.6 times more than amphotericin B, used as reference drug compounds.     

Synthesis and anti-tumor activity of 2-amino-3-cyano-6-(1H-indol-3-yl)-4-phenylpyridine derivatives in vitro

A series of novel 2-amino-3-cyano-6-(1H-indol-3-yl)-4-phenylpyridine derivatives were synthesized and their cytotoxic activity against A549, H460, HT-29 and SMMC-7721 cell lines was evaluated in vitro. Among them, ten compounds (10, 11, 14, 16, 17, 26, 27, 29, 30 and 31) displayed excellent anti-tumor activity against different cell lines. The most promising compound 27 showed strong anti-tumor activity against A549, H460, HT-29 and SMMC-7721 cell lines with IC₅₀ values of 22, 0.23, 0.65 and 0.77 nM, which were 2.6-, 83-, 1.1 × 10³- and 2.0 × 10³- fold more active than MX-58151 (IC₅₀ values of 0.058, 0.019, 0.70 and 1.53 μM), respectively.     

Synthesis, in vitro antimicrobial and in vivo antitumor evaluation of novel pyrimidoquinolines and its nucleoside derivatives

Seven series of pyrimidoquinoline derivatives have been synthesized, tetrazolo[4′,3′:-1,2]pyrimido[4,5-b]quinoline (3), 2-aminopyrimido[4,5-b]quinoline (4), triazolo[4′,3′:1,2]-pyrimidoquinoline (5a,b, 10), imidazolo[3′,2′:1,2]pyrimido[4,5-b]-quinoline (8a,b), 6-chloro-2-methylthiopyrimido[4,5-b]quinoline (12), acetylated nucleosides (16, 17a,b) and deacetylated nucleosides (18, 19a,b). Some of the novel pyrimidoquinoline derivatives possess highly activity toward the bacteria and fungi species. The new quinolines derivatives were evaluated for their anticancer activity toward human cancer cell lines by the National Cancer Institute (NCI). Most of them had excellent growth inhibition activity, having LD₅₀ values in the low micromolar to nanomolar concentration range.     

Synthesis and evaluation of aroylthiourea derivatives of 4-β-amino-4'-O-demethyl-4-desoxypodophyllotoxin as novel topoisomerase II inhibitors

A novel series of aroylthiourea derivatives of 4-β-amino-4′-O-demethyl-4-desoxy- podophyllotoxin were synthesized. Their cytotoxicities against three cancer cell lines were investigated by MTT assay. The kDNA decatenation assay indicated that compounds 5a, 5f, 5h and 5l inhibited topoisomerase II-mediated kDNA decatenation. DNA flow cytometric analysis revealed that compound 5a induced cell cycle arrest at G2/M phase in HCT-116 cell line.     

Synthesis and structure-activity relationship of 2-thiopyrimidine-4-one analogs as antimicrobial and anticancer agents

Considering that some thiopyrimidines were previously reported as potential therapeutics, the present study achieved novel analogs of bioactive 2-substituted thiopyrimidines-4-(3H)-ones via base catalyzed alkylation reaction of 2-thiouracil using alkyl and aralkyl bromides. The title compounds were 2-(1-butylthio)pyrimidine-4(3H)-one (5a), 2-(2-butylthio)pyrimidine-4(3H)-one (5b), 2-(cyclohexylmethylthio)pyrimidine-4(3H)-one (5c), 2-(benzylthio)pyrimidine-4(3H)-one (5d) and 2-(1-adamantylthio)pyrimidine-4(3H)-one (5e). Bioactivity tests revealed that thiopyrimidines 5a, 5c, 5d and 5e exhibited antimicrobial activity. The thiopyrimidine-4-one (5c) showed complete inhibition against Streptococcus pyogenes and Branhamella catarrhalis as well as antifungal action against Candida albicans. Significantly, the 1-adamantylthiopyrimidine (5e) was shown to be the most potent cytotoxic compound against multidrug-resistant small cell lung cancer (H69AR). Their structure-activity relationships were discussed.     

Synthesis and biological activity of 7H-benzo[4,5]indolo[2,3-b]-quinoxaline derivatives

New 7-(2-aminoethyl)-7H-benzo[4,5]indolo[2,3-b]quinoxalines (13-20) were synthesized with high yields starting from 3H-benzo[e]indole-1,2-dione. These compounds were screened for the cytotoxicity, anti-viral activity, interferon inducing ability and DNA affinity compared with the corresponding 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxaline derivatives (1-12). It was shown, that compounds 13-20 bind to DNA stronger (lg К_a = 6.23-6.87) than compounds 1-12 (lg К_a = 5.57-5.89). Anti-viral activity is significantly reduced with annulations of benzene ring in Indoloquinoxaline moiety 13-20.     

Synthesis and anticancer evaluation of novel 2-cyclopropylimidazo[2,1-b][1,3,4]-thiadiazole derivatives

A series of 2,5,6-trisubstituted imidazo[2,1-b][1,3,4]-thiadiazole derivatives 4(a-k) have been prepared by reaction of 2-amino-5-cyclopropyl-1,3,4-thiadiazole and an appropriate phenacyl bromide. Further 5-bromo 5(a-k) and 5-thiocyanato 6(a-k) derivatives were synthesized in order to study the effect of these substituents on antitumor activity. Structures of these compounds were established by IR, ¹H NMR, ¹³C NMR and Mass spectroscopy. Seven compounds were granted NSC code at National Cancer Institute (NCI), USA for anticancer activity at a single high dose (10⁻⁵ M) in full NCI 60 cell panel. Among the compounds tested, 5-bromo-6-(4-chlorophenyl)-2-cyclopropylimidazo[2,1-b][1,3,4]thiadiazole 5b (NSC D-96022/1) was found to be the most active candidate of the series at five dose level screening with degree of selectivity toward Leukemic cancer cell line.     

Derivatives of pyrrolo[3,4-d]pyridazinone, a new class of analgesic agents

A series of N2-{2-[4-aryl(benzyl)-1-piperazinyl(piperidinyl)]ethyl}pyrrolo[3,4-d]pyridazinones 4 and related derivatives 5 were synthesized as potential analgesic agents. The structures of the new compounds were elucidated by micro, spectral and X-ray analysis. Analgesic activity of the compounds was investigated in the phenylbenzoquinone induced ‘writhing’ and ‘hot plate’ test in mice and at radioligand binding assay. At ‘writhing’ test all compounds, without exception, were more active than acetylsalicylic acid (ASA) with ED₅₀ values ranging from 0.04 to 11 mg/kg (i.p.) (ED₅₀ for ASA - 39.15 mg/kg). Analgesic effect at the ‘hot plate’ test was observed for three compounds 4c,e,f at the dose 3-5 times higher then that of morphine (ED₅₀-3.39 mg/kg). At radioligand binding assay of 4c,e,f only compound 4f exhibited affinity for the μ-opioid receptors similar to that of Tramadol. The acute toxicity of the pyrrolopyridazinones 4, 5 were also studied and non toxic effect was observed at the 2000 mg/kg (5a 1420 mg/kg) i.p. dose level. On the basis of the available pharmacological data S-A relationship is discussed. The preferred conformational characteristic of 4, taken 4c as an example, was also described.     

Overcoming human P-glycoprotein-dependent multidrug resistance with novel dihydro-β-agarofuran sesquiterpenes

Sixteen (1-16) dihydro-β-agarofuran sesquiterpenes were isolated from the fruits of Maytenus jelskii and evaluated against mammalian cells with a multidrug resistance phenotype mediated by the overexpression of the human P-glycoprotein. Their stereostructures have been elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR techniques, CD studies, chemical correlations and biogenetic means. Eight compounds from this series were discovered as potent chemosensitizers (1, 2, 4, 6, 8, 9, 11 and 14), showing similar effectiveness to or higher than the classical P-glycoprotein reversal agent verapamil, a first-generation chemosensitizer, when reversing resistance to daunomycin and vinblastine. Detailed structure-activity relationships revealed that aromatic substituents at the 6 and 9-position of the sesquiterpene scaffold were able to modulate the intensity of inhibition.