Novel 4-nitroimidazole analogues: synthesis, in vitro biological evaluation, in silico studies, and molecular dynamics simulation.

A new series of 4-nitroimidazole bearing aryl piperazines 7-16, tetrazole 17 and 1,3,4-thiadiazole 18 derivatives was synthesized. All derivatives were screened for their anticancer activity against eight diverse human cancer cell lines (Capan-1, HCT-116, LN229, NCI-H460, DND-41, HL-60, K562, and Z138). Compound 17 proved the most potent compound of the series inhibiting proliferation of most of the selected human cancer cell lines with IC50 values in the low micromolar range. In addition, compound 11 exhibited IC50 values ranging 8.60-64.0 µM against a selection of cancer cell lines. These findings suggest that derivative 17 can potentially be a new lead compound for further development of novel antiproliferative agents. Additionally, 17-18 were assessed for their antibacterial and antituberculosis activity. Derivatives 17 and 18 were the most potent compounds of this series against both Staphylococcus aureus strain Wichita and a methicillin resistant strain of S. aureus (MRSA), as well as against Mycobacterium tuberculosis strain mc26230. The antiviral activity of 7-18 was also evaluated against diverse viruses, but no activity was detected. The docking study of compound 17 with putative protein targets in acute myeloid leukemia had been studied. Furthermore, the molecular dynamics simulation of 17 and 18 had been investigated.

Design, Synthesis, Docking Studies and Molecular Dynamics Simulation of New 1,3,5-Triazine Derivatives as Anticancer Agents Selectively Targeting Pancreatic Adenocarcinoma (Capan-1).

On the basis of remarkable anticancer profile of s-triazine nucleus, a new series of 2-methoxy-4-(3-morpholino-5-(arylamino)phenoxy)benzaldehyde derivatives 11 a-u was prepared and evaluated for in vitro antiproliferative activity against eight diverse human cancer cell lines (Capan-1, HCT-116, LN229, NCI-H460, DND-41, HL-60, K562 and Z138). Compounds 11 o, 11 r and 11 s were the most potent anticancer agents on pancreatic adenocarcinoma (Capan-1) cell line with IC50 value of 1.4, 5.1 and 5.3 µM, respectively, while compounds 11 f, 11 g, 11 k, 11 l and 11 n displayed selective activity against the pancreatic adenocarcinoma (Capan-1) cell line with IC50 values of 7.3-11.5 µM. These results indicate that derivative 11 o may serve as a promising lead compound for the ongoing development of novel antiproliferative agents. The docking studies were conducted to predict the interactions of derivative 11 o with putative protein targets in pancreatic adenocarcinoma (Capan-1) cell line, specifically the prenyl-binding protein PDEδ. Furthermore, the analysis of the molecular dynamics simulation results demonstrated that complex 11 o promoted a higher stability to the prenyl-binding protein PDEδ.

New tamoxifen analogs for breast cancer therapy: synthesis, aromatase inhibition and in silico studies.

A new class of tamoxifen analogues, using McMurry reaction conditions, is described. The scheme involved the conversion of ketoprofen (6) into amide derivatives 7 and 8, by coupling with N1,N1-substituted propan-1,3-diamine derivatives in the presence DIC and HOB. Treatment of 7 and 8 with various ketones under McMurry reaction conditions afforded the tamoxifen analogues 9-16. All the analogues were screened in vitro for their aromatase inhibitory and antiproliferative activity against MCF-7 breast cancer cells. Compounds 10, 11 and 12 showed a potent activity against MCF-7 cell lines breast cancer with IC50 values of 0.070, 0.042 and 0.077 µM of selectivity index (SI) 3.0, 2.5 and 2.6, respectively. Further, 12 exhibited potent activity against estrogen receptor (14.7 ± 2.4 nM), while compound 10 was the most active analogues against aromatase with IC50 of (0.070 nM). Furthermore, all new compounds were docked into human placental aromatase enzyme and estrogen receptor and showed very good correlations with experimental IC50. Therefore, we can consider these designed compounds as starting scaffold to design an efficient drug against estrogen receptor and aromatase.Communicated by Ramaswamy H. Sarma.

Synthesis, Aromatase Inhibitory, Antiproliferative and Molecular Modeling Studies of Functionally Diverse D-Ring Pregnenolone Pyrazoles.

BACKGROUND: Aromatase, a cytochrome P450 hemoprotein that is responsible for estrogen biosynthesis by conversion of androgens into estrogens, has been an attractive target in the treatment of hormonedependent breast cancer. Design of new steroidal aromatase inhibitors becomes imperative. OBJECTIVE: Synthesis and biological evaluation of two classes of structurally and functionally diverse D-ring pregnenolone pyrazoles as type I aromatase inhibitors and antiproliferative agents. METHODS: Pregnenolone (1) was converted to 3ß-hydroxy-21-hydroxymethylidenepregn-5-en-20-one (2), which upon cyclization with phenylhydrazine generated regioisomeric pairs of pyrazoles 4 and 5. Further, Knoevenagel condensation of pregnenolone (1) with 3-oxo-3-phenylpropanenitrile (6) produced 2-benzoyl-3-(3b-hydroxyandrostan- 5-ene-20-ylidene)-but-2-enenitrile (7), which upon cyclization with hydrazine or phenylhydrazine generated the pyrazoles 8 and 9. All new steroidal derivatives were tested for their aromatase inhibition activity using Dibenzylfluorescein (DBF) based fluorescence assay developed by Stresser et al. Antiproliferative activities were measured using Sulforhodamine B assay. The activities were promising and there was a coherence between aromatase inhibitory and antiproliferative activities. RESULTS: The study reveals the immense potential of pregnenolone pyrazoles as aromatase inhibitors for the treatment of breast cancer. Molecular docking studies proved efficient binding of the new steroidal analogs on human placental aromatase. CONCLUSION: In the overall study, most of the compounds exhibited potential activity for the treatment of hormone dependent breast cancer. Compounds 4c and 4d were found to be the most promising pharmacons. Furthermore, compounds 4c and 4d were applied for their molecular docking study on human placental aromatase to predict their possible binding modes with the enzyme. These studies revealed that such molecules have high scope and potential for further investigation towards the treatment of estrogen dependent breast cancer.

A novel pregnene analogs: synthesis, cytotoxicity on prostate cancer of PC-3 and LNCPa-AI cells and in silico molecular docking study.

New pregnene analogs of N-hydroxamic acid 6, imino-propane hydrazides 7 and 8 as well as the aryl amides 9-11, oxadiazole, pyrazole and sulfinyl analogs 13-15, via the hydrazide analog 5 of methyl ((5-pregnen-3ß,17ß-diol-15α-yl)thio)propanoate (4) were synthesized. The in vitro cytotoxic activities of selected synthesized steroids against two human prostate cancer cell lines (PC-3, and LNCaP-AI) were evaluated by MTT assay. Compound 10 was the most active cytotoxic agent among these steroids against PC-3 and LNCaP-AI cell lines with inhibition of 96.2%, and 93.6% at concentration levels of 10.0 µM and 91.8%, and of 79.8% at concentration of 1.0 µM, respectively. Molecular docking study of 10 showed a hydrogen bonding with the amino acid Asn705 residue of the receptor 1E3G, together with hydrophobic interactions. Therefore, compound 10 can be considered as a promising anticancer agent due to its potent cytotoxic activity.

Synthesis of arylated coumarins by Suzuki-Miyaura cross-coupling. Reactions and anti-HIV activity.

Arylated coumarins were prepared by site-selective Suzuki-Miyaura cross-coupling reaction of the bis(triflate) of 4-methyl-6,7-dihydroxycoumarin. Triarylated coumarins were prepared by Suzuki-Miyaura cross-coupling reactions of 3-bromo-4-methyl-2-oxo-2H-chromene-6,7-diylbis(trifluoromethanesulfonate). The in vitro anti-HIV activity of the products was investigated. Two lead structures with considerable activities were identified.

Synthesis and Fluorescence Properties of new Monastrol Analogs Conjugated Fluorescent Coumarin Scaffolds.

A mild and efficient method has been used for the synthesis of ethyl 4-(3-hydroxphenyl)-6-methyl-2-thioxo-1,3-dihydroprimidine-5-carboxylate (monastrol) (2), via Biginelli reaction. Alkylation of 2 with the fluorescent coumarin 3 afforded the new thioether analog 4. Similarly, ethyl 4-(6,8-dichloro-2-oxo-2 H-chromen-3-yl)-6-methyl-2-thioxo-1,2,3,4-tetrahydro-pyrimidine-5-carboxylate (6) was prepared. The synthesized compounds are fluorescent active and show wavelength of maximum absorption (λmax) in UV or visible region in MeOH at room temperature.

Synthesis, and Fluorescence Properties of Coumarin and Benzocoumarin Derivatives Conjugated Pyrimidine Scaffolds for Biological Imaging Applications.

Series of coumarin and 5,6-benzomcomarin substituted pyrimidine derivatives 11-15 and 22-25 were synthesized, aiming to develop new imaging fluorescent agents. Analogously, treatment of 4-chloropyrimidine analog 16 with coumarin 3-carbohyrazide 5 under MWI condition followed by boiling with NH4OAc in HOAc furnished coumarin-1,2,4-triazolo-pyrimidine analog 18. The fluorescence property was investigated spectrophotometrically in MeOH with Rhodamine 6G as standard dye. All the compounds showed emission in the region between 331 and 495 nm. The quantum yield of all the compounds were found to be weak, except methyl benzocoumarin 3-carboxylate 22 which showed (ΦF = 0.98) in comparison to Rhodamine 6G as standard (ΦF = 0.95).

New biaryl-chalcone derivatives of pregnenolone via Suzuki-Miyaura cross-coupling reaction. Synthesis, CYP17 hydroxylase inhibition activity, QSAR, and molecular docking study.

A new class of steroids is being synthesized for its ability to prevent intratumoral androgen production by inhibiting the activity of CYP17 hydroxylase enzyme. The scheme involved the synthesis of chalcone derivative of pregnenolone 5 which was further modified to the corresponding biaryl-chalcone pregnenolone analogs 16-25 using Suzuki-Miyaura cross-coupling reaction. The synthesized compounds were tested for activity using human CYP17α hydroxylase expressed in Escherichia coli. Compounds 21 was the most active inhibitor in this series, with IC50 values of 0.61µM and selectivity profile of 88.7% inhibition of hydroxylase enzyme. Molecular docking study of 21 was performed and showed the hydrogen bonds and hydrophobic interaction with the amino acid residues of the active site of CYP17.

A new pregnenolone analogues as privileged scaffolds in inhibition of CYP17 hydroxylase enzyme. Synthesis and in silico molecular docking study.

A new series of 17-(N-(arylimino)-5-pregnen-3ß-ol derivatives 19-32 as well as carboxylate and acrylate analogues of pregnenolone 37-40 were synthesized and evaluated for their inhibitory activity against human CYP17 hydroxylase expressed in Escherichia coli. Compounds 32 and 37 were the most potent analogues in this series, showing inhibition activity with IC50 = 2.11 and 1.29 µM, respectively. However, the analogue 37 revealed a better selectivity profile (83.21% inhibition of hydroxylase), which is a leading candidate for further development. Molecular docking study of 37 showed binding with the amino acid residues of CYP17 through hydrogen bonds and hydrophobic interaction.

New CYP17 hydroxylase inhibitors: synthesis, biological evaluation, QSAR, and molecular docking study of new pregnenolone analogs.

A new series of pregnenonlone analogs were synthesized and evaluated for their inhibitory activity against cytochrome P450 (CYP17 hydroxylase enzyme). In general, the 5-aryl-1,3,4-thiadiazol-2-yl)-imino-pregnenolone derivatives 11-15 were more active than the sulfonate 24-31 and the ester 37-41 analogs. Derivative 12 showed optimal activity in this series, with IC50 values of 2.5 µM compared with the standard abiraterone (IC50 = 0.07 µM). However, the analogs 11 and 25 showed a better selectivity profile (81.5 and 82.7% inhibition of hydroxylase, respectively), which may be a useful lead in CYP17 inhibition studies. Molecular docking studies demonstrated quite similar binding patterns of all new pregnenolone derivatives at the active site of CYP17 through hydrogen bonding and hydrophobic interaction.

Synthesis of potential pyrimidine derivatives via Suzuki cross-coupling reaction as HIV and kinesin Eg5 inhibitors.

A series of 4-amino-5-((4-chlorophenyl)diazenyl)-6-(alkylamino)-1-methylpyrimidin-2-one derivatives 7-16 were prepared by nucleophilic displacement of 6-chloro-pyrimidine 6 by various amines. 4-Amino-5-((aryl-4-yl)diazenyl)-6-aryl-1-methylpyrimidin-2-one analogs 19-27, as well as 4-amino-5-((aryl-[1,1'-biphenyl]-4-yl)diazenyl)-6-aryl-1-methylpyrimidin-2-one 29-31 and 4-amino-6-aryl-1-methylpyrimidin-2-one 34-34, were synthesized via Suzuki cross-coupling reaction, using Pd(PPh3)4 as a catalyst and arylboronic acids as reagents. All compounds were evaluated for their antiviral activity against the replication of HIV-1 and HIV-2 in MT-4. Compounds 6, 16, 27, and 29 showed a 50% effective concentration of >2.15, >3.03, >2.29, and >1.63 µM, respectively, but no selectivity was observed (selectivity index < 1). Two of the newly synthesized pyrimidines 12 and 29 exhibited moderate kinesin Eg5 inhibition.

Synthesis and antiviral activity of new substituted methyl [2-(arylmethylene-hydrazino)-4-oxo-thiazolidin-5-ylidene]acetates.

A series of new methyl [2-(arylmethylene-hydrazono)-4-oxo-thiazolidin-5-ylidene]acetates (5a-o) were synthesized via cyclocondensation of thiosemicarbazones (3a-o) with dimethyl but-2-ynedioate (4) in good yields under solvent-free conditions. The environmentally friendly solvent-free protocol overcomes the limitations associated with the customary protracted solution phase synthesis and afforded the title compounds in a few minutes. Compounds 5b-i and 5h-o were evaluated for their antiviral activity against the replication activity of HIV-1 and HIV-2 in MT-4 using the MTT assay. The same compounds were also evaluated in vitro for their selective antiviral activity against hepatitis C virus (HCV) in the Huh 5-2 replicon system (type 1b, Con1 strain).

Exploration of the in vitro antiviral activity of a series of new pyrimidine analogues on the replication of HIV and HCV.

BACKGROUND: In continuation of our search for new anti-HIV and anti-HCV agents, the suggestion, synthesis and structure elucidation of a new series of 2,6-diamino-4-alkylthio- or (2-benzylhydrazinyl)-5-p-chlorophenylazopyrimidines), 2,6-diamino-4-(2-benzylhydrazinyl)-5-(aryl-[1,1'-biphenyl]-4-yl)pyrimidines, 2,6-diamino-4-(aryl)-5-(aryl[1,1'-biphenyl]-4-yl) pyrimidines), 6-(aryl)-1,3-dimethyl-5-nitro pyrimidine-2,4-dione and 6-amino-4-methoxy-N,N-dimethyl-6-arylpyrimidines were described. METHODS: The anti-HIV-1 (strain IIIB) and HIV-2 (strain ROD) activity of the newly synthesized pyrimidine analogues was evaluated in vitro in human MT-4 cells using the MT-4/MTT assay. Similarly, the same compounds were evaluated in vitro for their selective antiviral activity against HCV in the Huh 5-2 replicon system (type 1b, Con1 strain). RESULTS: None of the tested compounds exhibited inhibition of HIV-1 and HIV-2 replication in cell culture. Even though many compounds yielded a 50% effective concentration in the HCV replicon system with selectivity indexes up to 6.9, none of the compounds matched the selection criteria of a selective inhibitor of virus replication in this assay (that is, >70% inhibition at concentrations that do not elicit an anti-metabolic effect on the host cells). CONCLUSIONS: Structural modification of these compounds might optimize their anti-HCV activity by introducing diverse and potent functional groups at the pyrimidine backbone, like nitrile residue. Because of the nature of the molecules, these new derivatives will also be evaluated for their potential anti-HIV activity.

THEORETICAL MODEL OF CARBON NANOTUBES AS DELIVERY TO FLUOROURACIL (Anticancer) / MODELO TEÓRICO DE NANOTUBOS DE CARBONO COMO LIBERADORES DE FLUOROURACILO (Anticancerígeno) / MODELO TEÓRICO DE NANOTUBOS DE CARBONO COMO LIBERADORES DE FLUOROURACIL (Anticancerígeno)

The quantum modeling interaction properties of fluorouracil radicals on the single walled carbon nanotubes surface is researched via MNDO/d calculations. We have studied the effect of diameter, length, position and rotational characteristics of CNT on binding fluorouracil. Our results suggest that the binding energy is lower as the CNT diameter increases, while as the CNT length increases the binding energy initially increases and then slightly increases.

Las propiedades de interacción, según el modelo cuántico, de los radicales de flourouracil ubicados en la superficie de los nanotubos de carbono de pared simple se investigan a través de cálculos MNDO/d. Hemos estudiado el efecto del diámetro, la longitud, la posición y las características rotacionales de CNT en la síntesis de fruorouracil. Nuestros resultados sugieren que la energía de síntesis baja en la medida en que aumenta el diámetro, mientras que a medida que aumenta la longitud, la energía de síntesis inicialmente disminuye y luego aumenta levemente.

As propriedades da interação, segundo o modelo quântico, do radicais de flourouracil localizados na superfície de nanotubos de carbono com paredes simples são pesquiçadas a traverso de cálculos MNDO/d. Estudamos o efeito do diâmetro, comprimento, posição e características rotacionais do CNT na síntese de fruorouracil. Nossos resultados sugerem que a energia de síntese baixa à medida que aumenta o diâmetro, enquanto que à medida que o comprimento aumenta, a energia de síntese inicialmente diminui e depois aumenta um pouco.

Synthesis, crystal structure and anti-HIV activity of 2-adamantyl/adamantylmethyl-5-aryl-1,3,4-oxadiazoles.

Two series of 2-adamantyl/adamantylmethyl-5-aryl-1,3,4-oxadiazoles (4a-l and 5a-l) were synthesized by cyclodehydration of adamantan-1-carboxylic acid/adamantylacetic acid with various aryl hydrazides (3a-l) in the presence of POCl(3). The synthesis was supported by spectroanalytical techniques and verified further by crystal structure determination of compounds 4e and 5k. The synthesized compounds were screened for their inhibitory activity against HIV-1 and HIV-2 in MT-4 cells. Compound 5b exhibited a moderate activity in vitro for the replication of both virus types, suggesting for further structural modification as a new lead in the development of an antiviral agent.

Synthesis, QSAR and anti-HIV activity of new 5-benzylthio-1,3,4-oxadiazoles derived from α-amino acids.

2-(1-[(4-Chloro/methylphenylsulfonylamino)alkyl]-5-thioxo-4,5-dihydro-1,3,4-oxadiazoles (4a-e) were synthesized, in four steps, via the sulfonyl derivatives of l-amino acids (l-alanine, l-methionine and l-phenylalanine) 1a-e, the esters 2a-e, the hydrazides 3a-e and finally the cyclization to 4a-e. Alkylation of 4a-e with 1.0 mole eq. of substituted benzyl halides furnished S-benzyl derivatives 5a-t, while 1.1 mole eq. yielded major 5a-t and minor amount of 6a-d. Alternatively, treatment of 4a-e with 2.0 mole eq. of substituted benzyl halides furnished 6a-d only. The structures of 5b and 5l were further confirmed by single crystal X-ray analysis. Compounds 5a-t and 6a-d showed no selective inhibition against HIV-1 and HIV-2 replication in MT-4 cells. However, 5f and 5j-5q exhibited some inhibitory activity against both types with EC(50) values (>11.50 - >13.00 µg/mL). These results suggest that the structural modifications of these compounds might lead to the development of new antiviral agents. The quantum structure-activity relationship of these novel structural congeners is discussed.

Amino acid derivatives, part 4: synthesis and anti-HIV activity of new naphthalene derivatives.

A new series of 2-(naphthalen-2-yloxy)-N-[(aryl-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl] acetamides 5a-f was synthesized from naphthalene-derived glycine derivative 2 via the hydrazinoacetamide analogs 4a-f. Alternatively, treatment of 4a with H(2)SO(4) afforded 2-(naphthalen-2-yloxy)-N-((5-(phenylamino)-1,3,4-thiadiazol-2-yl)methyl) acetamide 6a. Alkylation or sulphonylation of 5a afforded the S-alkylated derivatives 7 and 8, respectively. Interestingly, treatment of 3 with methoxide ion gave the triazine derivative 9. The synthesized compounds have been screened for their inhibitory activity against HIV-1 and HIV-2 in MT-4 cells. However, 7 was found to be the potent inhibitor in vitro for the replication of HIV-1 (EC(50 )= 0.20 microg/mL), suggesting a new lead in the development of an antiviral agent.

Platinum and palladium-triazole complexes as highly potential antitumor agents.

The palladium complexes [(dppe)Pd(L)(2)PdCl(2)], [(dppe)Pd(L)(2)PtCl(2)], [(dppp)Pd(L)(2)PdCl(2)], [(dppm) Pd(L)(2)NiCl(2)], and [(dppm)Pd(L)(2)SnCl(4)] 15-19 were prepared. The antiproliferative activity of the newly synthesized complexes as well as their previously prepared analogues 3-14 and 20-26 were screened against a large panel of human cancer cell lines derived from haematological CD4(+) human T-cells containing an integrated HTLV-1 genome (MT-4). The complex 12a, b exhibited remarkable antiproliferative activity against MT-4, CD4(+) human acute T-lymphoblastic leukemia (CCRF-CEM), human splenic B-lymphoblastoid cells (WIL-2NS), human acute B-lymphoblastic leukemia (CCRF-SB), skin melanoma (SK-MEL-28), and prostate carcinoma (DU145) cell lines (CC(50 )= 0.5 microM, 0.4 +/- 0.05 microM, 0.6 +/- 0.05 microM, 0.4 +/- 0.1 microM, and 0.8 +/- 0.2 microM, respectively), meanwhile, 9a, b, 14a, b, and 23 showed significant activity against the CCRF-SB cell lines (CC(50) = 0.6 +/- 0.06 microM, 0.7 +/- 0.05 microM, 0.6 +/- 0.05 microM, and 0.8 +/- 0.15 microM, respectively). Further, 19 exhibited activity against the CCRF-CEM cell line (CC(50 )= 0.4 +/- 0.05 microM).

Microwave-assisted synthesis of acyclic C-nucleosides from 1,2- and 1,3-diketones.

A simple, rapid and regioselective approach for the synthesis of C-acyclic nucleosides 3, 4, 6, and 9 of dihydropyrimidine, imidazole and indeno[1,2-b]pyridine-9-one derived from 1,2- and 1,3-diketones was performed. By using DMF or pyridine as solvent or bentonite clay as a support, in the presence of TMSTf, ZnCl(2), NH(4)OAc, or NH(4)NO(3), all the desired products were obtained within 5-25 minutes under microwave irradiation (MWI). Acid hydrolysis of 6 and 9 afforded the free acyclic C-nucleosides 7 and 10, respectively. Upon treatment with NaOMe under MWI, 3 and 14 rearranged to the C-nucleoside 4 and 16.