Some pyrazole and pyrazolo[3,4-d]pyrimidine derivatives: synthesis and anticancer evaluation.

5-Amino-1-p-tolyl-1H-pyrazole-4-carbonitrile (1) was used for the preparation of some novel pyrazoles and pyrazolo[3,4-d]pyrimidines 2-10. Moreover, the cytotoxicity and in vitro anticancer activities of the prepared compounds were also assessed against the MCF-7 breast cancer, HepG2 liver cancer, and A549 lung carcinoma cell lines, along with investigation of the effect of the synthesized compounds on the expression of urokinase plasminogen activator (uPA). The tested compounds exhibited remarkable cytotoxic activity against MCF-7 and HepG2 cells. Among the tested compounds, 2 and 9 revealed promising anticancer activity compared to the activity of the commonly used anticancer drug, doxorubicin, by inhibiting the expression of uPA.

Synthesis and isomerization of some novel pyrazolopyrimidine and pyrazolotriazolopyrimidine derivatives.

4-Imino-1-p-tolyl-1,4-dihydropyrazolo[3,4-d]pyrimidin-5-ylamine (2) and (1-p-tolyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)-hydrazine (3) were prepared starting from ethyl 4-cyano-1-p-tolyl-1H-pyrazol-5-ylimidoformate (1). The structure of compound 3 was confirmed through preparation of the pyrazole derivatives 4 and 5. Also, the synthesis and structural characterization of pyrazolo[4,3-e][1,2,4]triazolo[4,3-c]pyrimidine derivatives 7 and 9 and their isomerization to pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives 6 and 8, respectively, under different suitable reaction conditions were reported. Moreover, the syntheses of 2-substituted-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives 10 and 11 was described.

Anticancer evaluation of some newly synthesized N-nicotinonitrile derivative.

Some novel N-nicotinonitrile derivatives 3-14 have been synthesized starting with compound 1. The key step of this work is the coupling between compound 1 and activated sugars to afford the corresponding cyclic nucleosides 3-6. Moreover, the cytotoxicity and in vitro anticancer evaluation of the prepared compounds have also been assessed against breast MCF-7 cancer, liver HepG2 cancer and lung A549 carcinoma cell lines with investigation the effect of the synthesized compounds on the expression of urokinase plasminogen activator (uPA). The results revealed that, although all the compounds showed no anticancer activity against A549 cells without showing any effect on the expression of uPA, the tested compounds exhibited remarkable cytotoxicity activity against MCF-7 and HepG2 cell lines. Among the tested compounds, compounds 11 and 12 revealed promising anticancer activity compared to the activity of the commonly used anticancer drug, doxorubicin with inhibiting the expression of uPA.

New pyrimidinone and fused pyrimidinone derivatives as potential anticancer chemotherapeutics.

A series of novel substituted pyrimidinones and fused pyrimidinones (compounds 3-18) were synthesized starting with oxiranylmethanone 2. The in vitro cytotoxicity against a human breast adenocarcinoma (MCF-7) cell line was investigated and most of the tested compounds showed potent cytotoxic activity against the MCF-7 cell line comparable to the activity of the commonly used anticancer drug cisplatin. Treatment of MCF-7 cells with increasing doses (2, 5, 10, and 20 µg/mL) of the tested compounds revealed that the activity of superoxide dismutase and the level of hydrogen peroxide were significantly increased, while the activities of catalase and glutathione peroxidase and the levels of reduced glutathione were significantly lowered compared with control MCF-7 cells. In general, derivatives 11 and 16 revealed the highest anticancer activity among the tested compounds.

Studies on the reactivity of (9-Methyl-5,6-dihydronaphtho[1â,2â:4,5]-thieno[2,3-d]pyrimidin-11-yl)hydrazine towards some reagents for biological evaluation.

(9-Methyl-5,6-dihydronaphtho[1â,2â:4,5]thieno[2,3-d]pyrimidin-11-yl)hydrazine (1) was used as a precursor for preparation of some novel 1-(9-methyl-5,6-dihydronaphtho[1â,2â:4,5]thieno[2,3-d]pyrimidin-11-yl)-1H-pyrazoles 2â7, -1H-isoindole-1,3(2H)-dione 8, and -pyridazin-3(2H)-one 9. Moreover, the acyclic C-nucleosides 10 and 11 were prepared by treating compound 1 with D-glucose. The in vitro antimicrobial activity of the tested compounds was evaluated by measuring the zone diameters and some of the prepared products showed potent antimicrobial activity in compared with those of well known drugs (standard). In general, the non-acetylated sugar hydrazone derivative 10 showed the highest antibacterial and antifungal potency among the tested compounds and standard with IZ = 22, 21 and 22 mm and MIC = 62.5 and 31.25 Îg/ml, respectively.

A facile synthesis and anti-avian influenza virus (H5N1) screening of some novel pyrazolopyrimidine nucleoside derivatives.

Treatment of 5-amino-1-(9-methyl-5,6-dihydronaphtho[1',2':4,5]thieno[2,3-d]pyrimidin-11-yl)-1H-pyrazole-4-carbonitrile (1) with formic acid afforded pyrazolo[3,4-d]pyrimidin-4-one derivative 2. The sodium salt of the latter compound (generated in situ) was treated with some alkyl halides to afford the corresponding N-substituted compounds 3-7. The siloxy derivative 8 (generated also in situ from 2) was ribosylated and glycosylated to yield compounds 9 and 11, respectively. Deprotection of compounds 9 and 11 in methanolic ammonia produced the free nucleosides 10 and 12, respectively. Moreover, the prepared compounds were tested for antiviral activity against H5N1 virus [A/chicken/Egypt/1/2006] and some of them revealed moderate results compared with the other tested compounds.

Synthesis and screening of some novel fused thiophene and thienopyrimidine derivatives for anti-avian influenza virus (H5N1) activity.

Several derivatives containing dihydronaphtho, naphtho[2,1-b]thiophene and thieno[2,3-d]pyrimidine ring systems were prepared starting from 2-amino-4,5-dihydronaphtho[2,1-b]thiophene-1-carbonitrile (1). Structure characterization of the thioxo derivative 7 was also performed and its reaction with some chloro and bromoalkyl reagents was studied. Moreover, the prepared products were tested for antiviral activity against H5N1 virus [A/chicken/Egypt/1/2006 (H5N1)] by determination of both EC50 and LD50 and confirmed by plaque reduction assay on MDCK cells. Compounds 5, 7 and 8 showed the highest effect compared with the other tested compounds.

Anti-HAV activity of some newly synthesized triazolo[4,3-b]pyridazines.

6-Phenyl-[1,2,4]triazolo[4,3-b]pyridazine-3(2H)-thione 2 was used as precursor for the preparation of some novel 3-S-substituted-6-phenyl-[1,2,4]triazolo[4,3-b]pyridazine derivatives 3-11. Furthermore, the preparation of 1-[2-(6-phenyl-[1,2,4]triazolo[4,3-b]pyridazin-3-ylsulfanyl)-acetyl]-1H-pyrazole derivative 13 and 5-(6-phenyl-[1,2,4]triazolo[4,3-b]pyridazin-3-ylsulfanylmethyl)-[1,3,4]oxadiazole derivatives 15 and 17, are described. Some of the prepared products revealed a promising antiviral activity against hepatitis-A virus (HAV, MBB-cell culture adapted strain). Plaque reduction infectivity assay was used to determine virus count reduction as a result of treatment with the test compounds. Compound 15 showed the highest effect on HAV compared to the other tested compounds.

Synthesis, isomerization, and antimicrobial evaluation of some pyrazolopyranotriazolopyrimidine derivatives.

6-Amino-5-imino-pyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidine derivative 4 and pyrazolo-[4',3':5,6]pyrano[2,3-d]pyrimidin-5-ylhydrazine derivative 5 were prepared starting from 6-amino-3-methyl-4-(p-nitrophenyl)-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile 1. The synthesis and structure characterization of 9,11-dihydropyrazolo[4',3':5,6]pyrano[3,2-e][1,2,4]triazolo[4,3-c]pyrimidine derivatives 7 and 9 and their isomerization to 9,11-dihydropyrazolo[4',3':5,6]pyrano[3,2-e] [1,2,4]triazolo[1,5-c]pyrimidine derivatives 6 and 8, respectively, under different suitable reaction conditions are reported. Moreover, the synthesis of 9,11-dihydropyrazolo[4',3':5,6]pyrano[3,2-e] tetrazolo[1,5-c]pyrimidine derivative 14 and N(9)-acyclic nucleoside 15 are described. Some of the prepared products showed potent antimicrobial activity.

Synthesis of pyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidine derivatives for antiviral evaluation.

6-Amino-3-methyl-4-(4-nitrophenyl)-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (1) was used as a precursor for preparation of some novel 3,7-dimethyl-4-(4-nitrophenyl)-2,4-dihydropyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidine derivatives 3-6, and some of their corresponding N(2)- and C(5)-S-acyclic nucleosides 7 and 8. Furthermore, the preparation of 5-amino-1-[3,7-dimethyl-4-(4-nitrophenyl)-2,4-dihydropyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidin-5-yl]-1H-pyrazole derivatives 10-16 were described. Some of the prepared products were selected and tested for antiviral activity against Herpes Simplex Virus type-1 (HSV-1).

Synthesis and biological evaluation of some pyrimidine, pyrimido[2,1-b][1,3]thiazine and thiazolo[3,2-a]pyrimidine derivatives.

4,6-Diamino-1H-pyrimidine-2-thione (1) was used for the preparation of pyrimidine derivatives 2-5. Compound 5 was cyclized to produce pyrimido[2,1-b][1,3]thiazine derivative 6 which was condensed with p-chlorobenzaldehyde to give compound 7. The latter compound was reacted with hydroxylamine to give isoxazolo[4,5-d]thiazino[2,3-a]pyrimidine 8. Compound 8b was treated with 2-chloroethyl methyl ether to afford compound 9. Similarly, compound 3 reacted with chloroacetic acid to give thiazolo[3,2-a]pyrimidine 10, which was condensed with p-chlorobenzaldehyde to give compound 11. Compound 11 was condensed with hydroxylamine to give isoxazolo[4,5-d]thiazolo[2,3-a]pyrimidine 12. Compound 12b was treated with 2-chloroethyl methyl ether to afford compound 13. Biological evaluation of some prepared products showed that many of them revealed promising antimicrobial activity.