Magda N. A. Nasr

Pyrido[2, 3-d]pyrimidines and pyrimido[5',4':5, 6]pyrido[2, 3-d]pyrimidines as new antiviral agents: synthesis and biological activity.

A series of 7‐amino‐ and 7‐oxo‐5‐aryl‐6‐cyanopyrido[2, 3‐d]pyrimidines, 4 and 11, respectively, and pyrimido [5′, 4′:5, 6]pyrido[2, 3‐d]pyrimidine derivatives 6 and 7 was synthesized and investigated as antiviral agents. Different synthetic strategies for the preparation of the target compounds were explored. A synthetic procedure for 4 and 11 starting with 6‐amino‐1, 2, 3, 4‐tetrahydro‐2, 4‐dioxopyrimidine, proper aldehyde, and malononitrile or ethyl cyanoacetate, respectively, in a one‐pot reaction proved to be the method of choice for preparation of compounds of such type. Construction of another pyrimidine ring on the pyridine nucleus of compound 4 was achieved either by reaction with phenyl iso(thio)cyanate or with formic acid to yield 6 and 7, respectively. The structure of the prepared compounds was confirmed through elemental analysis and spectral investigation. Most of the newly synthesized compounds were subjected to antiviral activity testing against herpes simplex virus (HSV) where some of them show good activities.

Synthesis and Antibacterial Activity of Fused 1, 2, 4‐Triazolo[4, 3‐a]quinoxaline and Oxopyrimido[2′, 1′:5, 1]‐1, 2, 4‐triazolo[4, 3‐a]quinoxaline Derivatives

A new series of potential antibacterial agents having tricyclic 1, 2, 4‐triazolo‐[4, 3‐a] quinoxaline fused with one or more heterocyclic rings was synthesized via several routes. The tricyclic 1‐amino‐4‐chloro‐1, 2, 4‐triazolo[4, 3‐a] quinoxaline (2 ) and tetracyclic 1, 6‐diamino‐bis‐1, 2, 4‐triazolo[4, 3‐a:3, 4‐c] quinoxaline (3) were synthesized from 2, 3‐dichloroquinoxaline (1) with two or four equivalents of thiosemicarbazide, respectively. Compound 2 was allowed to react with different aldehydes, alkoxides, cyclic amines, phenyl isothiocyanate, and t‐butyl isocyanate to afford the corresponding quinoxaline derivatives. Moreover, compound 2 reactedwithhydrazine hydrate to give compound 4 which was cyclized by carbondisulfide inalcoholic potassium hydroxide to give the tetracyclic compound 5 . Compound 2 was subjected to another cyclocondensation reaction using diethyl ethoxymethylene malonate (DEMM), dimethyl acetylenedicarboxylate (DMAD), and ethyl cyanoacetate to give the tetracyclic compounds 18 , 20 , and 21, respectively. All the synthesized compounds were evaluated in vitro for antibacterial activity; compounds 18 and 20 were found to display the greatest antibacterial activities. Structural identification was provided by elemental analyses, IR, and 1H‐NMR spectroscopy.

Synthesis and biological evaluation of new curcumin derivatives as antioxidant and antitumor agents

Twenty-four new compounds were prepared, taking curcumin as a lead, in order to explore their antioxidant and antitumor properties. The capacities of these derivatives to scavenge the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS.+), and to protect human red blood cells (RBCs) from oxidative haemolysis were investigated. In addition, the percentage viability of different cell lines (Hep G2, WI38, VERO and MCF-7) was tested. The result of the antitumor testing was generally in accordance with those of the antioxidant assays. Compounds which bear o-methoxy substitution to the 4-hydroxy function in the phenyl ring (7g, 5g and 3g) exhibited significantly higher ABTS.+-scavenging, antihaemolysis, and antitumor activities than other derivatives. In addition, molecular modelling studies were carried out for biologically active and inactive compounds, to study the structure–activity relationship, with the aim to elucidate which portions of the molecules are critical for the antioxidant and antitumor activity.

Synthesis and antitumor activity of new pyrido[2,3- d ]pyrimidine derivatives

New series of pyrido[2,3-d]pyrimidines such as; 5-(4-aryl-5-sulfanyl-4H-[1,2,4]triazol-3-yl) 1H,3H,8H-pyrido[2,3-d]pyrimidine-2,4,7-triones 6, 7; S-[3-(2,4,7-trioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidin-5-yl)-4-(4-substituted phenyl)-4H-[1,2,4]triazol-5-yl]-2-(4-phenylpiperazin-1-yl)ethanethioates 10, 11; 2,4,7-trioxo-N′-[(4-substituted piperazin-1-yl)acetyl]-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidine-5-carbohydrazides 13–16 and N′-arylidene-2,4,7-trioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidine-5-carbohydrazides 17–19 was synthesized through the reaction of the key intermediate 2,4,7-trioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidine-5-carbohydrazide 3 with different reagents. The structures of the newly synthesized compounds were elucidated through microanalysis, IR, 1H NMR, 13C NMR, and mass spectroscopy. These compounds have been subjected to in vitro antitumor evaluation by bleomycin-dependant DNA damage assay. The most active antitumor compound 6 was selected for further in vivo evaluation of antineoplastic activity against Ehrlich ascites carcinoma in mice. It was observed that our target compound has a potent antitumor activity.

Synthesis and antiviral activity of new 3-methyl-1,5-diphenyl-1H-pyrazole derivatives

A new series of 4-substituted 3-methyl-1,5-diphenyl-1H-pyrazoles 4–11 has been synthesized and evaluated for its in vitro antiviral activity and cytotoxicity against herpes simplex virus type-1 grown on Vero African green monkey kidney cells through plaque-reduction assay method using acyclovir as a positive control. The synthesis was achieved through Claisen-Schmidt condensation reaction of 3-methyl-1,5-diphenyl-1H-pyrazole-4-carbaldehyde (3) with acetophenone derivatives to give various enones 4a–f which are considered an important synthon for the construction of different heterocyclic rings as isoxazoline, pyrazoline, pyrimidine, pyridine, and fused pyridine via several synthetic routes. Biological evaluation of the prepared compounds showed that 3-(4-methylphenyl)-5-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl)-4,5-dihydroisoxazole (5f), 6-(4-methylphenyl)-N-[(3-(methylsulfanyl)phenyl)]-4-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl)pyrimidin-2-amine (7), 6-(4-bromophenyl)-4-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl)-2-oxo-1,2-dihydropyridine-3-carbonitrile (8), and 2-amino-6-(4-bromophenyl)-4-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl) pyridine-3-carbonitrile (9) exhibited strong antiviral activity with IC50 (0.02, 0.04, 0.03, 0.03), respectively, compared to the used reference drug. The synthesized compounds were characterized by physical constants and the structures of the title compounds were confirmed by IR, 1H NMR, mass spectra, and elemental analyses.

Synthesis, molecular modeling and anticancer activity of new coumarin containing compounds

A series of new coumarin containing compounds were synthesized from 4-bromomethylcoumarin derivatives 2a, b and different heteroaromatic systems 4a-e, 6a-d, 8, 10via methylene thiolinker. Twenty-four compounds were screened biologically against two human tumor cell lines, breast carcinoma MCF-7 and hepatocellular carcinoma HePG-2, at the national cancer institute, Cairo, Egypt using 5-fluorouracil as standard drug. Compounds 5h, 7d, 7h, 9a, 13a and 13d showed strong activity against both MCF-7 and HepG-2 cell lines with being compound 13a is the most active with IC50 values of 5.5 µg/ml and 6.9 µg/ml respectively. Docking was performed with protein 1KE9 to study the binding mode of the designed compounds.

Synthesis and biological evaluation of new 3-(4-substituted phenyl)aminoquinoxaline derivatives as anticancer agents

Abstract Quinoxaline derivatives 4–11 were synthesized and evaluated for their in vitro growth inhibitory activities against liver carcinoma cell line (HEPG2) using the sulforhodiamine B assay. The synthesis was achieved by reaction of 2,3-dichloroquinoxalines 2a,b with 4-aminoacetophenone to give the corresponding compounds 3a,b. Claisen-Schmidt condensation reaction of 3a,b with furfuraldehyde gave enones 4a,b, which were transformed into pyridines 6a,b, 8a,b, isoxazolines 9a,b, pyrazolines 10a–d, and pyrimidines 11a,b via several synthetic routes. Virtual screening was carried out by molecular modeling evaluation of the designed compounds. Biological evaluation of the prepared compounds showed that most of the synthesized compounds exhibit more than 50% growth inhibitory.

Molecular modeling and synthesis of new 1,5-diphenylpyrazoles as breast cancer cell growth inhibitors

Abstract New pyrazoles have been synthesized and evaluated as breast cancer cell growth inhibitors. Condensation of the substituted pyrazole-4-carbaldehyde 1 with acetophenone and chloroacetophenone afforded α, β-unsaturated ketones 2 and 3, respectively. Compounds 2 and 3 were subjected to different reactions using hydrazine hydrate, substituted hydrazine hydrate, hydroxylamine, o-phenylenediamine, malononitrile under different conditions affording 4-substituted pyrazole derivatives 4–28. Structure elucidation of these compounds was conducted using IR, 1H NMR, 13C NMR, mass spectral data and elemental analysis. Antitumor activity of target compounds was tested against MCF-7 cell line (human breast cancer). Compounds 4, 10 and 20 show significant antitumor activity against breast cancer. Docking was performed with protein 1UYK to study the binding mode of the designed compounds.