Ahmed H. Bedair

Heteroaromatization with 4-Hydroxycoumarin Part II: Synthesis of Some New Pyrano[2,3-d]pyrimidines, [1,2,4]triazolo[1,5-c]pyrimidines and Pyrimido[1,6-b]-[1,2,4]triazine Derivatives

A variety of novel [1,2,4]triazolo[1,5-c]pyrimidine-13-ones (4a-f) and (5b-d) could be obtained via reaction of 9-amino-7-(4’-chlorophenyl)-8,9-dihydro-8-imino-6H,7H-[1]benzopyrano[3`,4`:5,6]pyrano[2,3-d]pyrimidine-6-one (3) with a variety of reagents. Pyrano[2,3-d]pyrimidine-6-ones 5a, 8a-c and pyrimido[1,6-b][1,2,4]-triazine-3,14-dione (6) were also prepared. The antimicrobial activity of some of the synthesized compounds was tested.

Synthesis of Hydroxyquinoline Derivatives, Aminohydroxychromene, Aminocoumarin and Their Antibacterial Activities

Some new diaminochromenes (3a-f, 7a-c, and 10), 7-amino-4-aryl-coumarins (8a,b), 7-hydroxy-4-aryl-1,2-dihydroquinolines (9a-c) and 2-amino-7-hydroxy-4-(4-chlorophenyl)-4H-chromenes (16a-d) were synthesized viu Michael addition of different substituted aminonaphthol (1), aminophenol (6), resorcinol derivatives (15a-d), chloronaphthol (17) and 4-hydroxycoumarin (19) with a-cyanocinnamonitriles (2a-c) and ethyl α-cyanocinnamate (2d-f). 2-Acetylamino-7-amino-4-(4-chlorophenyl)-4H-chromene-2-carbonitrile (14) was obtained as a unique product via hydrazinolysis of ethoxymethyleneamino derivative (13). The formation of coumarins (8a,b) and quinolines (9a-c) were anomalous case. Structures of the titled compounds cited in this article were elucidated by spectrometric data (IR, 1 H NMR, 1 3 C NMR (APT) and EMS). All of the newly synthesized compounds were evaluated for antimicrobial activities, where 16b and 16c exhibited activity against staphylococcus aureus (ATCC 25923).

Synthesis, reactions and antimicrobial activities of 8-ethoxycoumarin derivatives.

Condensation of 3-acetyl-8-ethoxycoumarin (3) with thiosemicarbazide gave ethylidenehydrazinecarbothioamide 5, which was transformed into the thiazolidin-4-one derivatives 6,7. Interaction of 3 with DMF/POCl3 gave β-chloroacroline derivative 8. Treatment of 3 with malononitrile gave benzo[c]chromone and 2-aminobenzonitrile derivatives 9 and 10, respectively with respect to the reaction conditions. Condensation of 3-(2-bromoacetyl)-8-ethoxycoumarin (4) with o-phenylenediamine gave 3-(quioxaline-2-yl)-8-ethoxycoumarin hydrobromide (11), while 4 reacted with 2-aminopyridine to give chromenopyridopyrimidine derivative 12. Condensation of 4 with potassium thio-cyanate/methanol gave an unexpected derivative, 2H-chromeno-3-carboxy(methyl-carbonimidic)thioanhydride 16, which upon treatment with (NH2)2·H2O gave 3-ethoxy-2-hydroxybenzaldehyde azine 19. Interaction of 4 with thiourea derivatives gave thiazole derivatives 20a–c. The structures of the newly synthesized compounds were confirmed by their spectra data. The newly synthesized compounds were also screened for their antimicrobial activity.

Synthesis, Reactions and Biological Evaluation of Some New Naphtho[2,1-b]furan Derivatives Bearing a Pyrazole Nucleus

Vilsmeier formylation of 2-(1-phenylhydrazonoethyl)naphtho[2,1-b]furan (2) gave 3-naphtho[2,1-b]furan-2-yl-1-phenyl-1H-pyrazole-4-carbaldehyde (3), which was reacted with C- and N-nucleophiles to afford naphthofuranpyrazol derivatives 4-8. Treatment of 2-[(3-(naphtho[2,1-b]furan-2-yl)-1-phenyl-1H-pyrazol-4-yl)methylene]-malononitrile (4a) with reactants having active hydrogen and Et₃N gave the corresponding pyrazoline, pyran and chromene addition product derivatives 10, 12 and 13, consisting of three different connected heterocyclic moieties. Reaction of 1-((3-(naphtho[2,1-b]furan-2-yl)-1-phenyl-1H-pyrazol-4-yl) methylene)-2-phenylhydrazone (6b) with AcONa and ethyl bromoacetate or chloroacetone afforded the thiazolidinone and methylthiazole derivatives 14 and 15, respectively. In addition, intramolecular cyclization of 6d with Ac₂O afford the corresponding 1,3,4-thiadiazol-2-yl acetamide derivative 16. The structures of the synthesized compounds were confirmed by IR, ¹H-NMR/¹³C-NMR and mass spectral studies. Compound 14 showed promising effects against the tested Gram positive and negative bacteria and fungi.

Synthesis and Biological Screening of 4-Benzyl-2H-phthalazine Derivatives

Preparation of 4-benzyl-2-substituted phthalazin-1-one derivatives 2-8 is reported. Condensation of 4-benzyl-1-chlorophthalazine (9) with a series of different nucleophiles gave 4-benzylphthalazin-1-ylamino derivatives (10-13 and 16) and 4-amino-2-[N′-(4-benzylphthalazin-1-yl)-hydrazino]-6-arylpyrimidine-5-carbonitriles (14a,b). Interaction of 9 with ambident anions was also studied. 5-Benzyl-6,6a,12-triazobenzo[a]-anthracen-7-one (15) is obtained from 9 and anthranilic acid derivatives. Treatment of 16 with (EtO)3CH/Ac2O under reflux afforded the corresponding ethoxymethylene derivative 17, while aqueous ammonium hydroxide treatment afforded carboxamide derivative 18. The structures of the newly synthesized derivatives were confirmed by their elemental analysis, IR, 1H NMR, 13C NMR and mass spectral studies. Antimicrobial activities of some selected compounds were also studied and some of these were found to exhibit promising effects against Gram-positive and Gram-negative bacteria and fungi.

Synthesis of 9-Methoxy and 9-Acetoxy-3-amino-1-(4-methoxyphenyl)- 1H-benzo[f]chromene-2-carbonitriles via 2-(Imino-piperidin-1-yl-methyl)- 3-(4-methoxyphenyl)acrylonitrile as Intermediate

Several new 1H-benzo[f]chromene derivatives (3aÐd) were prepared by the reaction of 7-substituted-2-naphthols (1a,b) with substituted α-cyano-4-methoxycinnamonitriles (2a,b) together with 2-(imino-piperidin-1-yl-methyl)-3-(4-methoxyphenyl)acrylonitrile (4) as intermediate. Also, the reaction of 1a,b with 4 without catalyst afforded 9-methoxy and 9-acetoxy- 3-amino-1-(p-methoxyphenyl)-1H-benzo[f]chromene-2-carbonitrile (3b,e). The reaction of 3a,b with different electrophilic and nucleophilic reagents afforded the 12H-7-oxa-8,10-diazabenzo[ a]anthracene derivatives 5, 9, 10 and 1H-benzo[f]chromene derivatives 6Ð8, 11.

Synthesis and characterization of new diiodocoumarin derivatives with promising antimicrobial activities.

Summary A series of 6,8-diiodocoumarin-3-N-carboxamides (4–11) were prepared. Treatment of ethyl 6,8-diiodocoumarin-3-carboxylate (1) with ethyl cyanoacetate/NH4OAc gave ethyl 2-(3-carbamoyl-6,8-diiodocoumarin-4-yl)-2-cyanoacetate (12) and 2-amino-4-hydroxy-7,9-diiodocoumarino[3,4-c]pyridine-1-carbonitrile (13), and treatment with acetone in the presence of NH4OAc or methylamine gave the ethyl 4-oxo-2,6-methano-2-methyl-3,4,5,6-tetrahydro-8,10-diiodobenzo[2,1-g]-2H-1,3-oxazocine-5-carboxylate derivatives 14a,b. All compounds were evaluated for their antimicrobial activity and the compounds 12–14a,b exhibited a pronounced effect on all tested microorganisms.

Preparation and characterization of humic acid-carbon hybrid materials as adsorbents for organic micro-pollutants.

The present work involves the preparation of novel adsorbent materials by the insolubilization and hybridization of humic acid (HA) with carbon. The prepared materials were characterized by N2 adsorption, elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, solid-state 13C cross polarization magic angle spinning nuclear magnetic resonance, and low-field nuclear magnetic resonance (NMR) relaxometry on wetted samples. The water solubility of these materials and the lack of effect of oxidants were also confirmed. With this background, the adsorption capacities toward phenol, 2,4,6-tricholrophenol, and atrazine were evaluated, using these as model compounds for organic micropollutants of concern in water. Experimental results show that the prepared materials are mesoporous and have a higher surface area than humic acid and even than the porous carbon in the case of carbon coating. They retain the basic features of the starting materials with lowered functional group content. Moreover, there are interesting new features. NMR relaxometry shows that equilibration of water uptake is very fast, making use in water simple. They have higher adsorption capacities than the pure materials, and they can be applied under a wide range of environmental conditions.

Synthesis and Antimicrobial Activity of Thioxopyrimidines and Related Derivatives

The interaction of thiourea with activated cyanoolefins under different reaction conditions were studied, in which a variety of thiopyrimidines (8, 9, 12, 18, 20, & 21) and related derivatives (10, 11, 14, 16, & 17) were obtained respectively. Also, the reactions of thiopyrimidines (8, 9) with different electrophilic and nucleophilic reagents were reported. IR, 1H NMR, 13 C NMR and mass spectra for the newly synthesized compounds were studied. Most of the obtained compounds were screened against Gram-postive and Gram-negative bacteria and fungi, for which some of these derivatives gave promising results.

New bioactive compounds from the marine-derived actinomycete Nocardiopsis lucentensis sp. ASMR2

Abstract In the search for new bioactive compounds from extremophilic actinomycetes, a new marine actinomycete strain, Nocardiopsis lucentensis sp. ASMR2 has been isolated and taxonomically identified from marine plants collected in the Red Sea at Hurghada coasts. A large-scale fermentation of the strain on modified rice solid medium was performed, followed by work-up and purification of the obtained extract using a series of chromatographic purifications, delivering the novel butenolide system 3′-hydroxy-N-(2-oxo-2,5-dihydrofuran-4-yl)propionamide (1a) along with the naturally new 4-methoxy-2H-isoquinolin-1-one (2). Furthermore, eight known bioactive compounds are also reported, namely, indole-3-carboxylic acid, indole-3-acetic acid, indole-3-acetic acid methyl ester, furan-2,5-dimethanol, tyrosol, glycerol linoleate, cyclo-(Tyr, Pro), and adenosine. The chemical structures of the new compounds (1a, 2) were confirmed by extensive one- and two-dimensional (1D and 2D) nuclear magnetic resonance (NMR) spectroscopy, electron ionization high resolution (EI-HR) mass spectrometry, and by comparison with literature data. The antimicrobial activity of the strain extract, as well as of compounds 1a and 2, were studied using a panel of pathogenic microorganisms. The in vitro cytotoxicity of the bacterial extract and compounds 1a and 2 were studied against the human cervix carcinoma cell line (KB-3-1) and its multidrug-resistant subclone (KB-V1).