Abdel-Galil M. Khalil

Synthesis and antimicrobial activities of some new thiazole and pyrazole derivatives based on 4,5,6,7-tetrahydrobenzothiophene moiety.

2-(5-oxothiazolidinone)-cyanoacetamido derivative 3 was prepared in two steps by reaction of 2-(2-cyano-acetylamino)-4,5,6,7-tetrahydro-benzo[b]thiophene-3-carboxamide (1) with phenyl isothiocyanate and chloroacetyl chloride, which diazocoupled with p-tolyldiazonium chloride in pyridine to afford the corresponding hydrazono derivative 4. Also, condensation of 3 with p-anisaldehyde gave the corresponding arylidine derivative 5. Treatment of 2 with dimethyl sulfate afforded the ketene N,S-acetal 9 which give 5-amino pyrazole derivative 10 upon treatment with hydrazine hydrate. Compound 10 was used as key intermediate for synthesis of pyrazolo[5,1-c][1,2,4]triazine 13a, b, pyrazolo[5,1-a]pyrimidine 14-17 and pyrolo pyrazole 18 derivatives. Finally, condensation of 1 with DMF-DMA afforded the corresponding acryloamide derivative 19, which afforded the corresponding pyrazole derivative 20 upon heating with hydrazine hydrate. All new synthesized compounds were evaluated as antimicrobial agents; some of them exhibited promising activities.

Synthesis and antibacterial activity of some new thiazole and thiophene derivatives

Dibenzobarrelene 1 was reacted with cyanoacetic acid hydrazide and thiosemicarbazide to give the corresponding 3-oxo-propiononitrile and thioamide derivatives 2 and 16, respectively. The base-catalyzed reaction 3-oxo-propiononitrile derivative 2 with phenyl isothiocyanate yielded the non-isolable intermediate 3. Treatment of 3 with dilute HCl afforded the corresponding thiocarbamoyl derivative 4. The intermediate 3, thiocarbamoyl 4 and thioamide derivatives 16 were utilized as key intermediates for the synthesis of some new thiazole 5, 6a, 6b, 7, 8, 10a, 10b, 12, 14a, 15, 17a, 17b, and 18; and thiophene 13a-d derivatives, respectively. The newly synthesized compounds were characterized by IR, (1)H NMR, (13)C NMR and mass spectral studies. Representative compounds of the synthesized product were tested and evaluated as antibacterial agent.

Synthesis and antibacterial activity of some new heterocycles incorporating phthalazine

3-(1,4-Dioxo-3,4,4e,5,10,10a-hexahydro-1H-5,10-benzeno-benzo[g]phthalazin-2-yl)-3-oxo-propiononitrile (1) was utilized as key intermediate for the synthesis of some new iminocoumarin 2, chromenone 3, aminothiazole 4, triazepine 5a, b and 6, hydrazono-propiononitrile 7, pyridopyrazotriazine 8, monobromo 9, dibromo 10 quinoxaline 11, ketene N,S-acetal 13, ketene S,S-diacetal 17 and 18a, b and methyl dithioate 20 derivatives, respectively. The newly synthesized compounds were characterized by IR, (1)H NMR, (13)C NMR and mass spectral studies. Representative compounds of the synthesized product were tested and evaluated as antibacterial agent.

Synthesis and antimicrobial of new anthraquinone derivatives incorporating pyrazole moiety.

Treatment of 2-cyano-N-(9,10-dioxo-9,10-dihydro-anthracen-2-yl)-acetamide (1) with phenyl isothiocyanate/dimethylsulphate afforded the corresponding ketene N,S-acetal 2 which upon treatment with hydrazine hydrate and 4-aminoantipyrine afforded the pyrazolo derivatives 3 and 4, respectively. 3-aminopyrazole derivative 3 was utilized as key intermediate for the synthesis of pyrazolo[3,4-d]pyrimidine 5, pentaaza-as-indacene 6, triaza-cyclopenta[c]phenanthrene 7, pyrazolo[1,5-a]pyrimidine 8, 9 and (dimethyl-pyrrol-1-yl)pyrazole 10 derivatives. Furthermore, treatment of 1 with DMF/DMA gave the corresponding acrylamide derivative 11 which upon treatment with hydrazine hydrate afforded the corresponding 3-aminopyrazole derivative 12. Moreover, coupling of 1 with 4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-diazonium chloride gave the hydrazone derivative 13 which upon cyclization with acetic acid afforded the corresponding pentaaza-fluorene derivative 14. Representative compounds of the synthesized products were evaluated as antimicrobial agents. Some of these compounds exhibited promising activities.

Synthesis, antitumor, cytotoxic and antioxidant evaluation of some new pyrazolotriazines attached to antipyrine moiety

Iminopropanehydrazonoyl cyanide 4 was achieved upon reaction of antipyrine diazonium salt 2 with 3-iminobutanenitrile (3) in EtOH/AcONa. 3-Aminopyrazole derivative 5 was obtained upon reaction of 4 with hydrazine hydrate. Diazodization of 5 afforded the diazonium salt 6 which coupled with active methylene compounds 7-10, 19, 20, 25, 29 and 32 in pyridine to give aryl hydrazone derivatives 11-14, 21, 22, 26, 30 and 33, respectively. Refluxing of compounds 11-14, 21, 22, 26 and 33 in acetic acid afforded the pyrazolotriazines 15-18, 23, 24, 28 and 35, respectively. The newly synthesized compounds were screened for their cytotoxic and antioxidant activities. The results showed clearly that compounds 4, 5, 13, 22, and 24 displayed promising in vitro anticancer activity against four different cell lines (HepG2, WI 38, VERO and MCF-7). Compounds 4 and 22 are the more potent antioxidant and anticancer agents. On the other hand, most of the compounds exhibited good cytotoxic activity toward (EAC).

A Convenient Regiospecific Synthesis of New Conjugated Tetrazole Derivatives via the Reaction of Dienones with the Tetrachlorosilane-Sodium Azide Reagent and their NMR Structural Assignment

Summary. Several new 1-aryl-, aralkyl-, and heteroaryl-5-(4-phenylbuta-1,3-dienyl)tetrazole derivatives and annulated tetrazole derivatives were efficiently and regiospecifically prepared in nearly quantitative yield via a facile one step reaction of dienones with a combination of tetrachlorosilane and sodium azide in acetonitrile under mild conditions. A complete structure assignment of three representative examples of the tetrazoles was achieved by advanced 2D NMR measurements including COSY, TOCSY, HSQC, HMBC, NOESY, and ROESY experiments.

Synthesis and study of some new 1,3-isoindoledione derivatives as potential antibacterial agents.

In an effort to establish new candidates with improved antibacterial activities, we reported here the synthesis and in vitro antibacterial evaluation of various series of 2-substituted-3a,4,9,9a-tetrahydro-4,9-benzeno-benz[f]isoindole-1,3-diones: 4-acetyl-phenyl 2, 2,2-dibromoacetylphenyl 3, benzimidazole 4, acetylbenzimidazole 5, aminophenyl 6, acetamide 7, naphthalene 8, disulfide 9, mercaptophenyl 10, hydroxyphenyl 11, phenyl ester 12, triazole 13, benzothiophene 14, benzothiazole 15 phenylazo 16a, b and aminomethane 17 derivatives. The newly synthesized compounds were characterized by (IR, (1)H NMR, (13)C NMR and mass spectrum studies). Representative compounds of the synthesized products were established and evaluated as antibacterial agents.

Synthesis and Antimicrobial of Certain New Thiazolidinone, Thiazoline, and Thiophene Derivatives

2-Cyano-N-(9,10-dioxo-9,10-dihydro-anthracen-2-yl)-acetamide (1) was utilized as a key intermediate for the synthesis of thiazolidin-4-one 2 and thiocarbamoyl 5 derivatives via reaction with 2-sulfanylacetic acid and phenyl isothiocyanate, respectively. Compound 5 reacted with different α-halo compounds to give thiazolidin-5-one 4, thiazolidine 7a,b, thiazolidin-4-one 8, and thiophene derivatives 10a,b. Thiazoline 6 and tetrahydro-benzothiophene 12 derivatives were obtained via a one-pot reaction of compound 1 with phenyl isothiocyanate/sulfur and cyclohexanone/sulfur, respectively. Representative compounds of the synthesized products were evaluated as antimicrobial agents. Some of these compounds exhibited promising activities. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Efficient synthesis of some new functionalized 3-amino- and 5-aminopyrazoles derivatives

Cyanoacetic acid hydrazide derivatives were utilized as key intermediates for the synthesis of some new 3-amino- and 5-aminopyrazole derivatives. Coupling of N′-phenylsulfonyl-2-cyanoacetohydrazide (1) and 1-(2-cyanoacetyl)-4-phenyl thiosemicarbazide (4) with different aryl diazonium chlorides afforded the corresponding 5-amino-1-substituted-4-pyrazolin-3-one derivatives 3 and 6, respectively. Treatment of ketene dithioacetal 9 and ketene-N,S-acetal 13 with hydrazine and/or benzenesulfonyl hydrazide furnished the corresponding 3-amino-5-1H-pyrazole-4-carbohydrazide derivatives 10, 11, and 14. The structures of the new synthesized compounds were elucidated and confirmed by elemental analyses and spectral data.

Spiramycin, a Macrolide Antibiotic

Spiramycin is produced by Streptomyces ambofaciens. It is a mixture of compounds, similar in their elementary composition as well as in their physical, chemical, and bacterial properties. Its anti-bacterial spectrum includes mainly Gram-positive organisms and Neisseria. The fermentation medium of Streptomyces ambofaciens consists of corn steep liquor, glucose, CaCO3, NaCl, and MgSO4. Mode of action of spiramycin on microorganisms was represented in the review article. Spiramycin is used in animal nutrition, especially in poultry.