Hussein F. Zohdi

Synthesis and antitumor activity of 5-trifluoromethyl-2,4- dihydropyrazol-3-one nucleosides.

2,4-Dihydropyrazole glucosides 3a-3c were prepared and tested for their antitumor activity. The structures of these compounds were established by (1)H and (13)C-NMR spectroscopy. Glucoside 3b shows an in vitro IC(50) value of 16.4 muM against proliferation of the human promyelotic leukemia (HL60) cell line.

Atom-Efficient, Solvent-Free, Green Synthesis of Chalcones by Grinding

Abstract An improved Claisen–Schmidt condensation reaction of methyl ketones and aromatic aldehydes can be achieved by grinding at room temperature in the absence of solvents. This process is simple, efficient, economical, and environmentally benign compared to classical reactions.

Green synthesis and antimicrobial evaluation of some new trifluoromethyl-substituted hexahydropyrimidines by grinding

A series of trifluoromethyl-substituted hexahydropyrimidine derivatives were efficiently synthesized in excellent yields via one-pot three-component reaction of aromatic aldehydes, ethyl trifluoroacetoacetate and thiourea(urea) in presence of p-toluenesulfonic acid under solvent-free conditions at room temperature by grinding. The present method does not involve any hazardous organic solvent and has proven to be simple, efficient, environmentally benign and cost-effective compared with the classical synthetic methods. These compounds were screened for their antibacterial activities against Escherichia coli and Bacillus thuringiensis and found to exhibit remarkably better antibacterial activities than the control drug.

Heterocyclic synthesis with isothiocyanates : an expeditious synthetic route for polyfunctionally substituted 3-(thiazol-2'-ylidene)pyridines and their fused derivatives

Abstract The reaction of phenyl isothiocyanate with the Knovenagel condensated active methylene compounds 1a-d gave the non-isolable salts 3a-d . The latter underwent in-situ heterocyclization on treatment with some halogenated compounds e.g. phenacyl bromide, ethyl bromoacetate δ-bromoacetoacetanilide, ethyl δ-bromoacetoacetate and δ-bromo-β-oxo-butyronitrile into the corresponding polyfunctionally substituted 3-(thiazol-2′-yliene)pyridine derivatives, which could also be annulated into fused heterocyclic ring systems. Chemical and spectroscopic evidences for the structure of the new compounds are described.

A simple and green procedure for the synthesis of 5-arylidene-4-thiazolidinones by grinding

Abstract An improved green Knoevenagel condensation of various aromatic aldehydes with 4-thiazolidinones in the presence of anhydrous ammonium acetate can be achieved by grinding at room temperature in the absence of solvents. This process is simple, efficient, economical, and environmentally benign compared to classical reactions.

Reaction of 3-phenyl-5-aminopyrazole with carbon disulfide: A novel synthesis of 3-(3′-phenylpyrazol-5′-yl)-4-phenylpyrazol-2-thione as well as of pyrazolo[3,4-d]thiazole and pyrano[2,3-d]thiazole derivatives

Summary3-Phenyl-5-aminopyrazole (1) reacts with carbon disulfide, followed byin situ reaction with α-haloketones3a–c, to afford5,7a, and7b, respectively. Compounds5 and7 were further utilized for the formation of heterocycles and their fused derivatives.Zusammenfassung3-Phenyl-5-aminopyrazol (1) reagiert mit Schwefelkohlenstoff und anschließendin situ mit den α-Halogenketonen3a–c zu5,7a und7b. Die Verbindungen5 und7 wurden weiter zu Heterocyclen und ihren kondensierten Derivaten umgesetzt.

Synthesis and antimicrobial evaluation of some new thienopyridine, pyrazolopyridine and pyridothienopyrimidine derivatives

Thieno[2,3-b]pyridines 7, 8, 9 were obtained via the S-alkylation of 3 with a variety of alkylating agents followed by cyclization in a basic medium. On the other hand, compound 3 reacted with methyl iodide to give compound 10 which was converted to pyrazolo[3,4-b]pyridine derivative 13 by reaction with hydrazine hydrate. Pyrido[3′, 2′:4,5]thieno[3,2-d]pyrimidines derivatives 14, 16 were obtained by reaction of 7 with each of formic acid and formic/formamide, respectively. Furthermore, compound 14 was obtained by the reaction of 8 with formamide. Structures of the newly synthesized products were determined by elemental analysis and spectral data.

REACTIONS WITH HYDRAZONOYL HALIDES XIX1: SYNTHESIS OF SOME PYRAZOLE AND 5-ARYLAZOTHIAZOLE DERIVATIVES

Abstract Hydrazonoyl chlorides 1 reacted with 2-aryl-1-cyano-1-thiazol-2-ylethenes 2 in presence of triethyl-amine to give the cycloadducts 4. which were converted to the corresponding pyrazoles 5 by the action of sodium methoxide. The reaction of hydrazonoyl halides 1 and 6 with each of 2-aryli-dene-2-cyanoethanethioamides 7 and 2-arylhydrazono-2-cyanoethanethioamides 14 in ethanolic tri-ethylamine or ethanolic sodium hydroxide solutions, has been investigated. Structures of all the products were established on the basis of their spectral data and alternative synthesis.

Utilization of thiazolylacetonitriles in the synthesis of thiophene, thiazole, pyrazolo[1,5-a]pyrimidine and pyrazolo [5,1-c]triazine derivatives

Thiazolylcyanothioacetanilides react with α-haloketones and haloesters to give the corresponding thiophene or thiazole derivatives according to the reaction conditions. Pyrazolo[1,5-a]pyrimidines and pyrazolo[5,1-c]triazines were synthesized by reaction of 3-amino-4-(4′-arylthiazol-2′-yl)-5-phenylaminopyrazole with different reagents. Structures of the new compounds were confirmed by elemental analyses, spectral data, and alternative methods of synthesis whenever possible.

HETEROCYCLIC SYNTHESIS WITH ISOTHIOCYANATE AND SULFUR: A NOVEL ROUTE FOR THE SYNTHESIS OF PYRIDINO[2,3-d]THIAZOLE, THIAZOLO[4′,5′:2,3] PYRIDINO[4,3-d]PYRIDAZINE AND THIAZOLO[4,5-b]ISOQUINOLINE DERIVATIVES

Abstract The reaction of phenyl isothiocyanate and sulfur with the Knovenagel condensated adducts la-e afforded the pyridino[2,3-d]thiazole derivatives 3a-e. The latter compounds proved to be versatile starting materials for the synthesis of polyfunctionally substituted thiazolo[4′,5′:2,3]pyridino[4,3-d]pyridazine and thiazolo[4,5-b)isoquinoline derivatives. Chemical and spectroscopic evidence for the structures of the new compounds, along with a sequence leading to their formation is described.