Hanafi H. Zoorob

Peculiar reaction behaviour of barbituric acid derivatives towards aromatic amines

Abstract 5-Benzoylethyl barbituric acid derivatives 2a-c were prepared as useful precursors for the synthesis of pyrimidine fused heterocycles. Their behaviour as 1,5-diketocompounds towards aniline derivatives afforded the pyrimidoquinoline derivatives 6a-e. On the other hand, fusion of o -substituted anilines with 1,3-dimethyl barbituric acid derivatives 8a,b gave the corresponding benzazoles 10a-e. Furthermore, the reaction of 1,3-dimethyl barbituric acid (1) with catechol/K3|Fe(CN)6| or β-ketoester (19)/SiCl4 gave the benzofuro adduct 13a and the diphenylphenyl barbituric acid derivative 18, respectively.

Advances in the Chemistry of Aminoisoxazole

Abstract This review article is a survey of the literature on aminoisoxazoles. It describes the methods of synthesis and chemical reactions of aminoisoxazoles as building blocks for the synthesis of polyfunctionalized heterocyclic compounds. GRAPHICAL ABSTRACT

Efficient regioselective synthesis and potential antitumor evaluation of isoxazolo[5,4-b]pyridines and related annulated compounds.

The reaction of 5‐amino‐3‐methylisoxazole with appropriate α,β‐unsaturated ketones gave the corresponding isoxazolo[5,4‐b]pyridines. Treatment of 1 with 2,6‐dibenzylidenecyclohexanone or 2‐benzylidenedimedone afforded the corresponding isoxazolo[5,4‐b]quinoline derivatives. 4,6,8,9‐Tetrahydroisoxazolo[5,4‐b]quinolin‐5‐one derivative was also obtained by multicomponent condensation reaction of 1 with dimedone and benzaldehyde. Heterocyclic annulation of the isoxazolo[5,4‐b]pyridine system was achieved via reaction of 1 with benzylidene derivatives of indandione, quinuclidone, pyrazolone, and oxazolone. A representative of some newly synthesized compounds was evaluated as antitumor agents.

New synthetic approach to coumarino[4,3-b]pyridine systems and potential cytotoxic evaluation

The reaction of 4-aminocoumarin (2) with appropriate α,β-unsaturated ketones gave the corresponding coumarin [4,3-b]pyridines. Thus, treatment of 2 with (E)-3-(4-nitrophenyl)-1-phenylprop-2-en-1-one, (1E,4E)-1,5-diphenylpenta-1,4-dien-3-one, (Z)-ethyl 3-(4-chlorophenyl)-2-cyanoacrylate, and (2E,6E)-2,6-dibenzylidenecyclohexanone (3, 6 and 12) afforded the corresponding coumarino[4,3-b]pyridines 5, 7 and coumarino[4,3-b]quinoline derivatives 13, respectively. Heterocyclic annulations of coumarino [5,4-b]pyridine system were achieved via reaction of 2 (in situ) with benzylidene derivatives of indandione to give 15 which was also obtained by multicomponent condensation reaction of 2 (in situ) with indandione and benzaldehyde. A representative sample of new synthesized compounds was evaluated as cytotoxic agents.Graphical Abstract

Advances in the domain of 4-amino-3-mercapto-1,2,4-triazine-5-ones

This review summarizes results from a literature survey concerning the synthesis and reactions of 4-amino-3-mercapto-1,2,4-triazine-5-ones reported by research groups from 1983 to mid. 2015.

Synthesis, antioxidant, and antitumor evaluation of certain new N-substituted-2-amino-1,3,4-thiadiazoles

Reaction of 2-amino-1,3,4-thiadiazole (1) with chloroacetyl chloride afforded the chloroacetamide 2 which used as starting compound for the synthesis of 2-thiocyanatoacetamide 3 and N-(1,3,4-thiadiazol-2-yl)acetamides 5–9 via reaction of 1 with various reagents. Treatment of 9 with 4-(piperidin-1-yl)benzaldehyde or DMF-DMA afforded the arylidenes 10 and 11, respectively. Cyclization of the later compound with hydrazine hydrate gave the pyrazole derivative 12. Furthermore, coupling of 9 with 4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-diazonium chloride afforded hydrazone derivative 13, which cyclized in acetic acid to afford 1,2,4-triazine derivative 14. Moreover, 1,3,4-thiadiazoles 15, 19, 22, and 23 were achieved via reaction of 1 with different nucleophiles. Finally, 1-phenyl-1H-pyrazol-5(4H)-one when subjected to react either with 15 or with diazonium salt of 1 afforded pyrazole derivative 16 or bis-1,3,4-thiadiazole derivative 18, respectively. Some of these compounds were screened for their cytotoxicity and antioxidant activities which showed promising results.Graphical AbstractIn an effort to establish new candidates with improved activities, we reported herein the synthesis and antitumor and antioxidant evaluation of various series of N-substituted-2-amino-1,3,4-thiadiazoles. Newly synthesized compounds were characterized by (IR, 1H NMR, 13C NMR, high resolution mass spectra, and mass spectra). The representative compounds were evaluated as antitumor and antioxidant activities. Some of the prepared compounds exhibited promising activities.

Developments in the Chemistry of 2-Pyridone

Abstract The focus of our review is on the methods of synthesis and chemical reactivity of 2-pyridone and some derivatives as 2-chloro-3-nicotinonitrile in addition to the biological activity of the 2-pyridone moiety. GRAPHICAL ABSTRACT

Synthesis and antimicrobial and antioxidant activities of simple saccharin derivatives with N-basic side chains

A new class of N-basic side chains was obtained from 2,3-dihydro-2H-3-oxobenzo[d]isothiazole and aliphatic or aromatic aldehydes. Secondary amines (morpholine, N-methylpiperazine and ethyl isonipecotate) afforded tertiary N-basic side chains (4–6), while dibasic secondary amines (such as piperazine) gave bis-tertiary N-basic side chains (2). On the other hand, the use of mono- or dibasic primary amines namely; aniline, anisidine, phenyl hydrazine, o-hydroxy benzoic acid hydrazide, hydrazine hydrate, and ethylenediamine (instead of secondary amines) afforded secondary N-basic side chain as mono component or as bis component 7a-c, 9a-c, 11 and 12a-c. In addition, secondary Mannich base was synthesized via Michael addition to the corresponding aldimine. The new compounds were investigated for antioxidant and antimicrobial activities. Compounds 2, 7c and 12a exhibited significant antimicrobial activity, whereas compounds 7a, 7b, 9b, 9c and 11 exhibited high antioxidant activity as compared to ascorbic acid, These compounds showed the best protective effect against DNA damage induced by bleomycin.

Studies on Quinolinedione: Synthesis, Reactions, and Applications

Abstract In this account we present the rapidly expanding bibliography of published research concerning the progress in the area of quioline-2,4-dione chemistry, including synthetic strategies. GRAPHICAL ABSTRACT

Synthesis and biological evaluation of some new Thiazolo[3,2-a][1,3,5]triazine derivatives

Abstract2-Iminothiazolidin-4-one (1) was utilized for the synthesis of several new thiazolo[3,2-a][1,3,5]triazine derivatives. 3-Phenyl-3,4-dihydro-2H-thiazolo[3,2-a][1,3,5]triazin-6(7H)-one (2) was prepared according to Mannich procedure. Both compounds 1 and 2 reacted with aromatic aldehydes to afford arylidene derivatives 3–7. Compounds 5–7 were obtained through another two routes of preparation, first when applying Mannich reaction to compounds 3 and 4 and second by reacting compounds 2 with activated olefins 11 catalyzed by triethylamine, also, the reaction of 2 with bis arylidene 16 afforded compound 18. Compound 2 reacted with both mono and di-aromatic diazonium salts to furnish 2-aryl-azothiazolo[3,2-a]triazines 20 and 21 or bis[2-azothiazolo[3,2-a]triazine]phenylene 22, respectively. Thiocarbamoyl derivatives 25 and 26 were prepared through the reaction of active methylene and imino group in 1 with phenylisothiocyanate and carbon disulfide, respectively. Structures confirmation, geometry, and biological evaluation were applied for the newly prepared compounds.Graphical Abstract