Yasser A. Elossaily

Selenium-Containing Heterocycles: Synthetic Investigation of 3-Amino-2-Ethylselenopyridine Carboxylate Using Sodium Borohydride

3-amino-4,6-dimethyl-2-ethylseleno[2,3-b]pyridine carboxylate (5) was prepared by a reaction of dipyridyl diselenide derivative (3) with sodium borohydride as a reducing agent followed by α-haloester. The reaction of 5 with hydrazine hydrate afforded the corresponding carbohydrazide 8. The benzylidene derivative 9 provided novel heterocycles of pyrimidoseleno pyridine and thiazinoseleno pyridine derivatives (10–12), upon treatment with triethylorthoformate, acetic anhydride, and carbon disulfide, respectively.

Synthesis and antimicrobial activity of novel benzo[f]coumarin compounds

The acetyl benzo[f]coumarin condensed with phenyl hydrazine to afford the corresponding phenyl hydrazone which cyclized into the pyrazolyl benzocoumarin under Vilsmeier reaction conditions. The pyrazolylaldehyde was used as starting material for synthesis of other heterocyclic compounds containing pyrazolylbenzocoumarin moiety. The ethyl benzo[f]coumarin carboxylate were subjected to react with other reagents to synthesize thiazolidinyl and oxadiazolyl derivatives attached to benzocoumarin system. Some of novel synthesized compounds showed highly antibacterial and antifungal activities.

A Convenient Synthesis of Some New Indeno[1,2-b]Pyridines and Indeno[1,2-b] Thieno[3,2-e]Pyridine Derivatives with Potential Biological Activity

3-Cyano-5-oxo-4(2-thienyl)-indeno[1,2-b]pyridin-2-[1H]thione 3 was prepared from indanone 1 with arylidene cyanoacetamide or from arylideneindanone 2 with cyanoacetamide. S-Alkylation of 3 with halogenated compounds afforded compounds 4a–h . Compounds 4d–h underwent ring closure with sodium ethoxide to produce indenothienopyridines 5 a–e , respectively. Treatment of 3 using ethylchoroacetate or chloroacetone gave compounds 6 and 7 , respectively. Compounds 5a and 5d were reacted with carbon disulphide in pyridine to give compounds 8a and 8b . Most of the synthesized compounds were screened in vitro for their antimicrobial activities against four species of bacteria and six species of fungi using Chloramphenicol (5%) and Terbinafine (5%) as a standard.

Synthesis and Reactions of Some New Spiropyranthiazoline Derivatives

Pyrano[2,3-d]thiazoline-7-spiro-3′-(1′-substitutedindoline-2′-ones) 5a,b has been synthesized and reacted with some nucleophile reagents to afford new spirothiazolino[4,5:2′,3′]pyrano[6′,5′-d]pyrimidine derivatives 6a,b–13a,b, which are analogues of some reported biologically active spiroheterocyclic compounds.

A convenient synthesis, reactions and biological studies of some novel selenolo[2,3-c]pyrazole compounds as antimicrobial and anti-inflammatory agents

Abstract5-Chloro-3-methyl-1-phenylpyrazole-4-carbonitrile 3 was reacted with selenium in the presence of sodium borohydride and chloroacetamide to afford selanyl acetamide 5, which underwent Thorpe–Ziegler cyclization upon heating with sodium ethoxide to give the novel synthesized 4-amino-3-methyl-1-phenyl-1H-selenolo[2,3-c]pyrazole-5-carboxamide compound (6). The latter compound was used as a versatile precursor for synthesis of other heterocyclic rings, namely pyrimidine, imidazopyrimidine and thiadiazinopyrimidine fused to selenolo[2,3-c]pyrazole moiety. The newly synthesized compounds and their derivatives were characterized by elemental and spectral analysis (IR, 1H NMR, 13C NMR and mass spectrometric analyses). Furthermore, some of these synthesized compounds were screened against various pathogenic bacterial and fungal strains. The results demonstrate that most of the synthesized compounds possess a significant antibacterial activity against gram-positive and gram-negative bacteria. Also, some of these compounds showed a remarkable antifungal activity, especially Candida albicans. On the other hand, some of the synthesized compounds possess high anti-inflammatory activity using carrageenan-induced rat paw edema assay compared with indomethacin.Graphical AbstractThe present work discussed synthesis of new selenolo[2,3-c]pyrazoles fused to other heterocyclic rings, namely pyrimidine, imidazopyrimidine and thiadiazinopyrimidine. Some of the synthesized compounds showed remarkable antibacterial, antifungal and anti-inflammatory activities.

Synthesis and reactions of some new pyrrolylthieno[2,3-D]quinoxaline and pyrrolopyrazinothienoquinoxalines

The synthesis of 3-pyrrolyl-2-substituted thieno[2,3-b]quinoxalines from the precursor 3-amino derivatives are described. Synthesized compounds were subjected to reactions with other reagents to synthe-size polyfused heterocyclic incorporated thienoquinoxaline moiety. Some of the synthesized compounds were screened for their antibacterial and antifungal activities.

REACTIONS OF 4-ALKYLIDENE (ARYLIDENE)-1-PHENYLPYRAZOLIDINE-3,5-DIONE

Reactions of 4-alkylidene(arylidene)-1-phenylpyrazolidine-3,5-dione with oxidizing (chromium trioxide/acetic acid) as well as with reducing (sodium borohydride/methanol) agents were carried out. Phenylhydrazine reacted with 4-arylidene-1-phenylpyrazolidine-3,5-diones via fission of exo C=C bond to give 1-phenylpyrazolidine-3,5-dione and the corresponding aryl hydrazones.

The Synthesis of Some Pyrazolyl- and Thiazolylthienopyridines

2-acetyl-3-amino-4,6-dimethylthieno[2,3-b]pyridine 1 reacted with dimethoxy-tetrahydrofuran in acetic acid and ethyl cyanoacetate in the presence of ammonium acetate or with NaNO2 in the presence of an AcOH/HCl mixture to produce 2–4. Compound 2 reacted with aromatic aldehydes, semicarbazide hydrochloride, thiosemicarbazide, and phenyl hydrazine or with hydrazine hydrate to give compounds 5a–c and 11a–d, respectively. Chalcone 5 reacted with hydrazines, hydroxylamine hydrochloride, or thiourea to produce compounds 6–9. Thiosemicarbazone 11b reacted with α -haloester to produce the corresponding thiazolidinone derivatives 12a, b ; also it reacted with ω -bromoacetophenone to give thiazoline derivatives 13a, b .

One-pot synthesis of 5-[1-substituted 4-acetyl-5-methyl-1H-pyrrol-2-yl)]-8-hydroxyquinolines using DABCO as green catalyst

Abstract A green and simple method for the synthesis of the title compounds 4 by the reaction of 5-chloroacetyl-8-hydroxyquinoline (1), pentane-2,4-dione (2), and amines 3 in the presence of a catalytic amount of 1,4-diazabicyclo[2.2.2]octane at 60°C is described. The procedure is amenable for the synthesis of other substituted pyrroles. Short reaction time, environmentally friendly procedure, and excellent yields are the main advantages. The structures of products 4a–n were characterized by 1H NMR, IR, and MS spectra.