Mahmoud Al-Refa'i

• Professor (Full) at Al al-Bayt University

This review highlights the multifaceted usefulness of o-halobenzyl halides as pivotal substrates for the construction of five- to nine-membered cyclic structures with the aid of transition metals as catalysts. These privileged entities engage dual active sites, enabling the combination of both intermolecular benzylation and intramolecular arylation...

The synthesis and bioactivity studies of a series of (1′R,2′S,7a′S)‐2′‐(2,5‐dichlorothiophene‐3‐carbonyl)‐1′‐(aryl)‐1′,2′,5′,6′,7′,7a′‐hexahydrospiro[indoline‐3,3′‐pyrrolizin]‐2‐one derivatives are described here. The spirooxindole title compounds were obtained from the regio‐ and diastereoselective 1,3‐dipolar cycloaddition reaction between an int...

The furo[2,3-b]pyridine moiety is an important scaffold for many biologically active compounds, therefore, the spectral data of the derivative 1-(3-Amino-6-(2,5-dichlorothiophen-3-yl)-4-phenylfuro[2,3-b]pyridin-2-yl) ethenone (FP1) were investigated. Analysis of absorption-pH profile and Förster cycle of FP1 revealed that its excited state is more...

The p-toluene sulfonic acid (p-TSA) catalyzed cascade ring closing transformation has been executed for the preparation of novel spiroquinazolinone compounds 4 and 5 by the reaction between anthranilamide and cyclohexanone followed by subsequent acylation. These molecules were then examined against the inhibitory activity of Acetylcholinesterase (A...

A series of new 4-aryl-6-(2,5-dichlorothiophen-3-yl)-2-methylpyridine-3-carbonitrile derivatives 4(a-u) were synthesized starting with Friedel-Crafts acylation of 2,5-dichlorothiophene to form compound (1), which undergoes Claisen-Schmidt condensation with the corresponding aryl aldehyde 2(a-u) to produce chalcones 3(a-u) as intermediate compounds....

The title compound, C 14 H 18 O, I, was obtained as a side product during an attempt to synthesize (E)-3-(4-tert-butylphenyl)-1-(2,5-dichlorothiophen-3-yl)prop-2-en-1-one from the reaction of 1-(2,5-dichlorothiophen-3-yl)ethanone and 4-tert-butylbenz-aldehyde and KOH solution in methanol. It turned out that methanol which was used is a mixture of m...

The asymmetric unit of, C14H10Cl2OS, I, consists of one independent molecule with E configuration about the CC bond. The molecular structure composed of two aromatic rings, the 2,5-dichlorothiophenyl and the tolyl that are linked by the central –CO—CHCH– unit. The molecule is planar as indicated by the dihedral angle [4.27°] between the aromatic ri...

The title crystal structure is assembled from the superposition of two mol­ecular structures, (E)-1-(5-chloro­thio­phen-2-yl)-3-(3-methyl­thio­phen-2-yl)prop-2-en-1-one, C12H9ClOS2 (93%), and (Z)-1-(5-chloro­thio­phen-2-yl)-3-(3-methyl­thio­phen-2-yl)prop-1-en-1-ol, C12H11ClOS2 (7%), 0.93C12H9ClOS2·0.07C12H11ClOS2. Both were obtained from the react...

A series of 2-methoxypyridine-3-carbonitrile (5a-i)-bearing aryl substituents were successfully synthesized in good yields by the condensation of chalcones (4a-i) with malononitrile in basic medium. The condensation process, in most cases, offers a route to a variety of methoxypyridine derivatives (6a-g) as side products in poor yields. All new com...

The synthesis, crystal structure and structural motif of two thio­phene-based cyano­acrylate derivatives, namely, ethyl (E)-2-cyano-3-(3-methyl­thio­phen-2-yl)acrylate (1), C11H11NO2S, and ethyl (E)-2-cyano-3-(thio­phen-2-yl)acrylate (2), C10H9NO2S, are reported. Derivative 1 crystallized with two independent molecules in the asymmetric unit, and d...

In the title compound, C16H16Cl2N2O2S, the pyrazole ring has an envelope conformation with the C atom bearing the phenyl ring being the flap. The dihedral angles between the central pyrazole ring (all atoms) and pendant thio­phene and phenyl rings are 2.00 (14) and 81.49 (12)°, respectively. In the crystal, weak C—H⋯O, Cl⋯π and π–π stacking inter­a...

The present research work describes the synthesis of new series of nicotinonitrile (2) and furo[2,3-b]pyridine (3) heterocycles bearing thiophene substituent. The nicotinonitrile derivatives were prepared from the corresponding 3-cyano-(2H)-pyridones (1a–f) in excellent yields. The ring cyclization of the nicotinonitrile derivatives (2a–f) in the p...

A new series of furo[2,3-b]pyridine derivatives bearing aryl substituents were synthesized in two steps, where, the cyano-(2H)-pyridones (1a-l) were converted to the corresponding nicotinonitriles (2a-l), followed by the Thorpe-Ziegler ring cyclization to the furo[2,3-b]pyridine derivatives (3a-l). All new compounds were characterized by 1D-NMR exp...

Furopyridine III, namely 1-(3-amino-4-(4-(tert-butyl)phenyl)-6-(p-tolyl)furo[2,3-b]pyridin-2-yl)ethan-1-one, synthesized from 4-(4-(tert-butyl)phenyl)-2-oxo-6-(p-tolyl)-1,2-dihydropyridine-3-carbonitrile I in two steps. The title compound is characterized by NMR, MS and its X-ray structure. The molecular structure consists of planar furopyridine ri...

Chalcones (5a-h) were prepared in high yields via the condensation of 3-acetyl-2,5-dichlorothiophene (3) with aryl aldehydes (4a-h). The reaction of the resulting chalcones with thiourea in the presence of a catalytic amount of hydrochloric acid provided the 1,3-thiazin-2-amine derivatives (6a-g) in moderate yields. All new compounds were character...

A series of 3,4-dihydropyrimidine-2(1H)-thiones (3a-i) were synthesized in moderate yields via a one-pot reaction of 3-acetyl-2,5-diclorothiophene (1), aryl aldehydes (2a-i) and thiourea in methanolic solution of potassium hydroxide under reflux conditions. All newly synthesized compounds were characterized by extensive NMR analysis, including ¹D N...

The title compound was prepared by the condensation of an equimolar mixture of 1-(2,5-dichlorothiophen-3-yl)-3-(4-methoxyphenyl)prop-2-en-1-one, malononitrile and sodium hydroxide. The molecular structure was fully characterized using different spectroscopic methods. Mass ESI–HRMS measurements were performed. The HRESIMS analysis revealed the molec...

Two new pyrazoline derivatives, namely 5-(4-bromophenyl)-3-(5-chlorothiophen-2-yl)-1-phenyl-4,5-dihydro-1H-pyrazole (3) and 5-(4-bromophenyl)-3-(2,5-dichlorothiophen-3-yl)-1-phenyl-4,5-dihydro-1H-pyrazole (4) have been synthesized and characterized based on their spectral (IR, 1H and 13C NMR and MS) data and microanalysis. The fluorescence properti...

The rimJ gene, which codes for a crotonyl-CoA carboxylase/reductase, lies within the biosynthetic gene cluster for two polyketides belonging to the polyene macrolide group (CE-108 and rimocidin) produced by Streptomyces diastaticus var. 108. Disruption of rimJ by insertional inactivation gave rise to a recombinant strain overproducing new polyene d...

New Complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and Tin(II) with 3-methyl-2-(pyridine-2-yl-methylene-hydrazinocarbonyl)quinoxaline-4-oxide (LHP) and 2-(2-hydroxy benzylidene-hydrazinocarbonyl)-3-methylquinoxaline-4-oxide (LHS) were prepared. The new complexes were characterized by elemental analysis, conductivity, magnetic m...

The phytochemical investigation of the ethanolic extract of the aerial parts of Melilotus indicus resulted in the isolation of eight known flavonoids, namely; catechin (1), epicatechin (2), taxifolin (3), quercetin (4), quercetin 3-O-β-D-glucopyranoside (5), and quercetin 3-O-α-L-rhamnopyranoside (6), isorhamnetin 3-O-β-D-glucopyranoside (7) and is...

The title compound was prepared by the condensation of (E)-1-(2,5-dichlorothiophen-3-yl)-3-(4-methoxy)prop-2-en-1-one and thiourea in the presence of KOH. In the title compound, C34H28Cl16N4O2S4, the asymmetric unit consists of two independent molecules and four independent chloroform molecules. The heterocyclic pyrimidine-2(1H)-thione rings adopt...

Cyanamidium salts 1 undergo ene reactions with ylidenecyanamide derivatives 5 to afford conjugated iminium salts 12. The N,N,N0-trialkylcyanamidium salts 1 react as the ene, and the ylidenecyanamide derivatives 5 react as the enophile components to form the 2-azoniaallene salts 11 followed by the formation of conjugated iminium salts 12 as cationic...

The title compound, C17H26BrNO, exhibits a small twist between the amide residue and the benzene ring [C—N—C—C torsion angle = 29.4 (5)°]. In the crystal, the amido NH group is involved in N—H⋯O hydrogen bonding, which connects mol­ecules into chains parallel to the c axis.

via interaction of deprotonated 2,5-dichlorothiophene-3-sulfonamide with carbon disulfide under reflux, followed by alkylation with alkyl halides. Employment of dimethyl sulfate afforded the isomeric 2-methyl-3-thione derivative 8 together with the expected 3-(methylthio) derivative 7a in a molar ratio of 1 : 4. Treatment of 7a or 10 with ethylamin...

2-Alkyl/arylamino-6-chlorothieno[3,2-e]-1,3-thiazin-3-one derivatives were prepared in one-pot synthesis by refluxing alky/arylisothiocyanates and 2,5-dichloro-3-thiophene-carboxamide.

The compound (E)-4-Hydroxy-3-methyl-N'-(thiophen-2-ylmethylene)-1,4-dihydroquinoxaline-2-carbohydrazide (C15H13N4O2S) is a stable free radical quinoxaline derivative. It was prepared by treatment of an acidified ethanolic solution of 3-methyl-2-(thiophen-2-ylmethylenehydrazinocarbonyl)quinoxaline-4-oxide with a solution of CuSO4 center dot 5H(2)O....

A series of 3-(alkylthio)-6-chlorothieno[2,3-e][1,4,2]dithiazine 1,1-dioxides (7a - e) were prepared via interaction of deprotonated 2,5-dichlorothiophene-3-sulfonamide with carbon disulfide under reflux, followed by alkylation with alkyl halides. Employment of dimethyl sulfate afforded the isomeric 2-methyl-3-thione derivative 8 together with the...

Abstract The title compound crystallizes in the monoclinic space group C2/c space group, with unit cell dimensions of a = 15.6684(3) Å, b = 7.3974(2) Å, c = 21.2669(5) Å; β = 106.7770(10)° (Z = 8). In the title compound, NH4 +·C5HClNO2S4 –·1.5 H2O, the 1,4,2-dithiazine ring adopts a distorted half-chair conformation. The structure displays several...

A new brominated indole alkaloid, designated as bromoanaindolone, was isolated from culture media of the cyanobacterium Anabaena constricta and was identified as 6-bromo-3-hydroxy-3-methyl-indol-2-one with a slight excess of the (3R) enantiomer. The molecular structure was elucidated on the basis of IR, MS and NMR data. This extracellular metabolit...

In present studies, the synthesis and characterization of mixed-ligand complexes of Zn(II) and Cd(II) diallyldithiocarbamate (aldtc) with 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen) were reported. The new complexes [M(aldtc)(2)(NN)]; [M = Zn, Cd; NN = bipy and phen] have been characterized by partial elemental analyses and using IR, (1)H...

In present studies, the synthesis and characterization of mixed-ligand complexes of Zn(II) and Cd(II) diallyldithiocarbamate (aldtc) with 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen) were reported. The new complexes [M(aldtc)2(NN)]; [M = Zn, Cd; NN = bipy and phen] have been characterized by partial elemental analyses and using IR, 1 H and...

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Multinuclear Pt(II) complexes of 2,2′-bipyrimidine (bipm) were prepared and characterized by elemental analyses and standard spectroscopic techniques. The complexes were formulated as [Pt(bipm) 2 ][PtCl 4 ]PhCN (1), [Pt 3 (μ-bipm) 2 (bipm) 2 ]Cl 6 (2), [Pt 2 (μ-bipm)(bpy)Cl 2 ]Cl 2 (3), [Pt 3 (μ-bipm) 2 (biq) 2 ]Cl 6 ·Me 2 CO·MeCN (4), [Pt 3 (μ-bip...

The complexes [Cu(biq) 2 ]Cl 2 and [Cu(biq) 2 ]BF 4 ·biq (biq?=?2,2'-biquinoline) have been prepared and characterized. The interconversion to copper(I) complex [Cu(biq) 2 ]BF 4 ·biq, from [Cu(biq) 2 ]Cl 2 has been established. The new complexes have been characterized by elemental analysis, conductivity and magnetic measurements, IR, UV-vis and 1...

Complexes of Cu(II), Mn(II), Co(II), Ni(II), Hg(II), Cd(II) and Rh(III) with 2-pyridine carboxaldehyde-N-methyl-N-2-pyridylhydrazone ( pamph) have been prepared and characterized. The new complexes have been characterized by elemental analysis, conductivity and magnetic measurements, IR, UV–vis and 1H NMR spectroscopic methods. The microbiological...