Ahmed M. M. El-Saghier

A Novel Synthesis of Imidazo[2,1-d][1,2,4]triazine and Imidazo[2,1-d][1,2,5]triazepine Derivatives via Ketene-N,N-acetal

Abstract The ketene-S,S-acetal Iwas preparedunder phase-transfer catalysis (PTC) in benzene-carbonate two phase system using tetrabutylammonium bromide as thecatalyst. Upon treatment with 1,2-diaminoethane, followed by hydrolysis with sodium methoxide, I gave 2-(2-oxopropylidene)imidazoline III. Bromination of III and replacement of bromine by hydrazine afforded 2-(1-hydazino-1,2-oxopropylidene)imidazoline V. Compound V was used as a precursor for the preparation of the previously unreported fused nitrogen heterocyclic ring system of imidazotriazine VI, VIII, XI, XII and imidazotriazepine IX, X.

A Novel Synthesis of Heterocyclic Compounds Derived from α-Ketoketene S,S-Acetal

Abstract Novel heterocyclic compounds were prepared by the reaction of 2-acetyl-2-oxopropylidene s,s-acetal with different amino compounds namely, hydrazine hydrate, phenylhydrazine, guanidine hydrochloride, thiosemicarbazide, o-phenylenediamine, o-aminophenol or o-amino-thiophenol in different molar ratios.

Synthesis and Reactions of Some Pyrazine Derivatives

Abstract The pharmacodynamic properties1-3 of substituted amino pyrazines as well as their importance in the synthesis of pteridine and other polyfused heterocyclic systems is well known4,5. In this investigation we aim to prepare a new series of condensed heterocyclic systems containing the pyrazine nucleus.

Effect of ammonium groups on the properties of anion conductive membranes based on partially fluorinated aromatic polymers

A series of anion exchange membranes (QPE-bl-9) based on a partially fluorinated hydrophobic segment and oligophenylene as scaffolds for ammonium cations were synthesized to evaluate the effect of the various ammonium groups derived from trimethyl amine (TMA), dimethyl hexyl amine (DMHA), methyl imidazole (MIm), dimethyl imidazole (DMIm), tributyl amine (TBA), and dicyclohexyl methyl amine (DCHMA) on the membrane properties. QPE-bl-9 membranes were well characterized by 1H NMR spectroscopy, in which all the peaks were assigned to the supposed structure. The TEM images of QPE-bl-9–TMA, –MIm, –DMIm and –DMHA membranes showed small hydrophilic/hydrophobic phase separated morphology (hydrophilic domains 1–3 nm). QPE-bl-9–TMA (1.6 mequiv. g−1) exhibited the highest hydroxide ion conductivity (101 mS cm−1 at 80 °C) among the tested membranes, followed by QPE-bl-9–DMHA (62 mS cm−1) and QPE-bl-9–DMIm (62 mS cm−1). The alkaline stability of the membranes was tested in 1 M KOH at 60 °C for 1000 h. QPE-bl-9–TMA exhibited the highest retention of the conductivity (58%), which was higher than that of the Tokuyama A201 anion exchange membrane (29%). The post stability test IR analyses suggested that the major degradation mechanism of the QPE-bl-9 membranes in alkaline solution involved the decomposition of the ammonium groups. The QPE-bl-9 membranes retained their mechanical stability after the stability test, as proved by DMA analyses.

Synthesis and Reactions of Five-Membered Heterocycles Using Phase Transfer Catalyst (PTC) Techniques

Phase transfer catalysts (PTCs) have been widely used for the synthesis of organic compounds particularly in both liquid-liquid and solid-liquid heterogeneous reaction mixtures. They are known to accelerate reaction rates by facilitating formation of interphase transfer of species and making reactions between reagents in two immiscible phases possible. Application of PTC instead of traditional technologies for industrial processes of organic synthesis provides substantial benefits for the environment. On the basis of numerous reports it is evident that phase-transfer catalysis is the most efficient way for generation and reactions of many active intermediates. In this review we report various uses of PTC in syntheses and reactions of five-membered heterocycles compounds and their multifused rings.

2,2′-[(1,3,4-Thia­diazole-2,5-di­yl)bis­(sulfanedi­yl)]diaceto­nitrile

In the title compound, C6H4N4S3, the 1,3,4-thiadiazole ring is essentially planar, with an r.m.s. deviation of 0.001 Å. The two N—C—S—C torsion angles in the molecule are −23.41 (15) and 0.62 (14)°. One acetonitrile group is above the plane of the 1,3,4-thiadiazole ring and the other is below it, indicating syn and anti orientations. In the crystal, C—H⋯N hydrogen bonds link the molecules into ribbons along [010].

2-(4-Oxo-3-phenyl-1,3-thia­zolidin-2-yl­idene)propanedi­nitrile

In the title compound, C12H7N3OS, the five-membered 1,3-thiazolidine ring is nearly planar [maximum deviation = 0.032 (2) Å] and makes a dihedral angle of 84.14 (9)° with the phenyl ring. In the crystal, molecules are linked by C—H⋯N hydrogen bonds into infinite chains along [-101]. C—H⋯π interactions contribute to the arrangement of the molecules into layers parallel to (101).

Synthesis, Structural Stability Calculation, and Antibacterial Evaluation of Novel 3,5-Diphenylcyclohex-2-en-1-one Derivatives

Abstract Starting with 3,5-diphenylcyclohex-2-en-1-one, 3,5-diphenylcyclohex-2-en-1-semicarbazone, 1-chloro-3,5-diphenylcyclohex-2-en-2-carbaldehyde, and 3,5-diphenylcyclohex-2-en-1-hydrazone were synthesized via the reactions with semicarbazide hydrochloride, POCl3/ dimethylformamide, and hydrazine hydrate, respectively. These products were used as key intermediates for the preparation of novel series of tetrahydrobenzothiadiazol-1-oxide, indazole, benzo-thiazepines, pentahydroxyhexylidene and N-thiazines. Some of these derivatives exhibit high antibacterial activity against Gram-positive bacteria. GRAPHICAL ABSTRACT

Crystal structure of poly[di-μ-aqua-{5-[(1Z)-2-(4-chloro-phen-yl)-1-cyano-ethenyl]-1,2,3,4-tetra-zol-1-ido-κN (1)}sodium].

In the title compound, [Na(C10H5ClN5)(H2O)2]n, infinite chains of [Na(H2O)2]+ cations having a diamond-shaped cross-section and running parallel to the b axis are formed. O—H⋯N hydrogen bonds to the anions generate layers parallel to (100) which have the chlorobenzenecyanoethenyl substituents protruding from both surfaces. The sodium ion makes a short contact of 2.4801 (13) Å with the N atom of the tetrazolide ring which is syn to the cyano N atom.

Ethyl 3-amino-5-anilino-4-cyano­thio­phene-2-carboxyl­ate

In the title compound, C14H13N3O2S, the dihedral angle between the thiophene and phenyl rings is 24.95 (8)°. The molecular structure is consolidated by intramolecular N—H⋯O and C—H⋯S interactions. The crystal structure features N—H⋯N and N—H⋯O hydrogen bonds forming centrosymmetric R 2 2(12) dimers, which are linked into a two-dimensional network parallel to (011) with an S(6)R 2 2 S(6) motif. In addition, π–π stacking interactions [centroid–centroid distance = 3.7013 (12) Å] occur between the thiophene and phenyl rings of adjacent molecules.