Ahmed M. Soliman

Synthesis and biological activity of dihydroimidazole and 3,4-dihydrobenzo[4,5]imidazo[1,2-a][1,3,5]triazins.

Reaction of 2-guanidinobenzimidazole with halogenated active methylenes and ketones gave dihydroimidazole and 3,4-dihydrobenzo[4,5]imidazo [1,2-a][1,3,5]triazin derivatives in very good yield. The anti-bacterial evaluation of the newly synthesized products against broad spectrum of bacteria was performed. Most of products showed high inhibitory effect. All compounds have been characterized based on IR, (1)H NMR, (13)C NMR and Mass spectra.

Synthesis of Dihydroimidazole Derivatives under Solvent Free Condition andTheir Antibacterial Evaluation

Reaction of 2-guanidinobenzoxazole with several halogenated active methylene compounds has revealed formation of the corresponding dihydroimidazole derivatives under solvent free conditions in excellent yield. The anti-bacterial evaluation of the newly synthesized products against different types of Gram-positive and Gramnegative bacteria was performed. Most of products showed high inhibitory effect. The structure of all compounds has been characterized by on IR, 1H-NMR, 13C-NMR, Mass spectrum and some X-ray diffractions.

2-(Piperidin-1-yl)-6-(1H-pyrrol-1-yl)pyridine-3,5-dicarbonitrile.

The piperidine ring of the title compound, C16H15N5, adopts a chair conformation. The pyridine ring is essentially planar, with a maximum deviation of 0.035 (3) Å. The pyrrole and pyridine rings are almost coplanar, forming a dihedral angle of 3.48 (14)°. In the crystal, no classical hydrogen bonds were found. In the crystal, the molecules are linked by aromatic π–π stacking [centroid–centroid separations = 3.4984 (16) and 3.9641 (15) Å between pyrrole and pyridine rings and between pyridine rings, respectively].

2-(1,3-Benzothia-zol-2-yl)guanidine.

In the title comound, C8H8N4S, one of the two independent molecules is essentially planar (r.m.s. deviation = 0.025 Å), while the other is slightly buckled (r.m.s. deviation = 0.131 Å) with the guanidine unit bent out of the plane of the fused-ring system by 16.8 (1)°. In the crystal, intermolecular N—H⋯N hydrogen bonds between the two independent molecules give rise to a hydrogen-bonded dimer. Addtional weak intermolecular N—H⋯N hydrogen bonds connect these dimers into chains along [010]. An intramolecular N—H⋯N hydrogen bond is also observed in each independent molecule.

2-(Morpholin-4-yl)-6-(1H-pyrrol-1-yl)­pyridine-3,5-dicarbonitrile

In the title compound, C15H13N5O, the morpholine ring adopts a chair conformation. The dihedral angle between the pyrrole ring and the pyridine ring is 28.93 (14)°. In the crystal, the molecules are linked by C—H⋯O hydrogen bonds occur, and aromatic weak π–π stacking [centroid–centroid separation = 4.178 (2) Å] and C—H⋯π interactions consolidate the packing.

2-Amino-4-phenyl-4H,10H-1,3,5-triazino[1,2-a]benzimidazol-3-ium chloride.

2-Guanidinobenzimidazole condenses with benzaldehyde in the presence of hydrochloric acid to form 2-amino-3,4-dihydro-4-phenyl-1,3,5-triazino[1,2-a]benzimidazole, which was isolated as its hydrochloride, C15H14N5 +·Cl−. The positive charge of the cation is formally placed on the double-bonded N atom of the dihydrotriazine ring. The six-membered dihydrotriazine that is fused with the benzimidazole ring system is relatively flat (r.m.s. deviation = 0.106 Å), with the methine C atom deviating most [0.164 (1) Å] from the mean-square plane. The phenyl ring connected to the methine C atom is disordered over two positions in a 0.558 (1):0.442 (1) ratio; the two orientations are aligned at 85.1 (1) and 89.6 (1)° with respect to the dihydrotriazine ring. In the crystal, adjacent cations and anions are linked by N—H⋯N and N—H⋯Cl hydrogen bonds, generating a double chain running along the b axis.

Epichlorohydrin cross-linked β-cyclodextrin: an environmental method for the synthesis of 2-arylbenzothiazoles derivatives in water

ABSTRACT In the present study, we report an environmentally benign synthesis of 2-arylbenzothiazoles derivatives from o-aminothiophenol and aldehydes in aqueous medium using β-cyclodextrin polymer as a catalyst and air as an oxidant. The polymer showed excellent catalytic activity, recovered, reused six times, and the catalyst efficiency remained unchanged. This suggests that the catalyst is an efficient and green catalyst for the synthesis of 2-arylbenzothiazoles derivatives and the obtained results could be promising for industrial synthesis of 2-arylbenzothiazoles derivatives. GRAPHICAL ABSTRACT

2-Amino-6-(dimethyl­amino)pyridine-3,5-dicarbonitrile

The title compound, C9H9N5, is slightly twisted from planarity, with a maximum deviation of 0.0285 (13) Å from the pyridine plane for the C atom bearing the amino group. The cyano groups are on different sides of the pyridine plane, with C- and N-atom deviations of 0.072 (3)/0.124 (4) and −0.228 (4)/−0.409 (5) Å from the pyridine plane. In the crystal, N—H⋯N and C—H⋯N hydrogen bonds connect the molecules into zigzag chains running along the c axis.

4-(4-Chloro-benz-yl)-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one.

The five-membered ring of the title compound, C17H15ClN2O, is almost planar (r.m.s. deviation = 0.008 Å), and its phenyl subsitutent is aligned at 34.9 (1)° with respect to this ring. The angle at the methylene C atom is opened to 116.4 (2)°. In the crystal, adjacent molecules are linked by an N—H⋯O hydrogen bond, generating a linear chain along the a axis.

2-(1,3-Benzothia-zol-2-yl)guanidin-2-ium acetate.

In the title compound, C8H9N4S−·C2H3O2 −, the cation is essentially planar (r.m.s deviation = 0.037 Å) with the guanidine unit bent out of the plane of the fused-ring system by 4.6 (3)°. In the asymmetric unit, the cations and anions are linked into R 2 2(8) motifs. In the crystal, further N—H⋯O and N—H⋯N hydrogen bonds link the components into a two-dimensional network.