Volume 72, Issue 1

The title compounds have raised considerable medical and broad public interest in that sildenafil is used as an agent against male erectile dysfunction; iso-sildenafil is not in clinical use. A comparison of their structural and electronic properties therefore seems of interest. The electron densities of iso-sildenafil and the cationic and neutral forms of sildenafil were examined by the application of the invariom formalism relying on diffraction data reported in the literature. The electron-density distributions obtained were subjected to topological analysis using the quantum theory of atoms in molecules (QTAIM) formalism to yield bond topological and atomic properties. Moreover, molecular Hirshfeld surfaces and electrostatic potentials (ESPs) were calculated. A number of structural and electronic differences were thus identified between sildenafil and the iso-analog. In both sildenafil structures, the phenyl ring and the pyrazolopyrimidine fragment are practically coplanar (planar conformation), whereas in the iso-analog they exhibit an angle of 44° (inclined form). Related to differences in molecular structure are completely different hydrogen bonding patterns and differences in the ESPs, the latter ones being influenced by different methylation at the pyrazolopyrimidine fragment. Iso-sildenafil is present as a hydrogen-bond dimer in the crystal, and the ESP of this dimer is dominated by a surrounding positive potential.

Bio-guided fractionation of the guggul gum resin of Commiphora mukul HOOK using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay for the breast cancer cell line MDA-MB-231 led to the isolation of a new C17 norditerpene named myrrhanone C ( 1 ) along with two known polypodane-type triterpenes, namely, myrrhanone B ( 2 ) and myrrhanol B ( 3 ). The structures of the isolated compounds were elucidated by means of 1D ( 1 H and 13 C) and 2D (correlation spectroscopy, heteronuclear single-quantum coherence, heteronuclear multiple-bond correlation, and nuclear Overhauser effect spectroscopy) NMR spectroscopy as well as mass (electrospray ionization-mass spectroscopy) spectral analyses. Interestingly myrrhanone C ( 1 ) was able to induce a substantial decline in cell proliferation. It reduced the viability of cancer cells by almost 81% and 87% at concentrations of 50 and 100 μg mL −1 , respectively. Myrrhanone B ( 2 ) and myrrhanol B ( 3 ) showed a concentration-dependent growth inhibitory effect on cancer cells, with the latter being slightly more cytotoxic than the former at both the concentrations tested. Furthermore, myrrhanone C ( 1 ) and myrrhanone B ( 2 ) showed good α-glucosidase and urease inhibition.

The ethanol soluble part of the leaves of Clerodendrum formicarum , a Lameacious plant of Cameroon, afforded two new lignin glycosides named formiside and seco -formiside. Structures of both the isolated constituents have been elucidated with the aid of 1D and 2D NMR spectroscopic techniques.

Morpholinium hydrogen sulfate as an ionic liquid was employed as a catalyst for the synthesis of a biologically active series of multi-substituted imidazoles by a four-component reaction involving the combination of benzil with different aromatic aldehydes, ammonium acetate, and 1-amino-2-propanol under solvent-free conditions. The key advantages of this method are shorter reaction times, very high yield, and ease of processing. Furthermore, the resulting products can be purified by a non-chromatographic method and the ionic liquid catalyst is reusable. All of these novel compounds have been fully characterized from spectral data. The X-ray crystal structures of two representative molecules are also detailed.

A new Schiff base, 4-allylamine- N -( N -5-methylsalicylidene)-1,8-naphthalimide ( 1 ), has been designed and synthesized by combining a 1,8-naphthalimide moiety as a fluorophore and a Schiff base as a recognition group. Its photophysical properties were investigated by absorption and fluorescence spectroscopy, and this sensor exhibits a high fluorescence quantum yield of 0.75–0.91 inorganic solvents of different polarity. It also shows high selectivity for Cu 2+ over other ions with fluorescence quenching in aqueous medium (pH=7.2). The reason for this phenomenon (fluorescence quenching) is attributed to the formation of a 1:1 complex between 1 and Cu 2+ according to the Job plot and fluorescence titration. The sensor can be applied to the quantification of Cu 2+ in a linear fashion from 0.5 to 5 μM with a detection limit of 0.23 μM. Additionally, the association constant ( K a ) between Cu 2+ and 1 is 1.328×10 6 M − 1 in aqueous media.

A new cyanido-bridged bimetallic copper(II)–silver(I) complex, [Cu(Dach) 2 -Ag(CN) 2 -Cu(Dach) 2 ][Ag(CN) 2 ] 3 ( 1 ) (Dach= cis -1,2-diaminocyclohexane), has been prepared and characterized by IR spectroscopy and single crystal X-ray analysis. The crystal structure of complex 1 consists of a centrosymmetric trinuclear cation and three non-coordinated [Ag(CN) 2 ] − ions assembled in the form of a trimer, {[Ag(CN) 2 ] − } 3 . The complex ion is made up of two [Cu(Dach) 2 ] 2+ units connected by a bridging [Ag(CN) 2 ] − anion. The copper atom in the complex ion assumes a distorted square pyramidal geometry with CN − nitrogen atoms occupying the apical position. The trinuclear units are joined by hydrogen bonding to form irregular chains.

Two new highly acetylated steroids, named dysiroid A ( 1 ) and dysiroid B ( 2 ), together with a known compound ( 3 ) were isolated from the marine sponges Dysidea sp. The chemical structures of 1 and 2 were elucidated by spectroscopic analyses including 1D and 2D NMR experiments and high-resolution electrospray impact mass spectroscopy. Their in vitro antimicrobial activities against a panel of bacterial strains were evaluated. Compounds 1 and 2 showed potent activity against some of the strains with minimum inhibitory concentrations ranging from 4 to 8 μg mL −1 .

During our search for novel bioactive compounds from extremophilic actinomycetes, the new Streptomyces griseorubens sp. ASMR4 was isolated from a soft coral collected in the Red Sea at the Hurghada coast, Egypt, and characterized taxonomically. It was fermented on large scale using a modified solid rice medium as the first example for actinomycetes so far. Work-up and purification of the strain extract using different chromatographic techniques afforded the new oxaphenalene derivative, 8-hydroxy-2-(2-hydroxypropyl)-7-acetyl-1-oxaphenalene ( 1a ), together with seven known metabolites: ferulic acid ( 2 ), glycerol linoleate, linoleic acid methyl ester, (3 R ,4 R )-3,4-dihydroxy-3-methylpentan-2-one/(3 S ,4 R )-3,4-dihydroxy-3-methylpentan-2-one, anthranilic acid, phenylacetic acid, and benzoic acid. The chemical structure of the new compound ( 1a ) was confirmed by extensive 1D and 2D NMR spectroscopy, high-resolution electron impact mass measurements, and by comparison with literature data. The antimicrobial activity of the strain extract and compounds 1a and 2 were studied using a panel of pathogenic microorganisms. The in vitro cytotoxicity of the bacterial extract was studied against the human cervix carcinoma cell line (KB-3-1) and its multi-drug-resistant subclone (KB-V1).

Rb 3 [H(HSO 4 ) 2 ][S 2 O 7 ] (monoclinic, C 2/ c (no. 15), a= 1638.75(6), b= 768.52(3), c= 1187.88(4) pm, β= 106.805(2)°, V= 1432.14(9)·10 6 pm, Z= 4) was obtained from the reaction of Rb 2 [CO 3 ] (99.9%, not dried, 150 mg, 0.6 mmol) with neat SO 3 in a torch-sealed glass ampoule. The remaining quantity of water in the starting material was obviously sufficient to lead to an H-containing substance. The structure shows the unprotonated disulfate anion [S 2 O 7 ] 2− adjacent to the hydrogenium- bis -hydrogensulfate anion [H(HSO 4 ) 2 ] − with the central hydrogen atom located close to a center of inversion.

Orthorhombic In 3 B 5 O 12 was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 12.2 GPa and 1500°C. Its structure is isotypic to the rare earth analogs RE 3 B 5 O 12 ( RE =Sc, Er–Lu). In the field of indium borate chemistry, In 3 B 5 O 12 is the third known ternary indium borate besides InBO 3 and InB 5 O 9 . The crystal structure of In 3 B 5 O 12 has been determined via single-crystal X-ray diffraction data collected at room temperature. It crystallizes in the orthorhombic space group Pmna with the lattice parameters a =12.570(2), b =4.5141(4), c =12.397(2) Å, and V =703.4(2) Å 3 . IR and Raman bands of In 3 B 5 O 12 were theoretically determined and assigned to experimentally recorded spectra.

The intermetallic aluminum compound HP-CePtAl was synthesized by arc melting of the elements with subsequent high-pressure/high-temperature treatment at 1620 K and 10.5 GPa in a multianvil press. The compound crystallizes in the hexagonal MgZn 2 -type structure ( P 6 3 / mmc ) with lattice parameters of a =552.7(1) and c =898.8(2) pm refined from powder X-ray diffraction data. With the help of single crystal investigations ( wR =0.0527, 187 F 2 values, 13 variables), the proposed structure type was confirmed and the mixed Pt/Al site occupations could be refined. Magnetic susceptibility measurements showed a disappearance of the complex magnetic ordering phenomena, which are observed in NP-CePtAl.

Two complexes, {Mn(hfac) 2 (BIPMO)} n ( 1 ), {Cu(hfac) 2 (BIPMO)} n ( 2 ) [hfac=1,1,1,5,5,5-hexafluoro-pentane-2,4-dionato(–), BIPMO=bis(4-(1 H -imidazol-1-yl)phenyl)methanone], with the V-shaped ligands were synthesized and characterized by infrared spectroscopy, elemental analyses, along with single-crystal X-ray diffraction analyses. The X-ray diffraction studies have shown that the metal ions in 1 and 2 are both six-coordinated to two nitrogen atoms of two BIPMO ligands and four oxygen atoms of two hfac ligands to form a distorted octahedral geometry. Each BIPMO ligand acts as a bridging ligand to link two adjacent metal(II) atoms to form a helical chain in the crystal structure.