Volume 76, Issue 3-4

Two series of sulfonylureas derivatives including 24 compounds ( 4 , 7 , 5a – 5o , 8a – 8h ), among them 17 new derivatives, have been synthesized and evaluated for their α -glucosidase inhibitory activity. Compounds 5c , 5h and 8e showed significant in vitro α -glucosidase inhibition with IC 50 values of 5.58, 79.85 and 213.36 µ m , respectively, comparing with the standard compounds acarbose (IC 50  = 268.29 µ m) and glipizide (IC 50  = 300.47 µ m ). The preliminary structure-activity relationships (SARs) of the synthesized compounds were also investigated.

To explore candidate fungicides from plant secondary metabolites, 16 novel obovatol-type phenazine derivatives were semi-synthesized from obovatol isolated from the leaves of Magnolia obovata Thunb. The antifungal activity of synthesized compounds was investigated in vitro against four phytopathogenic fungi using the spore germination method. The bioassay results showed that eight derivatives ( 8b , 8g , 8h – k , 8i′ , and 8k′ ) exhibited better antifungal activity against Fusarium solani than two positive controls, especially compounds 8b (IC 50  = 64.61 μg mL −1 ) and 8i′ (IC 50  = 79.97 μg mL −1 ) showed pronounced inhibition of spore germination activity against F. solani . They could be used as lead compounds for further structural optimization. Additionally, the preliminary structure-activity relationships (SARs) illustrated that the introduction of a benzene ring monosubstituted with electron-withdrawing groups into the obovatol scaffold could lead to potentially antifungal compounds.

Fluorine analogs of the dicamba and tricamba herbicides were synthesized. Their herbicide activities were compared with the activities of the pattern herbicides dicamba and tricamba.

Three guanidine-derived tri-substituted ligands viz . N -pivaloyl- N ′, N ″-bis-(2-methoxyphenyl)guanidine (L 1 ), N -pivaloyl- N ′-(2-methoxyphenyl)- N ″-phenylguanidine (L 2 ) and N -pivaloyl- N ′-(2-methoxyphenyl)- N ″-(2-tolyl)guanidine (L 3 ) were reacted with Cu(II) acetate to produce the corresponding complexes. The significance of the substituent on N ″ for the resulting molecular structures and their packing in the solid state has been studied with respect to the structural specifics of the corresponding Cu(II) complexes. The key characteristic of the guanidine-based metal complexation with Cu(II) is the formation of an essentially square planar core with an N 2 O 2 donor set. As an exception, in the complex of L 1 , the substituent’s methoxy moiety also interacts with the Cu(II) center to generate a square-pyramidal geometry. The hydroxyl groups of the imidic acid tautomeric forms of L 1 –L 3 , in addition to N″, are also bonded to Cu(II) in all three complexes rather than the nitrogen donor of the guanidine motif.

The development of new prostate cancer protein receptor cytochrome P450 17A1 inhibitors offers the possibility of generating structures of increased potency. To this end, the chalcone analogs 7 and 8 were prepared from treatment of methyl 3 - oxo-3 H -benzocoumarin-2-carboxylate ( 4 ) with aryl aldehydes. Treatment of 7 and 8 with three anti-inflammatory drugs, flurbiprofen, ketoprofen and ibuprofen, in the presence of POCl 3 /DMAP gave the ester analogs 9 – 12 . Analogously, treatment of ethyl 3 - oxo-3 H -benzocoumarin-2-carboxylate ( 15 ), prepared previously from 2-hydroxy-1-naphthaldehyde ( 13 ) and dimethylmalonate ( 14 ), with various arylamines: 4-bromoaniline, 2-amino-6-methylpyridine, amino-antipyrine and 2-amino-5-nitrothiazole, in the presence of potassium tert -butoxide gave the benzocoumarine-3-arylamide analogs. The in vitro cytotoxic activities of 9 – 12 and 16 – 19 were evaluated against human prostate cancer cell lines (PC-3) and normal human liver epithelia (WRL-68) by MTT assay. Compounds 10 and 17 were the most active cytotoxic agents among the series against PC-3 cells with IC 50 values of 71.35 and 78.25 μg mL –1 with SI values of 3.0 and 4.2, respectively (calculated from the cytotoxicity effects of 10 and 17 on the normal human liver epithelia [WRL-68]). Furthermore, compounds 11 and 12 were tested against breast cancer (HER2 cell lines), prostate cancer (DU-135 cell lines) and MCF-7 but were inactive. Molecular docking studies between the protein receptor CYPP450 17A1 and compounds 10 and 17 revealed that these compounds primarily form hydrophobic interactions with the receptor.

A new salt (CH 6 N 3 )[ t -Cr(C 2 O 4 ) 2 (H 2 O) 2 ]·2H 2 O ( 1 ) (CH 6 N 3 +  = guanidinium cation) has been synthesized and characterized by single-crystal X-ray diffraction, FT-IR and UV–Vis spectroscopies, elemental and thermogravimetric analyses. In the crystal structure of 1 , the chromate(III) ion lies on an inversion center in the form of an elongated octahedron. The coordination sphere consists of four oxygen atoms of two chelating oxalato ligands in the equatorial plane and two axial oxygen atoms of water ligands. The structural feature of focal interest in the structure of 1 is the formation of pillars of [Cr(C 2 O 4 ) 2 (H 2 O) 2 ] − complex anions and CH 6 N 3 + guanidinium cations, with the next-neighbor cations rotated by an angle of 60° relative to each other. O–H···O and N–H···O hydrogen bonds play an important role in the construction of the three-dimensional network. The electron paramagnetic resonance (EPR) and magnetic properties of 1 have also been investigated.

The compounds ScCl 3 ·3H 2 O (SCTH) and [{Sc(H 2 O) 5 ( μ -OH)} 2 ]Cl 4 ·2H 2 O (SCOH), have been synthesised and characterised by single-crystal XRD, 45 Sc NMR spectroscopy and DFT calculations, with the crystal structure of SCTH reported here for the first time. From 45 Sc NMR measurements under static and MAS conditions, both chemical shift and quadrupolar coupling parameters have been determined. The quadrupolar coupling constants χ for the octahedrally coordinated scandium sites in SCTH are 2.0 ± 0.1 MHz for Sc(1) and 3.81 ± 0.05 MHz for Sc(2). For SCOH, where the hepta-coordination of the single scandium site constitutes a less symmetric electronic environment, 14.68 ± 0.05 MHz was found. DFT calculations for the static SCTH structure consistently overestimate the quadrupolar coupling constants, indicating the possible presence of crystal water dynamics on the NMR time scale.

Reaction of 8-bromo-7-ethyl-3-methylxanthine 1 with zerovalent group 10 metal complexes gave via an oxidative addition of the C–Br bond the neutral complexes trans -[ 2 ] (M = Pd) and trans -[ 3 ] (M = Pt) bearing a theobromine-derived azolato ligand. While the oxidative addition to [Pd 0 (PPh 3 ) 4 ] gave exclusively trans -[ 2 ], the reaction with the more substitution-inert [Pt 0 (PPh 3 ) 4 ] yielded after 1 day the kinetic product cis -[ 3 ], which was converted under heating for a total of 3 days completely into the thermodynamically more stable complex trans -[ 3 ]. Treatment of trans -[ 2 ], trans -[ 3 ] or the mixture of cis -/ trans -[ 3 ] with the proton source HBF 4 ⋅Et 2 O led to complexes trans -[ 4 ]BF 4 , trans -[ 5 ]BF 4 and a mixture of cis / trans -[ 5 ]BF 4 with retention of the original ratio of cis to trans , respectively. The molecular structures of the azolato complexes trans -[ 2 ] and trans -[ 3 ] and of the theobromine derived p NHC complexes trans -[ 4 ]BF 4 and trans -[ 5 ]BF 4 have been determined by X-ray diffraction studies.

A new Cu(II) complex, [Cu 2 (1,3-BMIB)(OBA) 2 ] n ( 1 ) (1,3-BMIB = 1,3-bis(2-methyl-1 H -imidazol-1-yl)benzene, H 2 OBA = 4,4′-oxybis(benzoic acid)) was hydrothermally synthesized and has been structurally characterized. Complex 1 possesses a 3D 2-fold interpenetrating framework based on [Cu(OBA)] n layers with a Schläfli symbol {4 12 .6 3 }. Complex 1 displays excellent photocatalytic properties in the degradation of methylene blue (MB) and rhodamine B (RhB).

The intermetallic compound LaNi 11.8–11.4 Si 1.2–1.6 was synthesized by arc-melting and its crystal structure was determined using powder and single-crystal X-ray diffraction data. The compound adopts the cubic CaCu 6.5 Al 6.5 -type structure (space group Fm 3‾$\bar{3}$ c , Pearson code cF 112, Z  = 8), which is a partially ordered ternary derivative of the NaZn 13 type: a  = 11.256(4) Å, V  = 1426.1(15) Å 3 , R  = 0.0133, wR  = 0.0285 for 93 reflections with I >  2 σ ( I ) for LaNi 11.4 Si 1.6 ; a  = 11.25486(8) Å, V  = 1425.68(2) Å 3 , R p  = 4.17%, R wp  = 5.85%, R B  = 3.44% for LaNi 11.8 Si 1.2 . One of its crystallographic positions (96 i ) is occupied by a mixture of Ni and Si atoms. The structure of this new silicide can be represented as a packing of Ni-centered icosahedra and La-centered snub cubes, which are packed in a CsCl-related manner.