New Organic-Inorganic Hybrid Compounds Based on Sodium Peroxidomolybdates (VI) and Derivatives of Pyridine Acids: Structure Determination and Catalytic Properties

Two organic-inorganic hybrids based on sodium peroxidomolybdates(VI) and 3,5-dicarboxylic pyridine acid (Na-35dcpa) or N-oxide isonicotinic acid (Na-isoO) have been synthesized and characterized. All compounds contain inorganic parts: a pentagonal bipyramid with molybdenum center, and an organic part containing 3,5-dicarboxylic pyridine acid or N-oxide isonicotinic acid moieties. The type of organic part used in the synthesis influences the crystal structure of obtained compounds. This aspect can be interesting for crystal engineering. Crystal structures were determined using powder X-ray diffraction or single crystal diffraction for compounds Na-35dcpa and Na-isoO, respectively. Elemental analysis was used to check the purity of the obtained compounds, while X-ray Powder Diffraction (XRPD) vs. temp. was applied to verify their stability. Moreover, all the compounds were examined by Infrared (IR) spectroscopy. Their catalytic activity was tested in the Baeyer-Villiger (BV) oxidation of cyclohexanone to ε-caprolactone in the oxygen-aldehyde system. The highest catalytic activity in the BV oxidation was observed for Na-35dcpa. The compounds were also tested for biological activity on human normal cells (fibroblasts) and colon cancer cell lines (HT-29, LoVo, SW 620, HCT 116). All compounds were cytotoxic against tumor cells with metastatic characteristics, which makes them interesting and promising candidates for further investigations of specific anticancer mechanisms.

Newly-Obtained Two Organic-Inorganic Hybrid Compounds Based on Potassium Peroxidomolybdate and Dicarboxypyridinic Acid: Structure Determination, Catalytic Properties, and Cytotoxic Effects of Eight Peroxidomolybdates in Colon and Hepatic Cancer Cells

Two new organic-inorganic hybrid compounds containing dicarboxylic pyridine acids have been obtained and characterized. Both compounds are potassium oxidodiperoxidomolybdates with 2,6-dicarboxylicpyridine acid or 3,5-dicarboxylicpyridine acid moieties, respectively. The chemical formula for the first one is C₁₄H₇K₃Mo₂N₂O₁₈ denoted as K26dcpa, the second C₇H₄K₁Mo₁N₁O_11.5-K35dcpa. Their crystal structures were determined using single crystal (K26dcpa) or XRPD-X-ray powder diffraction techniques (K35dcpa). The purity of the compounds was confirmed by elemental analysis. Their thermal stability was determined with the use of non-ambient XRPD. In addition, they were examined by IR spectroscopy methods and catalytic activity studies were performed for them. Catalytic tests in the Baeyer-Villiger reaction and biological activity have been performed for eight compounds: K26dcpa, K35dcpa, and six peroxidomolybdates previously obtained by our group. The anti-proliferative activity of peroxidomolybdenum compounds after 24 h of incubation was studied in vitro against three selected human tumor cell lines (SW620, LoVo, HEP G2) and normal human cells (fibroblasts). The data were expressed as IC₅₀ values. The structure of the investigated oxodiperoxomolybdenum compounds was shown to have influence on the biological activity and catalytic properties. It has been shown that the newly-obtained compound, K35dcpa, is a very efficient catalyst in the Baeyer-Villiger reaction. The best biological activity results were obtained for Na-picO (previously obtained by us), which is a very effective anti-cancer agent towards SW 620 colorectal adenocarcinoma cells.

A New Way to Quinazolines, Perimidines and Dibenzo[d,f][1,3]Diazepines

A synthesis of quinazolines, perimidines and dibenzo[d,f][1,3]diazepines is described. The method involves rearrangements following cyclisation of 2-anilino-2-methoxy-3-oxo-N-phenylbutanethioamides with aromatic 1,3-and 1,4-diamines.

The Synthesis of a New Fused Heterocyclic System: Hexahydro[1,5]Oxathiocino[2,3-b]Pyrazine

A brief synthesis of the new heterocyclic system of 1,2,3,7,8,10a-hexahydro-6 H,10 H-[1,5]oxathiocino[2,3- b]pyrazin-10-imine was achieved, starting from piperazin-2-one derivatives and 1,3-dibromopropane.

Effects of a carane derivative local anesthetic on a phospholipid bilayer studied by molecular dynamics simulation

Molecular dynamics (MD) simulations of two hydrated palmitoyloleoylphosphatidylcholine (POPC) bilayers each containing eight carane derivative (KP-23) local anesthetic (LA) molecules in neutral (POPC-LA) or protonated (POPC-LAH) forms were carried out to investigate the effect of KP-23 and its protonation on the bilayer. 3-ns trajectories were used for analyses. A pure POPC bilayer was employed as a reference system. In both POPC-LA and POPC-LAH systems a few KP-23 molecules intercalated into the bilayer and moved near the bilayer/water interface. They were located on the hydrophobic core side of the interface in the POPC-LA bilayer, but on the water phase side in the POPC-LAH bilayer. The order of the POPC chains was higher in the POPC-LA bilayer than in the pure POPC bilayer and was lower in the POPC-LAH bilayer. Interactions between polar groups of KP-23 and POPC or water were responsible for a lower hydration of POPC headgroups in POPC bilayers containing KP-23 than in the pure POPC bilayer. KP-23 molecules were found to form aggregates both in POPC-LA and POPC-LAH bilayers. Due to higher amphiphilicity of LAH, the LAH aggregate was more micelle-like and larger than the LA one. The results demonstrate the rapid timescales of the initial processes that take place at and near the bilayer interface as well as details of the atomic level interactions between local anesthetic and the lipid matrix of a cell membrane.

Synthesis of 1,4-diazines by ring expansion of 1,3-diazines

Fully saturated piperazin-3-one and quinoxalin-3-one derivatives were prepared by reactions of 2-anilino-2-ethoxy-3-oxothiobutanoic acid anilide with aliphatic 1,2-diamines. An unusual ring expansion of the intermediate 1,3-diazines leads to 1,4-diazines. Moreover, quinoxalin-3-one derivatives from chiral trans-1,2-diaminocyclohexane were obtained with diastereoselectivity >95%.

Synthesis of zwitterionic compounds: fully saturated pyrimidinylium and 1,3-diazepinylium derivatives via the novel rearrangement of 3-oxobutanoic acid thioanilide derivatives

An unusual rearrangement following cyclization of 2-anilino-2-ethoxy-3-oxothiobutanoic acid with aliphatic 1,3- as well as 1,4-diamine leads to zwitterionic derivatives of 2-hydroxypropanoic acid. Moreover, with aromatic 1,2-diamines, fused heterocyclic systems such as pteridine, quinoxaline, and pyrido[2,3-b]pyrazine are obtained.

Comparative investigations of hydroxyamine carane derivative and its R,S-diastereoisomers with strong local anesthetic activity

Our previously conducted pharmacological screening led as to the discovery of the strong local anesthetic activity of the compound designated as KP-23. Earlier crystallographic studies revealed that the compound KP-23 crystallized in diastereoisomeric form in lowest symmetry. The aim of these comparative investigations was to evaluate anesthetic activity of KP-23 and its R,S-diastereoisomers, which were synthesized at the Institute of Organic Chemistry, Biochemistry and Biotechnology, Wroclaw University of Technology.

Refinement of hexamethylenetetramine based on diffractometer and imaging-plate data

Two data sets were collected on single crystals of hexamethylenetetramine (urotropin) using a four-circle diffractometer with Cu Kα radiation and an imaging-plate two-dimensional detector with Mo Kα source using the rotation method. Both data sets extend to the same limit of sin θ/λ = 0.62 Å−1, corresponding to a resolution of 0.81 Å. Different processing protocols were employed for the two sets of data. Structure refinements carried out separately with each data set led to equivalent results of comparable accuracy. The imaging-plate scanner was able to provide X-ray data of high quality in a significantly shorter time than the diffractometer.

Structural investigation of the new potent DNA alkylator spiro(2H-1,3,2-benzodiazaphosphole-2,2',lambda 5 [1,3,5,2,4,6] triazatriphosphorine),4',4',6',6'-tetrakis(1-aziridinyl)-1,3,4',4',6', 6',-hexahydro

The molecular structure of spiro(2H-1,3,2-benzodiazaphosphole-2,2',lambda 5 [1,3,5,2,4,6] triazatriphosphorine), 4',4',6',6'-tetrakis(1-aziridinyl)-1,3,4',4',6',6'-hexahydro (CAS 133586-94-4), a recently synthesized potent cytostatic, was determined using X-ray diffraction method. The substance crystallizes in P2(1)2(1)2(1) orthorhombic space group. The unit cell contains 8 formal molecules coupled into 4 pseudo-centrosymmetric dimers by double intermolecular hydrogen bonds. The compound revealed, besides previously determined long-term chemical stability and good water solubility, also radiation stability. In spite of having less aziridinyl groups than 1,3,5,2,4,6-triazatriphosphorine,2,2,4,4,6,6-hexakis (1-aziridinyl)-2,2,4,4,6,6-hexahydro (N3P3Az3, Az = aziridinyl, CAS 52-46-0; Myko 63) the compound is twice more cytostatically active. Hypotheses attributing high cytostatic activity to the existence of conjugated pi-electron systems in the molecule and dimeric structures are discussed.

Synthesis and CLOGP correlation of imidooxy anticonvulsants

Continuing structure-activity studies on the anticonvulsant activity of analogs of N-(benzyloxy)-2-azaspiro[4.4]nonane-1,3-dione (2a), which displayed anti-electroshock seizure (MES) activity and a protective index (TD50/ED50) of > 4.5 are reported. An in-depth analysis of this moiety was studied employing the Topliss structure activity and the Craig plot analytical approaches as well as a semiempirical method. CLOG P analysis was also applied to this series after experimentally determining the NOR fragment. All compounds were minimized and these physicochemical parameters correlated to anticonvulsant activity. Several interesting substituted benzyloxy compounds emerged from this study: the 2',4'-dichloro (2b), 4'-(trifluoromethyl) (2c), 2'-bromo (2d), 3'-chloro (2o), 2'-chloro (2r), 2'-fluoro (2p), and 3'-fluoro (2w) analogs, all of which had comparable, or better activity than the parent unsubstituted analog (2a). X-ray crystal analysis of the active 2a versus inactive N-benzyl-2-azaspiro[4.4]nonane-1,3-dione (10) is discussed.

Molecular structure and antiaggregating activity of the potent local anaesthetic (-)-4-[2-hydroxy-3-(N-isopropylamino)-propoxyimino]-cis-carane

The molecular structure of (-)-4-[-2-hydroxy-3-(N-isopropylamino)- propoxyimino]-cis-carane (C16H30O2N2.HCl), a recently synthesized potent local anaesthetic, including the absolute configuration at 4 chirality centres was determined using X-ray diffraction method. The substance crystallizes in diastereoisomeric form in lowest symmetry (triclinic P1 space group). Determined intermolecular close contacts between chlorine atoms and nitrogen and hydroxyl oxygen are the main determinants of crystal packing. In the crystalline state nitrogen of the isopropylamine group has quaternary coordination. The influence of the title compound on blood platelets aggregation induced by adenosine diphosphate was studied. The results of parallel tests conducted for lidocaine and bupivacaine show that the antiaggregating activity of the title compound is much stronger. This property could be attributed to the monoterpene part of its molecule, in analogy to the observed cyclic adenosine monophosphate inhibitory action of forskolin (diterpene).