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Herein, high-valence-state Mn(V) oxide, barium manganate(V) (Ba3(MnO4)2), is examined as an anode electrocatalyst of a H+-conducting solid oxide steam electrolysis cell (H-SOEC). Ba3(MnO4)2 comprises C3v-symmetric MnO43− oxo-anions with three long Mn–O bonds and one short Mn–O bond at room temperature. Ba3(MnO4)2 caused a conductivity jump by one order of magnitude at approximately 600 °C owing to the antiferromagnetic/paramagnetic phase transition, accompanied by a shape change of the tetrahedral MnO43− anions from C3v to Td symmetry, as confirmed by the electrical conductivity measurements and the extended X-ray absorption fine structure at an elevated temperature. Hence, the Ba3(MnO4)2 base anode of the H-SOEC exhibited improved performance, with anode polarization resistances being lower than those of Sm0.5Sr0.5CoO3, a well-known H-SOEC anode material. Impedance analysis in terms of oxygen and water partial pressure revealed that the superior performance of the Ba3(MnO4)2 base anode can be attributed to the extended reaction area. Since abundant unoccupied 3d states of the high-valence-state Mn5+ cations are favorable for charge transfer interactions with water electron donors, thereby facilitating water adsorption, the oxygen evolution reaction could occur directly over the electrode surface, and thus the reaction sites were not limited to the gas–electrode–electrolyte triple phase boundary.

Perovskite-based on lanthanum manganate material has attracted much attention in a few years recently because it can produce a change in properties based on substitute composition. This study successfully synthesized perovskite based on lanthanum manganate La0.7Ba0.3Mn1-xNixO3 (x = 0, 0.1, 0.2, and 0.3) using sol-gel method. Samples were characterized using X-Ray Diffraction (XRD) whose raw data was subsequently analyzed using the Rietveld refinement method on GSAS-EXPGUI software. For x = 0 – 0.2 single-phase of rhombohedral crystal structure with space group R-3c was formed. But, for x = 0.3, multi-phases were formed with one of them was BaMnO3 with rhombohedral crystal structure and space group R-3m. The characterization using Vibrating Sample Magnetometer (VSM) showed decrease of the magnetic properties in base material along with the increasing of x composition indicated by the lowering slopes of corresponding hysteresis curves and the decreasing value of magnetization along with its susceptibility.

Compact capacitive energy storing/harvesting systems could play a key role in the urgent need for more energy-efficient technologies to address both energy and environmental issues. Therein, the purpose of the present work is to develop and investigate epoxy/BaMnO4 nanocomposites at various filler concentrations, which could be applicable as compact materials systems for energy storage and harvesting. Broadband dielectric spectroscopy was used for studying the dielectric properties and the relaxation processes of the examined nanodielectrics. The energy storing/retrieving ability of the nanocomposites was also evaluated via DC charge–discharge experiments. The coefficient of energy efficiency (neff) was found for all prepared nanocomposites to evaluate the energy performance of the systems. Dielectric data divulge the existence of two matrix-related relaxations, i.e., α-mode and β-mode, attributed to the glass-to-rubber transition of the polymer matrix and re-orientation of polar side groups, respectively. Interfacial polarization was also identified in the low-frequency and high-temperature region. The 7 phr BaMnO4 nanocomposite exhibits the best performance in terms of the stored and harvested energies compared to all systems. On the other hand, the 5 phr, 3 phr and 1 phr nanocomposites display optimum energy performance, reaching high values of neff.

The properties of anticorrosive coatings based on epoxy resin pigmented with barium manganate (IV) produced by ceramic method have been investigated. Electrochemical tests of coatings based on the developed primer showed inhibiting properties with respect to corrosion processes and also demonstrated that the coatings retain a high adhesion even after exposure to an electrolyte solution for 1000 hours. It has been established that the inclusion of the synthesized pigment in the coatings increases their ability to inhibit sub-film corrosion in steel.

A promising electrode material barium manganate (BaMnO3) for electrochemical supercapacitor was prepared by solution combusted manganese tartrate complex process. Several analytical tools such as X-ray diffractometry, FT-IR spectroscopy, diffuse reflectance spectra, TG/DTA, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been used to characterize the BaMnO3 nanomaterial. Electrochemical properties of the synthesized composites were elucidated by cyclic voltammetry and galvanostatic charge–discharge measurements. This material showed excellent cycling capability, even at the high current and excellent capacity retention with the best combination of coulombic efficiency of 93.9% and specific capacitance of 141.6 F g−1 after 500 cycles. These results clearly indicate the high rate discharge performances of BaMnO3 and it can be recognized as high-performance electrode material.

An efficient synthetic approach to 2E,4E and 2E,4Z isomers of ethyl 5-chloropenta-2,4-dienoate has been developed on the basis of one-pot oxidation–olefination of readily accessible (E)- and (Z)-3-chloroprop-2-en-1-ols by the action of barium manganate and ethyl (triphenyl-λ5-phosphanylidene)acetate.

This work describes a route for extracting manganese and zinc from spent zinc–manganese dioxide dry cells via fusion of the electroactive components with potassium hydroxide to form potassium manganate (K 2 MnO 4 ) and soluble zincates. The fused mass was dissolved in aqueous KOH and the insoluble matter was separated. Under the best optimal conditions, 70–78 wt% of manganese was solubilized as K 2 MnO 4 whereas 30–44 wt% of zinc was solubilized as [Zn(OH) 4 ] 2− ions. Lead was the only minor component dissolved in detectable amounts. Manganese was isolated by a one-step precipitation procedure as barium manganate (BaMnO 4 ) or via crystallization of K 2 MnO 4 . Lead and excess barium were isolated as sulfate by adding K 2 SO 4 . Zinc was precipitated as hydroxide after neutralizing the alkaline solution with H 2 SO 4 . pH control is essential to avoid decomposition of manganate ions and for the sequential precipitation of leached elements. K 2 SO 4 was partially recovered as by-product after partial evaporation of the neutralized solution.

A one-pot, tandem oxidation–Wittig procedure has been developed in which the reacting components are generated in situ from alcohols, triphenyl phosphine, and ethyl bromoacetate using barium manganate as a mild oxidizing agent without the addition of an external base.

1,5,7-Triazabicyclo[4.4.0]dec-1-ene (TBD) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-1-ene (MTBD) promote the efficient formation of sulfonium ylides from sulfonium salts in the Corey–Chaykovsky epoxidation of aldehydes and provide excellent yields of the corresponding epoxides. This reaction protocol can be further adapted to allow for the development of both sequential and tandem-oxidation–epoxidation protocols from aldehydes generated in situ by manganese dioxide (MnO2) or barium manganate (BaMnO4) mediated oxidation reactions.

A one-pot, tandem oxidation–Wittig procedure has been developed in which the reacting components are generated in situ from alcohols, triphenyl phosphine, and ethyl bromoacetate using barium manganate as a mild oxidizing agent without the addition of an external base. The authors are grateful to Institute for Advanced Studies in Basic Sciences (IASBS) Research Council, Shiraz University and Iran National Science Foundation (INSF-Grant number of 94010666) for support of this work. C. Nájera is also thankful to The Spanish Ministerio de Economia y Competitividad (MINECO) (projects CTQ2013-43446-P and CTQ2014-51912-REDC), FEDER, the Generalitat Valenciana (PROMETEOII/2014/017) and the University of Alicante for financial support.

Barium manganate nanofibers were successfully synthesized for the first time after heat treatment of composite nanofibers of polyvinyl pyrrolidone (PVP), barium acetate and manganese acetate using electrospinning technique. Different PVP concentrations were used and the results show that PVP concentration had played important role in the formation, uniformity, homogeneity and particularly in the reduction of nanofibers diameter. Crystal structure, microstructure, elemental analysis and surface morphology were studied using X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. X-ray diffraction results show that at low temperature there is no crystallinity in the fibers sample and at ∼400 °C formations of barium manganate crystalline phase starts and finally at 700 °C all the nanofibers became single phase. The first two high intensity peaks (1 0 1) and (1 1 0) give an average crystallite size of about 20 nm. The scanning electron micrographs show that the morphology of the fibers is smooth and uniform at low temperature and become slightly porous at intermediate temperature and finally at high temperature of 700 °C the fibers become highly porous, shrank and their average diameter reduced from ∼400 nm to about 100 nm. These fibers are made of grains with sizes ranging from 15 to 30 nm. Energy dispersive X-ray spectroscopy and Fourier transform infra-red results are also in good agreement with XRD and SEM results.

Synthesis of 2,4,6-trisubstituted pyrimidines by tandem oxidation/heterocyclocondensation of propargylic alcohols and amidines is effected rapidly and efficiently under microwave dielectric heating using barium manganate as oxidant. Irradiation at 150 °C in ethanol–acetic acid for 45 min results in dramatic improvements in yield over the corresponding manganese dioxide-mediated method and establishes a rapid route to triarylpyrimidines in order to investigate their photophysical properties.

The novel 3-fold symmetric 1,3,5-tris(1H-imidazol-2-yl)benzene, having a propensity for a 3-fold salt formation by hydrogen bonding at the periphery, was prepared from oxidation of the hexahydro imidazole precursor. The transformation proved difficult and, of the many reagents tried, only barium manganate and o-iodoxy benzoic acid were successful. The oxidation to the aromatic 1,3,5-tris imidazolyl benzene produces dramatic changes, particularly when the X-ray structures of their tris-TFA (trifluoroacetic acid) salts are compared. While the hexahydro precursor exhibited a herringbone type arrangement in the crystal, the oxidation resulted in almost co-planar molecules that formed parallel stacks separated by 3.57 A between the atoms in separate planes. 1,3-Bis(1H-imidazole-2-yl)benzene is an attractive core unit for assembly using a variety of auxiliaries. Several attempts to complex the bis-imidazole with organic acids failed. These efforts lead to the serendipitous discovery of a novel tetrameric assembly, mediated by water molecules, which was confirmed by crystallization of the bis imidazole from water. Differing Patterns in the Self-Assembly of Radially Anchored Imidazoles, 1,3,5-Tris(1 H -imidazol-2-yl)benzene and 1,3-Bis(1 H -imidazol-2-yl)benzene A. Infinite stacks of the TFA salt from 1,3,5-tris(1H-imidazol-2-yl)benzene with a separation of 3.57 A between atoms in separate planes (The TFA moiety has been omitted for clarity). B. Tetrameric assembly of 1,3-bis(1H-imidazol-2-yl)benzene, mediated by water molecules. Differing Patterns in the Self-Assembly of Radially Anchored Imidazoles, 1,3,5-Tris(1 H -imidazol-2-yl)benzene and 1,3-Bis(1 H -imidazol-2-yl)benzene Y.B.R.D. Rajesh, (2) Subramania Ranganathan, (2)* Richard D. Gilardi (1,3) and Isabella L. Karle, (1)* (1) Laboratory for the Structure of Matter, Naval Research Laboratory, Washington, D.C. 20375-5341 (2) Discovery Laboratory, Organic III, Indian Institute of Chemical Technology, Hyderabad 500 007, India (3) Retired

The electrocatalysis of the oxygen reduction reaction by Lanthanum Barium Manganate, (La0.5Ba0.5MnO3) (LBM) has been studied by cyclic voltammetry using the rotating ring-disc electrode technique (RRDE) in alkaline medium. From the ring-disc data and other kinetic parameters it has been assumed that the oxygen reduction occurs by dissociative chemisorption at low overpotentials. At higher overpotentials, the formation of hydrogen peroxide (HO2 - in this case) has been observed on this electrocatalyst. The apparent exchange current density value for oxygen reduction on LBM has been found to be 4 x 10-8 Acm-2, while the corresponding Tafel slope is 0.115 V per decade. The possible reaction mechanism for electroreduction of oxygen on this oxide catalyst has been discussed.

This paper was focused on the development of prototypes for flat plate RAM™ (rechargeable alkaline manganese dioxide) cells. In contrast to cathodes used in cylindrical RAM™ cells, the mechanical stability is a significant issue for the preparation of flat plate cathodes. Therefore, the choice of an appropriate binder, e.g. Oppanol, is very important. In this work, an improved preparation process of flat plate RAM™ cathodes was developed by investigating the single steps of the preparation method. It was further demonstrated that the most critical factor of zinc electrode performance was the electrolyte content of the anode gel. Best overall cell performance was achieved at 40% zinc amount and a Zn/ZnO ratio of 5.0, in combination with an electrolyte content of 50.5%. In order to stabilise the γ-structure of manganese dioxide and to enhance rechargeability, the addition of barium compounds was also studied. Cell cycling has shown that flat plate RAM™ cells with BaSO 4 -modified cathodes outperformed control cells by 24%, mainly because of the minimised fade of discharge capacity. Moreover, the admixture of barium manganate to the cathode yielded more than 15% capacity improvement after 25 cycles, compared to the barium sulfate additive.

A new aromatic annulation reaction based on sequential Horner-Emmons and Claisen condensation reactions is described. The method is high yielding and provides a rapid entry to arylnaphthalenes. The lignan natural products justicidin B 1, retrojusticidin B 2, taiwanin C 3, justicidin E 4, chinensin 5 and retrochinensin 6 have all been synthesised in good overall yield using this protocol, demonstrating its potential in multiple parallel synthesis. The selective oxidation of diols 34-36 to the corresponding retrolactones with barium manganate(VI) is also noteworthy.

Manganese blue is a synthetic barium manganate(VI) sulphate compound that was produced from 1935 to the 1990s and was used both as a blue pigment in works of art and by conservators in the restoration of paintings. The photophysical properties of the compound are described as well as the setup needed to record the spatial distribution of the pigment in works of art.

Barium manganate has been used as an inexpensive and convenient reagent for efficient oxidation of a variety of 1,4-dihydropyridine derivatives to pyridine derivatives in refluxing benzene with excellent yields.

1,5,7-Triazabicyclo[4.4.0]dec-1-ene (TBD) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-1-ene (MTBD) promote the efficient formation of sulfonium ylides from sulfonium salts in the Corey–Chaykovsky epoxidation of aldehydes and provide excellent yields of the corresponding epoxides. This reaction protocol can be further adapted to allow for the development of both sequential and tandem-oxidation–epoxidation protocols from aldehydes generated in situ by manganese dioxide (MnO2) or barium manganate (BaMnO4) mediated oxidation reactions.

Microwave irradiation of a range of diols at 150 °C in acetonitrile in the presence of three equivalents of barium manganate facilitates a novel tandem oxidation/heterocyclocondensation to give the corresponding lactone, including both small and medium ring lactones, in only one hour and in high yield without the need for chromatographic purification.

Oxidation with barium manganate of the enol of tetraacetylethane (10) affords tetraacetylethylene (7a) in good yield. Treatment of the 1,3-diketones 15a and b with iodosobenzene in the presence of boron trifluoride does not result in oxidative coupling yielding 10 and diacetyldibenzoylethane 17, respectively, as has been reported by Moriarty et al. Instead the known difluoroborylenolates 16 are formed. Oxidative coupling of the sodium enolate of 15b with iodine affords the meso-tetraketone meso-17 and diacetyldibenzoylethylene (E)-7b besides small amounts of rac-17 and the bisenol 19. In the presence of 1,4-diazabicyclo[2.2.2]octane, meso-17 and 19 tautomerise yielding identical equilibrium mixtures of meso-17, rac-17, and 19 (26:29:45). Dehydrogenation with 5,6-dichloro-2,3-dicyanobenzoquinone of meso-17 yields (E)-7b and an isomer (77:23) which was assigned structure (Z)-7b on the basis of spectroscopic evidence. – Tetraacetylethylene (7a) reacts with 1,2-dimethylenecyclohexane to afford two different [4+2]cycloadducts, viz. the spirocyclic dihydropyran 25 (30 %) and the tetraacetyloctalin 27. Whereas the latter is stable, the former isomerises to the latter on heating. Formation of both [4+2]cycloadducts and the isomerisation 25 27 are interpreted by invoking the zwitterion 26 as common intermediate. Monoolefines that cannot generate stable carbenium ions don't give [4+2]cycloadducts with 7a. In contrast, α-methylstyrene yields the oxa Diels–Alder product 30. The structures of (E)-7b, 19, 25, and 27 are established by X-ray diffraction analyses.

Oxidative deprotection of various trimethylsilyl and tert-butyldimethylsilyl ethers of alcohols with KMnO4 and BaMnO4 in the presence of varieties of Lewis acids in dry acetone and dry acetonitrile at room temperature are studied. BaMnO4 shows more chemoselectivity than KMnO4

Active manganese dioxide (AMD) and commercially available barium manganate (BM) are highly efficient oxidizing agents for oxidative coupling of thiols to their corresponding disulfides in excellent yields under solvent-free conditions at room temperature.

Twofold extrusion reactions are chemical transformations in which two small inorganic molecules or atoms connecting carbon or nitrogen atoms are lost, generating the corresponding carbon-carbon or carbon-nitrogen double bonds. These reactions are particularly useful for the preparation of sterically hindered alkenes and imines. The inorganic species liberated in twofold extrusion reactions can be molecular nitrogen, sulfur, selenium, tellurium, sulfur dioxide, sulfur monoxide, carbon dioxide or carbon monoxide. The most common precursors for twofold extrusion reactions are 1,3,4-thiadiazolines, which thermally extrude molecular nitrogen affording thiiranes. These thiiranes can be readily desulfurized to afford the corresponding alkenes using tertiary phosphines. The corresponding 1,3,4-selenadiazolines thermally extrude both molecular nitrogen and atomic selenium directly affording alkenes. Alkenes can also be prepared by formal extrusions of molecular nitrogen plus sulfur dioxide or sulfur monoxide. Extremely sterically hindered imines can be prepared by extrusions of molecular nitrogen and sulfur or selenium from in situ generated heterocyclic precursors. Other less common twofold extrusion reactions are also reported. The detailed preparations of the required precursors for the twofold extrusion reactions as well as the mechanisms of these extrusion processes are discussed in this chapter. The utility of twofold extrusion reactions in the preparations of ‘molecular rotors’ and other extremely sterically hindered alkenes is presented. The steric limitations of the twofold extrusion reactions are discussed along with comparisons of these reactions with other alkene- and imine-forming synthetic methods. The Tabular Survey covers material through the end of 2009. Keywords: Extrusion; twofold extrusion; alkene; imine; 1,3,4-thiadiazolines; 1,3,4-selenadiazolines; [nitrogen, sulfur, selenium, tellurium, sulfur dioxide, sulfur monoxide, carbon dioxide and carbon monoxide (all with extrusion)]; thiocarbonyl ylide; tertiary phosphine; diazo compounds; thiones; selones; sulfenes; selenirane; azines; chelotropic extrusion; Barton-Kellogg reaction; Staudinger-Pfenninger reaction; Schonberg reaction; thiadiazoline-1,1-dioxides; thiirane 1,1-dioxide; thiirane 1-oxide; oxathiolan-4-ones; lead tetraacetate; barium manganate; diselenium dibromide; thiocarbonyl-S-imide; copper powder; photochemical extrusion; flash vacuum pyrolysis (FVP); rhodium (II) acetate; 1,3-dithiacyclopentanes; hydrazones; thiaziridine 1,1-dioxides; p-toluenesulfonylhydrazones; 1,2,3-thiadiazolines; alkenes (sterically hindered); imines (sterically hindered); N-sulfonylamines; retrocyclization; iminium salts (sterically hindered); geminal dihalides; nanoscale devices; photonic devices; thiophosgene; O-thioesters; O-selenoesters; enol ethers; dithioesters; thioenol ethers; thionolactones; thioamides; thiolactams; trithiocarbonates; ketene thioacetals; thioacyl halides; thionitroso compounds; thiatriazoline; trimethyl orthoformate; hydrogen sulfide; triphenylphosphoranylidene hydrazones

A short synthsis of the pentacyclic marine alkaloid ascididemin 1 (four steps, 21% yield) from 1,10-phenanthroline 16 is described. The key step, photocyclisation of the quinoneimine 14 in sulphuric acid, is the first such aza stilbene photocyclisation of a quinoneimine. Intermediate 14 is prepared in a single, but low yielding, step from the quinone 4 in an aza Wadsworth-Emmons reaction, or in much better yield from the epoxide 17 by treatment with 2- iodoaniline and triethylaluminium, followed by oxidation with barium manganate.

A number of fluorescent 4,5-dihydro-3H-1,2,4-triazole-3,5-diones have been made. Intra-inter-electrophilic substitution by the triazoledione moiety on the activated naphthalene ring of 4-[6-(5-dimethylamino-1-naphthylsulfonamido)hexyl]-4,5-dihydro-3H-1,2,4-triazole-3,5-dione 4a3 leads to rapid decomposition. The dienophilicity of the triazoledione moiety in 4-pyren-1-yl-4,5-dihydro-3H-1,2,4-triazole-3,5-dione 4d is dramatically lowered by steric shielding. Insertion of a three-carbon spacer unit into the latter compound, to give the 3-pyren-1-ylpropyl analogue 4e, affords a valuable fluorogenic reagent for the analysis of trace levels of 1,3-dienes. Powdered barium manganate is shown to be an excellent solid-phase oxidant for conversion of urazoles into 1,2,4-triazole-3,5-diones.

Active manganese dioxide (AMD) and commercially available barium manganate (BM) are highly efficient oxidizing agents for oxidative coupling of thiols to their corresponding disulfides in excellent yields under solvent-free conditions at room temperature.

Oxidation with barium manganate of the enol of tetraacetylethane (10) affords tetraacetylethylene (7a) in good yield. Treatment of the 1,3-diketones 15a and b with iodosobenzene in the presence of boron trifluoride does not result in oxidative coupling yielding 10 and diacetyldibenzoylethane 17, respectively, as has been reported by Moriarty et al. Instead the known difluoroborylenolates 16 are formed. Oxidative coupling of the sodium enolate of 15b with iodine affords the meso-tetraketone meso-17 and diacetyldibenzoylethylene (E)-7b besides small amounts of rac-17 and the bisenol 19. In the presence of 1,4-diazabicyclo[2.2.2]octane, meso-17 and 19 tautomerise yielding identical equilibrium mixtures of meso-17, rac-17, and 19 (26:29:45). Dehydrogenation with 5,6-dichloro-2,3-dicyanobenzoquinone of meso-17 yields (E)-7b and an isomer (77:23) which was assigned structure (Z)-7b on the basis of spectroscopic evidence. – Tetraacetylethylene (7a) reacts with 1,2-dimethylenecyclohexane to afford two different [4+2]cycloadducts, viz. the spirocyclic dihydropyran 25 (30 %) and the tetraacetyloctalin 27. Whereas the latter is stable, the former isomerises to the latter on heating. Formation of both [4+2]cycloadducts and the isomerisation 25 27 are interpreted by invoking the zwitterion 26 as common intermediate. Monoolefines that cannot generate stable carbenium ions don't give [4+2]cycloadducts with 7a. In contrast, α-methylstyrene yields the oxa Diels–Alder product 30. The structures of (E)-7b, 19, 25, and 27 are established by X-ray diffraction analyses.

Barium manganate has been used as an inexpensive and convenient reagent for efficient oxidation of a variety of 1,4-dihydropyridine derivatives to pyridine derivatives in refluxing benzene with excellent yields.

A new aromatic annulation reaction based on sequential Horner-Emmons and Claisen condensation reactions is described. The method is high yielding and provides a rapid entry to arylnaphthalenes. The lignan natural products justicidin B 1, retrojusticidin B 2, taiwanin C 3, justicidin E 4, chinensin 5 and retrochinensin 6 have all been synthesised in good overall yield using this protocol, demonstrating its potential in multiple parallel synthesis. The selective oxidation of diols 34-36 to the corresponding retrolactones with barium manganate(VI) is also noteworthy.

Alcohols are oxidised rapidly to the corresponding carbonyl compounds by montmorillonite KSF or silica supported barium manganate, under solvent-free conditions and microwave irradiation.

Microwave irradiation of a range of diols at 150 °C in acetonitrile in the presence of three equivalents of barium manganate facilitates a novel tandem oxidation/heterocyclocondensation to give the corresponding lactone, including both small and medium ring lactones, in only one hour and in high yield without the need for chromatographic purification.

Synthesis of 2,4,6-trisubstituted pyrimidines by tandem oxidation/heterocyclocondensation of propargylic alcohols and amidines is effected rapidly and efficiently under microwave dielectric heating using barium manganate as oxidant. Irradiation at 150 °C in ethanol–acetic acid for 45 min results in dramatic improvements in yield over the corresponding manganese dioxide-mediated method and establishes a rapid route to triarylpyrimidines in order to investigate their photophysical properties.

A short synthsis of the pentacyclic marine alkaloid ascididemin 1 (four steps, 21% yield) from 1,10-phenanthroline 16 is described. The key step, photocyclisation of the quinoneimine 14 in sulphuric acid, is the first such aza stilbene photocyclisation of a quinoneimine. Intermediate 14 is prepared in a single, but low yielding, step from the quinone 4 in an aza Wadsworth-Emmons reaction, or in much better yield from the epoxide 17 by treatment with 2- iodoaniline and triethylaluminium, followed by oxidation with barium manganate.

Oxidation of phenols, specially the hindered phenols has been carried out with barium manganate in non-aqueous media under heterogeneous conditions and the results of these studies are described in this paper.

Electronic industrial wastewater sludge in Taiwan is normally passed through an acid-extraction process to reclaim most of the copper ions, the remaining residue may still need to be treated by various stabilization technologies using suitable additives. Cement solidification is used as the common method to stabilize the industrial wastewater sludge in Taiwan. However, this method has the disadvantage of an increase in waste volume. In the present study selective additives such as sodium sulfide, barium manganate and different phase of alumina were tested as a possible alternate additive to stabilize the heavy metal ion in the treated solid waste sludge via microwave heating treatment. The effects of additive amount, power of microwave irradiation and reaction time have been studied. Heavy metal leaching capacity is determined by using standard toxicity characteristic leaching procedure test and elemental content in the leachate is analyzed by inductively coupled plasma analysis. Sodium sulfide is effectively stabilizing the leaching copper ion with high selectivity in the presence of microwave irradiation and finally stabilized in the form of copper sulfide, which is a significant reaction to stabilize the copper ion leaching in the waste sludge. Complete stabilization of heavy metal ion and copper ion content (5mgL(-1)) in industrial sludge is achieved by heating the microwave treated barium manganate and alumina additives by adopting suitable reaction conditions. Hybrid microwave and conventional heating process with minor amount of additive providing the efficient heavy metal stabilization for treated electronic industry waste sludge.

The allylic alcohol in ribose-protected zeatin riboside 1, was oxidised to an aldehyde by barium manganate. Heating of the resulting aldehyde in chloroform allowed the cyclization of the N 6 -chain into a 3-methylpyrrole ring. After deprotection of the ribose, the title compound was obtained and identified to a new metabolite of zeatin riboside. Its aglycone was synthesized through a similar route from N-9 protected zeatin.

Two convenient methods were developed to transformKMnO 4 into barium permanganate and other permanganate saltsvia BaMnO 4 or Mn 2 O 7 intermediates. Pure BaMnO 4 was preparedby the reaction of KMnO 4 with KI in the presence of BaCl 2 andNaOH. Hydrothermal reaction of barium manganate with excesscarbon dioxide for 1.5 h at 100 °C led to barium-permanganatewith almost quantitative yield. Mn 2 O 7 waspreparedbymeansofthe reaction of KMnO 4 and sulfuric acid monohydrate in a two-phase (CCl 4 -H 2 SO 4 .H 2 O) system. In the presence of excess barium Introduction Barium permanganate has been in use for a long time as auseful starting material (s 75 g/L in water at 18 °C, T dec 170 °C) for the preparation of other permanganate salts [1].It has also been applied as a selective solid phase oxidantin organic chemistry [2]. In spite of the widespread appli-cation, however, its convenient synthesis has not beenachieved yet. Potassium permanganate is the only commer-cially available permanganate compounds, but its trans-formation into pure barium permanganate cannot be per-formed directly [3]. Two synthetic precursor, however, na-mely BaMnO

Dried manganese dioxide (MnO2), potassium permanganate (KMnO4) and barium manganate (BaMnO4) in the presence of anhydrous aluminum and ferric chlorides performed efficient deprotection of S,S- acetals , 1,3-dithiolanes and 1,3-dithianes, in dry CH3CN at room temperature. Thioacetals derived from enolizable carbonyl compounds remained almost intact.

Nanoparticles are extensively used as efficient drug carriers in various biological studies. PEGylated barium manganate powder consisting of nanoparticles was synthesized using a hydrothermal technique. The nanoparticle morphology of the powder was confirmed via scanning electron microscopy. The average diameter of the nanoparticles was ∼90 nm. The x-ray diffraction pattern revealed that these nanoparticles consisted of single phase polycrystalline 2H-BaMnO3. The PEGylated BaMnO3 nanoparticles were loaded with 5-aminolevulinic acid (5-ALA) to evaluate their drug carrying potential. The toxicity of these nanoparticles was tested against the Hep2c cell line and found to be suitable for biological applications. It was seen that the drug uptake was a million times higher in the case of encapsulation compared to a conventional drug delivery system. This new formulation may find extensive use in nanomedicine as a multidrug delivery system.

Alcohols are oxidised rapidly to the corresponding carbonyl compounds by montmorillonite KSF or silica supported barium manganate, under solvent-free conditions and microwave irradiation.

Active manganese dioxide and commercially available barium manganate are used for the efficient oxidation of benzylic and aromatic allylic alcohols and biaryl acyloins under solvent-free conditions.

A number of fluorescent 4,5-dihydro-3H-1,2,4-triazole-3,5-diones have been made. Intra-inter-electrophilic substitution by the triazoledione moiety on the activated naphthalene ring of 4-[6-(5-dimethylamino-1-naphthylsulfonamido)hexyl]-4,5-dihydro-3H-1,2,4-triazole-3,5-dione 4a3 leads to rapid decomposition. The dienophilicity of the triazoledione moiety in 4-pyren-1-yl-4,5-dihydro-3H-1,2,4-triazole-3,5-dione 4d is dramatically lowered by steric shielding. Insertion of a three-carbon spacer unit into the latter compound, to give the 3-pyren-1-ylpropyl analogue 4e, affords a valuable fluorogenic reagent for the analysis of trace levels of 1,3-dienes. Powdered barium manganate is shown to be an excellent solid-phase oxidant for conversion of urazoles into 1,2,4-triazole-3,5-diones.