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Copper-catalyzed C(aryl)–Se bond formation by the reaction of diaryl diselenides with triarylbismuthanes in the presence of copper(I) acetate (10 mol%) and 1,10-phenanthroline (10 mol%) under aerobic conditions led to the formation of unsymmetric diaryl selenides in moderate to excellent yields. This reaction proceeded efficiently; all three aryl groups in the bismuthane and both the selanyl groups in the diaryl diselenide were transferred to the coupling products.

A skeletal transformation of α-pyrones having electron-withdrawing groups at the 3,5-positions into dihydrofurans was developed. Using dimethylsulfoxonium methylide as the methylene-transfer reagent, the α-pyrones were converted into dihydrofurans as major products and 1-methylthiopyran-1-oxides as minor products. The selectivity of the dihydrofuran formation was improved by optimizing the reaction conditions.

Pyrrolophenanthridinone derivatives including the natural products were readily synthesized by samarium(II)-mediated reductive cyclization of aryl radical onto a benzene ring under mild reaction conditions. This methodology was applied to the concise synthesis of anhydrolycorinone, a natural pyrrolophenanthridinone and a precursor of hippadine and anhydrolycorine.

A novel method for indole skeleton synthesis under mild conditions mediated by samarium(II) diiodide has been developed. The reaction of N-allenyl-2-iodoaniline derivatives with SmI2 in the presence of HMPA and i-PrOH at 0 °C afforded indole derivatives in high yields.

A novel yellow chlorophyll catabolite, Ed -YCC, was isolated from leaves detached from Egeria densa shoots, in which chlorophyll degradation and anthocyanin synthesis were induced in 0.1 M fructose solution under light illumination as a plant senescence process, a model of autumnal leaf coloration. Structure elucidation was accomplished by various NMR techniques including 2D-INADEQUATE.

An efficient synthesis of 6-substituted 3-(alkoxycarbonyl)-5-aryl-α-pyrones is reported. This methodology consists of the successive manipulation of an addition–elimination reaction between benzyl ketone derivatives and dimethyl methoxymethylenemalonate, and an acid-catalyzed condensation reaction. The synthesis is applicable to various 5-p-substituted-aryl 6-substituted α-pyrones and good to excellent yields were obtained over two steps from benzyl ketone derivatives that were easily prepared from phenylacetic acid by the Negishi coupling or the Claisen decarboxylation reaction.

Dimethylsulfoxonium methylide (II) is prepared in situ from trimethylsulfoxonium iodide and sodium hydride.

In situ generated dimethylsulfoxonium methylide is used to synthesize the title compounds in moderate yields.

O—Si bonds in various alkyl and aryl silyl ethers are efficiently cleaved by a new SO3H silica gel on which alkylsulfonic acid group are immobilized.

The concomitant addition of the histone deacetylase inhibitor and the DNA methyltransferase inhibitor to the culture medium of an entomopathogenic fungus, Isaria tenuipes, greatly enhanced its secondary metabolite production and led to the isolation of tenuipyrone (1), a novel polyketide with an unprecedented tetracyclic ring system bearing a spiroketal structural component, along with two known C10-polyketides, cephalosporolide B (2), which is a plausible biosynthetic precursor of 1, and cephalosporolide F (3).

Tandem Michael—aldol, double Michael, and double Michael—aldol reactions with the chiral amine (I) allow efficient and stereoselective access to functionalized amines with up to five contiguous chiral centers in one pot.

[(C 2 H 5 ) 2 NH 2 ] 4 Na[H 2 PTi 2 W 10 O 40 ]•11H 2 O cristallise dans P2 1 2 1 2 1 avec a=17,934, b=18,699, c=20,461 A, Z=4; affinement jusqu'a R=0.056. L'anion [H 2 PTi 2 W 10 O 40 ] 5− possede une structure Keggin avec deux sites d'atomes metalliques occupes par des atomes Ti. L'anion conserve l'orientation preferentielle dans le cristal et l'etude des sites occupes revele des sites substitues. L'isomere C 2 est predominant. Les longueurs W-Ti sont plus courtes de 0,05 A que les longueurs W-W correspondantes

The magnetic field effects on NO adsorption on iron oxides were observed at 303 K. Ferrimagnetic magnetite and maghemite showed magnetic field induced adsorption (magnetoadsorption); i.e., NO adsorption was promoted with an increase in external magnetic field (1-7.6 kG). Hematite (parasitic ferromagnetism) also showed magnetoadsorptivity. Antiferromagnetic iron oxyhydroxides ({alpha}-, {beta}-, and {gamma}-FeOOH) showed magnetic field induced desorption (magnetodesorption). On the other hand, an antiferromagnetic NiO and a ferrimagnetic {delta}-FeOOH exhibited magnetoadsorptivity and magnetodesorptivity, respectively. The magnetoadsorptivity of magnetites depended on the preheating conditions and that of {delta}-FeOOH was independent of its magnetism susceptibility. The results suggest that surface sites and porosity, i.e., adsorption state of NO, rather than solid magnetism would play an important role in the magnetic interactions between solid surfaces and NO molecules under a magnetic field.

Peroxo complexes prepared by the reaction of titanoundecatungstophosphate (PTiW11O405−) and dititanodecatungstophosphate (PTi2W10O407−) with hydrogen peroxide are characterized by means of the 183W NMR spectroscopy and the single crystal X-ray diffractometry. Electronic spectra and permanganate titration analyses indicated that one peroxo ligand attaches to the PTiW11O405− anion and two peroxo ligands attach to the PTi2W10O407− anion. 183W NMR spectra showed that the Cs symmetry of the PTiW11O405− anion and the C2 symmetry of the PTi2W10O407− anion are retained in the respective peroxo derivatives. Single crystal X-ray structures of the diisopropyl ammonium salt of PTiW11O405−, the diisopropyl ammonium salt of PTiW11O39(O2)5− and the isopropyl ammonium salt of PTi2W10O38(O2)27− indicated that the peroxo anions retain the α-Keggin structures of their parent anions. It was inferred that the peroxo ligands are substituted for the terminal oxygen atom at the TiO6 octahedra with the side-on format.

The two‐color (1+1’) threshold photoelectron spectra of naphthalene in a supersonic free jet have been recorded via nine vibronic levels of the S1 electronic state up to about 1420 cm−1 above the S1 band origin. The threshold photoelectron spectra recorded via the S1 band origin and via totally symmetric ag vibronic levels show significant intensity in Δν=+1 transitions in nontotally symmetric vibrations having b1g symmetry indicating that the ionization transition gains significant intensity through a vibronic coupling mechanism between the two lowest doublet cationic states. The strongest departure from the expected Δν=0 propensity in the threshold photoelectron spectra occurs through excitation of the totally symmetric 8 mode having ag symmetry indicating that a considerable displacement occurs along the normal coordinate of this 8 mode upon ionization from the S1 state. The superior resolution of the threshold photoelectron technique over conventional photoelectron methods has allowed accurate values ...

High resolution two‐color threshold photoelectron spectra of tropolone and 9‐hydroxyphenalenone (9‐HPO) isolated in a free jet expansion have been measured to study the proton tunneling phenomena in the cation ground state (D0). The tunneling splitting widths of the D0 zeroth vibrational level for the both molecules lie within our experimental accuracy (2 cm−1), indicating that the proton tunneling is inhibited when compared to that obtained in their respective neutral states. By means of a comparative study of these two molecules, the tunneling inhibition has been explained in terms of a large contribution from the electronic factor which represents the changes in charge distribution of the π electrons upon ionization. The geometric factor, which is associated with the ring planarity is less important in determining the rate of tunneling in the D0 state. In the case of tropolone, we have found that the measurement of an out‐of‐plane skeletal vibration in various electronic states make it possible to desc...

Asymmetric Michael addition of zinc enolate to a chiral nitroolefin was improved and the method was applied to the synthesis of (-)-Δ 9(12) -Capnellene [(-)-6], (-)-aphanorphine [(-)-7], and (-)-eptazocine [(-)-8]. Whisky lactone (28) was also prepared by taking advantage of tandem Michael addition-MPV-reduction, which was capable of constructing three contiguous chiral centers of 1,3-mercaptoalcohols. In addition, (+)-negamycin [(+)-35] was synthesized by using the Michael addition of a chiral amine [(-)-31] as a key step with the best overall yield and with shortest steps to date. Efficient synthesis of galanthamine [(-)-51] was attained by a novel strategy of remote asymmetric control of intramolecular Michael addition of phenolic hydroxyl group to the dienone moiety. Moreover, epibatidine [(-)-42] was synthesized by using the Diels-Alder reaction, of which the dienophile, chiral allene dicarboxylate, was prepared by asymmetric crystallization. Finally, the first synthesis of naturally occurring form of dichroanal B (71), dichroanone (72), and taiwaniaquinone H (73) were achieved by using intramolecular asymmetric Heck reaction.

The title compound, Na 6 H 3 [SmW 10 O 36 ].28H 2 O, coexists of a decatungstosamarate anion, six fivefold- or sixfold-coordinated Na + cation and water molecules of crystallization. The decatungstosamarate anion is comprised of two [W 5 O 18 ] 6- moieties chelating to a central Sm 3+ cation, which has tetragonal antiprismatic coordination with D 4 symmetry and Sm-O distances of 2.41-2.46 A

The decatungstogadolinate anion in the title compound, Na 8 H[GdW 10 O 36 ].30H 2 O, has approximately D 4d symmetry, with Gd-O and W-O distances of 2.39(2)-2.42(2) A and 1.69(2)-2.34(2) A, respectively

The thermolysis of N-t-alkyl-, and N-aryl-(2,2-dichlorocyclopropyl)methyleneamines yielded directly 1-t-alkyl, and 1-aryl-3-chloropyrroles as the major products along with a slight amount of the 2-chloro isomers. The transformation to the 3-chloropyrroles was enhanced in polar solvents. But basic additives directed the thermal rearrangement into the 1,2-bond cleavage of the cyclopropane ring, leading to the 2-chloropyrroles. On the other hand, (difluorocyclopropyl)methyleneamines were pyrolyzed exclusively to 3-fluoropyrroles under 1,3-bond cleavage. The ionic mechanism involving a heterolytic dissociation of chlorine atom under 1,3-bond scission of the cyclopropane ring is proposed for the rearrangement to 3-chloropyrroles, while a homolytic cleavage pathway is proposed for 3-fluoropyrroles. The present thermolysis supplies a unique preparative tool for 2-, and 3-halo-4-phenylpyrrole derivatives.

The structure of bis(hexaaquasamarium) octamolybdate hexahydrate, Sm 2 (H 2 O)H 2 [Mo 8 O 27 ].6H 2 O, consists of [(Mo 8 O 27 ) 6− ]∞ chains supported by hydrated Sm 3+ cations. Sm 3+ has tricapped trigonal prismatic coordination with Sm-O distances of 2.38-2.66 A. Mo-O distances in the octamolybdate unit are 1.68-2.49 A

Reaction of [(n-C4H9)4N]4[Mo8O26] with nitrate salts of rare earth metals yields two different series of new compounds [Ln(Mo8O26)2]5- and [{Ln(NO3)3}2(Mo8O26)]4- (Ln = Y, La, Ce, Pr, Nd, Gd, Yb) as tetra-n-butylammonium salts. X-ray structural analyses of [(n-C4H9)4N]5[La(Mo8O26)2]·CH3CN [monoclinic, space group P21/c, a = 25.8332(6) A, b = 17.5054(7) A, c = 32.6565(12) A, β = 91.699(2)°, Z = 4] and [(n-C4H9)4N]4[{La(NO3)3}2(Mo8O26)]·2CH3CN [monoclinic, space group P21/n, a = 17.702(2) A, b = 17.2646(12) A, c = 18.965(2) A, β = 102.132(3)°, Z = 2] revealed that these compounds contain the Mo8O26 unit as their building block.

Five new quassinoids, named vilmorinines B-F, have been isolated from the cortex of Ailanthus vilmoriniana. Their structures were established by various spectroscopic methods.

During an investigation of drugs for improving the β-cell response to glucose, we found that 4-cyclohexyl-4-oxobutyric acid selectively improved glucose-stimulated insulin release and glucose tolerance in both normal and diabetic rats. A series of 4-cycloalkyl-4-oxobutyric acids and related compounds were synthesized and evaluated for their effects on the glucose tolerance test and fasting euglycemia. This study elucidated the structural requirements for drug activity and determined that the optimum compound was 4-(trans-4-methylcyclohexyl)-4-oxobutyric acid 7 (JTT-608). This compound improved glucose tolerance from an oral dose of 3 mg/kg and did not change fasting euglycemia even at an oral dose of 30 mg/kg. Selective improvement of glucose-induced insulin secretion was observed in studies using neonatal streptozotocin rats (nSTZ rats) and perfused pancreases isolated from nSTZ rats.

4-Aza-2,3-dehydro-4-deoxypodophyllotoxin analogues 3a-n were synthesized through quinolines 2a-n. Comparison of their cytotoxicity against P-388 leukemia cells revealed that the steric effects of the ring B substituents on the activity are greater than the electronic effects, while the presence of a methoxy group on the ring E is not essential to exhibit potent cytotoxicity. Analogues 3a and 3b proved to be more than twice as cytotoxic as natural podophyllotoxin (1).

We synthesized flavin-containing PNA monomer unit 5 from lumiflavin and prepared PNAs containing a flavin moiety (FPNA) by the standard t Boc chemistry. Each PNA oligomer was purified by reversed-phase HPLC and characterized by MALDI-TOF MS and UV spectra. Thermodynamic analyses indicated that the PNA oligomer containing a flavin moiety near the amino terminal considerably stabilized the PNA–DNA hybrids.

Novel octanor- and nonanor-triterpenoids, malabanones A (1) and B (2), which incorporate a unique tricyclo[4.3.1.01,6]decane unit in the structure, were isolated from the stem bark of Ailanthus malabarica DC. Their structures were elucidated by the analysis of spectral data. Compounds 1 and 2 were considered to be biosynthesized from ailanthol (3), which was also isolated from this plant.

The synthesis of the abeo-abietane-type diterpenoids, i.e., (−)-dichroanal B, (−)-dichroanone, and taiwaniaquinone H, was achieved by using the intramolecular asymmetric Heck reaction. Our synthetic routes required fewer steps and gave a much higher overall yield and ee within shorter steps than those for racemic and antipodal forms reported to date (10, 12, and 13 steps with an overall yield of 50%, 40%, and 39%, and 94%, 98%, and 98% ee, respectively).

The reductive Mg-promoted defluorinative-silylation of 2,2,3,3,3-pentafluoropropiophenone readily produces the α-trifluoromethyl enol silyl ether, which then react with electrophiles to give a variety of 2-substituted-3,3,3-trifluoropropiophenones in excellent yields. The same protocol is applicable for the preparation of enol silyl ether of 3,3,3-trifluoropropiophenone. Fluoride ion catalyzed 1,2-desilylative-defluorination of 2,3,3,3-tetrafluoro-2-trimethylsilyloxypropiophenone provided 3,3,3-trifluoro-1-phenyl-1,2-propanedione in a good yield.

Demethylation of N-methyl group in N-methyl-N-arylmethyl-α-amino esters was accomplished by the oxidation of the amino group using the N-iodosuccinimide (NIS)/acetonitrile system followed by treatment with O-methylhydroxylamine hydrochloride. This combination of reagents could provide a complementary method to catalytic hydrogenolysis, which certainly cleaves N-arylmethyl groups, in organic synthesis.

Enantioselective nucleophilic addition of Grignard reagents to N-(2-pyridylsulfonyl)imines in the presence of bis(oxazoline) afforded products with good enantioselectivity. Dynamically induced chirality on the sulfur by coordination of a chiral Lewis acid to a pyridyl nitrogen and one of the sulfonyl oxygens fixes the conformation of the complex and induces enantioselectivity. Since the 2-pyridylsulfonyl group can be easily removed after the addition reaction, it acts not only as a protecting group but also as an efficient stereocontroller.

A new molecular oxide, [(IMo(7)O(26))(2)](6)(-), that has a self-contained structure has been synthesized. Its structural relevance both to the rutile structure and several molecular oxides that had been classified as "strange ones with odd structures" has given some insights as to why those species assume such structures. The novel yet self-contained nature of the structure suggests the existence of a new class of molecular oxides of related structures.