Synthesis of 2,3-dihydro-1H-pyrroles by intramolecular cyclization of N-(3-butynyl)-sulfonamides.

Hydroamination of 3-butynamine derivatives to give non-aromatic 2,3-dihydropyrroles was achieved by using PdCl2 or AuCl as the catalyst. With microwave-assisted heating, up to 92% isolated yield was obtained from this intramolecular 5-endo-dig cyclisation. The cyclopentane- and cyclohexane-fused 2,3-dihydropyrroles were transformed into the corresponding N-tosyl-pyrrolidine-2-carboxylic acids.

Titanosilicates with Strong Phase-Matched Second Harmonic Generation Responses.

The search for new and efficient nonlinear optical (NLO) materials has been an active research because of their technological importance in laser applications. Although a large number of frequency-doubling oxides, phosphates, borates, and fluoride-containing borates were found, no transition-metal silicate with useful NLO properties has been reported. We have now synthesized and grown crystals of two new titanosilicates, Li2K4[(TiO)Si4O12] and Li2Rb4[(TiO)Si4O12], by using a flux and supercritical hydrothermal method. Their unique 3D framework structures contain highly compressed TiO5 square pyramids which are arranged one over the other to form infinite ···Ti-O···Ti-O straight chains with alternating short and long Ti-O distances. These two materials meet the requirements for efficient second harmonic generation including lack of center of inversion symmetry, large susceptibility, phase matching, transmitting at wavelengths of interest, resistant to laser damage, and thermally stable. These attributes make them very attractive for frequency-doubling materials.

K2Ca4[(UO2)(Si2O7)2]: A Uranyl Silicate with a One-Dimensional Chain Structure.

A new uranyl silicate, K2Ca4[(UO2)(Si2O7)2], with a 1D chain structure has been synthesized from a solution of mixed alkali- and alkaline-earth-metal cations under hydrothermal conditions at 550 °C and 1400 bar and characterized by single-crystal X-ray diffraction and photoluminescence spectroscopy. It crystallizes in the triclinic space group P1̅ (No. 2) with a = 6.6354(2) Å, b = 6.6791(2) Å, c = 9.6987(3) Å, α = 98.324(2)°, ß = 93.624(2)°, γ = 112.310(2)°, and Z = 1. Its crystal structure consists of a 1D chain of uranyl disilicate formed of corner-sharing UO6 tetragonal bipyramids and Si2O7 double groups. The adjacent chains are separated by K(+) and Ca(2+) cations. It is the first example of uranyl silicate with a 1D chain structure.

High-temperature, high-pressure hydrothermal synthesis, characterization, and structural relationships of layered uranyl arsenates.

Five new uranyl arsenates, Na14[(UO2)5(AsO4)8]·2H2O (1), K6[(UO2)5O5(AsO4)2] (2a), K4[(UO2)3O2(AsO4)2] (2b), Rb4[(UO2)3O2(AsO4)2] (3), and Cs6[(UO2)5O2(AsO4)4] (4), were synthesized by high-temperature, high-pressure hydrothermal reactions at about 560 °C and 1440 bar and were characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and photoluminescence spectroscopy. Crystal data for compound 1: triclinic, P1, a = 7.0005(3) Å, b = 12.1324(4) Å, c = 13.7428(5) Å, α = 64.175(2)°, ß = 89.092(2)°, γ = 85.548(2)°, V = 1047.26(7) Å(3), Z = 1, R1 = 0.0185; compound 2a: monoclinic, P21/c, a = 6.8615(3) Å, b = 24.702(1) Å, c = 7.1269(3) Å, ß = 98.749(2)°, V = 1193.89(9) Å(3), Z = 2, R1 = 0.0225; compound 2b: monoclinic, P21/c, a = 6.7852(3) Å, b = 17.3640(8) Å, c = 7.1151(3) Å, ß = 98.801(3)°, V = 828.42(6) Å(3), Z = 2, R1 = 0.0269; compound 3: monoclinic, P21/m, a = 6.9783(3) Å, b = 17.4513(8) Å, c = 7.0867(3) Å, ß = 90.808(3)°, V = 862.94(7) Å(3), Z = 2, R1 = 0.0269; compound 4: triclinic, P1, a = 7.7628(3) Å, b = 9.3324(4) Å, c = 11.9336(4) Å, α = 75.611(2)°, ß = 73.136(2)°, γ = 86.329(2)°, V = 801.37(5) Å(3), Z = 1, R1 = 0.0336. The five compounds have layer structures consisting of uranyl square, pentagonal, and hexagonal bipyramids as well as AsO4 tetrahedra. Compound 1 contains chains of discrete uranyl square and pentagonal bipyramids, 2a contains three-polyhedron-wide ribbons of edge- and corner-sharing uranyl square and pentagonal bipyramids, 2b and 3 contain dimers of edge-shairing pentagonal bipyramids that share edges with hexagonal bipyramids to form chains, and 4 contains one-polyhedron-wide zigzag chains of edge-sharing uranyl polyhedra. The double sheet structure of 1 is new, but the chain topology has been observed in an organically templated uranyl sulfate. Compound 2b is a new geometrical isomer of the phosphuranylite group. The sheet anion topologies of 2a and 4 can be obtained by splitting the ß-U3O8-type sheet into complex chains and connecting the chains by arsenates.

Enhanced performance of benzothieno[3,2-b]thiophene (BTT)-based bottom-contact thin-film transistors.

Three new benzothieno[3,2-b]thiophene (BTT; 1) derivatives, which were end-functionalized with phenyl (BTT-P; 2), benzothiophenyl (BTT-BT; 3), and benzothieno[3,2-b]thiophenyl groups (BBTT; 4; dimer of 1), were synthesized and characterized in organic thin-film transistors (OTFTs). A new and improved synthetic method for BTTs was developed, which enabled the efficient realization of new BTT-based semiconductors. The crystal structure of BBTT was determined by single-crystal X-ray diffraction. Within this family, BBTT, which had the largest conjugation of the BTT derivatives in this study, exhibited the highest p-channel characteristic, with a carrier mobility as high as 0.22 cm(2) V(-1) s(-1) and a current on/off ratio of 1×10(7) , as well as good ambient stability for bottom-contact/bottom-gate OTFT devices. The device characteristics were correlated with the film morphologies and microstructures of the corresponding compounds.

High-temperature, high-pressure hydrothermal synthesis and characterization of a salt-inclusion mixed-valence uranium(V,VI) silicate: [Na9F2][(U(V)O2)(U(VI)O2)2(Si2O7)2].

A salt-inclusion mixed-valence uranium(V,VI) silicate, [Na9F2][(U(V)O2)(U(VI)O2)2(Si2O7)2], was synthesized under hydrothermal conditions at 585 °C and 160 MPa and structurally characterized by powder and single-crystal X-ray diffraction (XRD). The valence states of uranium were established by U 4f X-ray photoelectron spectroscopy (XPS). The structure contains two-dimensional (2D) sheets of uranyl disilicate with the composition [UO2Si2O7], which are connected by U(1)(V)O6 tetragonal bipyramids to form thick layers. The Na(+) cations are located at sites in the intralayer and interlayer regions. In addition to Na(+) cations, the interlayer region also contains F(-) anions such that infinite chains with the formula FNa1/1Na4/2 are formed. The same type of chain was observed in K2SnO3. The title compound is not only the first example of salt-inclusion metal silicate synthesized under high-temperature, high-pressure hydrothermal conditions, as well as the first salt-inclusion mixed-valence uranium silicate, but it is also the first mixed-valence uranium(V,VI) silicate in the literature. Crystal data: [Na9F2][(U(V)O2)(U(VI)O2)2(Si2O7)2], triclinic, P1 (No. 2), a = 5.789(1) Å, b = 7.423(2) Å, c = 12.092(2) Å, α = 90.75(3)°, ß = 96.09(3)°, γ = 90.90(3)°, V = 516.5(2) Å(3), Z = 1, R1 = 0.0241, and wR2 = 0.0612.

High-temperature, high-pressure hydrothermal synthesis, crystal structures, and spectroscopic studies of a uranium(IV) phosphate (Na10U2P6O24) and the isotypic cerium(IV) phosphate (Na10Ce2P6O24).

A uranium(IV) phosphate, Na10U2P6O24, was synthesized under hydrothermal conditions at 570 °C and 160 MPa and structurally characterized by single-crystal X-ray diffraction. The valence state of uranium was established by UV-vis and U 4f X-ray photoelectron spectroscopy. The powder sample has a second-harmonic-generation signal, confirming the absence of a center of symmetry in the structure. The structure contains UO8 snub-disphenoidal polyhedra that are linked to monophosphate tetrahedra by vertex and edge sharing such that a three-dimensional framework with intersecting 12-sided circular and rectangular channels is formed. All 10 sodium sites are situated inside the channels and are fully occupied. This is the first uranium(IV) phosphate synthesized under high-temperature, high-pressure hydrothermal conditions. The isotypic cerium(IV) phosphate, Na10Ce2P6O24, was also synthesized under the same hydrothermal conditions. It is the first structurally characterized Ce(IV) phosphate with a P/Ce ratio of 3. Crystal data of Na10U2P6O24: orthorhombic, P212121 (No. 19), a = 6.9289(3) Å, b = 16.1850(7) Å, c = 18.7285(7) Å, V = 2100.3(2) Å(3), Z = 4, R1 = 0.0304, and wR2 = 0.0522. Crystal data of Na10Ce2P6O24: orthorhombic, P2(1)2(1)2(1) (No. 19), a = 6.9375(14) Å, b = 16.215(3) Å, c = 18.765(4) Å, V = 2111.0(7) Å(3), Z = 4, R1 = 0.0202, and wR2 = 0.0529.

Synthesis of the decalin core of codinaeopsin via an intramolecular Diels-Alder reaction.

We describe the synthesis of the decalin core of codinaeopsin (1), a tryptophan-polyketide hybrid natural product with promising antimalarial activity (IC50 4.7 µM, against Plasmodium falciparum), via an intramolecular Diels-Alder (IMDA) reaction. A convergent synthesis was developed to prepare the precursors for the IMDA reaction in 10 steps. The exo cycloadducts were derived from thermal, IMDA reactions of the substrates containing a Weinreb amide or ester conjugated dienophile, and the endo adducts were from Lewis acid promoted reactions of the substrates with a formyl group. Both exo and endo products of the IMDA were exclusively isolated and characterized by NMR spectroscopy. One endo cycloadduct was further confirmed with X-ray crystallography. Theoretical calculations reveal the influence of the substituents of the decalin core on the IMDA process.

Risk of primary Sjogren's Syndrome following human papillomavirus infections: a nationwide population-based cohort study.

Introduction: Viral infection is an exogeneous factor for primary Sjogren's syndrome (pSS). This study investigated the association between human papillomavirus (HPV) infections and pSS through a nationwide population based cohort study. Methods: Patients with HPV infections between January, 1999 and December, 2013 were included. The incidence of new-onset pSS in patients with HPV infections and non-HPV controls were derived. The multiple Cox regression model derived the risk of pSS in patients with HPV infections. Subgroup analysis and sensitivity analysis were performed to validate the association. Results: During a follow-up period of 12 years, the adjusted hazard ratio (aHR) of pSS in patients with HPV infections was significantly higher than that in non-HPV controls (aHR=1.64, 95% CI=1.47-1.83, P<0.001). The risk of pSS increased with age and the risk increased by 2.64-fold (95% CI= 2.37-2.93) for those older than 45 years. The significant association between HPV infections and the risk of pSS persisted in the sensitivity analysis restricted in HPV infections that lasted over 12 months (aHR=1.63, 95%CI=1.45-1.83, P<0.0001). Subgroup analyses revealed that both male (aHR=1.83, 95%CI=1.47-2.28, P<0.0001) and female (aHR=1.58, 95%CI=1.40-1.79, P<0.0001) patients with HPV infections and HPV-infected patients aged between 16 and 45 years (aHR=1.60, 95%CI=1.34-1.91, P<0.0001) and over 45 years (aHR=1.67, 95%CI=1.46-1.91, P<0.0001) were associated with a significantly greater risk of pSS. Conclusion: Patients with HPV infections presented with a significantly higher risk of pSS, regardless of age and sex.

High-temperature, high-pressure hydrothermal synthesis and characterization of an open-framework uranyl silicate with nine-ring channels: Cs2UO2Si10O22.

A new uranium(VI) silicate, Cs(2)UO(2)Si(10)O(22), has been synthesized by a high-temperature, high-pressure hydrothermal method and characterized by single-crystal X-ray diffraction, luminescence, and solid state NMR spectroscopy. It crystallizes in the monoclinic space group P2(1)/c (No. 14) with a = 12.2506(4) Å, b = 8.0518(3) Å, c = 23.3796(8) Å, ß = 90.011(2)°, and Z = 4. Its structure consists of silicate double layers in the ab plane which are connected by UO(6) tetragonal bipyramids via four equatorial oxygen atoms to form a 3D framework with nine-ring channels parallel to the b axis where the Cs(+) cations are located. The photoluminescence emission spectrum at room temperature consists of one broad structured band which is typical of uranyl. The (29)Si MAS NMR spectrum is consistent with the crystal structure as determined from X-ray diffraction, and the resonances in the spectrum are assigned. A comparison of related uranyl silicate structures is made.

Cs8U(IV)(U(VI)O2)3(Ge3O9)3·3H2O: a mixed-valence uranium germanate with 9-ring channels.

A mixed-valence uranium(IV,VI) germanate has been synthesized under high-temperature, high-pressure hydrothermal conditions. The structure contains discrete U(IV)O(6) octahedra and U(VI)O(6) tetragonal bipyramids, which are connected by three-membered single-ring Ge(3)O(9)(6-) anions to form a three-dimensional framework with 9-ring channels. The U 4f X-ray photoelectron spectroscopy spectrum was measured to identify the valence states of the uranium.

Gastric foreign body: a comb.

The ingestion of a foreign body is a common occurrence. Psychiatric patients and prisoners may swallow objects on purpose. Occasionally emergent exploratory laparotomy may be indicated if the diagnosis is uncertain, and emergent removal of the foreign body may be needed to prevent substantial risk of serious complications including perforation, fistula, or gastrointestinal bleeding.

Anti-addition of Dimethylsulfoxonium Methylide to Acyclic α,ß-Unsaturated Ketones and Its Application in Formal Synthesis of an Eicosanoid.

Cyclopropanation using dimethylsulfoxonium methylide (Corey-Chaykovsky reaction) was examined with a series of linear α,ß-unsaturated ketones, and the results showed that the major trajectory for the addition of the sulfur ylide to the enones is anti, related to the γ-substituent. The stereochemical assignment for the generated cyclopropanes was achieved by X-ray crystallography or comparing with the reported spectroscopic data. We found that the diastereoselectivity was influenced by several factors, including the protecting groups, solvents, and temperatures, and good anti/syn ratios (>10:1) were often obtained using the tert-butyldimethylsilyl and tert-butyldiphenylsilyl-protected substrates. The method was applied to a formal synthesis of a natural eicosanoid with good efficiency.

Intramolecular Locked Dithioalkylbithiophene-Based Semiconductors for High-Performance Organic Field-Effect Transistors.

New 3,3'-dithioalkyl-2,2'-bithiophene (SBT)-based small molecular and polymeric semiconductors are synthesized by end-capping or copolymerization with dithienothiophen-2-yl units. Single-crystal, molecular orbital computations, and optical/electrochemical data indicate that the SBT core is completely planar, likely via S(alkyl)⋯S(thiophene) intramolecular locks. Therefore, compared to semiconductors based on the conventional 3,3'-dialkyl-2,2'-bithiophene, the resulting SBT systems are planar (torsional angle <1°) and highly π-conjugated. Charge transport is investigated for solution-sheared films in field-effect transistors demonstrating that SBT can enable good semiconducting materials with hole mobilities ranging from ≈0.03 to 1.7 cm2 V-1 s-1 . Transport difference within this family is rationalized by film morphology, as accessed by grazing incidence X-ray diffraction experiments.

Asymmetric synthesis of (-)-brevipolide H through cyclopropanation of the α,ß-unsaturated ketone.

Brevipolides are 5,6-dihydro-γ-pyrone derivatives, first reported in 2004 as the inhibitors of the chemokine receptor CCR5 and exhibiting cytotoxicity against cancer cells. Starting from the C2 symmetric diene-diol 2, ent-brevipolide H was synthesized for the first time in 11 steps. The anti-addition of the sulfur ylide to the α,ß-unsaturated enones was developed to give the key cyclopropane moiety. The synthetic (-)-brevipolide H showed an IC50 value of 7.7 µM against PC-3 cells.

Hydrothermal synthesis of a three-dimensional organic-inorganic hybrid network formed by poly(oxomolybdophosphate) anions and nickel coordination cations.

A novel organic-inorganic hybrid nickel molybdenum(V) phosphate has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic susceptibility. The structure consists of poly(oxomolybdophosphate) anions linked by both Ni(II) cations and 4,4-bipyridine bridging ligands to form a three-dimensional open-framework structure with large cavities where the uncoordinated 4,4'-bipyridinium cations and lattice water molecules are located. This is the first example of an extended framework solid containing poly(oxomolybdophosphate) anions interconnected by both transition-metal complexes and organic moieties. Crystal data: (4,4'-H2bpy)[Ni(4,4'-bpy)(H2O)2Ni(0.5)Mo6(OH)3O12(HPO4)4].2H2O, orthorhombic, space group Pccn (No. 56), a = 27.745(2) A, b = 16.158(1) A, c = 22.819(2) A, V =10230.3(1) A(3), and Z = 8.