Study on the synthesis and crystal structure of tetrahyhrated tetraaquotris(4-mono-chloroacetylantipyrine)samarium (Ⅲ) perchlorate

Based on the phase equilibrium study of the system Sm(ClO4)3-4-monochloroace-tylantipyrine (C13H13ClN2O2)-H2O at 30℃, we have synthesized the title complex [Sm(C13H13Cl. N2O2)3(H2O)4](C1O4)3.4H2O. The single crystal structure analysis on RASA-IIS Rigaku diffrac-tometer shows that the coordination number of the metal ion is nine and the geometry of the complex is tricapped trigonal prism. Two of the three molecules of organic ligand act as bidentate chelated through both carbonyl oxygens to the metal ion, but the other one as a monodentate coordinated only through the ring carbonyl oxygen, the side chain carbonyl is far away from the central ion. The crystal is monoclinic, space group P21, a = 18.013(4), 6 = 14.709(3), c = 10.536(3) A, β=94.69(2)°, V=2782(1) A3, Z=2.     

De novo synthesis of the enantiomers Ins(1,2,3,4)P4 and Ins(1,2,3,6)P4—regiospecificity of their enzymatic dephosphorylation

The first total synthesis of Ins(1,2,3,4)P₄ and Ins(1,2,3,6)P₄ is presented. Starting from p-benzoquinone, we took advantage of the C₂-symmetry of conduritol-B intermediates. The target compounds were dephosphorylated by several enzymes, and the resulting InsP₃ isomers were identified. Some of these enzymatic conversions were found to be preparatively applicable and to allow the synthesis of Ins(1,2,3)P₃, Ins(2,3,6)P₃ and Ins(1,2,4)P₃.     

Regio- and stereoselective synthesis of 3- and 5-(C-glycosyl)-4-nitroisoxazolidines by nitrone–nitroalkene [3+2] cycloaddition reactions

Cycloaddition reactions of nitrones, including sugar nitrones, with nitroalkenes, including sugar nitroolefins, led with complete regioselectivity and stereospecificity to 4,5-trans-4-nitroisoxazolidines in 51–78% global yields. The endo/exo stereoselectivity depends on the type of sugar derivative used. As expected, the best π-diastereofacial selectivity was observed when both partners were sugar derivatives. Isomerisation of the first formed diastereomers by the action of silica gel was observed in some cases. Absolute configurations for two crystalline products were assigned by X-ray diffraction methods.     

Hydrothermal synthesis,structure and properties of a heteronuclear Co(III)–Ag(I) complex with the 2,6-pyridine-dicarboxlate

A new Ag/Co coordination polymer, [AgCo(PDC)₂] (1) (H₂PDC?=?2,6-pyridine-dicarboxylic acid) was synthesized under hydrothermal condition. X-ray crystallographic study reveals that 1 is a 2D network and has a previously unexplored coordination mode. Solid state fluorescence and thermogravimetric analysis (TGA) have been performed.     

Rh(I)-catalyzed [5+1] cycloaddition of vinylcyclopropanes and CO for the synthesis of α,β- and β,γ-cyclohexenones

A cationic Rh(I)-catalyzed [5 + 1] cycloaddition of vinylcyclopropanes and CO has been developed, affording either β,γ-cyclohexenones as major products or α,β-cyclohexenones exclusively, under different reaction conditions.     

One pot synthesis of α,α-bis(N-arylamido) lactams via iodide-catalyzed rearrangement of β,β-bis(N-arylamido) cyclic ketene-N,O-acetals

Five and six-membered cyclic ketene-N,O-acetals, generated in situ from 2,3-dimethyl-2-oxazolinium iodide or 2,3-dimethyl-2-oxazinium iodide and triethylamine, reacted with aryl isocyanates in refluxing THF producing α,α-bis(N-arylamido) lactams via the iodide-catalyzed rearrangement of β,β-bis(N-arylamido) cyclic ketene-N,O-acetal intermediates. The cyclic ketene-N,O-acetal generated in situ from 2,3,4,4-tetramethyl-2-oxazolinium iodide reacted with isocyanates to give β,β-bis(N-arylamido) cyclic ketene-N,O-acetals, which do not readily rearrange. The two methyls at C-4 hindered the nucleophilic attack of iodide on C-5, which is required for rearrangement.     

Base-promoted O-deprotonation/alkylation reaction of P(O)–OH compounds with alkyl halides

A novel base-promoted O-deprotonation/alkylation reaction of P(O)–OH compounds with alkyl halides has been developed. The protocol is practical, representing a simple way to produce a broad spectrum of functionalized phosphinates, phosphonates, and phosphates from basic starting materials with good to excellent yields. A plausible mechanism was proposed for this reaction.     

The design and synthesis of a novel organophosphorus compound containing the structure of both β-amino acid and β-aminophosphonate

<正>A novel organophosphorus compound containing the structure of bothβ-amino acid andβ-aminophosphonate is designed and synthesized.Arbuzov reaction with P(OEt)_3,the N-Boc protected iodide 3 cannot provide the desired product but 2-oxazolidinone 4 because of the neighboring-group participation of the Boc moiety.To avoid the intramolecular participation of the carbamates,the Ts protecting group is employed and the Ts-protected iodide 5 affords the target product successfully.     

Total synthesis and structure confirmation of the annonaceous acetogenins 30(S)-hydroxybullatacin,uvarigrandin a,and 5(R)-uvarigrandin a (narumicin I?)

A synthesis of the bistetrahydrofuran Annonaceous acetogenins 30(S)-hydroxybullatacin, uvarigrandin A, and 5(R)-uvarigrandin A through application of a previously disclosed four-component modular approach is described in which extended core segments are coupled to a C4- or C5-hydroxy butenolide terminus. The butenolide termini segments were prepared from (S)- or (R)-malic acid. Spectral properties of synthetic 30(S)-hydroxybullatacin and uvarigrandin A, as well as their Mosher ester derivatives, were in close agreement to the reported values for the natural substances. The synthetic 5(R)-uvarigrandin A is possibly identical to narumicin I, but subtle differences in the reported NMR spectra prevented an unambiguous assessment of this point.     

Regio- and diastereoselective Reformatsky reaction of chiral fluoroalkyl α,β-unsaturated N-tert-butanesulfinyl ketimines: Efficient asymmetric synthesis of β-fluoroalkyl β-vinyl β-amino esters

Highly regio- and diastereoselective Reformatsky reaction of stable, chiral fluoroalkyl α,β-unsaturated N-tert-butanesulfinyl ketimines was developed, which provided an efficient method for the asymmetric synthesis of structurally diverse β-tetrasubstituted β-fluoroalkyl β-vinyl β-amino esters in good yields and with excellent diastereoselectivities (dr up to 96:4).     

Regio- and Diastereoselectivity in the Thiomethylation of α-(1-Hydroxyalkyl)acrylate Derivatives

The regio-and diastereoselectivity of reactions of selected α-(1-hydroxyalkyl)acrylate derivatives with sodium methanethiolate have been investigated. The hydroxy compounds typically undergo conjugate addition with up to 66% d.e., while the acetoxy and bromo analogues favour S_N' and S_N reactions, respectively.     

On the structure of the β-cyclodextrin inclusion complex with 4-acetoxy-1-(2-ethoxyethyl)-4-phenylpiperidine

Russian Chemical Bulletin - Specific features of the structure of the synthesized inclusion complex of 4-acetoxy-1-(2ethoxyethyl)-4-phenylpiperidine with β-cyclodextrin were considered. The...     

Investigations in the systems Sr–As–O–X (X = H,Cl): Preparation and crystal structure refinements of the anhydrous arsenates(V) Sr3(AsO4)2, Sr2As2O7, α- and β-SrAs2O6, and of the apatite-type phases Sr5(AsO4)3OH and Sr5(AsO4)3Cl

The previously uninvestigated atomic arrangements of six strontium arsenate(V) phases in the systems Sr-As-O-X (X = H, Cl) have been determined. Single crystals of Sr₃(AsO₄)₂ and Sr₅(AsO₄)₃Cl were grown from a borate and NaCl melt, respectively, whereas single crystals of α- and β-SrAs₂O₆ and of Sr₅-(AsO₄)₃OH were obtained under hydrothermal conditions. Microcrystalline samples of Sr₂As₂O₇ were prepared by solid-state reaction of As₂O₅ with SrCO₃ and, alternatively, by thermolysis of SrHAsO₄. Crystal structure determinations based on powder X-ray diffraction data using the Rietveld method (Sr₂As₂O₇), and from single-crystal X-ray diffraction data (all other phases) revealed isotypism with known structure types (except β-SrAs₂O₆ which represents a new structure type). Sr₃(AsO₄)₂ crystallizes in the K₂Pb(SO₄)₂ structure type; Sr₂As₂O₇ is isotypic with the high-temperature polymorphs of Ca₂P₂O₇ and Sr₂V₂O₇, but itself shows no polymorphism; Sr₅(AsO₄)₃OH and Sr₅(AsO₄)₃Cl crystallize with the hydroxylapatite and chloroapatite structure, respectively; SrAs₂O₆ is dimorphic. Like all other known M^IIAs₂O₆ metaarsenates (M = Mn, Co, Ni, Sr, Pd, Cd, Hg, Pb), the α-polymorph crystallizes in the PbSb₂O₆ structure type, whereas the novel β-polymorph is the first example of a M^IIAs₂O₆ superstructure with a doubled c-axis. Additional analytical methods using Raman spectroscopy and thermal analyses support the results of the X-ray structure work.     

Synthesis of volatile copper(II) β-diketonates, β-ketiminates, and β-diiminates. The problem of synthesis of copper(II) Bis(2,2,6,6-tetramethyl-3-methylaminoheptane-5-onate)

The methods of synthesis of the copper(II) β-diketonates, β-ketiminates, and β-diiminates containing in the composition CH₃, CF₃, C(CH₃)₃, and Ph substituents were summarized. At the formation of metallocycles with 2,2,6,6-tetramethyl-3-methylaminoheptane-5-one ligand the intraligand repulsion of tret-butyl group and the methyl group at the nitrogen atom is noted, impeding the complexation.     

Thermodynamic model and structure of CaO–P2O5 glasses

The distribution of Q-units of CaO–P₂O₅ glasses was described by the thermodynamic model of Shakhmatkin and Vedishcheva. The glass was considered as the ideal solution of CaO, P₂O₅, CaP₂O₆, Ca₂P₂O₇, and Ca₃P₂O₈. In the first step, molar Gibbs energies of considered species were taken from the FACT thermodynamic database. The obtained result was compared with ³¹P solid-state NMR study of Roiland. It was shown that the calculated values were in fairly good agreement with the experimental values. After that, the nonlinear regression treatment was used for optimization of molar Gibbs energies by minimizing the sum of squares of deviations between experimental and calculated Q-distribution. In such a manner, the non-ideality of the system was reflected. In the studied case, no significant improvement of obtained results was achieved by this procedure—thus, the ideal solution assumption included in the thermodynamic model of Shakhmatkin and Vedishcheva holds very well for the studied binary glasses.     

Structures,electronic and magnetic properties of the FexNy (x = 1–4, y = 1–4) adsorbed graphene

Research on Chemical Intermediates - The structures, electronic and magnetic properties of the FexNy (x?=?1–4, y?=?1–4) molecules adsorbed graphene have been...     

Syntheses, structure, and a Mössbauer and magnetic study of Ba(4)Fe(2)I(5)S(4)

The compound Ba4Fe2I5S4 has been prepared at 1223-1123 K by the "U-assisted" reaction of FeS, BaS, S, and U with BaI2 as a flux. A more rational synthesis was also found; however, the presence of U appears to be essential for the formation of single crystals suitable for X-ray diffraction studies. Ba4Fe2I5S4 crystallizes in a new structure type with two formula units in space group I4/m of the tetragonal system. The structure consists of a Ba-I network penetrated by (1)infinity[Fe2S4] chains. Each Fe atom, which is located on a site with 4 symmetry, is tetrahedrally coordinated to four S atoms. The FeS4 tetrahedra edge-share to form linear (1)infinity[Fe2S4] chains in the [001] direction. The Fe-Fe interatomic distance in these chains is 2.5630(4) A, only about 3% longer than the shortest Fe-Fe distance in -Fe metal. Charge balance dictates that the average formal oxidation state of Fe in these chains is +2.5. The M?ssbauer spectra obtained at 85 and 270 K comprise a single quadrupole doublet that has hyperfine parameters consistent with an average Fe oxidation state of +2.5. The M?ssbauer spectrum obtained at 4.2 K consists of a single magnetic sextet with a small hyperfine field of -15.5 T. This spectrum is also consistent with rapid electron delocalization and an average Fe oxidation state of +2.5. The molar magnetic susceptibility of Ba4Fe2I5S4, obtained between 3.4 and 300 K, qualitatively indicates the presence of weak pseudo-one-dimensional ferromagnetic exchange within a linear chain above 100 K and weak three-dimensional ordering between the chains at lower temperatures.