Crystal structure of 4,4″-dinitro-[3,3′,4′,3″]-tris-[1,2,5]-oxadiazole

The crystal structure of a new energetic compound of 4,4″-dinitro-[3,3′:4,3″]-tris-[1,2,5]-oxadiazole is studied.     

Synthesis and some chemical characteristics of 4″-nitro-3,3′:4′,3″-ter-1,2,5-oxadiazol-4-amine

A convenient preparation method was developed for 4″-nitro-3,3′:4′,3″-ter-1,2,5-oxadiazol-4-amine by substituting one nitro group of 4,4″-dinitro-3,3′:4′,3″-ter-1,2,5-oxadiazole at treating with equivalent quantity of ammonia in solvents of low polarity. In the reaction of the obtained amino-nitro derivative with N- and О- nucleophiles depending on the reaction conditions and the nucleophile nature either substitution of the nitro group occurs for the nucleophile residue to form 4″-alkoxy-, azido-, hydraznyl- or mono- and dialkylamino-[3,3′;4′,3″]-ter(1,2,5-oxadiazol)-4-ylamines, or the compound suffers an intramolecular cyclization affording 7Н-tri-1,2,5-oxadiazolo[3,4-b:3′,4′-d:3″,4″-f]azepines.     

Complexation of titanium(IV) with a new reagent, 2,3,4-trihydroxy-3′-nitro-4′-sulfoazobenzene

A new reagent, 2,3,4-trihydroxy-3′-nitro-4′-sulfoazobenzene (H ₃ L) is synthesized and studied. The dissociation constants of the reagent are determined by potentiometric titration: $ pK_{a_1 } $ = 4.52 ± 0.02; $ pK_{a_2 } $ = 6.29 ± 0.05, and $ pK_{a_3 } $ = 6.60 ± 0.21. The reaction of Ti(IV) with H₃L in the presence and absence of Triton X-114 (Tr) gives monoand mixed-ligand complexes, with λ_max = 445 nm and λ_max = 435 nm, respectively, at pH 4.5; the stability constants of the complexes Ti(OH)₂(H₂L)₂ and Ti(H₂L)₂(Tr) are logβ₁₂ = 8.51 ± 0.04 and logβ₁₂ = 10.72 ± 0.05, respectively. The mono(1: 2) and mixed-ligand (1: 2: 2) complexes obey the Beer law in the Ti(IV) concentration ranges 0.10–3.10 and 0.10–1.34 μg/mL, respectively. The effects of foreign ions and masking agents on the determination of Ti(IV) with the new reagent are studied. A procedure is developed for the photometric determination of Ti(IV) in soil samples selected at the Surakhany production field.     

Synthesis of New Pyrido[4″,3″:4″,5″]thieno[2″,3″:4,5]pyrimido[2,1-b][1,3,4]thiadiazine Derivatives

Ethyl 2-methyl-11-oxo-9, 10-dihydro-1 H , 11 H -pyrido[4",3":4',5']thieno[2',3':4,5]pyrimido[2,1-b][1,3,4]thiadiazine-8(7 H )-carboxylate 7 has been synthesised by the reaction of ethyl 3-amino-4-oxo-2-thioxo-1,3,4,5,6,8-hexahydropyrido[4',3':4,5]thieno[2,3-d]pyrimidine-7(2 H )-carboxylate 2 with allylbromide followed by treatment with bromine and subsequent dehydrobromination of the brominated product 5 with ethanolic sodium hydroxide. Its isomeric ethyl 2-methyl-11-oxo-9,10-dihydro-3 H ,11 H -pyrido[4",3Prime;:4',5']thieno[2',3':4,5]pyrimido[2,1-b][1,3,4]thiadiazine-8(7 H )-carboxylate 8 has been obtained by condensation of 2 with chloroacetone followed by cyclization of the intermediate 9 with p -toulenesulfonic acid. The thiadiazino derivatives 11 , 13 , 15 were prepared through the reaction of 2 with the appropriate f -halocarbonyl compounds followed by cyclization reactions of the intermediates 10 , 12 , 14 .     

A New Short Synthesis of 3, 3′-Methylene Bis[Coumarins] and 3,3-Methylene Bis[2-Diethylaminoquinolines]

Hitherto unknown six symmetrically and unsymmetrically substituted methylene bis(coumarins) and two methylene bis(quinolines) are synthesised by using 1:2 complex of N, N, N', N'-tetraethyl glutaramide with POCl₃ and its condensation with substituted salicyl-aldehydes and o-formyl acetanilides.     

A series of multidimensional MOFs incorporating a new N-heterocyclic building block: 5,5′-Di(pyridin-3-yl)-3,3′-bi(1,2,4-triazole)

Using the N-heterocyclic building block 5,5′-di(pyridin-3-yl)-3,3′-bi(1,2,4-triazole) (3,3′-H₂dbpt), four 3-D coordination polymers with diverse connectivity, [M(3,3′-dbpt)]_n, M=Co (1), M=Ni (2), M=Zn (3), and [Cd₂(3,3′-dbpt)Cl₂]_n (4), were constructed. By changing the central metal ions, 3,3′-H₂dbpt had three different coordination modes. Consequently, 1–3, which are isostructural, have a 3-D 4-connected topology with (4².8⁴) Schläfli symbol. 4 has a 3-D (4, 6)-topology, with (4³.6³)₂(4⁶.6⁶.8³) Schläfli symbol. Both 1 and 2 reveal weak antiferromagnetic behavior. In addition, 3 and 4 exhibit purple and blue emission bands, respectively. These results indicate that 3,3′-H₂dbpt is an excellent multi-connection linker to construct MOFs with interesting structures and properties.     

3,3′-bis(dipyrrolylmethenes) as new chelating ligands: Synthesis and spectral properties

Hydrobromides of three new alkyl-substituted tetrapyrrole ligands with an open chain, in which the dipyrrolylmethene fragments are linked by a CH₂-spacer at the 3,3′-pyrrole carbon atoms, were synthesized and studied by IR, ¹H NMR, and electronic absorption spectroscopy. As compared to the 2,2′ isomers (alkyl derivatives of biladiene-a,c) and monomers (2,2′-, 2,3′-, and 3,3′-dipyrrolylmethenes, the effect of structural factors is manifested in a considerable (up to 19–31 nm) bathochromic shift of the strong band in the electronic spectrum, an increase in the N-H stretching vibration frequency in the IR spectra (by more than 30 cm^?1), and a decrease in the stability of 3,3′-bis(dipyrrolylmethene) salts. The solvent effect is manifested in small changes in the quantitative characteristics of the electronic absorption spectra of 3,3′-tetrapyrrole hydrobromides in C₆H₆, CCl₄, CH₂Cl₂, CHCl₃, and alcohols. In DMF, DMSO, and C₅H₅N, the salts undergo solvolytic dissociation to the free ligands and HBr, which accelerates in dilute solutions (<10^?4 M) and with an increase in the electron-donor power of the solvent. The auxochromic effects of protons in the electronic absorption spectra of the salts, compared to ligands, were estimated quantitatively.     

Synthesis of dihydro-10H-pyrano[3′,4′: 5,6]pyrido[3,2:4″,5″]-thieno[3″,2″-d][3,1]oxazines and pyrimidines

Convenient methods have been developed for synthesizing dihydro-10H-pyrano[3,4:5,6]-pyrido[3,2:4,5]thieno[3,2-d][3,1]-oxazines and -pyrimidines. Optimum conditions have been established for the chlorodeoxygenation of condensed thieno-pyrimidin-4-ones.A. L. Mndzhoyan Institute of Fine Organic Chemistry, Armenian Academy of Sciences, Yerevan, 375014. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 250–253, February, 1995. Original article submitted November 15, 1994.     

Structure of a new compound synthesized by microwave heating: [H3N(CH2)6NH3)]·AlF5

A new hybrid material was synthesized by the microwave route from a mixture of Al₂O₃/HF/1,6 diaminohexane/EtOH. The structure of the hybrid fluoroaluminate, determined by single crystal X-ray diffraction, reveals a [H₃N(CH₂)₆NH₃]·AlF₅ formulation and a monoclinic symmetry with the space group P2₁, with a=7.898(1) Å, b=5.514(1) Å, c=12.672(3) Å, β=103.69(2)°, V=536.2(2) ų and Z=2. The unit cell contains infinite inorganic chains of [AlF₆] corner-sharing octahedra, linked each other by hexanediammonium cations.     

[Re(η2-CS3)4]3−, a new trithiocarbonate-containing rhenium(V) dodecahedral anion

The mononuclear complex (NMe₄)₃[Re(²-CS₃)₄] has been prepared by adding CS₂ to ReS^– ₄ in a mixture of MeOH and NH₃. During the reaction, Re^VII is reduced to Re^V, the measured diamagnetism (X = –3.04 × 10^–4cm³mol^–1) of the complex showing that the two added electrons are coupled. (NMe₄)₃[Re(²-CS₃)₄] crystallizes in the space group Fddd, a = 11.985(4) Å, b = 23.001(11) Å, c = 47.463(19) Å, V = 13085(9) ų. The reaction of CS₂ results in the formation of trithiocarbonates bonded to the rhenium in a dodecahedral geometry.     

Physical properties of a new iron(III) complex, [3-pmH · 3-pm][Fe(NCS)4(3-pm)2]

The iron(III) compound of formula [3-pmH · 3-pm][Fe(NCS)₄(3-pm)₂] (3-pm = 3-(hydroxymethyl)pyridine) has been prepared by reaction between iron(III) thiocyanate and 3-(hydroxymethyl)pyridine in ethanol. The characterization was based on elemental analysis, infrared spectra and magnetic measurements. Single crystal X-ray diffraction methods show the monoclinic P2(1)/c space group with unit cell parameters: a = 12.295(3) Å, b = 15.854(3) Å, c = 16.880(3) Å, β = 100.12(3)° and Z = 4. The asymmetric unit of the title compound consists of [3-pmH · 3-pm]⁺ and [Fe(NCS)₄(3-pm)₂]^? held together by ionic interaction and a hydrogen bond interaction (O(68)–H(68) ··· O(78)). The central metal ion is octahedrally coordinated by six nitrogens, four from NCS^? form the equatorial plane and two from two 3-(hydroxymethyl)pyridines occupy axial positions. Magnetic susceptibility data in the temperature range 1.8–300 K show that iron(III) is high-spin S = 5/2(⁵ T _2g). Structural parameters and IR spectra of similar complexes are compared and discussed.     

Preparation,crystal structure,and thermal decomposition of an azide energetic compound [Cd(IMI)2(N3)2]n (IMI = imidazole)

Cadmium(II) imidazole (IMI) azide [Cd(IMI)₂(N₃)₂]_n (1) was synthesized using imidazole and azide, and was characterized by the elemental analysis and FTIR spectrum. The crystal structure was determined by X-ray single crystal diffraction, and the crystallographic data show that the crystal belongs to orthorhombic, Pba2 space group, α?=?10.780(4) Å, b?=?13.529(5) Å, and c?=?3.6415(12) Å. Its crystal density is 2.080?g·cm^–3. Cd(II) is a six-coordinate with six nitrogens from four imidazoles and two azides with μ–1,1 coordination. The thermal decomposition mechanism was determined based on differential scanning calorimetry (DSC) and thermogravimetry-derivative thermogravimetry (TG-DTG) analysis, and the kinetic parameters of the first exothermic process were studied using Kissinger’s method and Ozawa’s method, respectively. The energy of combustion, enthalpy of formation, critical temperature of thermal explosion, entropy of activation (ΔS ^≠), enthalpy of activation (ΔH ^≠), and free energy of activation (ΔG ^≠) were measured and calculated. In the end, impact sensitivity was also determined by standard method.     

Synthesis,Crystal Structure,and Cytotoxic Property of Di(μ1’’,1’’-azide)bis(4-nitro-2-(3'-dimethylamino- n-propylimino)methylenephenolate)dizinc(Ⅱ)

The title azide-bridged dinuclear Schiff base zinc(II) complex [Zn2(C12H16N3O3)2- (μ1,1-N3)2] was prepared and characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 8.736(2), b = 14.850(3), c = 11.775(2) , β = 102.42(3)o, V = 1491.8(5) 3, Z = 2, Dc = 1.593 g/cm3, Mr = 715.36, λ(MoKα) = 0.71073 , μ = 1.669 mm-1, F(000) = 736, the final R = 0.0338 and wR = 0.0789. A total of 3411 unique reflections were collected, of which 2777 with I > 2σ(I) were observed. The molecule of the complex is located on a crystallographic inversion centre. Each Zn atom in the complex is five-coordinated by one Schiff base ligand and two bridging azide groups, forming a trigonal bipyramidal configuration. The Zn···Zn distance is 3.328(2) . In the crystal structure, molecules are linked through intermolecular C–H···N hydrogen bonds, forming layers parallel to the bc plane. The complex shows low cytotoxic property to both normal and carcinoma cells.     

Bis(4-benzhydryl-benzoxazol-2-yl)methane – from a Bulky NacNac Alternative to a Trianion in Alkali Metal Complexes

A novel sterically demanding bis(4-benzhydryl-benzoxazol-2-yl)methane ligand 6 (^4−BzhH2BoxCH₂) was gained in a straightforward six-step synthesis. Starting from this ligand monomeric [M(^4-BzhH2BoxCH)] (M=Na ( 7 ), K ( 8₁ )) and dimeric [{M(^4-BzhH2BoxCH)}₂] (M=K ( 8₂ ), Rb ( 9 ), Cs ( 10 )) alkali metal complexes were synthesised by deprotonation. Abstraction of the potassium ion of 8 by reaction with 18-crown-6 resulted in the solvent separated ion pair [{(THF)₂K@(18-crown-6)}{bis(4-benzhydryl-benzoxazol-2-yl)methanide}] ( 11 ), including the energetically favoured monoanionic (E,E)-(^4-BzhH2BoxCH) ligand. Further reaction of ^4−BzhH2BoxCH₂ with three equivalents KH and two equivalents 18-crown-6 yielded polymeric [{(THF)₂K@(18-crown-6)}{K@(18-crown-6)K(^4-BzhBoxCH)}]_n (n→∞) ( 12 ) containing a trianionic ligand. The neutral ligand and herein reported alkali complexes were characterised by single X-ray analyses identifying the latter as a promising precursor for low-valent main group complexes.     

Microwave Assisted Synthesis of 3,3',3″,3'″-o-,p-Phenylenedi-methylidinetetrakis-(4-hydroxy-2H-1-benzopyran-2-one)

Under microwave irradiation,2,2'-alkoxy-bridging or 4,4'-alkoxy-bridging dibenzaldehydes reacted with 4-hydroxycoumarin in DMF to give a series of 3,3',3″,3'″-o-and 3,3',3″,3'″-p-phenylenedimethylidinetetrakis-(4-hydroxy-2H-1-benzopyran-2-ones) in moderate yields.The structures of the synthetic coumarin derivatives were characterized with IR,1H NMR and MS spectroscopy as well as X-ray single crystallography.     

Synthesis of Novel 4β-(1, 2, 3-Triazol-1-yl) Podophyllotoxins as Potential Antitumor Drugs

The synthesis, characterization and in vitro antitumor activity of two novel podophyllotoxins, 4β-(5-methyl-1, 2, 3-triazol-1-y1)podophyllotoxin (5) and 4β-(5-phenyl-1, 2, 3-triazol-1-y1)podophyllotoxin (6), are described.     

Bis[2-(4′-Bromopyrazolyl-1′)-3-Tosylaminopyridinato]zinc(II): Synthesis,structure, and luminescence properties

2-(4′-Bromopyrazolyl-1′)-3-tosylaminopyridine (HL³) and its complex ZnL₂ (I) are synthesized, and their structures are studied by IR, UV, and ¹H NMR spectroscopy. The molecular structure of complex ZnL₂ is determined by X-ray diffraction analysis. The atomic structure of ZnL₂ is confirmed by the optimization of the molecular geometry using quantum-chemical calculations in the density functional theory approximation. The experimental bands in the absorption spectrum of complex I are interpreted on the basis of the calculations, and its photoluminescence properties are studied.     

3″,3″-二甲基吡喃[3’,4’]2,4,2’-三羟基查尔酮的首次全合成

以2,4-二羟基苯乙酮和2,4-二羟基苯甲醛为起始原料,经过C-异戊烯基化、保护酚羟基、羟醛缩合、去保护基反应首次成功地完成了天然产物3″,3″-二甲基吡喃[3’,4’]2,4,2’-三羟基查尔酮的全合成,总产率18.4%,其结构经1H NMR,IR和MS表征。中间体8未见文献报道。     

Synthesis of N,N′-bis[4-(1H-1,2,3-triazol-1-yl)furazan-3-yl]-methylenediamine derivatives

[3+2] Cycloaddition of azide groups of N,N′-bis(4-azidofurazan-3-yl)methylenediamine to 1,3-dicarbonyl compounds and malonodinitrile was shown to proceed regioselectively with the formation of the corresponding N,N′-bis[4-(1H-1,2,3-triazol-1-yl)furazan-3-yl]methylenediamine derivatives. The reactions of N,N′-bis(4-azidofurazan-3-yl)methylenediamine with cyanoacetic acid ethyl ester and amide led to the formation of the product of transformation of the azide group in the starting compound to the amino groups.     

Synthesis and Crystal Structure of a Dinuclear Complex: Bis[aqua(phen)(4-aba)copper(Ⅱ)nitrate(4-abaH)dihydrate]

The title complex has been obtained by the reaction of copper nitrate trihydrate with 4-abaH (4-abaH = 4-aminobenzonic acid) and phenanthroline in ethanol solution,and its structure was determined by X-ray crystallography with the following data: monoclinic,space group C2/c, Mr = 1266.13, Cu2C52H54N10O20, a = 25.884(5), b = 10.205(2), c = 20.849(4)(A), β= 106.34(3)°, Z = 4, V= 5284.7(18) (A)3, F(000) = 2616, Dc = 1.591 g/cm3, μ = 0.896 mm-1,the final R = 0.0441 and wR = 0.1148 for 4200 observed reflections (I ＞ 2σ(I)). In the molecule of the title complex, the asymmetric unit contains one half molecule. The Cu(Ⅱ) atom is five-coordinated by a terminal water molecule, a bidentate phenanthroline and two monodentate 4-aminobenzoate ligands forming a square pyramidal coordination environment. The two bridging 4-aminobenzoate ligands result in a dinuclear copper(Ⅱ) cluster with a short Cu-Cu distance (3.048 (A)) and a π-πstacking between the adjacent phenanthroline rings (2.96 (A)).