[Hg3]4+ Cation in Inorganic Crystal Structures

The crystal-chemical structure of the minerals and inorganic compounds kuznetsovite [Hg₃](AsO₄)Cl and terlinguaite [Hg₃][HgO₂]Cl₂, as well as [Hg₃]₃(AsO₄)₄ and [Hg₃]₂[HgO₂](PO₂ and their analogs, is considered from the viewpoint of the packing of large supramolecular atomic groups. The cationic layer of polyhedra around the large [Hg₃]⁴⁺ cations, alternating with the anionic layer of [HgO₂]^2-, (AsO₄)^3-, (PO₄)^3-, Cl^-, plays the major role in structure formation. Segregation of mercury cations of different valences possibly reflects the solid-state transformations occurring in nature and accompanied by mercury liberation.     

Highly regioselective synthesis of trifluoromethyl derivatives of pyrazolo[1,5-a]pyrimidines bearing fused cycloalkane rings using (2-ethoxycycloalkenyl)-2,2,2-trifluoroethanones

8-Trifluoromethyl-6,7-dihydro-5H-1,4,8a-triaza-s-indacene and 9-trifluoromethyl-5,6,7,8-tetrahydropyrazolo[5,1-b]quinazolines were efficiently generated by condensation of 5(3)-aminopyrazoles with (2-ethoxycycloalkenyl)-2,2,2-trifluoroethanones and isolated in excellent yields. The regiochemistry of the prepared compounds was established by ¹H, ¹³C and ¹⁹F NMR spectroscopy and X-ray diffraction analysis.     

五元瓜环与钕离子在四氯酸锌离子诱导下构筑的配合超分子自组装

在四氯酸锌离子诱导下,五元瓜环能与钕离子构筑形成二维配合超分子自组装。在HCl介质中,Zn²⁺容易形成四氯酸锌离子,在其诱导作用下,钕离子和五元瓜环端口羰基氧直接配位形成二维超分子自组装体。结果表明锌离子作为一种结构导向剂在形成瓜环基超分子自组装体中起到重要作用。     

The Synthesis of 13C9-15N-Labeled 3,5-Diiodothyronine and Thyroxine

Thyroid hormones undergo extensive metabolism to regulate hormone activity. A labeled thyroid hormone would be useful to track hormone metabolism through various pathways. While radiolabeled thyroid hormones have been synthesized and used for in vivo studies, a stable isotope labeled form of thyroid hormone is required for studying thyroid hormone metabolism by LC-MS/MS, an analytical technique that has certain advantages without the complications of radioactivity. Here we report the synthesis of ¹³C₉-¹⁵N-T₂ and ¹³C₉-¹⁵N-T₄, two labeled thyroid hormone derivatives suitable for in vivo LC-MS/MS studies.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Cyclocondensation of N-aryl-3-oxobutanethioamides with 5-amino-3-R-4-R1-pyrazoles

The cyclocondensation products of N-aryl-3-oxobutanethioamides with 5-amino-3-R-4-R¹-pyrazoles are 4-(arylamino)-2-methyl-7-R-8-R¹-pyrazolo[1,5-a]pyrimidine and pyrazolo[1,5-a]pyrimidine-4-thione derivatives, the ratio of which depends on the nucleophilicity of the starting 5-amino-3-R-4-R¹-pyrazoles and the presence of a proton donor solvent. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1550-1555, October, 2008.     

The first quaternary lanthanide(III) nitride iodides: NaM4N2I7 (M=La-Nd)

In attempts to synthesize lanthanide(III) nitride iodides with the formula M₂NI₃ (M=La-Nd), moisture-sensitive single crystals of the first quaternary sodium lanthanide(III) nitride iodides NaM₄N₂I₇ (orthorhombic, Pna2₁; Z=4; a=1391-1401, b=1086-1094, c=1186-1211 pm) could be obtained. The dominating structural features are chains of trans-edge linked [NM₄]⁹⁺ tetrahedra, which run parallel to the polar 2₁-axis [001]. Between the chains, direct bonding via special iodide anions generates cages, in which isolated [NaI₆]^5- octahedra are embedded. The IR spectrum of NaLa₄N₂I₇ recorded from 100 to 1000 cm^-1 shows main bands at υ=337, 373 and 489 cm^-1. With decreasing radii of the lanthanide trications these bands, which can be assigned as an influence of the vibrations of the condensed [NM₄]⁹⁺ tetrahedra, are shifted toward higher frequencies for the NaM₄N₂I₇ series (M=La-Nd), following the lanthanide contraction.     

Novel fluoro-substituted benzo- and benzothieno fused pyrano[2,3-c]pyrazol-4(1H)-ones

A straightforward, two-step synthesis of fluoro substituted chromeno[2,3-c]pyrazol- and [1]benzothieno[2′,3′:5,6]pyrano[2,3-c]pyrazol-4(1H)-ones, respectively, is presented. Hence, treatment of 1-substituted or 1,3-disubstituted 2-pyrazolin-5-ones with fluoro substituted 2-fluorobenzoyl chlorides or 3-chloro-6-fluoro-1-benzothiophene-2-carbonyl chloride using calcium hydroxide in refluxing 1,4-dioxane gave the corresponding 4-aroylpyrazol-5-ols, which were cyclized into the fused ring systems. 5-Fluorochromeno[2,3-c]pyrazol-4(1H)-one was obtained upon treatment of the 1-(4-methoxybenzyl) protected congener with trifluoroacetic acid. Treatment of 5-fluorochromeno[2,3-c]pyrazol-4(1H)-ones with methylhydrazine afforded novel tetracyclic ring systems such as 2-methyl-7-phenyl-2,7-dihydropyrazolo[4′,3′:5,6]pyrano[4,3,2-cd]indazole. Detailed NMR spectroscopic investigations (¹H, ¹³C, ¹⁵N, ¹⁹F) with the obtained compounds were undertaken.     

Synthesis and spectral properties of substituted 4-chlorooxazoloquinolines

Summary The treatment of a mixture of linearly and angularly annelated 2-substituted oxazolo[4,5-f]quinolones (5a–c) and oxazolo[5,4-g]quinolones (6a–c) and similarly the treatment of 2-substituted oxazolo[5,4-f]quinolones (7a–c) and oxazolo[4,5-g]quinolones (8b,c) with POCl₃ afforded substituted 4-chlorooxazolo[4,5-f]quinolines (9a–c) and 2-substituted 4-chlorooxazolo[5,4-f]quinolines (10b,c), respectively. Spectral characteristics of the synthesized derivatives (¹H and¹³C NMR, IR, UV, and MS) are discussed.Dedicated to Prof.Fritz Sauter on the occasion of his 65th birthday     

Reactions of 3,4-Dichloro-N-R-maleimides with Substituted 2-Thiouracils

Reactions of 3,4-dichloro-N-R-maleimides with substituted thiouracils at 40°C gave a 1:1 mixture of isomers of pyrrolothiazolopyrimidinetriones. Under conditions of thermodynamic control (100°C, 5 h) only pyrrolo[3',4':4,5]thiazolo[3,2-a]pyrimidine-4,6,8-triones were formed, hydrolysis of which followed by decarboxylation gave 5-oxo-5H-thiazolo[3,2-a]pyrimidine-2-carboxamide. The structure of N²-phenyl-6-methyl-5-oxo-5H-thiazolo[3,2-a]pyrimidine-2-carboxamide was confirmed by X-ray crystallography. Analogous cyclization of 3,4-dichloro-N-R-maleimides with 2-thioxoquinazol-4-one also gave a mixture of two isomers which were successfully separated by fractional crystallization.     

Synthesis and properties of [1,4]diazepino[6,5-b]indoles

1-Aryl-2-oxo-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole N-oxides were synthesized based on 3-(N"-aryl-N"-chloroacetyl)amino-2-formylindoles. Deoxidation of 2-oxo-1-phenyl-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole N-oxide afforded 1,2,3,6-tetrahydro- and 1,2,3,4,5,6-hexahydro[1,4]diazepino[6,5-b]indole derivatives. A new approach to the synthesis of pyrido[3,2-b]indole and pyrimido[5,4-b]indole derivatives was developed.     

α-氨基膦酸酯衍生物的合成及其表征

合成了一系列N端含有均三唑并噻二唑的α-氨基膦酸酯衍生物, 其结构经过红外、核磁共振氢谱、磷谱、质谱和高分辨质谱等确证.     

Aggregate, Polymer and Cluster Formation from Metal-Imino Carboxylate Complexes

Reaction of tris-(2-aminoethyl)amine (tren) andthe sodium salt of an -ketocarboxylic acid, typically sodium pyruvate, affordsin the presence of a lanthanide ion aseries of complexes and aggregates includingmononuclear, cyclic tetranuclear and polymerspecies of [L¹]^3- ([L¹]^3-=N[CH₂CH₂N=C(CH₃)COO^-]³).The aggregation of these and related d-block elementcomplexes with Na⁺ ions leadsto the formation of polymeric materials, and thefactors influencing the formation and controlof these various aggregation states are discussed.Metal cations also template the aggregationof the fragment [Ni(L²)] ([L²]^2- =CH₂[CH₂N = C(CH₃)COO^-]₂)to give, in high yield, the polynuclearaggregates {[Ni(L²)]₆M}^x+(M = Nd, Pr, Ce, La, x = 3; M = Sr, Ba, x = 2). The structures of{[Ni(L²)]₆M}^x+ show aninterstitial twelve co-ordinate, icosahedralcation M^x+ encapsulated by six [Ni(L²)]fragments. In the presence ofNa⁺, aggregation of [Ni(L²)] fragments affords {[Ni(L²)]₉Na₄(H₂O)(MeOH)(ClO₄)}³⁺ thestructure of whichshows four Na⁺ ions templating the formation ofa distorted tricapped trigonal prismatic[Ni(L²)]₉ cage. Thus, control overconstruction of various polynuclear cages viaself-assembly at octahedral junctions can beachieved using main group, transition metaland lanthanide ion templates.     

Synthesis of 2,6-dioxatricyclo[3.3.1.0]nonanes by intramolecular haloetherification and/or transannular hydroxycyclization of alkenes in [4+3]-cycloadducts

The synthesis of new difunctionalized 2,6-dioxatricyclo[3.3.1.0^3,7]nonanes is described. This type of structure is an interesting synthetic building block for potential bioactive molecules and it was prepared from 8-oxabicyclo[3.2.1]oct-6-en-3-one having a NHBoc function on C-1. This precursor was obtained by a [4+3] cycloaddition reaction of 2-tert-butoxycarbonylaminofuran and the oxyallyl cation generated in situ from 2,4-dibromo-3-pentanone. Reduction of the carbonyl group at C-3 was accomplished in high yield and stereoselective manner to afford the corresponding axial alcohol at C-3 as a major product. Further intramolecular haloetherification of this type of alcohols with NBS and I(py)2BF₄ led to the corresponding bromo and iodo-derivatives at C-8 of the 2,6-dioxatricyclo[3.3.1.0^3,7]nonane framework, in high yield. Epoxidation of 8-oxabicyclo[3.2.1]oct-6-en-3-ol followed by treatment with NaCN, NaN₃, and/or NaOH in MeOH afforded 8-hydroxy-2,6-dioxatricyclo[3.3.1.0^3,7]nonanes in high yield via a transannular hydroxycyclization mediated by a base and through an alkoxide intermediate. The new 2,6-dioxatricyclo[3.3.1.0^3,7]nonanes were tested for biological activity against HIV-1 virus and MT-4 lymphoid cell line, showing a low anti-HIV activity and a high degree of cytotoxicity.     

Regioselective N-alkylation of imidazo[4,5-b]pyridine-4-oxide derivatives: an experimental and DFT study

Regioselectivities were determined for N-alkylations of imidazo[4,5-b]pyridine-4-oxide and 2-methyl-imidazo[4,5-b]pyridine-4-oxide with benzyl bromide or benzyl iodide at RT using K₂CO₃ in DMF as a base. Experimental attempts have shown that N-1/N-3 ratios slightly varied according to the substitution on C-2 position. This was confirmed by DFT calculations in solvent phase. This computational study has shown first that this N-benzylation reaction passed through a S_N2 mechanism. Moreover, regioselectivity of N-benzylation has appeared essentially governed by ‘steric approach control’. It explained that opposite N-1/N-3 ratios were obtained with imidazo[4,5-b]pyridine-4-oxide and its 2-methyl-substituted analog. Finally, regioselectivities slightly varied with the nature of benzyl halide.     

Preparation of novel pyridine-fused tris-heterocycles; pyrido[4,3-e]pyrrolo-/pyrido[4,3-e]furano[2,3-c]pyridazines and pyrido[3,4-b]pyrrolo[3,2-d]pyrrole

Three novel pyrido-fused tris-heterocycles have been prepared based on a Suzuki coupling and subsequent cyclisation approach. Pyrido[4,3-e]pyrrolo[2,3-c]pyridazine (3b, 77%) and pyrido[4,3-e]furano[2,3-c]pyridazine (5b, 76%) were obtained by intramolecular diazocoupling. Successful diazocoupling of furan (5b) is thus reported for the first time by NOBF₄ generation of the diazonium intermediate. N-TIPS-pyrido[3,4-b]pyrrolo[3,2-d]pyrrole (TIPS-4b) was synthesised by thermal cyclisation of pyridyl nitrene in considerably higher yield (71%) than previously experienced from similar cyclisations, due to TIPS-activation.     

Cycloalkano[1″,2″:4,5;4″,3″:4′,5′]bis(pyrrolo[2,3-c]pyrimido[5,4-e]pyridazines): synthesis, structure and mechanism of their formation

Reactions of 3-alkylamino-6,8-dimethylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones with cyclohexyl- and cycloheptylamines in the presence of AgPy₂MnO₄ produce novel cycloalkano[1″,2″:4,5;4″,3″:4′,5′]bis(pyrrolo[2,3-c]pyrimido[5,4-e]pyridazines). Detailed information concerning the scope and mechanism of these transformations is discussed.     

Mercury(II) cyanide complexes with alkyldiamines: solid-state/solution NMR,computational, and antimicrobial studies

Mercury cyanide complexes of alkyldiamines (1–6), [Hg(L)(CN)₂] (where L?=?en (1,2-diaminoethane), pn (1,3-diaminopropane), N-Me-en, N, N′-Me₂-en, N, N′-Et₂-en, and N, N′-ipr₂-en), have been synthesized and characterized by elemental analysis, IR, ¹³C, and ¹⁵N solution NMR in DMSO-d₆, as well as ¹³C, ¹⁵N, and ¹⁹⁹Hg solid-state NMR spectroscopy. Complexes 1 and 2 have been studied computationally, built and optimized by GAUSSIAN03 using DFT at B3LYP level with LanL2DZ basis set. Binding modes of en and bn (where bn?=?1,4-diaminobutane) toward Hg(CN)₂ are completely different. Complexes with en and pn show chelating binding to Hg(II), while bn behaves as a bridging ligand to form a polymeric structure, [Hg(CN)₂-bn]_∞ [B.A. Al-Maythalony, M. Fettouhi, M.I.M. Wazeer, A.A. Isab. Inorg. Chem. Commun., 12, 540 (2009).]. The solution ¹³C NMR of the complexes demonstrates a slight shift of the ?C≡N (0.9 to 2?ppm) and ?C–NH₂ (0.25 to 6?ppm) carbon resonances, while the other resonances are relatively unaffected. ¹⁵N labeling studies have shown involvement of alkyldiamine ligands in coordination to the metal. The principal components of the ¹³C, ¹⁵N, and ¹⁹⁹Hg shielding tensors have been determined from solid-state NMR data. Antimicrobial activity studies show that the complexes exhibit higher antibacterial activities toward various microorganisms than Hg(CN)₂.     

Unusual scission of 3,7-dichlorobisisothiazolo[4,5-b:4",5"-e]pyrazine by nucleophiles

The reaction of 3,7-dichlorobisisothiazolo[4,5-b:4",5"-e]pyrazine with MeONa in MeOH afforded 3-chloro-5,6-dimethoxyisothiazolo[4,5-b]pyrazine. The reactions of the former with benzylamine, morpholine, and aniline gave rise to the corresponding N,N"-bis(5-amino-3-chloroisothiazol-4-yl)diazenes. In the case of benzylamine, 3,7-bis(benzylamino)bisisothiazolo[4,5-b:4",5"-e]pyrazine was isolated as a by-product. The crystal structure of N,N"-bis(5-benzylamino-3-chloroisothiazol-4-yl)diazene was established by X-ray diffraction analysis.     

Reactions of 4-Chloro-3-formylcoumarin with Arylhydrazines

The interaction of 3-formyl-4-coumarin with arylhydrazine hydrochlorides in the presence of sodium acetate gave the corresponding 3-arylhydrazonomethyl-4-chlorocoumarin, and with phenylhydrazine, 4-bromo- and 4-chlorophenylhydrazine hydrochlorides in the presence of two equivalents of triethylamine gave either 1-aryl- or 2-aryl[1]benzopyrano[4,3-c]pyrazol-4-ones depending on the reaction conditions. In reactions of 4-chloro-3-formylcoumarin with 2,4-dichloro-, 2,4-difluoro-, 2-hydroycarbonyl-, 4-nitro- and 3,5-di(trifluoromethyl)phenylhydrazine, 2-pyridyl- and 2-quinoxalylhydrazine in the presence of excess of triethylamine the 2-aryl[1]benzopyrano[4,3-c]pyrazol-4(2H)-ones were obtained exclusively. The structures of 1-phenyl- and 2-(2-pyridyl)[1]benzopyrano[4,3-c]pyrazolo-4(1H)ones were confirmed by X-ray crystallography. A simple method is proposed to distinguish between 1- and 2-substituted [1]benzopyrano[4,3-c]pyrazolo-4-ones on the basis of the ¹H NMR chemical shifts of the C(3)-H proton in two solvents - DMSO-d₆ and CDCl₃.     

Synthesis of derivatives of a new heterocyclic system,indolo[2,3-f][1,7]naphthyridine

3-(N"-Aryl-N"-chloroacetyl)amino-2-formylindoles were converted into 3-amino-1-aryl-2-oxo-1,2-dihydropyrido[3,2-b]indoles, which were used to synthesize derivatives of a new heterocyclic system, namely, indolo[2,3-f][1,7]naphthyridine. The structures of the resulting compounds were proved by IR and ¹H NMR spectroscopy and mass spectrometry.