1,2-Oxazoline durch Addition von Trimethylbenzonitriloxid an 2-Hydroxyethylamino-1,4-benzochinone und deren Chinolderivate

Summary Addition of trimethylbenzonitril oxide to 2-hydroxyethylamino-1,4-quinones and 3,4-dihydro-4-alkyl-8a-methoxy-2H-1,4-benzoxazin-6(8aH)-ones leads to 7,8,9a,9b-tetrahydro-3aH-1,2-oxazolo[4,5-h]-1,4-benzoxazin-4(6H)-ones. In order to determine constitution and conformation of the addition products an NMR-spectroscopic analysis and an X-ray crystal structure analysis of 6-benzyl-9a-hydroxy-3-mesityl-7,8,9a,9b-tetrahydro-3aH-1,2-oxazolo[4,5-h]-31,4-benzoxazin-4-(6H)-one3a were carried out at room temperature: C₂₅H₂₆N₂O₄,M _r=418.49, monoclinic, P2₁/n,a=13.716(6),b=19.993(6),c=15.348(6) Å, = 98.55(4)°,V=4162(1)ų,Z=8,d _x=1.336g/cm³,R=6.77%,R _w=4.55% (2994 observables, 560 parameters).

     

Oxidation of aromatic compounds: XII. Regio- and stereoselective oxidative dimerization of alkyl 3-arylpropynoates in the system CF<Subscript>3</Subscript>CO<Subscript>2</Subscript>H-CH<Subscript>2</Subscript>Cl<Subscript>2</Subscript>-PbO<Subscript>2</Subscript>

Regio- and stereoselective oxidative dimerization of alkyl 3-arylpropynoates in the system CF₃CO₂H-CH₂Cl₂-PbO₂ (1–30 h, 0–20°C) leads to dialkyl (E)-2,3-bis(arylcarbonyl)-2-butene-1,4-dioates with trans arrangement of the substituents at the double bond.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 9, 2004, pp. 1329–1333.Original Russian Text Copyright © 2004 by Savechenkov, Vasilev, Rudenko.For communication XI, see [1].     

Triphenylpyrylium salt-sensitized photoreactions of 1,4-diaryl-2,3-dioxabicyclo[2.2.2]octanes through competitive single electron-transfer pathway and proton-catalyzed pathway

2,4,6-Triphenylpyrylium tetrafluoroborate (TPPBF₄)-sensitized photoinduced electron-transfer (PET) reactions of 1,4-diaryl-2,3-dioxabicyclo[2.2.2]octanes 5 (a: Ar¹ = Ar² = p-MeOC₆H₄, b: Ar¹ = Ar² = p-MeC₆H₄, c: Ar¹ = Ar² = Ph) underwent novel fragmentation through their radical cations to give 1,4-diarylbutan-1,4-diones 6 accompanied by elimination of ethylene. On the other hand, 4-aryl-cyclohex-3-en-1-ones 7, p-substituted phenols 8, and 4-aryl-4-aryloxycyclohexanones 9 were produced through proton-catalyzed pathways when the PET reactions of 5 were performed in the absence of a certain base such as 2,6-di-tert-butylpyridine (DTBP). Particularly, the formation of 9 is consistent with the novel cationic rearrangement involving nucleophilic O-1,2-aryl shifts and C-1,4-aryl shifts.     

Reactions of 2H-3,4-dihydro-1,4-benzoxazin-6(8aH)-ones with 2,4,6-trimethylbenzonitrile oxide,III

Summary Regio-, stereo- and siteselectivity of the cycloadditions of trimethylbenzonitrile oxide with 2H-3,4-Dihydro-1,4-benzoxazin-6(8aH)-ones have been investigated. The structures of the obtained products were elucidated by means of homonuclear NOE difference spectroscopy and HMQC and HMBC spectra. The structure of 6-Benzyl-9a-methoxy-3-mesityl-9b-methyl-7,8,9a,9b-tetrahydro-3aH-1,2-oxazolo-[4,5-h]1,4-benzoxazin-4(6H)-on5 was elucidated from a single crystal X-ray structure analysis at ambient temperature: C₂₇H₃₀N₂O₄, M=446.55g/mol, monoclinic, P2₁/c,a=10.372 (34) Å,b=11.908 (21) Å,c=20.040 (34) Å, =97.16 (17)°,V=2455.8 (1.9)ų,Z=4,d _c=1.208g/cm³, =0.08mm^–1,R=0.0546.Dedicated to Prof. Ott with best wishes for his 70^th birthday     

Crystal Structures and Properties of New Mixed-Ligand Complexes of Nickel(II) Diisobutyldithiophosphinate with Imidazole and 3,5-Dimethylpyrazole

The reaction of Ni{(i-C₄H₉)₂PS₂}₂ with imidazole and 3,5-dimethylpyrazole in ethanol gave paramagnetic (_ef = 3.02 and 3.11 BM) mixed-ligand complex compounds [Ni(Im)₂{(i-C₄H₉)₂PS₂}₂] (I) and [Ni(Pyr){(i-C₄H₉)₂PS₂}₂] (II). Single crystals were grown and the crystal structures of I and II were determined from X-ray diffraction data (CAD-4 diffractometer, Mo radiation, 1483 , R = 0.0344 for I and 2630 , R = 0.0486 for II). The crystals are monoclinic with cell dimensions a = 12.845(2), b = 10.250(1), c = 13.431(1) , = 115.89(1)°, V = 1591(1) ³, Z = 2, d _calc = 1.281 g/cm³, space group (for I); a = 11.152(3), b = 12.483(2), c = 23.389(4) , = 100.78(1)°, V = 3199(2) ³, Z = 4, d _calc = 1.191 g/cm³, space group (for II). The structures consist of discrete monomer molecules. The coordination polyhedron of the Ni atom is a compressed octahedron NiN₂S₄ (in I) and a tetragonal pyramid NiNS₄ (in II) formed by four S atoms of the two cyclic bidentate ligands i-Bu₂ and the N atoms of two monodentate ligands (Im molecules in trans-positions) or the N atom of the monodentate Pyr ligand in complexes I and II, respectively. The character of interaction between molecules I and II and molecular packing modes are considered. The electronic spectra of the complexes are consistent with the symmetry of chromophores found from X-ray data.     

Adamantylazoles: VIII. Acid-catalyzed adamantylation of 1,2,4-triazol-5-ones

3-R-1,2,4-Triazol-5-ones are adamantylated in sulfuric acid. The reaction involves the N¹ atom of the ring. 4-Adamantyl-1-methyl-, 1-adamantyl-4-methyl-, and 1,4-diadamantyl-1,2,4-triazol-5-ones were also prepared. Therewith, it was found that N¹ exhibits a higher reactivity than N⁴.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 8, 2004, pp. 1377–1382.Original Russian Text Copyright © 2004 by Amandurdyeva, Saraev, Kuzmina, Golod.For communication VII, see [1].This revised version was published online in April 2005 with a corrected cover date.     

Oxygen replacement by fluorine in carbonyl derivatives of perfluoroaromatic compounds and isomerization of perfluoroindan-1,3-dione to perfluoro-3-methylenephthalide under the action of HF/SbF5

When acted upon by HF/SbF₅ at 95 °C, carbonyl groups of perfluorinated acetophenone (10), 3,4-dihydronaphthalen-1(2H)-one (8), 2,3-dihydronaphthalene-1,4-dione (9), benzocyclobutenone (6), benzocyclobutenedione (7) and indan-1-one (1) are converted into difluoromethylene groups to give the corresponding perfluoroaromatic products. Perfluoroindan-2-one (5), under the same conditions, is transformed to bis(perfluoroindan-2-yl) ether (21). On heating with HF/SbF₅, perfluoroindan-1,3-dione (2) isomerizes into perfluoro-3-methylenephthalide (4) at 95 °C, and gives 4,5,6,7-tetrafluoro-3-trifluoromethyl-phthalide (14) at 130 °C. Compound 4 in the absence of a solvent dimerizes giving perfluorodispiro[phthalide-3,1′-cyclobutane-2′,3″-phthalide] (18), and when heated with SbF₅ at 130 °C, it is converted into perfluoro-3-methylphthalide (3). When acted upon by HF/SbF₅ at 95 °C, perfluorinated benzoic acid (12) and phthalic anhydride (13) give the corresponding products with trifluoromethyl groups.     

Synthesis characterization and X-ray crystal structures of cis-1,4-diaminocyclohexane-platinum(II) nucleobase adducts

Platinum complexes of the type [Pt(cis-1,4-DACH)(L)₂]X, where cis-1,4-DACH = cis-1,4-diaminocyclohexane; L = adenine (ade) (1), hypoxanthine (hyp) (2), 9-methylguanine (9-megua) (3), cytosine (cyt) (4), or 1-methylcytosine (1-mecyt) (5); and X = SO₄ or Cl₂ groups, were synthesized and characterized by elemental analysis and by ¹H, ¹³C, and ¹⁹⁵Pt nuclear magnetic resonance spectroscopy. The crystals of [Pt(cis-1,4-DACH)(9-megua)₂]SO₄[9-megua-H]₂SO₄ (3) and [Pt(cis-1,4-DACH)(1-mecyt)₂]Cl₂ · 6H₂O (5) were also subjected to single-crystal X-ray diffraction. The base/PtN4 coordination plane dihedral angles were 74.55° and 85.61° in complex 3 and 78.12° and 81.80° in complex 5. The platinum had distorted square planar geometry in both complexes; the two adjacent corners were occupied by the two nitrogen atoms of cis-1,4-DACH, and the other two corners were occupied by the two N7 atoms of 9-megua in complex 3 and the two N3 atoms of 1-mecyt in complex 5. The cis-1,4-DACH, which has a unique twist-boat configuration, formed a seven-member chelating ring with platinum, which led to considerable strain during bidentate cis-1,4-DACH binding. Cations of both complexes 3 and 5 adopted C₂ molecular symmetry. These adducts were the models for the intrastand cross-links that were relevant to the binding of the Pt(II) antitumor drugs to DNA.     

Ruthenium Cluster Chemistry with Ph2PC6H4-4-C≡CH

The new phosphines Ph₂PC₆H₄-4-CCR [R=SiMe₃ (1), H (2)] have been used to prepare Ru₃(CO)₉(Ph₂PC₆H₄-4-CCSiMe₃)₃ (4) and Ru(CCC₆H₄-4-PPh₂)(PPh₃)₂(-C₅H₅) (3), respectively, the latter with a pendent phosphine. Reaction of 4 with carbonate or fluoride affords Ru₃(CO)₉(Ph₂PC₆H₄-4-CCH)₃ (5) with pendent terminal alkynyl groups, the identity of which was confirmed by a structural study. Reaction of 5 with [Ru(NCMe)(PPh₃)₂(-C₅H₅)]PF₆ or reaction of Ru₃(CO)₁₂ with 3 gives Ru₃(CO)₉{(Ph₂PC₆H₄-4-CC)Ru(PPh₃)₂(-C₅H₅)}₃ (6). Complexes 3–6 have been studied by cyclic voltammetry. Proceeding from Ru₃(CO)₁₂ to 4 or 5 shifts the cluster-centred reduction to more negative potential and affords facile cluster-centred oxidation. Proceeding from 4/5 and 3 to 6 results in similarly-located cluster-centred reduction and peripheral ruthenium-centred oxidation, but results in a lack of observable cluster-centred oxidation. Crystal data for 5·C₆H₁₄: space group P¯1, a=12.760(1) Å, b=17.077(1) Å, c=17.924(2) Å, =108.656(5)°, =96.344(5)°, =93.523(5)°, V=3658.4(6) ų, Z=2, R=0.078, R_w=0.105 for 5008 reflections [I>2.00(I)].     

Kinetics and mechanism of the oxidation of hydrogen peroxide by the octacyanotungstate(V) ion in alkaline aqueous media

Summary The oxidation of H₂O₂ by [W(CN)₈]^3– has been studied in aqueous media between pH 7.87 and 12.10 using both conventional and stopped-flow spectrophotometry. The reaction proceeds without generation of free radicals. The experimental overall rate law, , strongly suggests two types of mechanisms. The first pathway, characterized by the pH-dependent rate constant k _s, given by , involves the formation of [W(CN)₈· H₂O₂]^3–, [W(CN)₈· H₂O₂·W(CN)₈]^6– and [W(CN)₈· HO]^3– intermediates in rapid pre-equilibria steps, and is followed by a one-electron transfer step involving [W(CN)₈·HO]^3– (k _a) and its conjugate base [W(CN)₈·O]^4– (k _b). At 25 °C, I = 0.20 m (NaCl), the rate constant with H _a =40±6kJmol^–1 and S _a =–151±22JK^–1mol^–1; the rate constant with H _b =36±1kJmol^–1 and S _b =–136±2JK^–1mol^–1 at 25 °C, I = 0.20 m (NaCl); the acid dissociation constant of [W(CN)₈·HO]^3–, K ₅ =(5.9±1.7)×10^–10 m, with and is the first acid dissociation constant of H₂O₂. The second pathway, with rate constant, k _f, involves the formation of [W(CN)₈· HO₂]^4– and is followed by a formal two-electron redox process with [W(CN)₈]^3–. The pH-dependent rate constant, k _f, is given by . The rate constant k ₇ =23±6m ^–1 s ^–1 with and at 25°C, I = 0.20 m (NaCl).     

Interaction of Nitromethane with Modified Paramagnetic Defects on a Thermochemically Activated Silica Surface

It was found that the interaction of the modified paramagnetic defects SiO(CH₂) _n H₂ (n = 0.1) with nitromethane on a thermochemically activated silica surface at 300 K results in the formation of the following nitroxyl radicals: SiO(CH₂) _n CH₂ON( )CH₃ and SiO(CH₂) _n CH₂N( )CH₃. It was suggested that these radicals are the products of two different reactions of the modified paramagnetic defects: the first results from a reaction with free nitromethane; the second, from a reaction with nitromethane bound as complexes with diamagnetic surface defects.     

Extraktion des Rheniums als Tributylammoniumperrhenat

Zusammenfassung Durch Extraktion des Rheniums mit Methylenchlorid als [(C₄H₉)₃NH]ReO₄ im pH-Bereich 1–6 können Trennungen Re: Übergangsmetall= 110⁴ und Re^VIIMo^VI=160 erzielt werden. Durch Überführung des Rheniums in nichtwäßriger Phase in [(C₄H₉)₃NH]₃[ReO₂(SCN)₄] sind hierbei Rheniummengen ab 1,5 g bei 430 nm photometrisch bestimmbar.

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Summary Liquid-liquid extraction of rhenium as [(C₄H₉)₃NH]ReO₄ using dichloromethane within a pH-range of 1–6 enables separations Re: transition metal= 110⁴ (Re^VIIMo^VI=160). Photometric measurement (430 nm) of rhenium in non-aqueous solutions as [(C₄H₉)₃NH]₃[ReO₂(SCN)₄] allows the determination of 1.5 g of rhenium.

     

Simulation of donor-acceptor electron-transport systems in the example case of the oxidation of copper in media of organic solvents

The interaction of the onium salts [Me₂ Et=O]BF₄ ^–, [Me₂ =CH-OEt]BF₄ ^–, and [Me₃ =O]I^– with metallic copper in DMSO, DMF, and acetonitrile (AN) has been investigated. It has been shown that the reaction takes place with an intermediate step involving the formation of Cu(I) compounds. The complexes [Cu^I(AN)₄]BF₄, [Cu^II(DMSO)₅](BF₄)₂, [Cu^II(DMSO)₄(AN)₂](BF₄)₂, [Cu^II(DMSO)₂(DMF)(AN)](BF₄)₂, and [ME₃ ]₃Cu^II₄ · [Me₃ =O]I^– have been isolated and characterized. It has been established that dipolar onium compounds which simulate the intermediate products of the interaction of the components of donor-acceptor electron-transport systems are responsible for the oxidation of metals in organic complex-forming media.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1325–1330, June, 1991.     

Insertions of phenylacetylene with chelated bis(triphenylphosphine) - ruthenium(II)hydridocarbonyl complexes

Summary Phenylacetylene reacts stoichiometrically or in excess with the Ru—H bond of RuH(CO)(PPh₃)₂(L) (LH = 2-hydroxypyridine, 2-hydroxy-6-methylpyridine, acetylacetone, benzoylacetone, 2-hydroxyacetophenone, 2-hydroxypropiophenone, 2-hydroxybenzophenone and 4-methoxy-2-hydroxybenzophenone) in boiling benzene to give -vinylic or -vinylalkynyl complexes of the type Ru(CO)-(PPh₃)₂(L)(CH CHPh) and Ru(CO)(PPh₃)₂(L){C-(C CPh) CHPh} in good yield. The vinylic complex can also be obtained by reacting the sodio derivative of the chelating ligand with the 16e^– unsaturated complex, [Ru(CO)Cl(CH CHPh)(PPh₃)₂], in CH₂Cl₂/MeOH mixture at ambient temperature. These complexes have been characterized by elemental analyses, and i.r., ¹H, ¹³C and ³¹P n.m.r. spectroscopy.N.C.L Communication No. 5404.     

Oxychlorination of methane to methyl chloride at 300°C in the system palladium(II) complexes-heteropolyacids-silica gel

The activity of systems, applied to silica gel from chloride solutions, in the oxychlorination of CH₄ to CH₃Cl at 300° Cincreases in the order H₃[PMo₁₂O₄₀]9[PMo₆V₆O_40]2(PdCl₂-H₉[PMo₆V₆O₄₀] (or H₃[PMo₁₂O₄₀]))<(PdCl₂-Na_nH_9–n[PMo₆V₆O₄₀]). Additions of NaCl (molar ratio of the components NaClSiO₂7100) lead to an increase in the yield of CH₃Cl. The mechanisms of CH₄ oxidation have been discussed which are electrophilic with the participation of Pd(II) complexes and involve chlorides with the participation of surface Cl atoms.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 31, No. 1, pp. 29–33, January–February, 1995.     

Dissociation Constants of Protonated Cysteine Species in NaCl Media

The sulfur-containing biomolecule, cysteine has a role in physiological and natural environment because of its strong interactions with metals. To understand these interactions of metals with cysteine, one needs reliable dissociation constants for the protonated cysteine species [ CH(CH₂SH)COOH; H₃B⁺]. The values of dissociated constants, p , for protonated cysteine species (H₃B⁺ H⁺ + H₂B, K ₁; H₂B H⁺ + HB^–,K ₂; HB^– H⁺ + B^2–,K ₃) were determined from potentiometric measurements in NaCl solutions as a function of ionic strength, 0.5–6.0 mol-(kgH₂O)^–1 and between 5, and 45°C. The equations

Synthesis and Crystal Structure Investigation of Trinitrotriamminerhodium(III) [Rh(NO2)3(NH3)3]

Synthesis of the complex [Rh(NO₂)₃(NH₃)₃] is described. The compound crystallizes as monoclinic colorless plates. Crystal data: a = 7.176(10), b = 10.407(2), c = 10.989(2) , = 93.27°, V = 819.3(2) ³, space group , Z = 4, d _calc = 2.367 g/cm³. The structure is molecular and built of neutral complexes having cis-facial configuration. The unit cell of the crystal contains two independent complexes.     

Substituted metal carbonyls. Part 25: Unidentate,intramolecular, and intermolecular bridging modes of 1,1′-bis(diphenylphosphino)ferrocene inM 3S2(CO)9 (M = Fe,Ru) cluster derivatives

Carbonyl exchange of Fe₃(₃-S)₂(CO)₉ wioth1,1-bis(diphenylphosphino)ferrocene (dppf) in refluxing THF gives a cluster ligand with a pendant phosphine moiety, Fe₃(₃-S)₂(CO)₈ (gn¹-Ph₂PlC₅H₄)Fe(C₅H₄)P⁴ MePh₂)]1 ^–,4. Addition of 1 to AuCl(SMe₂) gives ClAu(-dppf) Fe₄(₃-S)₂(CO)₈,8 (45%). Spectroscopic evidence is also obtained for (OC)₈ (₃-S)₂Fe₃(-dppf) Os₃(CO)₁₁,7 and PdCl₂[(-dppf)Fe₃(₃-D)₂(CO)₈]₂,9, from1 and Os₃(CO)₁₁(CH₃CN) and PdCl₂CN)₂, respectively. Crystal data dor3: space group P2₁/n,a = 10.891(3) Å,b = 19.939(3) Å,c = 20.443(2) Å, 100.17(2)°.Z = 4, 3917 reflections,R = 0.049.     

The active analog approach applied to the pharmacophore identification of benzodiazepine receptor ligands

Summary Applied to seven potent benzodiazepine-receptor ligands belonging to chemically different classes, the active analog approach allowed the stepwise identification of the pharmacophoric pattern associated with the recognition by the benzodiazepine receptor.A unique pharmacophore model was derived which involves six critical zones: (a) a -electron rich aromatic (PAR) zone; (b) two electron-rich zones ₁ and ₂ placed at 5.0 and 4.5 Å respectively from the reference centroid in the PAR zone; (c) a freely rotating aromatic ring (FRA) region; (d) an out-of-plane region (OPR), strongly associated with agonist properties; and (e) an additional hydrophobic region (AHR).The model accommodates all presently known ligands of the benzodiazepine receptor, identifies sensitivity to steric hindrance close to the ₁ zone, accounts forR andS differential affinities and distinguishes requirements for agonist versus non-agonist activity profiles.Abbreviations Pyrazoloquinolines CGS (2-phenyl-2,5-dihydro pyrazolo [4,3-c] quinoline-3 (3H)-one) - Cinnolinones CIN (2-(4-methoxyphenyl)-benzo [h] 3-cinnolinone - Triazolophthalazines TZPH (3-(4-methoxyphenyl)-6 pyrrolidinotriazolo [4,3-a] phthalazine - Cyclopyrrolones RP 27267, CLO ([6-(5-chloro-2-pyridyl)-6,7-dihydro-7 oxo-5H-pyrrolo [3,4-b]pyrazin-5-yl] 4-methyl-l-piperazine carboxylate) - Phenylquinolines PK (phenyl-2 (morpholinocarbonyl methyl oxy)-4 quinoline - -Carbolines BCC (3-carboethoxy--carboline) - Benzodiazepines: Diazepam DZ (7-chloro-1,3-dihydro-1-methyl-5 phenyl-2H-1,4-benzodiazepin-2-one)     

Kristallstruktur und thermisches Verhalten der Additionsverbindungen von Trithiocyanursäure mit Tetrahydrofuran und 1,4-Dioxan

Summary The addition compounds trithiocyanuric acid-tetrahydrofuran (1), 2-trithiocyanuric acid-3-(1,4-dioxane) (2) and 2-trithiocyanuric acid-(1,4-dioxane) (3) were prepared and their thermogravimetric behaviour studied. X-ray crystal structure analyses of1 and2 were carried out at 100 K.1: (HNCS)₃·C₄H₈O,M _r=249.37, monoclinic, P 2₂/c,a=11.105 (1),b=12.715 (1),c=7.825 (1) Å, =83.32 (1)°,V=1097.4(1) ų,Z=4,d _x=1.509 g/cm³,R=3.65%,R _w=3.53% (1 929 observables, 147 parameters).2: 2 (HNCS)₃·3C₄H₈O₂,M _r=618.83, triclinic, ,a=4.339(1),b=12.471(1),c=13.265(1) Å, =73.08(1)°, =84.29(1)°, =80.73(1)°,V=677.1(2) ų,Z=1,d _x=1.518 g/cm³,R=4.20%,R _w=3.75% (2 521 observables, 223 parameters). Finally, the solubilities of cyanuric acid (4) and of trithiocyanuric acid (5) in water, methanol, tetrahydrofuran and 1,4-dioxane at 25°C were determined.