Synthesis of 4-(2-hydroxyaryl)-3-nitro-4H-chromenes

A combinatorial library of 4-(2-hydroxyaryl)-3-nitro-4H-chromenes was synthesized in high yield by C4-SMe substitution in N-alkyl/phenyl 4-(methylthio)-3-nitro-4H-chromen-2-amines with a variety of phenols. The reaction always provided C2 substitution in the phenol ring, dictated by hydrogen bond interactions between the phenolic hydroxyl group and the nitro group in 3-nitro-4H-chromenes. Reduction of the nitro group with concomitant hydrolysis of the enamine in 4-(2-hydroxyaryl)-3-nitro-4H-chromenes with Zn, Ac₂O in AcOH furnished hybrid amino-acid lactone incorporating ortho-tyrosine and phenyl alanine moieties.     

Effect of intramolecular hydrogen bond on the azide-tetrazole equilibrium of 5-(2′-hydroxyphenyl)tetrazolo[1,5-a]pyrimidine,-tetrazolo[1,5-c]pyrimidme, -tetrazolo[1,5-c]quinazoline,and 7-(2′-hydroxyphenyl)tetrazolo[1,5-c]pyrimidine

The intramolecular hydrogen bond between the phenolic hydroxyl and the pyrimidine nitrogen atom in the title compounds exerts a destabilizing effect on the tetrazole ring and shifts the azide-tetrazole equilibrium toward the azide form, especially in the case of tetrazolo[c]pyrimidine and -[c]quinazoline. It has been found that the introduction of a methoxy group into theortho-position of the phenyl fragment stabilizes the tetrazole tautomer more efficiently than introduction of this group into thepara-position.For preliminary communication, see Ref. l.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1494–1502, August, 1995.This work was carried out with financial support from Russian Foundation for Basic Research (Project No. 94-03-0836 la).     

Synthesis of 2-aryl-6-nitro-4-(<Emphasis Type="Italic">vic</Emphasis>-triazol-1-yl)-1<Emphasis Type="Italic">H</Emphasis>-indoles from <Emphasis Type="Italic">E</Emphasis>-2,4,6-trinitrostilbenes

A method is developed for the preparation of 4-(vic-triazol-1-yl)indoles that involves replacement of the ortho-NO₂ group in E-2,4,6-trinitrostilbenes by an azido group, condensation of E-2-azido-4,6-dinitrostilbenes with acetylacetone, replacement of the second ortho-NO₂ group in the resulting stilbenes by N₃, and subsequent thermolysis of the azide into the target indole. The reactions of E-2-azido-4,6-dinitrostilbenes with cyclohexane-1,3-dione gave E-2-amino-4,6-dinitrostilbenes, which can be used for selective transformation of the ortho-NO₂ group into an amino group in E-2,4,6-trinitrostilbenes. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1293–1296, May, 2005.     

Experimental and theoretical studies on group 1 metallacarboranes: Synthesis, structure and ab initio calculations of the NMR chemical shifts of the 1-(THF)-1-(TMEDA)-1-Na-2,4-(SiMe3)2-2,4-C2B4H5 and related carboranes

The reaction of gaseous HCl with either the disodium or dilithium compound of the [nido-2,4-(SiMe₃)₂-2,4-C₂B₄H₄]²⁻ dianion (I) in 1:1 stoichiometry in THF produced the monoprotonated species 1-Na(THF)₂-2,4-(SiMe₃)₂-2,4-C₂B₄H₅ (II) or 1-Li(THF)₂-2,4-(SiMe₃)₂-2,4-C₂B₄H₅ (III), in 81% and 80% yields, respectively. This method proved superior to that involving the direct reduction of the closo-C₂B₄ carborane by metal hydrides. II and III were characterized by elemental analysis, ¹H, ¹¹B and ¹³C NMR and IR spectra. Compound II was recrystallized from a mixture THF, hexane and TMEDA (1:2:1) to isolate colorless crystals of the mixed solvated species, 1-(THF)-1-(TMEDA)-1-Na-2,4-(SiMe₃)₂-2,4-C₂B₄H₅ (IV), which were subsequently used for X-ray diffraction studies. The structure of IV showed that the capping metal occupied the apical position above the open C₂B₃ face of the carborane and that a hydrogen atom was bridging the two adjacent boron atoms on that face. The ¹¹B and ¹³C NMR spectra calculated by GIAO (gauge independent atomic orbital) methods at the 6-311G^** level on the B3LYP/6-31G^* optimized geometries of I–III, and a number of related nido- and closo-carboranes, gave excellent agreement with experiment, even in compounds where electron correlation effects are known to be important.     

Synthesis of Diaminophosphonium Salts [Ph2(ArNH)2P]+Br− (Ar = o-MeC6H4, p-MeC6H4, p-Pr i C6H4, p-EtO2CC6H4, p-MeOC6H4)

The behavior of different anilines H₂NC₆H₄R (R = o-Me, p-Me, o-, m- and p? ⁱ Pr, p-OMe, p-CO₂Et) and 2,6-Me₂C₆H₃NH₂ towards trihalophosphoranes was studied. 2,6-Me₂C₆H₃NH₂ failed to form the diaminophosphonium salt [Ph₂PNH(2,6-Me₂C₆H₃)₂]Br, and the aminophosphine oxide Ph₂(2,6-Me₂C₆H₃NH)PO was the only isolated product. Both o- and p-toluidine gave the corresponding diaminophosphonium salts; however in the case of o-toluidine, the yield was low and a mixture with the respective aminophosphine oxide was observed. Anilines containing methoxy and ethoxycarbonyl groups in para-position form the diaminophosphonium salts in reasonable yields.     

Synthesis and recyclization reactions of 4-(o-R-phenyl)-3-imidazolines

1-Hydroxy-4-phenyl-3-imidazoline reacts with butyllithium to give the product oforthometallation of the phenyl group. Reactions of this compound with electrophiles followed by oxidation afford 4-(o-R-phenyl) derivatives of nitroxyl radicals. When a hydroxyalkyl group is present in theortho-position, an unusual pathway of the decay of stable nitroxyl radicals of the imidazoline series has been observed due to the existence of a spirobicyclic tautomer. The reaction of theo-metallated derivative with CS₂ leads to a profound transformation of the imidazoline ring and to the formation of isoindolethione. Fast recyclization into isoquinolines occurs in the case of the 4-(o-benzoyl)phenyl derivative of 3-imidazoline. The product ofo-metallation reacts with methyl nitrate to yield the 4-(o-hydroxy)phenyl derivative (a potential paramagnetic chelate-forming reagent) and theo-nitro derivative, the starting material for further chemical transformations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 899–903, May, 1994.     

MOLECULAR RECOGNITION OF AN ORGANIC MOLECULE THROUGH FORMING A CO-CRYSTAL COMPLEX Synthesis and Crystal Structure of [Cdphen3](BF4)2-2CNA

Abstract

The co-crystal 1:2 adduct [Cdphen₃](BF₄)₂-2CNA (1) (phen = phenanthroline-N ¹, N ¹⁰ and CNA = 4-chloro-2-nitro-benzenamine) has been prepared by crystallization of bis (tetrafluoroborate)tri-s(phenanthroline)cadmium(II), [Cdphen₃](BF₄)₂, in the presence of 4-chloro-2-nitrobenzenamine. Single crystal X-ray analysis revealed that the cadmium(II) ion exhibits a distorted octahedral geometry with Cd-N bond distances of 2.337(3)-2.374(3)Å. The organic guest molecules are packed with the plane of the molecules parallel to the phenanthroline ligands. Both intra- and intermolecular hydrogen bonding is important in the complex.     

Cyclization of ortho-(alk-2-enyl)anilines under the action of iodine

The reaction of ortho-(cyclohex-2-enyl)aniline with I₂ in nonpolar and polar solvents affords predominantly 1-iodohexahydrocarbazole and azatricyclotridecatriene, respectively. Under analogous conditions, 4-methyl-2-(1-methylbut-2-en-1-yl)aniline undergoes cyclization to form exclusively products with quinoline structures regardless of the solvent used.     

Heterocyclic variants of the 1,5-benzodiazepine system. V. Derivatives of 2-(ortho-R1-anilino)-4-(p-R2-phenyl)-3H-1,5-benzodiazepines

Mono-N-methylation of 2-(ortho-R₁-anilino)-4-(p-R₂-phenyl)-3H-1,5-benzodiazepines IV is achieved in moderate yield with sodium hydride in methyl iodide. Reaction of the N-methyl derivatives I with methoxyacetyl chloride gave the compounds II and III . The structure of all products was confirmed by ir, ¹H-nmr and mass spectrometry.     

Synthesis,characterization and luminescence of the tetranuclear gold cluster: [Au4{7,8-(PPh2)2-7,8-C2B9H10}2(PPh3)2]

A tetranuclear gold cluster has been synthesized by the reaction of [Au(PPh₃)NO₃] with the closo carborane diphosphine 1,2-(PPh₂)₂-1,2-C₂B₁₀H₁₀ in THF, and characterized by elemental analysis, FT-IR, ¹H and ¹³C?NMR spectroscopy and X-ray structure determination. The cluster crystallizes in the triclinic Pī, a?=?15.118(8)?Å, b?=?16.057(9)?Å, c?=?24.284(13)?Å, α?=?80.822(9)°, β?=?79.624(8)°, γ?=?81.938(8)°, Z?=?2, R ₁?=?0.0626, wR ₂?=?0.1894. A single crystal structure determination showed that four gold atoms form a tetrahedral framework. Among these four gold atoms, two were chelated by two nido carborane diphosphine [7,8-(PPh₂)₂-7,8-C₂B₉H₁₀]^? anions coming from the degradation of the initial closo ligand 1,2-(PPh₂)₂-1,2-C₂B₁₀H₁₀, while the other two were ligated to two PPh₃ groups. The luminescence of this cluster was also investigated in dichloromethane solution at room temperature.     

Hindered rotation of ligands in cis-[PtR2Cl2] complexes

The temperature dependence of the¹H NMR spectra ofcis-[Pt(II)R₂Cl₂] complexes was studied in DMSO at 18–100°C (R is 2-methyl and 2,5-dimethylpyridine). The broadening of the signals from the methyl groups or hydrogen atoms in theortho-positions of heteroaromatic ligands is due to the coexistence of two forms of thecis-complexes in solution. These forms arise from the hindered rotation of asymmetrical ligands around the Pt-N bond.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 424–425, February, 1993.     

Reactions of isomeric 3,6- and 3,5-di-tert-butyl-ortho-benzoquinones with NH3

The interaction of 3,6-di-tert-butyl-ortho-benzoquinone (1) and 3,5-di-tert-butyl-ortho-benzoquinone (2) with NH₃ in water—alcohol medium and with (NH₄)₂CO₃ in a solid phase has been studied. Redox processes with participation of a nucleophile of the medium take place for1, while2 reacts with NH₃ at the carbonyl group with transformation of the quinone imide. The mechanism of redox transformation of1 has been proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1789–1793, September, 1995.This work was carried out with financial support from the Russian Foundation for Basic Research (Project No. 94-03-08653).     

Synthesis of 2-aryl-6-(4-bromophenyl)-4-(2,2-dichlorovinyl)pyridines with the use of 1-aryl-5,5-dichloropenta-2,4-dien-1-ones

Heating 1-aryl-5,5-dichloropenta-2,4-dien-1-ones with 4-bromophenacylpyridinium bromide in AcOH in the presence of AcONH₄ gave 2-aryl-6-(4-bromophenyl)-4-(2,2-dichlorovinyl)pyridines. The reaction products were structurally characterized by¹H and¹³C NMR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 955–957, May, 2000.     

Zur Dimorphie von Nd3Cl[SiO4]2

On the Dimorphism of Nd₃Cl[SiO₄]₂ On reacting NdCl₃, Nd₂O₃, and SiO₂ (molar ratio: 1 : 4 : 6) at 850 °C in evacuated silica tubes, pale violet, hydrolysis resistant neodymium(III) chloride ortho‐silicate Nd₃Cl[SiO₄]₂ can be obtained within seven days. If equimolar amounts of NaCl are added as flux, rod‐ or platelet‐shaped, transparent single crystals of two modifications accumulate simultaneously. The one with the higher density (A‐Nd₃Cl[SiO₄]₂) crystallizes monoclinically (C2/c, no. 15; a = 1416.6(1), b = 638.79(6), c = 872.21(9) pm, β = 98.403(7)°; V_m = 117.55 cm³/mol, Z = 4), whereas the one with the lower density (B‐Nd₃Cl[SiO₄]₂) exhibits orthorhombic symmetry (Pnma, no. 62; a = 709.36(7), b = 1815.7(2), c = 631.48(6) pm; V_m = 122.45 cm³/mol, Z = 4). Two crystallographically independent Nd³⁺ cations exist in each of both crystal structures, which in the A type are surrounded by nine (1 Cl^– + 8 O^2–) and ten (2 Cl^– + 8 O^2–), whilst those in the B type by only two times eight (1 Cl^– + 7 O^2– and 2 Cl^– + 6 O^2–) anions, respectively. Thereby all oxygen atoms of both forms represent members of discrete ortho‐silicate tetrahedra ([SiO₄]^4–). Although both crystal structures are built of alternating anionic double layers {(Nd1)₂[SiO₄]₂}^2– and cationic single layers {(Nd2)Cl}²⁺, there is a higher cross‐linkage of the building units in the A‐type lattice, where the cations are coordinated by three and four tetrahedra edges of ortho‐silicate anions, compared to only two times two of them in the B type. From this an about 4% higher density of Nd₃Cl[SiO₄]₂ results for the A‐type structure (D_x = 5.55 g/cm³) in comparison with B‐type Nd₃Cl[SiO₄]₂ (D_x = 5.33 g/cm³).     

Synthesis and antioxidant properties of N-substituted aminomethyl derivatives of 2-isobornylphenol

A series of 2-isobornylphenol derivatives containing aminomethyl groups either at ortho-(monoderivatives) or ortho- and para-positions (bis-derivatives) relative to the hydroxy group of phenol moiety was synthesized. Antioxidant properties of the obtained compounds were comparatively evaluated using in vitro models. It was demonstrated that Mannich bases containing an n-octylaminomethyl group are significantly exceeding both starting 2-isobornylphenol and the standard antioxidant, 2,6-di-tert-butyl-4-methylphenol, by their ability to inhibit H₂O₂-induced erythrocyte hemolysis.

     

Triphenylethanediol-Derived 2-Chloro-1,3,2- dioxaphospholane: Synthesis,Structure, and Reaction with Chiral Alcohols

The reaction of (S)-1,1,2-triphenylethanediol (3) with phosphorus trichloride leads to the diastereoselective formation of (S _C,R _P)-2-chloro-1,3,2-dioxaphospholane (2). Its configuration has been determined by single crystal X-ray diffraction. When reacted with racemic secondary alcohols, diastereomeric phosphites are obtained, which display substantial shift differences in the ³¹P NMR spectra. Thus, chlorodioxaphospholane 2 can serve as derivatizing reagent for chiral secondary alcohols permitting to determine their enantiomeric excess.     

Raman and infrared spectra of6Li2C2O4 and7Li2C2O4

Raman and infrared spectra of polycrystalline⁶Li₂C₂O₄ and⁷Li₂C₂O₄ have been investigated in the wavenumber region from 1,800 to 40 cm^–1. The internal C₂O₄ ^–2 vibrations have been studied on the basis of a D_2h molecular structure and the correlation field splittings have been found to be about 40 cm^–1 for the stretching modes and about 15 cm^–1 for the bending modes. The external vibrations of the Li⁺ and C₂O₄ ^–2 sites have been discussed by considering the results of the factor group analysis and the⁶Li/⁷Li isotope effect on the normal vibrations.

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Raman- und Infrarot-Spektren von⁶Li₂C₂O₄ und⁷Li₂C₂O₄

Zusammenfassung Es wurdenRaman- und IR-Spektren von polykristallinem⁶Li₂C₂O₄ und⁷Li₂C₂O₄ im Bereich der Wellenzahlen von 1800 bis 40 cm^–1 untersucht. Die internen Schwingungen wurden auf der Basis einer D_2h Molekülstruktur analysiert. Für die Streckschwingungen wurde eine Korrelationsaufspaltung von etwa 40 cm^–1 gefunden, für die Deformationsschwingungen etwa 15 cm^–1. Die Diskussion der externen Schwingungen von Li⁺ und C₂O₄ ^–2 erfolgte unter Berücksichtigung der Resultate der Faktorgruppenanalyse und des⁶Li/⁷Li Isotopeneffekts auf die Normalschwingungen.

     

Diorganotin Complexes with N(4)-Phenylthiosemicarbazones: Synthesis,Spectroscopic Characterization,and Antibacterial Activity

Abstract

The organotin(IV) complexes, SnPh₂L^a (1), SnMe₂L^a (2), SnBu₂L^a (3), SnPh₂L^b (4), SnMe₂L^b (5), SnPh₂L^c (6), SnMe₂L^c (7), and SnBu₂L^c (8) were obtained by reaction of SnR ₂Cl₂ (R = Ph, Me, and Bu) with 1-(5-bromo-2-hydroxybenzylidene)-4-phenylthiosemicarbazide (H₂L^a), 1-((2-hydroxynaphthalen-1-yl)methylene)-4-phenylthiosemicarbazide (H₂L^b), and 1-(2-hydroxy-3-methoxybenzylidene)-4-phenylthiosemicarbazide (H₂L^c). The synthesized complexes have been investigated by elemental analysis, IR, ¹H NMR, and ¹¹⁹Sn NMR spectroscopy. The data show that the thiosemicarbazone acts as a tridentate dianionic ligand and coordinates via the thiol group, imine nitrogen, and phenolic oxygen. The coordination number of tin is 5. The in vitro antibacterial activities of the ligands and their complexes have been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and compared with the standard antibacterial drugs.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the following free supplemental files: Additional figures and tables]     

Novel Bifunctionalization of Activated Methylene: Base-Promoted Trifluoromethylthiolation of β-Diketones with Trifluoromethanesulfinyl Chloride

A novel bifunctionalization of activated methylene was achieved successfully through the base-promoted trifluoromethylthiolation of β-diketones or β-ketoesters with trifluoromethanesulfinyl chloride. A series of α-trifluoromethylthiolated α-chloro-β-diketones and α-chloro-β-ketoesters were obtained in moderate to good yields under mild conditions. When β-diketones containing a phenyl group with a hydroxyl or amino substituent at the ortho position were used as substrates, intramolecular trifluoromethylthiolation/cyclization reaction took place to give the corresponding cyclic products. Furthermore, the protocol could be extended to perfluoroalkylthiolation with the sodium perfluoroalkanesulfinate/POCl₃ system. On the basis of experimental results, plausible mechanisms are proposed.     

ortho‐Benzoxylation of N‐Alkyl Benzamides with Aromatic Acids Catalyzed by Ruthenium(II) Complex

A highly regioselective ortho‐benzoxylation of N‐alkyl benzamides with aromatic acids in the presence of [{RuCl₂(p‐cymene)}₂], AgSbF₆, and (NH₄)₂S₂O₈ in 1,2‐dichloroethane at 100 °C for 24 h affording ortho‐benzoxylated N‐alkyl benzamides by C?H bond activation is described. Further, Ru‐catalyzed alkenylation is done at the ortho C?H bond of benzoxylated N‐alkyl benzamides with alkenes in water solvent. Subsequently, the benzoxyl moiety of N‐alkyl benzamides was converted into a hydroxyl group in the presence of base or acid. A possible reaction mechanism was proposed to account for the present coupling reaction.