Synthese et Comportement Polarographique Des Cis et Trans Azoxycyclohexanes

Abstract

In order to compare the polarographic behaviour of cis and trans aliphatic azoxy compounds, synthesis and polarographic study of cis and trans azoxycyclohexanes are performed. The cis form is a new compound obtained by photoisomerisation of the trans compound. In acid medium the polarographic reduction process is the same for both forms: hydrazocyclohexane is the final reduction product. In alkaline medium the trans azoxy compound is electroinactive and the cis azoxy compound is reducible and leads to a mixture of trans azocyclohexane and hydrazocyclohexane.     

4,5-dihydro-5,5-dimethyl-3-oxo-3H-1,2,4-triazole-1-oxide. The unpredicted azoxy-regioisomer

Summary 4,5-Dihydro-5,5-dimethyl-3-oxo-3H-1,2,4-triazole (1) is converted to the title azoxy compound4 by peroxytrifluoroacetic acid. The structure assignment of4 is based on an X-ray analysis.Ab initio calculations were employed to rationalize the reaction path leading to the triazole-1-oxide4 and not to the expected regioisomer triazole-2-oxide3.

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4,5-Dihydro-5,5-dimethyl-3-oxo-3H-1,2,4-triazol-1-oxid. Das unerwartete Regioisomere

Zusammenfassung 4,5-Dihydro-5,5-dimethyl-3-oxo-3H-1,2,4-triazol (1) wird mit Trifluorperessigsäure in die Titel-Azoxy-Verbindung4 umgewandelt. Die Strukturzuordnung von4 basiert auf einer Röntgenstrukturanalyse. Mittelsab initio-Rechnungen wird versucht zu erklären, weshalb die Reaktion zum Triazol-1-oxid4 und nicht zum erwarteten regioisomeren Triazol-2-oxid3 führt.

     

Oxidation of 1-hydrazino-3,3-dimethyl-3,4-dihydroisoquinoline. X-ray,spectroscopic, and quantum-chemical study of the structure of 3,3-dimethyl-3,4-dihydroisocarbostyryl azine

3,3-Dimethyl-3,4-dihydroisocarbostyryl azine (2) has been synthesized by oxidation of l-hydrazino-3,3-dimethyl-3,4-dihydroisoquinoline (1). The crystal and molecular structures of compound 2 were determined. It has been established that in the solid state, compound2 exists as an azine tautomer. The IR, electronic, and NMR spectral data indicate that in solution the tautomeric form of2 does not change. A possible mechanism of the oxidation of1 to2 is suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2468–2474, December, 1995.The authors are grateful to Professor V. F. Zakharov (Russian University of People's Friendship) for recording the¹H NMR spectra.     

Calixarenes: Structure of an acetonitrile inclusion complex and some transition metal rimmed derivatives

The hostt-butylcalix[4]arene,1a, forms a 11 inclusion compound with acetonitrile as guest. The inclusion compound has been isolated and characterised by X-ray analysis of a twinned crystal at 123 K. The acetonitrile guest lies on a crystallographic four-fold symmetry axis passing through the centre of the bowl of1a which adopts a regular cone conformation. A known tetradentate and a new tridentate phosphinitocalix[4]arene derivative,2a and2c respectively, have been synthesized from1a and Ph₂Cl. Both2a and2c show a strong ability to coordinate with late transition metals and new complexes of gold(I), palladium(II) and platinum(II) are reported. Supplementary Data relating to this paper have been deposited with the British Library as Supplementary Publication No. SUP 92171 (5 pp.)This paper is dedicated to the commemorative issue on the 50th anniversary of calixarenes.     

Synthesis and study of organic nitrates of the heterofunctional series

The first representative of organic nitrates of the oxazoline series, 4,4-dihydroxymethyl-2-(3-pyridyl)-2-oxazoline dinitrate, was synthesized by the reaction ofN-nicotinoyltri(hydroxymethyl)aminomethane trinitrate hydronitrate (1) with a solution of KOH in alcohol. The reactivities of compound1 andN-nicotinoylethanolamine nitrate (nicorandil) in the reaction of intramolecular heterocyclization were compared. The structure of the compound synthesized has been established by X-ray diffraction analysis. For Part 1, see Ref. 1 Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 478–481, March, 1998.     

Synthesis ofN,N′-ditosyl-8, 19-dimethoxy-2,5-diaza-[6.1]-naphthyl-cyclophane: crystal and molecular structure of its 1∶1 chloroform solvate

The title compound, C₄₁H₄₀N₂O₆S₂, has been synthesised in good yield and was found to form a 11 inclusion compound with CHCl₃ and other organic solvents. The crystal and molecular structure of the CHCl₃ solvate has been determined by single crystal X-ray analysis and refined to anR-value of 0.034 for 3229 reflections. The compound is monoclinic, space groupP2₁/c, witha=15.316(1),b=14.515(1),c=18.720(3) Å, =101.98(1)^o, andZ=4. One molecule of chloroform is included in the crystal lattice. Supplementary data relevant to this article have been deposited with the British Library as Supplementary Publication No. SUP 82146 (9 pp.).     

2-Hydroxy-4-methoxy-trans-cinnamic acid as a precursor of herniarin inArtemisia dracunculus

The isolation of (E)-2-hydroxy-4-methoxycinnamic acid (1) fromArtemisia dracunculus L. supports strongly the assumption that this compound is an intermediate in the biosynthesis of 7-methoxycoumarin (herniarin,3). The structure of the UV-unstable compound1 was derived from¹H-NMR data and by comparison of the stable dimethylated derivative with synthetic (E)-2,4-dimethoxycinnamic acid methyl ester (2).Dedicated to Prof. Dr.Kurt L. Komarek on the occasion of his 60th birthday.     

Synthesis of Polyfunctional Drimanes from Drim-7,9(11)-diene and Drim-8-en-7-one

A series of 15 new polyfunctional drimanic compounds have been obtained by synthesis via dye-sensitized photooxygenation, bromination with N-bromosuccinimide, and electrochemical transformation of drim-7,9(11)-diene 1 and drim-8-en-7-one 2. Three alternative syntheses of 12-acetoxy-drim-7,9(11)-diene 8 and two of 11-bromo-drim-8(9)-en-7-one 10 have been accomplished. For the first time a drimanic compound 12 with an aromatic ring B has been synthesized and the experimental conditions for the selective bromination at C₁₁ and C₁₂ methyl groups of drim-8-en-7-one 2 have been optimized. The synthesized compounds are suitable intermediates for the preparation of natural drimane-type compounds and some of them have shown good antimicrobial and antifungal activities.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

An X-ray study of a 12-crown-4 host-guest complex. Crystal structure of the 4∶6 complex between 12-crown-4 and aminosulfuric acid

The title compound was prepared by treating a methanolic solution of 12-crown-4 with an aqueous solution of aminosulfuric acid. The crystal for X-ray analysis was obtained by recrystallization from acetone. The compound [(12-crown-4)₄·[NH₃SO₃)₆] (1) is monoclinic, space groupP2₁/a,a=21.900(8),b=15.499(5),c=18.079(5) Å, =67.85(2)°. Refinement led to a final conventionalR value of 0.0788 for 3280 reflections. Supplementary Data relating to this publication have been deposited with British Library as Supplementary Publication No. 82160 (22 pages) and include: the list ofF _obs,F _calc; tables of bond distances, bond angles and selected least square planes, as well as a figure of 12-crown-4 in C₄-conformation.     

Isolation and structure determination of a new flavone glycoside from seed residues of seabuckthorn (Hippophae rhamnoides L.)

In this study, a valid method was established for the isolation and purification of flavone glycosides from Hippophae rhamnoides L. seed residues using high-speed counter-current chromatography in one step, with a solvent system of ethyl acetate-methanol-n-butyl alcohol-water (9:1:0.5:9, v/v/v/v). A total of 28.8 mg compound I and 57.3 mg compound II were obtained from 200 mg of flavone H-glycosides rich extract, with purities of 98.3 and 96.4%, respectively. The structures of two compounds were identified by MS and NMR. 3-O-β-D-Sophorosylkaempferol-7-O-{3-O-[2(E)-2,6-dimethyl-6-hydroxyocta-2,7-dienoyl]}-α-L-rhamnoside is compound I and compound II named hippophanone is a new compound were identified by MS and NMR. The method was efficient and convenient, which could be used for the preparative separation of flavone glycosides from H. rhamnoides L. seed residues.     

Dieisen(III)-hexacyanoferrat(II)-oxid

The title compound3 has been obtained through the action of molecular oxygen upon di-iron(II)-hexacyanoferrate(II)1 which has been prepared by thermal decomposition of ammonium hexacyanoferrate(II)2 in vacuum.2 und3 have been characterized by analytical methods andMössbauer-spectroscopy.3 and the analogous halogen compounds are semiconductors with a conductivity of 2 to 5 · 10^–5 S/cm.2 is ideally suited for the quantitative absorption of oxygen from water and organic solvents.

Herrn Prof. Dres. mult.Viktor Gutmann, Institut für Anorganische Chemie der Technischen Universität Wien, mit besten Wünschen zur Vollendung des 65. Lebensjahres gewidmet.     

Effect of fluorine substitution on stretching vibrations of the azoxy group in azoxybenzenes

The IR and Raman spectra of azoxybenzene (I) and a number of its fluoroderivatives have been analysed, including the ¹⁵N and ¹⁸O labelled samples and complexes of some azoxybenzenes with SbCl₅. On the basis of the calculated frequencies and forms of normal vibrations of compound (I) in the valence force field, the vibration spectrum has been interpreted. The presence and number of fluorine atoms in the phenyl fragments of azoxybenzenes have practically no effect on the stretching frequencies of the azoxy group but considerably decrease the band intensity of vibrations of the azoxy and phenyl groups in the Raman spectra. Introduction of fluorine into the aromatic rings of azoxybenzenes considerably complicates complex formation with SbCl₅ at oxygen of the azoxy group.     

硫杂杯[4]芳烃氧化膦衍生物的合成与晶体结构

合成了部分取代的硫杂杯[4]芳烃氧化膦衍生物, 二(亚甲基二苯基氧化膦)对叔丁基硫杂杯[4]芳烃(化合物1), 培养了化合物的单晶, 用Smart 1000 CCD衍射仪测定了其晶体结构. 结果表明, 1的组成为: C₆₆H₇₀O₆P₂S₄•2CH₃OH, 属三斜晶系, P1空间群, 晶胞参数a＝1.3453(6) nm, b＝1.5289(7) nm, c＝1.7893(9) nm; α＝75.707(9)°, β＝69.131(8)°, γ＝79.734(9)°, Z＝2; V＝3.316(3) nm³, d＝1.215 g/cm³, F(000)＝1288, μ (Mo Kα)＝0.244 mm^－1, R₁＝0.0625, wR₂＝0.1372. 杯芳烃分子采取了锥式构象.     

1,1- Bis(diphenylphosphinoyl)ethanol. Synthesis and complexes with neodymium and copper nitrates

A preparative method for the synthesis of 1,1-bis(diphenylphosphinoyl)ethanol (1) has been elaborated. In CHCl₃ and MeCN solutions compound1 is associated into H-bonded dimers (-H 12 kcal mol^–1). Complexes of compound1 with Nd^III, Cu^II, and Cu^I nitrates have been studed. The H-bonded dimers are retained upon complexing.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 928–931, May, 1994.     

A New Tetraaza Macrotricycle and Its Inclusion Compound with Chloroform. Synthesis and Crystal Structures

A new tetrasubstituted tetraaza macrotricycle 1 was prepared and shown to form a crystalline inclusion compound with chloroform, 1 chloroform (1:2). Crystal structures of the two compounds are reported. In the unsolvated 1, tightly interlocked packing of the molecules involving -stacking interactions of the aromatic groups is determined while in the inclusion compound with chloroform the solvent molecules are accommodated into channels possessing C—H···FFN contact to 1.Supplementary Datarelevant to this publication have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication Nos. CCDC 221992 and 221993.     

Molecular recognition on supramolecular systems (XXXV)

A novel β-cyclodextrin derivative4 bearing a pyridinio group on the primary side was synthesized by the reaction of 2-aminopyridine with 6-β-cyclodextrin monoaldehyde3, and its complexation stability constants with several aliphatic amino acids have been determined in phosphate buffer solution ( pH = 7.2, 0.1 mol·L⁻¹) at 25 °C by using spectrofluormetric titrations. The stoichiometry is 1:1 for the inclusion complexation of amino acids with compound4. Circular dichroism study indicates that the aromatic moiety was embedded shallowly into the cyclodextrin cavity. As a spectral probe, the pyridinio group in the modified cyclodextrin can recognize not only differences of the size and shape of amino acid molecules, but also theL/D-amino acid chiral isomer. As compared with mono-[6-(1-pyridinio)-6-deoxy]-β-cyclodextrin5, compound4 switched the enantiomer preference forL- toD-isomer, and showed the highest enantioselectivity of 5.4 forD/L-serine. These results are discussed from the viewpoints of geometric compensation, induced-fit concept and cooperation of several weak interactions.     

The 7.25-hydrate oftert-butylamine. A semi-clathrate and complex variant of the cubic 12 Å structure type

Of the various hydrates oftert-butylamine, the title compound has been identified as the second-highest, melting incongruently at –19°C. Its crystal structure (orthorhombic, space groupPca2₁,Z=32 formula units per unit cell,a=24.80,b=16.440,c=25.29 Å) and the exact composition have been determined from X-ray diffraction at –150°C. The hydrate is a rather complex semi-clathrate, with the amine molecules not merely encaged, but also hydrogen-bonded, in a three-dimensional water host structure, which in turn is not fully four-connected. Nevertheless, it bears a clear relationship to the basic and genuine clathrate-hydrate cubic 12 Å type.Dedicated to Professor G. A. Jeffrey on his 80th birthday. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82196 (8 pages).Part 14 of the seriesHydrates of Weak and Strong Bases; for part 13 see [1].     

Beiträge zur Stereochemie der Additionsreaktionen an 3,4,5,6-Tetrahydropyridin-1-oxide. 2. Mitt.

4-tert-Butyl-3,4,5,6-tetrahydropyridine-1-oxide (1) and 6-butyl-3,4,5,6-tetrahydropyridine-1-oxide (2) were prepared and isolated in their monomeric forms. In many aprotic solvents these compounds are converted into their dimers. The main product in both cases is the addition product of identical enantiomers. In the case of compound1 a very small amount of an addition product of the optical antipodes is also formed, which is the thermodynamically most stable isomer. In contrast, compound2 yielded an addition product of the optical antipodes in larger amounts, with a thermodynamically less favourable structure. These dimerizations are solvent dependent, reversible and sensitive to steric hindrance.

     

Crystal structure of theβ-clathrate form of 4-p-hydroxyphenyl-2,2,4-trimethylselenachroman

In contrast top-hydroxyphenyl-2,2,4-trimethylchroman, Dianin's compound (1), or itsthia analogue2, the title seleno-ether has been found to form two crystallographically distinct types of clathrate. In the first-discovered form, the -modification of as yet undefined structure, the rhombohedral unit cell (R , a = 57.42(1) Å, c = 10.817(1) Å, [from EtOH]) has approximately four times the volume of that found in the clathrates of1 or2 and contains 72 host molecules. Recrystallisation of the selena-host fromn-hexane, however, produces another type of rhombohedral crystal: the-modification has space group R , witha=28.225(2)Å,c=10.859(1)Å, and 18 host molecules in the unit cell. A detailed X-ray study of this latter inclusion compound (host-guest ratio 6:1) has established its true clathrate nature; the disorderedn-hexane guest, showing electron density consistent with an extended planar zig-zag conformation, is found threading the hour glass-shaped cavity's central constriction. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82045 (25 pages).