Spectrophotometric determination of nickel with cyclohexylidine-ammonium 2-aminocyclohexylidene-1-cyclohexene-1-dithiocarboxylate

An (extraction)-spectrophotometric method is reported for the determination of nickel(II) with cyclohexylidineammonium 2-aminocyclohexylidene-l-cyclohexene-l-dithiocarboxylate. The violet 1:2 chelate is soluble in aqueous ethanolic or acetonic media at pH 6–9, or can be extracted into methyl isobutyl ketone. The molar absorptivity of the complex is about 2.5 × 10⁴ l mol^?1 cm^?1 at 550 nm.     

1,4-Dihydro-1λ5,4λ5-[1,4]diphosphinine und ein 1,4-Dihydro-1λ3,4λ3-[1,4]diphosphinin

1,4-Dihydro-1λ⁵,4λ⁵-[1,4]diphosphinines and a 1,4-Dihydro-1λ³,4λ³-[1,4]diphosphinine Reaction of thio- or dithiocarbonic acids with ethinyl amino phosphanes leads to 1,4-dihydro-1λ⁵,4λ⁵-[1,4]diphosphinine-1,4-disulfides. By this route compounds 4, 7 , and 8 have been prepared. Desulfurization of 4 with tri-n-butylphosphane results in 1,2,4,5-tetraphenyl-1,4-dihydro-1λ³,4λ³-[1,4]-diphosphinine 5 , which can be oxidized with tert-butyl-peroxide to the corresponding dioxide, 6 . From the reaction mixture of phenyl-phenylethinyl diethylamino phosphane and thioacetamide compound 4 and the unsymmetrical 1,4-dihydro-1λ⁵,4λ⁵-[1,4]diphosphinine 9 were isolated. Properties, nmr, ir and mass spectra of all new products are reported. A mechanism for the formation of 9 is suggested. The results of the X-ray structure determination of 8 and 9 are described.     

Zur Reaktion des 1-Lithio-3-(trimethylsilyl)-2,2,4,4,6,6-hexamethylcyclotrisilazans mit Silicium-Fluor-Verbindungen

The Reaction of 1-Lithio-3-(trimethylsilyl)-2,2,4,4,6,6-hexamethylcyclotrisilazane with Silicon-Fluoro Compounds 1-lithio-3-(trimethylsilyl)-2,2,4,4,6,6-hexamethylcyclotrisilazane reacts with fluoroorganylsilanes RR′SiF₂ (R = F, CH₃, sec-C₄H₉; R′ = CH₃, sec-C₄H₉, C₆H₅) to give mono- and disubstituted trimethylsilylhexamethylcyclotrisilazanes and LiF. The mass-, ¹H- and ¹⁹F-n.m.r. spectra are reported.     

Synthesis and Properties of Glass-Forming Hydrazones II [1]. Hydrazones Containing Bicarbazolyl Units

 A series of new glass-forming hydrazones containing bicarbazolyl units were synthesized starting from 9-(2-(9H-carbazol-9-yl)-cyclobutyl)-9H-carbazole and 9-(6-(9H-carbazol-9-yl)-hexyl)-9H-carbazole, and their thermal properties were studied. The correlation between their inclination to form glasses and their chemical structures are discussed. The results of a preliminary investigation of the photoelectric properties of amorphous films of the title compounds are briefly reported. The highest hole drift mobility was observed for 9-(2-(9H-carbazol-9-yl)-cyclobutyl)-9H-carbazole-3-carbaldehyde N,N-diphenylhydrazone; at high electric fields, it approaches 1 · 10⁻³ cm²/Vs.     

A new method for the conversion of aldehydes (RCH2CHO)to acetylenes (RC&.tbnd;CH) via 1-alkenylstannanes. Application to the synthesis of 9(O)-thia-Δ6-PGI1

A method for the conversion of aldehydes to acetylenes via 1-alkenylstannanes is reported, including its application to the synthesis of 9(O)-thia-Δ⁶-PGI₁.     

19F-detected dual-optimized inverted 1JCC 1,n-ADEQUATE

Modification of the recently reported ¹⁹F-detected 1,1-ADEQUATE experiment that incorporates dual-optimization to selectively invert a wide range of ¹J_CC correlations in a 1,n-ADEQUATE experiment is reported. Parameters for the dual-optimization segment of the pulse sequence were modified to accommodate the increased size of ¹J_CC homonuclear coupling constants of poly- and perfluorinated molecules relative to protonated molecules to allow broadband inversion of the ¹J_CC correlations. The observation and utility of isotope shifts are reported for the first time for 1,1- and 1,n-ADEQUATE correlations.     

Microbial transformation of cannabinoids. Part 3: Major metabolites of (3R, 4R)-Δ1-tetrahydrocannabinol

The metabolic transformations of the psychotropic cannabinoid (3R, 4R)-Δ¹-tetrahydrocannabinol (5) (=Δ¹-THC) by cultures of Fusarium Nivale, Gibberella fujikuroi (both Ascomycetes) and Thamnidium elegans (Phycomycetes) were investigated. A number of metaboilites, 1–4 and 6–9 were isolated from the incubations, partly purified and their structures elucidated by combined gas chromatography/mass spectrometry. Four of these metabolites, 1″-hydroxy-Δ¹-THC (4) 2″-hydroxy-β¹-THC (1) 6Δ-hydroxy-ζ¹-THC (8) and 2″,6Δ-dihydroxy-Δ¹-THC (9) so far have not been reported as microbial transformation products of 5 .     

Synthesis and Properties of Glass-Forming Hydrazones II [1]. Hydrazones Containing Bicarbazolyl Units

Summary.  A series of new glass-forming hydrazones containing bicarbazolyl units were synthesized starting from 9-(2-(9H-carbazol-9-yl)-cyclobutyl)-9H-carbazole and 9-(6-(9H-carbazol-9-yl)-hexyl)-9H-carbazole, and their thermal properties were studied. The correlation between their inclination to form glasses and their chemical structures are discussed. The results of a preliminary investigation of the photoelectric properties of amorphous films of the title compounds are briefly reported. The highest hole drift mobility was observed for 9-(2-(9H-carbazol-9-yl)-cyclobutyl)-9H-carbazole-3-carbaldehyde N,N-diphenylhydrazone; at high electric fields, it approaches 1 · 10⁻³ cm²/Vs. Received September 17, 2001. Accepted (revised) October 16, 2001     

Vibrational spectra of 1:2 ordered perovskites

The infrared and Raman spectra of some perovskites with general formula A₃BB′₂O₉ are reported, viz. Sr₃MgNb₂O₉, Sr₃CaNb₂O₉, Pb₃MgNb₂O₉, and Ba₃Gd₂WO₉. The interpretation is by far not as simple as for 1:1 ordered perovskites. Only a rough assignment of the internal modes of the niobate and tungstate octahedra can be made. The spectra of the niobates are very sensitive to the degree of order between the divalent metal ions and the Nb⁵⁺ ions among the smaller cation sublattice. This is evaluated qualitatively.     

Homonuclear Overhauser 1H-NMR. Experiments on the Carotenoid Pigments Lycopene and Prolycopene

The recently proposed structure of the carotenoid pigment prolycopene as the 7,9,7′,9′-tetra-cis isomer of lycopene has been unambiguously confirmed by a series of homonuclear Overhauser ¹H-NMR. experiments at 270 MHz. Comparative measurements are reported for lycopene.     

Triphospholes as 2e and 4e donors: Synthesis and structural characterization of the 1,2,4-triphosphole complexes η1-trans-[PtCl2(PEt3)(P3C2BuCH(SiMe3)2] and η1-η1-trans-[PtCl2(PEt3)2}2(μ-P3C2BuCH(SiMe3)2]

The first examples of η¹-complexes of 1,2,4-triphospholes are reported in which the ring acts as a 2e and a 4e donor. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:1–8, 1998     

The 1,3B 1— 1A 1 systems of the nitrite anion in a NaHCO 2 host crystal

The lower energy electronic transitions of the NO ^?₂ anion in a NaHCO ₂ host crystal at 4 K are reported and analyzea. The ¹B ₁— ¹A ₁ system, whose origin is at 25 649 cm ^?1, is seen in absorption and fluorescence accompanied by a long progression in the symmetric bending mode (ν′ ₂ = 626, ν″ = 820 cm ^?1). The implied change in the ONO bond angle is 9 ± 3 ⁰. The ³B ₁ → ¹A ₁ phosphorescence is quite weak with an extrapolated origin at 18 059 cm ^?1. The ¹B ₁ ← ¹A ₁ absorption linewidths, the lower-resolution fluorescence photoexcitation spectrum, and the relative phosphorescence and fluorescence intensities suggest the involvement of an intermediate state in populating the triplet manifold after excitation of the ¹B ₁ state.     

Electrophilic substitution of 1-methylindeno-1H-[2,1-b]pyridine

It is shown that electrophilic substitution of 1-methylindeno-1H-[2,1-b]pyridine takes place at the C₉ atom in the case of acylation (acetylation, benzoylation, and formylation), bromination, and nitration. Data from the ¹³C NMR spectrum of this pseudoazulene confirm sp² hybridization of the C₉ atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1238–1240, September, 1982.     

Comprehensive 1H and 13C NMR assignment of 13 protobassic acid saponins

This study aimed to carry out complete ¹H and ¹³C NMR assignment of 13 protobassic acid saponins, including arganins A–C ( 1 – 3 ) and F ( 4 ), butyrosides B–D ( 5 – 7 ), tieghemelin ( 8 ), 3′-O-glucosyl-arganin C ( 9 ), Mi-saponins A–C ( 10 – 12 ), and mimusopsin ( 13 ), recorded in methanol-d₄. This was accomplished by the analysis of high-resolution one-dimensional (1D) NMR (¹H and ¹³C), two-dimensional (2D) NMR (¹H–¹H COSY, HSQC, and HMBC), and selectively excited 1D TOCSY spectra. Before this study, ¹H and ¹³C NMR data of arganins A–C ( 1 – 3 ) and F ( 4 ) were partially assigned. Our effort leads to their complete assignment, especially the glycon residue, and revises some reported data. Some revisions of the ¹H and ¹³C NMR data in the glycon part of butyroside C ( 6 ), tieghemelin ( 8 ), Mi-saponin A ( 10 ), and mimusopsin ( 13 ) were made. Those data of butyrosides B and D ( 5 & 7 ) and Mi-saponin B ( 11 ), which had not been recorded in methanol-d₄, are provided. In addition, the ¹H and ¹³C NMR data of Mi-saponin C ( 12 ) are reported for the first time. These data, being recorded in methanol-d₄, should be more friendly for use as a reference for identifying the related triterpenoid saponins.     

Chemistry of the phenoxathiins IV. Synthesis of 9-substituted 1 -azaphenoxathiins

In an extension of recently reported syntheses of the I-azaphenoxathiin nucleus as well as several 7-substituted analogs, the synthesis of several 9-substituted members of this series is now reported. In addition, the first ¹³C-nmr spectral evidence of an interaction between a sulfur atom and the oxygen of an ortho-nilro group which has been previously observed only in X-ray erystallographic studies is also described. The possible consequences of this interaction on the reaction pathway leading to the cyclization of the 9-substituted J-azaphenoxathiin nucleus is also presented.     

Reactions of (Nonafluorocyclohexen-1-yl)xenon(II) Hexafluoroarsenate with Halide Anions

The products of the reaction between the electrophilic alkenylxenonium cation [1-Xe⁺–C₆F₉] and the halide anions I^?, Br^?, Cl^? and F^? depend on the hardness of the halide anion. With the soft halides I^? and Br^? Xe(II) is formally displaced by halogen as well in basic MeCN as in superacidic (AHF¹), whereas with hard fluoride and chloride no reaction takes place in AHF. In MeCN F^? initiates the formation of alkenyl radicals, which abstract hydrogen from the solvent, whereas Cl^? exhibits borderline character: RH and RCl formation. Possible reaction paths are discussed. The reactivity of the arylxenonium cation [C₆F₅Xe]⁺ in AHF toward halide ions is reported and the relative electrophilicity of the cations [C₆F₅Xe]⁺ and [1-Xe⁺–C₆F₉] is determined by the competitive reaction with Cl^?. In addition the synthesis of cyclohexene 1-CF₃–C₆F₉ from C₆F₅CF₃ and XeF₂ is performed and its electrophilicity is compared with that of the aromatic compound C₆F₅CF₃.     

An 1H and 13C NMR study of pentane-2,4-dione tellurium(II) compounds; chemical shifts, 125Te?1H and 125Te?13C couplings

¹H and ¹³C NMR data are reported for pentane-2,4-dione tellurium(II) compounds which contain a 6-membered tellurane ring bearing methyl or ethyl substituents. The ¹²⁵TeCH coupling constants are particularly interesting in that they are highly stereospecific, viz. ～60 Hz and 0–8 Hz for equatorial and axial protons, respectively, in the chair conformation. ¹J(TeC) and ²J(TeCC) couplings lie in the ranges 118–146 Hz and 44–49 Hz, respectively. Geminal HCH couplings in these compounds (9–11 Hz) are lower than analogous values in tellurane or in cyclohexane-1,3-diones.     

Laser induced D 1Π-a3∑ fluorescence of the nak molecule

Five systems of the D ¹Π-a³∑⁺ transition of NaK molecules, assigned as α, β,γ, δ and ? are observed with various single mode 4765 Å argon ion laser line excitations Among them, only system α had been reported and analyzed previously. The headsof these systems are at 15978, 16610, 16857, 16914 and 16671 cm^-1, respectively The estimated upper and lower vibrational levels for these systems are ν' = 12, 22, 31 ± 2, 35 ± 2 and 24 ± 2 of the D ¹Π state and ν″ = 0, 5, 8 ± 1, 9 ± 1, and 6 ± 1 of the X¹∑ state.     

Studies on β methyl-1-and 3-phenyl allyl chlorides

The hydrolysis of β-methyl-1- and 3-phenylallyl chlorides (1a and 1b) have been investigated in aqueous dioxan and the proposed mechanism compared with those reported for the corresponding 1- and 3-phenylallyl chlorides (2a and 2b). Hydrolysis of 1a and 1b proceeds via the same mechanism as 2a and 2b, respectively, with different behavior by the first intermediate. The first intermediate of 1a rearranges to the corresponding conjugated compound through a transition state rather than an intermediate. Theoretical calculations on the carbonium ions of 1 and 2 using a semiempirical MINDO/3 molecular orbital method show that the charge densities on carbon atoms of 1 are nearly the same as those of 2. The main difference is in the bond angle C¹-C⁸-C⁹.     

Substituent Effects on the 31P NMR Chemical Shifts of 1-Amino- and 1-Hydroxy-Alktlphosphonic Acids

Abstract

³¹P NMR chemical shift.s are reported for 14 1-amino-and 10 1-hydroxy-alkylphosphonic acids. To derive an exact 31 value of substituent interaction effects the ³¹P NMR data of some related free phosphonic acids are also reported.