Phytoecdysteroids of plants of the genusSilene XII. 5α-Ecdysterone 22-O-benzoate fromSilene scabrifolia

The new phytoecdysteroid 5α-ecdysterone 22-O-benzoate (I), C₃₄H₄₈O₃, mp 262–274°C (methanol-water) [α] _D ²⁰ +45.8° (methanol), has been isolated from the epigeal organ ofSilene scarbiofolia Kom. The alkaline hydrolysis of (I) led to 5α-ecdysterone (II) and benzoic acid. The isomerization of ecdysterone (0.6% KHCO₃ in CH₃OH) has yielded (II). Details of the IR, mass, and NMR spectra of compound (I) are given.     

Phytoecdysteroids of plants of the genus Silene. XI. 2-Deoxy-α-ecdysone 3-acetate from Silene scabrifolia

From the epigeal organs ofSilene scabrifolia Kom. has been isolated the new phytoecdysteroid 2-deoxy-α-ecdysone 3-acetate (II) (0.0011%), C₂₉H₄₆O₆, mp 216–218°, [α] _D ²⁰ +131.9° (methanol). The enzymatic hydrolysis of (II) led to 2-deoxy-α-ecdysone (I). The acetylation of 2-deoxy-α-ecdysone (I) yielded (II) and the 22-monoacetate (III) and 3,22-diacetate (IV) of 2-deoxy-α-ecdysone, which have been described previously. Details of the IR, UV, CD, mass, and NMR spectra are given for (I) and of the IR, mass, and NMR spectra for (III).     

Iron complexes of N-allylbenzotriazoles

Sodium benzotriazolide reacts with π-C₃H₅Fe(CO)₃I to give 1-N-allylbenzotriazoletricarbonyliron (I). The same product and the isomeric complex, 2-N-allylbenzotriazoletricarbonyliron (II), have been prepared independently, from the corresponding N-allylbenzotriazoles and Fe₂(CO)₉. The IR, ¹H NMR, and mass spectra of the complexes are reported. The structure of isomer I has been determined by X-ray diffraction. The crystals are monoclinic, P2₁/c, a = 10.65(1), b = 9.95(1), c = 12.90(1) Å, β = 113.69(7)°, d_calc = 1.39 g cm^?3, Z = 4.     

Spectroscopy and stereochemistry of the optically active copper(II), cobalt(II) and nickel(II) complexes with Schiff bases N,N′-(1R,2R)-(−)-1,2-cyclohexylenebis(3-methylbenzylideneiminato) and N,N′-(1R,2R)-(−)-1,2-cyclohexylenebis(5-methylbenzylideneiminato)

Schiff bases obtained from N,N′-(1R,2R)-1,2-cyclohexanediamine and 2-hydroxy-3-methylbenzaldehyde, 2-hydroxy-5-methylbenzaldehyde, have been used as ligands for copper(II), cobalt(II) and nickel(II). The complexes were characterized with UV–Vis, circular dichroism (CD), infrared, diamagnetic and paramagnetic ¹H NMR spectroscopy. CD spectra revealed exciton coupled π→π* transitions. Assignments of LMCT and d–d transitions in CD spectra of Ni(II), Co(II) and Cu(II) complexes is proposed. CD data are characteristic for central ion tetrahedral distortion from the planarity and λ conformation of the cyclohexane ring. ¹H NMR of Ni(II) complexes exhibited significant coordination shifts of CHN and ring protons which are in the closest proximity to Ni(II). The ¹H NMR paramagnetic spectra of Co(II) complexes revealed the most upfield shifted resonance at −60 ppm assigned to CHN and −28 ppm to hydrogen atom at C(5′) of the phenyl ring. Results of spectral analyses suggest central ions in a distorted square-planar geometry with N₂O₂ chromofore group.     

The isolation of intermediates in hydrogen halide additions to some iridium complexes

The complexes [Ir(cod)L_n]PF₆(I, L = PPh₃, PMePh₂; n = 2. L = PMe₂Ph; n = 3) react with HX to give [IrHX(cod)L₂]PF₆ (II, L = PMePh₂ or PMe₂Ph) or [IrHX₂(cod)(PPh₃)] (III). The intermediates [IrX(cod)L₂] have, in two cases (L = PMePh₂, X = I, Br), been directly isolated from the reaction mixtures at 0°C, and are also formed from I with KX (L = PPh₃, X = Cl; L = PMePh₂, X = Cl, Br, I); these intermediates protonate to give II (L = PMePh₂), or an equimolar mixture of III and I (L = PPh₃, X = Cl). Surprisingly, I₂ reacts with I in MeOH to give III (L = PPh₃). The stereochemistries of II and III were determined by < ¹H NMR and especially by new methods using ¹³C NMR spectroscopy. The complexes I exhibit a Lewis acid reactivity pattern.     

Structure of zangezurine

A new base with [α]_D +208° (c 0.7; methanol) has been isolated from the combined nonphenolic alkaloids ofPapaver zangezuricum A. D. Mikheev, and has been called zangezurine (I). The acetylation of (I) with acetic anhydride in pyridine yielded O-acetylzangezurine (II). The structure of zangezurine has been established on the basis of the UV, IR, mass, PMR, and¹³C NMR spectra of (I) and (II).     

(N,N-dimethylbenzylamine-2C,N)palladium(II) and -platinium(II) β-diketonates and thio-β-diketonates

(N,N-dimethylbenzylamine-2C,N)palladium(II) and -platinum(II) β-diketonates, DmbaML, have been synthesized by reaction of [DmbaMCl]₂ with the free ligand and KOH, or with the thallium(I) salt of the ligand. The various isomers formed have been investigated by ¹H and ¹⁹F NMR spectroscopy. Infrared and mass spectroscopic studies have also been made on the compounds.     

Steric control in the stereospecific complexation of chiral α-olefins to platinum(II)

The complexes trans-dichloro[R(CH₃)C^*HCH=CH₂](pyridine)platinum-(II), R = C₂H₅, i-C₃H₇, t-C₄H₉, have been prepared and their ¹H NMR and CD spectra investigated. The two diastereomers formed in the complexation of the chiral α-olefin to Pt^II are present in different concentrations in solution, the diastereomer of opposite absolute configuration at the two chiral centres being the prevailing one. The extent of stereoselectivity, evaluated both by NMR and CD, varies from 32% to 75% by changing the bulkiness of the R group. The preferred conformation of the two diastereomers for each complex has been established by NMR, taking into account the deshielding effect on the protons bound to saturated carbon atoms as well as J(HH) and J(PtH) coupling constants.     

Structures of the silver complexes with lutidines according to the NMR data. Crystal structure of [AgNO3(3,5-Lut)2]

The silver(I) nitrate complexes with 2,3-, 2,4-, 2,6-, and 3,5-lutidine (Lut, dimethylpyridine C₇H₉N), [AgNO₃(Lut)₂], are synthesized and studied by multinuclear NMR (¹H, ¹³C, and ¹⁵N) in various solvents (chloroform, dimethyl sulfoxide, and acetonitrile). The influence of steric and electronic factors of the organic ligand on the parameters of the NMR spectra is revealed. It is shown that the ¹⁵N NMR spectra are the most informative. The structure of complex [AgNO₃(3,5-Lut)₂] is determined. The crystals are monoclinic, space group C2/c, a = 14.599(1) Å, b = 8.422(1) Å, c = 12.954(1) Å, β = 99.60(1)°, V = 1570(2) ų, ρ_calcd = 1.625 g/cm³, Z = 4. The structure is built of discrete neutral complexes [AgNO₃(3,5-Lut)₂]. The coordination mode of the Ag⁺ ion includes two nitrogen atoms of two crystallographically equivalent lutidine ligands (Ag-N 2.194(5) Å, angle NAgN 147.6(3)°). The nitrate ion behaves as a weak chelating ligand with respect to the Ag⁺ ion (Ag…O 2.674(6) Å).     

1H, 13C and 29Si NMR study of α- and β-silylstyrenes and their adducts with dichlorocarbene

¹H, ¹³C and ²⁹Si NMR spectra for the α- and β-silylstyrenes (E)-PhCHCHSiR₃ (I) and PhC(SiR₃)CH₂ (II) (R = Cl, Me, Ph), and those for some dichlorocarbene adducts of I and II (R = Me, Ph), were examined. From the ¹³C NMR data, the phenyl substituent in the molecules I and II enhances the electronic effects of the organosilicon substituent at Cα, and weakens these effects on the C_α resonance. The degree to which polarization of the vinyl CC bond is polarized increases with increased electron-withdrawing properties of substituent R in the SiR₃ group in compounds I and II, and correlates with the reduced reactivity of the bond toward electrophilic dichlorocarbene. Several long-range coupling constants (CC) in the molecules I, II and in their adducts with :CCl₂ were measured. The estimated CC is a useful aid for the study of electronic effects in organosilicon compounds.     

Alkaloids ofAconitum coreanum. I. Structure of acorine

Two C₂₀-diterpene alkaloids have been isolated from the epigeal part ofAconitum coreanum (Levl.) Rapaics: the known 14-hydroxy-2-isobutyrylhetesine (I) (Guan-Fu base Z) and a new one — acorine (II), C₂₂H₂₉NO₅, mp 214–215°C (from acetone), α _D ²⁰ +9° (c 0.01; methanol), for which the structure of 2-acetyl-14-hydroxy-hetesine has been established. Details of the IR, mass, and¹³C NMR spectrum of (I) and (II) and of the PMR spectrum of (II) are given.     

The 31P NMR spectra of ArCr(CO)2P(C6H5)3 compounds in neutral and acidic media

The ³¹P NMR spectra of C₆H₅XCr(CO)₂P(C₆H₅)₃ (X = H, CH₃, OCH₃, N(CH₃)₂, COOCH₃) (I), p-C₆H₄X₂Cr(CO)₂P(C₆H₅)₃ (X = COOCH₃)(II) and C₆H₃X₃Cr(CO)₂P(C₆H₅)₃ (X = CH₃) (III) complexes in neutral and acidic media were investigated. The protonation of complexes I and III in trifluoroacetic acid results in the greater upfield shielding of ³¹P{¹H} signal. In this case the complexes I (X = H, CH₃, OCH₃) are completely protonated at the metal, complex I (X = COOCH₃)is partially protonated, while no protonation occurs in the case of complex II.Temperature-dependence of the ³¹P{¹H} NMR spectra was investigated for complexes I (X = H, OCH₃) in a 1/10 mixture of trifluoroacetic acid and toluene and for complexes I (X = COOCH₃) and II in trifluoroacetic acid. The degree of protonation was found to increase with decreasing temperature.     

Substituted cyclopentadienyl complexes: II. 13C NMR spectra of some [(η5-C5H4Me)Fe(CO)(L)I] complexes

The ¹³C {¹H} NMR spectra of a series of complexes [(η⁵-C₅H₄Me)Fe(CO)(L)I] (L  t-BuNC, P(OMe)₃, PMe₃, PMe₂Ph, PMePh₃, PPh₃ and P(C₆H₁₁)₃) have been recorded and the five cyclopentadienyl resonances assigned to ring carbon atoms by means of CH correlated spectra. It has been observed that the C atoms ortho to the ring methyl group (C(2) and C(5)) as well as the quaternary C atom are always coupled to the ligand P atom. A correlation between the chemical shift difference Δ(C(2) – C(5)) and the Tolman cone angle, θ, has also been established.     

Synthesis and characterization of some new Co(II) and Cd(II) macroacyclic Schiff-base complexes containing piperazine moiety

Three Cd(II) or Co(II) macroacyclic Schiff-base complexes [CoL¹Br]ClO₄ (1), [CdL²Cl]ClO₄ (2) and [CdL³(NO₃)]ClO₄ (3) were prepared by template condensation of 2-pyridinecarboxaldehyde and three different amines containing piperazine moiety, N,N′-bis(2-aminoethyl)piperazine, N,N′(2-aminoethyl)(3-aminopropyl)piperazine and N,N′-bis(3-aminopropyl)piperazine, in the presence of Co(II) or Cd(II) metal ions, respectively. All complexes have been studied with IR, FAB mass and microanalysis and for complex (3) by ¹H and ¹³C NMR spectra. One of these complexes, [CdL³(NO₃)]ClO₄ (3) has been characterized through X-ray crystallography. In complex (3), the Cd(II) ion is coordinated by the six nitrogen donor atoms from the ligand and by one oxygen atom from a monodentate nitrate ion in a N₆O environment.     

Synthesis, spectral and thermal properties of some transition metal(II) complexes with a novel ligand derived from thiobarbituric acid

Four novel metal(II) complexes, Ni(L)₂, Co(L)₂, Cu(L)₂, and Zn(L)₂ (L = 5-(2-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)hydrazono)-1,3-diethyl-2-thioxo-dihydropyrimidine-4,6(1H,5H)-dione), were synthesized using the procedure of diazotization, coupling and metallization. Their structures were identified by elemental analyses, ¹H NMR, ESI-MS and FT-IR spectra. The effect of different central metal(II) ions on absorption bands of the metal(II) complexes was researched. The thermal properties of the metal(II) complexes were investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC). Furthermore, the thermodynamic parameters, such as activation energy (E*), enthalpy (?H*), entropy (?S*) and free energy of the decomposition (?G*) are calculated from the TG curves applying Coats–Redfern method. The results show that the metal(II) complexes have suitable electronic absorption spectra with blue-violet light absorption at about 350–450 nm, high thermal stability with sharp thermal decomposition thresholds.     

Dzheiranbatanolide — A new guaianolide fromArtemisia fragrans

A new guaianolide which has been called dzheiranbatanolide (I), C₁₅H₂₀O₄, mp 186–188°C has been isolated from the epigeal part ofArtemisia fragrans Willd. The oxidation of (I) led to a keto derivative (II) with the composition C₁₅H₁₈O₄, mp 247–248°C. The structure of (I) has been established by the chemical and spectral (IR, UV, and¹³C NMR) analysis of (I) and (II).V. L. Komarov Institute of Botany, Academy of Sciences of the Azerbaijan SSR, Baku. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 595–598, September–October, 1984.     

Preparation of complexes of 1-amino-6,7-O-cyclohexylidene-4-azaheptane with transition metal acetates

1-Amino-6,7-O-cyclohexylidene-4-azaheptane (L) has been synthesized starting from 1-chloro-2,3-O-cyclohexylidenepropane prepared by the reaction of epichlorohydrin with cyclohexanone, catalyzed by BF₃OEt₂. Complexes of this ligand with Co(II), Ni(II) and Cu(II) acetates were prepared. The structures of the ligand and its complexes are proposed based on the elemental analyses, IR, UV-VIS, and ¹H and ¹³C NMR spectra, magnetic susceptibilities, and conductomety data.     

Metal complexes of 4,5-dimethylpyrazole-3-carboxaldehyde phenylthiosemicarbazone

Several new transition metal complexes derived from 4,5-dimethyl-3-carboxaldehyde phenyl- thiosemicarbazone, LH, have been synthesized. The complexes are of stoichiometry, [CoL₂]X, X = Cl⁻, Br⁻, ClO⁻₄ or NO⁻₃, [MnL₂] and [CuX_nL_m], X = Cl⁻, Br⁻, NCS⁻ or N⁻₃; n = 1 or 0; m = 1 or 2 and L = the anion of LH. All complexes have been characterized by elemental analysis, spectral (i.r., electronic, NMR, ESR) and magnetic measurements. The ligand acts as tridentate monobasic co-ordinated to the metal ion via azomethine, pyrazole (N²) nitrogen atoms and the thiolo-sulphur. The ligand field and ESR parameters are used to interpret the nature of bonding of LH with the metal ion, ground state and the ligand field strength of LH and the various co-ordinated simple ions. The coupling constants of various co-ordinated nuclei with copper (II) are estimated from ESR spectra of copper (II) complexes.     

Hindered rotation in trimethylenemethane—Fe(CO)3 complexes

^>13C NMR spectra have been recorded for trimethylenemethane—Fe(CO)₃ (I) as well as its acetyl (II), 1-hydroxyethyl (III), 1-acetoxyethyl (IV) and ethyl (V) derivatives respectively. Compounds II–IV exhibit 3 distinct ¹³CO resonances at room temperature. These signals undergo a reversible broadening and merge into a single sharp signal on warming. δGG^? for Fe(CO)₃ rotation at the coalescence points is 17–18 kcal mol^?1. The rotational barrier is electronic in origin.     

Antimicrobial,antioxidant and SOD activities of copper(II) complexes derived from 2-aminobenzothiazole derivatives

A series of Cu(II) complexes have been synthesized from bidentate Schiff base ligands (by condensation of Knoevenagel condensate of acetoacetanilide (obtained from substituted benzaldehydes and acetoacetanilide) and 2-aminobenzothiazole). They were characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR, UV–vis., molar conductance, magnetic moment, ESR spectra and electrochemical studies. Based on the magnetic moment, ESR, and electronic spectral data, a distorted square planar geometry has been suggested for the complexes. Antibacterial and antifungal screening of the ligands and their complexes reveal that all the complexes show higher activities than the ligands. The antioxidant activities of the ligands and complexes were determined by superoxide and hydroxyl radical scavenging methods in vitro, indicating that the complexes exhibit more effective antioxidant activity than the ligands alone. The results show that the Cu(II) complexes also have similar superoxide dismutase activity to that of native Cu, Zn-SOD. All complexes exhibit suitable Cu(II)/Cu(I) redox potential (E_1/2) to act as synthetic antioxidant enzyme mimics.