新型茼蒿素类似物的合成和抗虫构效关系研究

Twenty-one tonghaosu analogs were synthesized via hydroamination or selective reduction of the endocyclic double bond of the corresponding dienol spiroketals. Structures of all the new compounds were confirmed by ^1H NMR, IR, MS, HREIMS or elemental analysis. Their antifeedant activity against large white butterfly （Pieris brassicae L） and larvicidal activity toward mosquito （Culex quinquefasciatus Say） were examined. Some of them exhibited antifeeding activities comparable to or stronger than tonghaosu Z-1. Based on the activity data, the preliminary structure-activity relationship was also discussed, which might be instructive for finding out lead compounds with better bioactivities in the future.     

Synthesis and physical characterization of model hard segments based on diphenyl methane diisocyanate and hydroquinone bis(2‐hydroxyethyl) ether

Hard segment model compounds based on diphenyl methane diisocyanate (MDI) and hydroquinone bis(2‐hydroxyethyl) ether (HQE) were synthesized; these models were end‐capped with ethanol (E) or 2‐phenoxyethanol (F). NMR spectroscopy and GPC analysis confirm the expected structure: R‐(MDI‐HQE)_p−1‐MDI‐R′ (where p = 1, 2, 3; R, R′ = E, and/or F if p =1). Intrinsic viscosity revealed a Mark–Houwink exponent of 0.73, and a value of 4.76 × 10⁻² cc/g was obtained for K; applying the Mark–Houwink equation on a MDI–HQE polymer a MW of 2650 was calculated, while a value of 2872 was achieved by GPC analysis using a specifically drawn calibration curve. Thermal analysis reveals the crystalline nature of these models and the increase of melting temperature with the number of repeating units; an extrapolated value ranging from 274 to 361 °C, depending on selected structure for the first term of the oligourethane series, was calculated for the polymer using the Flory's equation accounting for chain end defects. Calorimetric traces and GPC analyses on annealed samples show an extensive degradation of models having higher melting temperature (p > 1), in this case a broad high molecular weight mixture, which contains also significant amounts of short oligourethanes or byproducts, was generally observed. A comparison of the melting behavior of this series with similar models based on MDI but with a different chain extender (1,4‐butanediol, BDO) seems to indicate an increase in the melting temperature. This evidence can be tentatively attributed to the longer aromatic sequences present in the hydroquinone containing models. The investigation of the characteristics of these hard models gives predictive information useful for better understanding properties/structure relationships of polyurethane elastomers containing similar hard sequences. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1473–1487, 1999     

3-Ferrocenyl-3-(1-naphthyl)cyclopropene. Synthesis, structure, and chemical transformations

Crystalline 3-ferrocenyl-3-(1-naphthyl)cyclopropene was prepared by dehydrobromination ofZ- andE-2-bromo-1-ferrocenyl-1-(1-naphthyl)-cyclopropanes by Bu^tOK in DMSO. The resulting compound and the startingZ-monobromocyclopropane were characterized by X-ray diffraction analysis. The obtained cyclopropene reacts with 1,3-diphenylisobenzofuran to give a [4+2]-cycloadduct. The small ring opens upon treatment with HBF₄ etherate to afford isomericZ- andE-prop-1-enes and 1-ferrocenyl-3H-benzo[e]indene. Thermolysis of this cyclopropene results in the formation of 1-ferrocenyl-9bH-benzo[e]indene. In all cases, opening of the small ring is accompanied by exclusive alkylation of the naphthalene moiety. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 499–506, March, 1998.     

Determination of heats of the thermal gas-phase formation of intermediates with overlapping spectra

The previously proposed procedure for the determination of heats of thermal gas-phase reversible reactions using kinetic spectroscopy was extended for the case of the formation of two intermediate species with overlapping UV spectra. The model problem was solved, and the error of the method was estimated. Applicability of the method was shown for the reversible formation of trimethylenemethane (TMM) and but-1-ene-2,4-diyl from methylene-cyclopropane. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 28–34, January, 1998.     

A comparative study of the synthetic paths from 1-butyne to 2E,4Z-heptadien-1-ol

2E,4Z-Heptadien-1-ol (1), the key intermediate in the synthesis of the grapevine moth sex pheromone, was obtained from 1-butyne by a number of alternative procedures, including various variants of the stereocontrolled building of the conjugatedE,Z-diene system (Cadiot—Chodkiewicz cross-coupling, alkyne—vinyl halide cross-coupling catalyzed by palladium complexes, anionotropic allylic rearrangement, partialcis- andtrans-reduction of the triple bond). None of them could provide for configurational uniformity of1. The most acceptable path to obtain1 in multigram amounts appears to be that which proceeds via the conjugated diynol and enynol intermediates with subsequent catalyticcis-hydrogenation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 769–772, April, 1993.     

Immobilization of proteins as a tool for studying primary structure around their cysteinyl residues

The primary structure around the single cysteinyl residue of chicken pepsin was investigated by binding the protein via this residue to an insoluble carrier. Carriers stable towards reagents used for the fragmentation of proteins and sequence analysis were prepared by coupling a spacer arm to polyN-hydroxymethyl acrylamide using a thioether bond that is potentially cleavable by mercuric ions (1). Phenacyl bromide group, attached to the free end of the spacer, reacted rapidly and specifically with the cysteinyl residue of chicken pepsin. Up to 300 mg of the enzyme were bound to 1 g of carrier. The polymer-bound protein was cleaved by trypsin or by cyanogen bromide or by a sequence of both. Fragments of 40–120 amino acid residues, depending on the method of cleavage, remained attached to the polymer through the cysteinyl residue. The compositions and partial sequences of these fragments revealed that the cysteinyl residue is located within or in the vicinity of a loop in the molecule formed by a disulfide bond.     

Stoichiometry and mechanism of protonation of alkali metal salts of benzophenone radical anions by weak proton donors and its relevance to the base-catalyzed decomposition of benzopinacol

The Stoichiometry of the protonation of lithium and potassium salts of benzophenone radical anions and of the lithium salt of the fluorenone radical anion by methanol has been measured and found to be [(Ar₂C=O)^–]/[MeOH] =21. This result, which was obtained by the method of magnetic titration, implies that paramagnetism decays by the reaction between a ketyl anion and a ketyl radical (i.e., a protonated ketyl anion). The reactivities of alkali metal salts of fluorenone radical anions in relation to methanol exhibit a pronounced dependence on the nature of the counterion. No kinetic deuterium isotope effect has been found for the protonation of the lithium salt of the benzophenone radical anion in tetrahydrofuran (THF) bytert-pentyl alcohol. The lithium salt of the benzophenone radical anion inN,N,N,N-tetramethylethylenediamine (TMEDA) behaves markedly differently. Namely, its protonation by methanol exhibits 1 1 Stoichiometry and it reacts considerably more slowly withsec-butyl alkohol,K(THF)/K(TMEDA) = 2.5. Benzopinacol undergoes decomposition by an alkoxide base to diphenyl ketyl, which decays into an equimolar mixture of benzophenone and benzhydrol. The reaction follows second-order kinetics and the specific rate constants exhibit an inverse relationship with respect to the initial concentration of the alkoxide. With a very strong base benzopinacol decomposes into two diphenyl ketyl anions. On the basis of this information as well as on studies of products, relevant mechanisms are proposed for the protonation of ketyl anions and for the decomposition of aromatic pinacols in basic media.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 83–91, January, 1995.     

Quenching of Singlet Oxygen by Tertiary Aliphatic Amines. Structural Effects on Rates and Products

A kinetic and product study of the reaction of a series of α‐methyl‐substituted N‐methylpiperidines with thermally generated ¹O₂ in MeCN was carried out. It was found that as the number of α‐methyl groups (Me in α‐position relative to the N‐atom) increases, the rate of ¹O₂ quenching (physical plus chemical) slightly decreases. This finding shows that, with respect to the reaction rate, steric effects are much more important than electronic effects as the latter should have produced the opposite result. The opposite outcome was instead found for the chemical quenching that leads to the N‐demethylation products and N‐formyl derivatives. The same trend was observed for the ratio between N‐demethylation and formation of the N‐formyl derivatives (NH/NCHO ratio). All these results are consistent with the mechanism reported in Scheme 1 where an exciplex is first formed that by a H‐atom transfer process produces an α‐amino‐substituted C‐radical. The latter forms the product of N‐demethylation by one electron oxidation, or affords the N‐formyl derivative by radical coupling (Scheme 1). Similar results were obtained with N,N‐dimethylcyclohexanamine. However, this ‘acyclic’ amine exhibited behaviors quite distinct from those of the N‐methylpiperidines series, with respect to reaction rate, extent of chemical quenching, and NH/NCHO ratio.     

Synthesis of acetonylmalonaldehyde and its interaction with aminoazoles

Acetonylmalonaldehyde (1) was obtained for the first time by hydrolysis of 2,5-dimethoxy-5-methyltetrahydrofuran-3-carbaldehyde. The interaction of1 with 3-amino-5-methylpyrazole, 3-amino-1,2,4-triazole, 2-aminobenzimidazole, and 5-aminotetrazole results in the formation of functionally substituted azolopyrimidines. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1226–1228, June, 1997.     

Ajanolide A, a new germacranolide fromAjania fruticulosa

A new germacranolide, ajanolide A, was isolated from aerial parts ofAjania fruticulosa by means of extraction with CHCl₃ and adsorption chromatography. This compound was identified as (1(10)E,3S,4Z,6R,7S,11R)-3-acetoxygermacra-1(10),4-dien-12,6-olide ((1S,7S,10R,13R)-7-acetoxy-4,8,13-trimethyl-11-oxabicyclo[8.3.0]trideca-4(E),8(Z)-dien-12-one) by X-ray diffraction analysis. 2D¹H−¹H (COSY) and¹³C−¹H (COSY) NMR spectroscopy was used for assigning the¹H and¹³C NMR signals in the spectra of ajanolide A. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 167–170, January, 1998.     

Immobilization of single-strand specific nuclease (S1 nuclease) fromAspergillus oryzae

S1 nuclease fromAspergillus oryzae (EC 3.1.30.1) was coupled to gelatin-alginate composite matrix using the residual free aldehyde groups on the surface of glutaraldehyde crosslinked matrix. The immobilized enzyme retained approximately 10% activity of the soluble enzyme. When partially purified enzyme was bound to the matrix, the immobilized preparation did not show any detectable enzyme activity. However, the activity could be restored when the coupling was carried out in the presence of a coprotein or substrate. The optimum pH of the immobilized S1 nuclease shifted to 3.8 from 4.3 for the soluble enzyme. Also, optimum temperature increased to 65°C after immobilization. Bound S1 nuclease showed increased pH and temperature stabilities. Immobilization brought about a twofold decrease in the Michaelis-Menton constant (K _m).     

Radical Cyclization of 1,n-Enynes and 1,n-Dienes for the Synthesis of 2-Pyrrolidone

2-Pyrrolidones have aroused enormous interest as a useful structural moiety in drug discovery; however, not only does their syntheses suffer from low selectivity and yield, but also it requires high catalyst loadings. The radical cyclization of 1,n-enynes and 1,n-dienes has demonstrated to be an attractive method for the synthesis of 2-pyrrolidones due to its mild reaction conditions, fewer steps, higher atom economy, excellent functional group compatibility, and high regioselectivity. Furthermore, radical receptors with unsaturated bonds (i. e. 1,n-enynes and 1,n-dienes) play a crucial role in realizing radical cyclization because of the ability to selectively introduce one or more radical sources. In this review, we discuss representative examples of methods involving the radical cyclization of 1,n-enynes and 1,n-dienes published in the last five years and discuss each prominent reaction design and mechanism, providing favorable tools for the synthesis of valuable 2-pyrrolidone for a variety of applications.     

Synthesis and crystal structure of the Sm(ButNCHCHNBut)2(bpy) complex

Reaction of Sm(bpy)₄ (bpy is 2,2′-bipyridyl) with di-tert-butyldiazabutadiene (dad) in tetrahydrofuran (THF) affords the mixed-ligand complex Sm(dad)₂(bpy) (1). Complex1 was isolated as black paramagnetic crystals readily soluble in THF, 1,2-dimethoxyethane (DME), toluene, and ether. Compound1 was characterized by IR and ESR spectroscopy, X-ray diffraction analysis, and by the results of magnetic measurements. Based on the difference between the Sm−N bond lengths and on the data of IR spectroscopy, the following formal charge distribution in the molecule of complex1 was proposed: Sm³⁺(dad)²⁻(dad)¹⁻(bpy)⁰. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1860–1862, October. 1997.     

Conformational flexibility of partially hydrogenated rings in the repeating units of rigid-chain heterocyclic polymers

The conformational flexibility of partially hydrogenated rings in naphthylimide, naphthalic anhydride, and some of their derivatives used as model compounds for the repeating unit in rigid-chain heterocyclic polymers, was studied by the semiempirical quantum-chemical AM1 method. The partially hydrogenated rings in all of these compounds possess conformational flexibility. Transition from a planar equilibrium form to a distorted sofa conformation with a torsion angle of ±20° results in an increase in the energy of less than 1 kcal mol⁻¹. The high flexibility of partially hydrogenated rings, along with other factors, can cause finite length of the Kuhn segment in rigid-chain heterocyclic polymers. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 1, pp. 64–66, January 1997.     

Combined study of thermochemical properties of nitroform and its salts

A combined method for determination of the standard enthalpies of formation of nitroform and its salts was proposed. The enthalpies of dissolution of nitroform and its ammonium, hydrazinium, guanidinium, and potassium salts in water were measured. The enthalpy of combustion of hydrazinium salt of nitroform was determined by a combustion calorimetry, and its standard enthalpy of formation was calculated. The enthalpy of formation of trinitromethyl anion in indefinitely diluted aqueous solution −24.94±0.79 kJ mol⁻¹, was calculated on the basic of the data obtained for enthalpies of formation and dissolution of ammonium and hydrazinium salts of nitroform. Standard enthalpies of formation of nitroform and its salts were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2451–2454, December, 1998.     

One-step synthesis of the chelate oxides of bis(trialkylantimony) by an oxidative method

The chelate oxides of bis(trimethylantimony) (Me₃SbL¹)₂O (i = 1 or 2, L¹-acetylacetonate, L² - trifluoroacetylacetonate) and bis(triethylantimony) (Et₃SbL¹)₂O have been obtained in 79–85% yields by a one-step oxidation of trialkylantimony withtertbutylhydroperoxide in the presence of -diketones in benzene at 20 °C.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 154–155, January, 1995.This work was carried out with financial support from the Russian Foundation for Basic Research (Project No. 94-03-08846).     

Evaluation of important fatty acid ratios in poultry feed lipids by ATR FTIR spectroscopy

A rapid, simple and reproducible single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopic method was developed for determination of the n − 6, n − 3 and ratio of n − 6:n − 3 polyunsaturated fatty acids (PUFAs) in poultry feed lipids using partial least squares (PLS) regression. Data for n − 6, n − 3 and ratio of n − 6:n − 3 was acquired by gas chromatography (GC) and used as a standard values for FTIR calibration. The best regression results were achieved using first derivatives of the 1475–650 cm⁻¹ spectral region for n − 6, n − 3 and ratio of n − 6:n − 3 with high regression coefficients (R²) of 0.999, 0.994 and 0.998, respectively and low RMSEP values of 1, 0.06 and 0.83, respectively. The results of the present study revealed that FTIR could be used for rapid and accurate determination of n − 6, n − 3 and ratio of n − 6:n − 3 PUFAs present in poultry feed lipids.     

Transformation of Amino Acids into Nonracemic 1‐(Heteroaryl)ethanamines by the Enamino Ketone Methodology

N‐Protected L ‐phenylalanines 1a,b were transformed, via the corresponding Weinreb amides 2 and ethynyl ketones 3 , into chiral enamino ketones 4 (Scheme 1). Similarly, L ‐threonine 6 was transformed in four steps into the enamino ketone 10 . Cyclocondensations of 4 and 10 with pyrazolamines 11 , benzenecarboximidamide ( 12 ), and hydrazine derivatives 18 afforded N‐protected 1‐heteroaryl‐2‐phenylethanamines 15a – e, 16, 17 , and 21a – k and 1‐heteroaryl‐1‐aminopropan‐2‐ols 23a,b in good yields (Schemes 2 and 3). Finally, deprotection by catalytic hydrogenation furnished free amines 22a – g and 24a,b (Scheme 3).     

Surface characterization and thermodynamics of adsorption of Sr2+, Ce3+, Sm3+, Gd3+, Th4+, UO 2 2+ on activated charcoal from aqueous solution

Surface parameters of the activated charcoal were measured using precise instrumental techniques for dehydration, carbon content, trace metals impurities, anions, bulk, tap and true densities, surface area, pore volume, porosity and average particle diameter. The adsorption of Sr²⁺, Ce³⁺, Sm³⁺, Gd³⁺, Th⁴⁺ and UO ₂ ²⁺ ions on activated charcoal from aqueous solution was studied as a function of temperature. Thermodynamic parameters such as HH ⁰ and S ⁰ were calculated from the slopes and intercepts of the linear variation of lnK ₁ vs. 1/T, whereK ₃ is obtained from Langmuir equation. The results show endothermic heats of adsorption, but negative free energy values indicate that the adsorption process of metal ions on activated charcoal is favored at high temperature. The value of isosteric heat of adsorption, calculated from the Clausius-Clapeyron equation, shows that the surface of the activated charcoal is heterogeneous with respect to activity. A wavelength dispersive x-ray fluorescence spectrometer was used for measuring the concentration of metal ions.     

Metalation of 2-Methyl-N-phenylbenzamide withn-butyllithium. Formation ofN,3-diphenyl-1-isoquinolinamine by subsequent reaction with benzonitrile

2-Methyl-N-phenylbenzamide was metalated with two equivalents ofn-butyllithium. Benzonitrile was allowed to react with the organometalic intermediate thus formed to yieldN,3-diphenyl-1-isoquinolinamine.

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Metallierung von 2-Methyl-N-phenyl-benzamid mitn-Butyllithium und Bildung vonN,3-Diphenyl-1-isochinolinamin durch anschließende Reaktion mit Benzonitril

Zusammenfassung Reaktion von Benzonitril mit der Di-Lithiumverbindung aus 2-Methyl-N-phenylbenzamid und 2 moln-Butyllithium liefertN,3-Diphenyl-1-isochinolinamin.