Differential recognition of geometric isomers by the boll weevil,Anthonomus grandis Boh. (Coleoptera: Curculionidae): Evidence for only three essential components in aggregation pheromone

For two decades, the aggregation pheromone of the boll weevil,Anthonomus grandis Boh. (Coleoptera: Curculionidae), was thought to consist of four compounds: I [(+)-(Z)-2-isopropenyl-1-methylcyclobutane ethanol]; II [(Z)-3,3-dimethyl-^I,-cyclohexane ethanol]; III [(Z)-3,3-dimethyl-^1,-cyclohexane acetaldehyde); and IV [(E)-3,3-dimethyl-^1,-cyclohexane acetaldehyde). Evidence is presented from behavioral and electrophysiological studies to show that only three of these components, I, II, and IV, are essential for attraction. Competitive field tests, in which each possible three-component blend was tested against the four-component mixture, demonstrated that omission of I, II. or IV resulted in decreased trap captures (P < 0.01). Trap captures by these blends lacking I, II, or IV resembled those by the hexane solvent alone in a similar experiment. However, omission of III did not significantly alter field attractiveness of the blend. Dosage-response curves constructed from electroantennogram responses of both males and females to serial dilutions of III, IV, and a 5050 mixture of the geometric isomers III and IV showed both sexes to be 10- to 100-fold more sensitive to IV than III. Data from the electrophysiological studies were consistent with a single acceptor type for the (E)-cyclohexylidene aldehyde, IV, for males, and possibly one or two acceptor types for III and IV for females. Possible roles for the (Z)-cyclohexylidene aldehyde, III, and implications for the pheromonal attractant currently used in boll weevil eradication/suppression programs are discussed.     

Stevensanaloge,Durch Nickelkomplexe Katalysierte Umlagerung Von Triarylphosphoryliden Und Darstellung Sowie Strukturbestimmung Von Phosphorylid-Nickeltricarbonylkomplexen

The Stevens rearrangement of the triarylphosphorusylids R₃ P=CHR′ (III) (R′ = H, CH₃, C₂ H₅) to diarylbenzylphosphines (V) is catalyzed by nickel complexes (e.g., (COD)₂ Ni (I)). Attempts to prepare trimesitylphosphine-methylene result in direct formation of dimesityl (mesitylmethyl) phosphine (XII) — the first recorded direct Stevens rearrangement of a phosphorusylid. Phosphorusylids react with nickeltetracarbonyl without rearrangement to give complexes of the type R₃P=CH_a · Ni(CO)₃ (XIV). The structure of XIV has been established by the IR and NMR spectra and confirmed by an X-ray structural determination.

1 B. L. Barnett and C. Krüger, J. Cryst. Mol. Struct., im Druck.

The ylid is bonded to the nickel through the C-atom with resulting hybridization from sp² towards sp³.     

Reaction of ketohexoses with acid in certain non-aqueous sugar solvents

Ketohexoses or potential ketohexoses react rapidly with acids at high temperatures in non-aqueous solvents (containing the grouping R·O·C·C·OH in their structures¹) to produce 5-hydroxymethyl-furfural (HMF). HMF reacts further to give the solvent ether (e.g., II, III or IV ) in a slow reaction. Several of these ethers have been reduced partially to mono-ethers of 2,5-di(hydroxymethyl)furan ( V, VI or VII ) and fully to mono-ethers of 2,5-di(hydroxymethyl)tetrahydrofuran ( VIII, IX or X ).     

Synthesis and Crystal Structures of a Lanthanum(III) 1D Polymer and a Mixed-Ligand Cerium(III) Binuclear Complex Derived from Pyridine-2,6-dicaboxylic Acid

Lanthanum(III) and cerium(III) complexes of pyridine-2,6-dicaboxylic acid (H₂Pydc) have been prepared and their crystal structures were determined by X-ray crystallography. The single crystal analysis reveals that the lanthanum(III) complex, 1 is polymeric consisting of {[La(Pydc)₂(H₂O)₂]·4H₂O} _n units linked through carboxylate oxygen atoms and exhibiting nine coordination number. Intermolecular O–H···O hydrogen bonds produce R ₁ ¹ (6), R ₄ ⁴ (16) and R ₄ ⁴ (20) rings, which lead to three-dimensional polymeric chains. The crystal structure of the cerium(III) complex, 2 [{Ce(Pydc)₃}{Ce(Pydc)(HO–CH₂CH₂–OH)(H₂O)₃}·6H₂O)] shows that the complex is a mixed-ligand binuclear system in which one cerium coordinated to three Pydc molecules, while the other cerium is bound to one Pydc, one oxygen atom of the other Pydc, one ethylene glycol and three water molecules. Each of the two Ce(III) ions is nine coordinated. Intermolecular O–H···O hydrogen bonds produce R ₂ ² (8) and R ₂ ² (20) rings, which lead to three-dimensional polymeric chains. The complexes were further investigated using elemental analysis, FTIR spectroscopy and thermogravimetric analysis.     

Studies on the Autoxidation of Phenyl Cycloalkanes

The products of the autoxidation of phenyl cyclopropane ( I ), phenyl cyclobutane ( II ), phenyl cyclopentane ( III ), phenyl cyclohexane ( IV ), phenyl cycloheptane ( V ) and phenyl cyclooctane ( VI ) were analyzed after reduction of the reaction mixtures with LiAlH₄. As products of the attack on the α-C H bonds the corresponding 1-phenyl cycloalkanols and 1-phenyl alkan-1-ols were found. In the case of phenyl cyclopropane some S_R2 ring opening probably takes place. The oxidabilities $ {\rm k}_{\rm p} /\sqrt {{\rm k}_{\rm t}} $, the chain termination constants k_t, the absolute chain propagation constants k_p and the relative chain propagation constant (k_p)_rel were determined for the phenyl cycloalkanes I — VI . As it is to be expected on the basis of the I-strain concept the autoxidation rate of phenyl cyclopentane ( III ) is considerably higher than that of phenyl cyclobutane ( II ) and phenyl cyclohexane ( IV ).     

Addition of dichlorocarbene to cis-1,4-poly(2-trimethylsilylmethyl-1,3-butadiene)

Summary Copolymers made up of 1,4-(2,3-dichloromethylene-2-trimethylsilylmethyl-1,3-butadiene) (I) and 1,5-(3-chloro-2-methylene-pent-3-ene) (II) units have been prepared by potassium fluoride elimination of trimethylchlorosilane from cis-1,4-poly(2.3-dichloromethylene-2-trimethylsilylmethyl-1,3-butadiene) (III). III was prepared by the addition of dichlorocarbene to 1,4-poly-(2-trimethylsilylmethyl-1,3-butadiene) (cis/trans = 9/1) (IV). Polymer III was characterized by ¹h, ¹³C and ²⁹Si NMR as well as by elemental analysis. The copolymer was characterized by ¹H, ¹³C and ²⁹Si NMR spectroscopy. The ratio of I and II units in the copolymer were determined by ¹H NMR and elemental analysis.     

On the photolysis of hydroxy alkylphenones and o-substituted derivatives. Laser flash photolysis and photocuring studies

1-Phenyl-2-acetoxy-2-methyl-propanone-1 (III) and 1-phenyl-2-methoxy-2-methyl-propanone-1 (IV) were irradiated at room temperature with 15 or 25 ns flashes of 265 nm or 347 nm light in Ar-saturated cyclohexane or benzene solution. Transient absorptions and emissions were recorded as a function of time between 300 and 550 nm. Triplet lifetimes of III in cyclohexane and benzene and of IV in p-dioxane were determined as ca. 2 μs. In contrast to the photolysis of 1-phenyl-2-hydroxy-2-methyl-propanone-1 (compound I) and of 1-[4-(2-propyl)-phenyl]-2-hydroxy-2-methyl-propanone-1 (compound II), α-cleavage occurs upon UV irradiation of III and IV to a minor or negligible extent. Triplets of III were found to react effectively with N-methyldiethanol amine, but a reaction with cyclohexane did not become noticeable. They react with O₂ with k(T + O₂) = 1.6 · 10⁹ l/mol s. Triplets of IV react with cyclohexane with k(T + CH) = 8.6 · 10⁵ l/mol s and with O₂ with k(T + O₂) = 1.1 · 10⁹ l/mol s. They are inert towards p-dioxane. Photocuring of a transparent acrylate coating system yielded the following results on the basis of pendulum hardness measurements: I and II exhibit excellent initiator effectivity, III and IV are not capable of initiating curing if applied without coinitiator, e.g. N-methyldiethanol amine. In the presence of the latter III and IV exhibit satisfactory curing capability. In conclusion: the high curing effectivity of I and II is due to the high yield and the high rate of α-cleavage. III and IV do not undergo α-cleavage and therefore do not initiate curing. The curing capability of III and IV in the presence of a coinitiator is due to the formation of ketyl radicals by a hydrogen transfer mechanism.     

Synthesis of phosphorus-containing polymers with potential bioactivity

Phosphorylation of poly(N-vinyl pyrrolidone-co-vinyl amine) and poly(N-vinyl pyrrolidone-co-glycidylcrotonate

1 Systematic name: (2,3-Epoxypropyl)crotonate.

) is realized by Atherton-Todd and Fields-Kabachnik reactions and by the means of direct interaction with phosphorus trichloride and phosphorus trichloride oxide. The composition and structure of the isolated final products was proved by NMR (¹H and ³¹P), IR spectroscopy and elemental analysis.     

Epoxidation of E-1,4-poly(2-triethylsilyl-1,3-butadiene) and E-1,4-poly-[2,3-bis(trimethylsilyl)-1,3-butadiene] Stereochemical analysis of E-1,4-poly(2,3-epoxy-2-triethylsilyl-1,3-butadiene) and E-1,4-poly-[2,3-bis(trimethylsilyl)-1,3-butadiene] by 13C and 29Si NMR

Summary Reaction of E-1,4-poly(2-triethylsilyl-1,3-butadiene) (I) with m-chloroperbenzoic acid (MCPBA) yields E-1,4-poly(2,3-epoxy-2-triethylsilyl-1,3-butadiene) (II). Similar reaction of E-1,4-poly[2,3-bis(trimethylsilyl)-1,3-butadiene] (III) with MCPBA gives E-1,4-poly[2,3-epoxy-2,3-bis(trimethylsilyl)-1,3-butadiene] (IV). The product polymers have been characterized by ¹H, ¹³C, and ²⁹Si NMR, IR, GPC, TGA and elemental analysis. ¹³C and ²⁹Si NMR permit Stereochemical analysis on the microstructures of II and IV.     

Dicyclopentadienoxidation. I,Unkatalysierte Flüssigphasenoxidation von Dicyclopentadien

Dicyclopentadiene Oxidation I. Uncatalyzed Liquid-Phase Oxidation of Dicyclopentadiene Dicyclopentadiene is oxidized by molecular oxygen to a mixture of the monoepoxides 2 and 3 . The identification of the epoxides 2 , 3 and 4 was executed with authentic samples prepared by epoxidation with peracetic acid or with tert-butylhydroperoxide in the presence of MoO₂(acac)₂

1 acac — Acetylacetonat

The main product is the substituted norbornene oxide 2 . Allylic oxidation is also observed. Remarkable amounts of hydroperoxides can be determined iodometrically. The formation of allylic oxidation products 7 , 8 , 9 and 10 was proved by GC-MS-analysis. It is shown that in the uncatalyzed liquid phase oxidation of dicyclopentadiene no more than 50% of epoxides are formed. The bisepoxide 4 was found in small amounts only at higher conversions of the dicyclopentadiene.     

Ground State Complexes between 5-(4-Carboxyphenyl)-10,15,20-Tritolyl Porphyrin and Benzoquinones

The interactions of 5-(4-carboxyphenyl)-10,15,20-tritolyl porphyrin (TTPa)

1 Abbreviations: TTPa: 5-(4-carboxyphenyl)-10,15,20-tritolyl porphyrin; BQ: 1,4-benzoquinone; DQ: 2,3,5,6-tetramethyl 1,4-benzoquinone; CHLQ: 2,3,5,6-tetrachloro 1,4-benzoquinone; DMSO: dimethyl sulfoxide

with benzoquinones have been studied by spectrophotometry and steady state and transient fluorescent methods. TTPa forms a 1:1 molecular complex with 1,4-benzoquinone, 2,3,5,6-tetramethyl 1,4-benzoquinone and 2,3,5,6-tetrachloro 1,4-benzoquinone in dimethyl sulfoxide at room temperature. The equilibrium constants for the interaction of TTPa with the different quinones were evaluated.     

Fracture behavior of coated/uncoated graphite-epoxy composites

The static delamination behavior of graphite/epoxy composite specimens subjected to mode I tensile opening (using UDCB

1 Uniform double cantilever beam.

specimens), and pure mode II shear loading (using ENF

2 End-notched flexural.

specimens) were studied. The graphite epoxy composites for the study were made from commercially treated fibers, with and without an electropolymerized interlayer. The mode I fracture energy (G_IC) was found to be significantly higher (more than 50 percent) for the coated fibers. However, this improvement was accompanied by a high reduction (more than 3 times) in the mode II fracture energy (G_IIC). This effect is apparently related to poor adhesion between the interlayer and the epoxy resin, which may be corrected by use of a “top layer” of appropriate composition to form chemical bonds between the phases. The fracture toughness (K_IC) of composites made with commercially treated fibers was also evaluated, using double side-notched specimens.     

Derivatization of keto fatty acids,Part IX. Synthesis and characterization of oxathiolanes

Oxathiolanes are prepared from the condensation of the oxo fatty acids with β- mercaptoethanol using BF₃etherate as catalyst. 10-Oxoundecanoic acid (I) reacts with the reagent promptly and gives 1-(ethylene oxathiolane) undecanoic acid (V). A similar reaction of 9-oxooctadecanoic acid (II) yields 9-(ethylene oxathiolane) octadecanoic acid (VII). Hemimercaptals (VI, VIII) are also isolated as minor products in the above reactions. Methyl 9,10-dioxooctadecanoate (III) is also found to react readily and affords methyl 9(10)- (ethylene oxathiolane)- 10(9)oxooctadecanoate (IX) as the sole product. There is no reaction with 2-oxooctadecanoic acid (IV). The spectral (infrared, nuclear magnetic resonance, mass) properties of oxathiolanes are detailed.     

Study of Chromatographic Separation of Cesium,Europium, and Cobalt on Different Types of Tungstocerate Column Matrices

Interactions of ¹³⁴Cs(I), ^152,154Eu(III), and ⁶⁰Co(II) ions from HCl acid solutions with tungstocerate(IV) gel matrices, dried at 50°C, have been individually investigated by the batch equilibration method. The selectivity sequence was found to be in the order: Cs(I) >Eu(III) >Co(II). The breakthrough capacities of 12‐tungstocerate(IV) for Cs(I), Eu(III), and Co(II) were found to be 1.00, 0.55, and 0.26 mmol/g of the sorbent, respectively. In addition, a mixture of these radionuclides [6.20 × 10^?3 M Cs(I), 3.53 × 10^?3 M Eu(III), and 1.4 × 10^?3 M Co(II)], in 150 ml of 0.02 M HCl solution was passed through 1‐g 12‐tungstocerate(IV) chromatographic column. Quantitative uptake of both ¹³⁴Cs(I) and ^152,154Eu(III) has been achieved, while only ?22% of ⁶⁰Co(II) has been retained. Then, quantitative elution of the retained fraction of Co(II) was achieved with 14 ml of 0.1 M HCl acid solution leaving Eu(III) and Cs(I) strongly retained onto the column. Quantitative elutions of Eu(III) and Cs(I) were achieved by passing 20 ml of 0.3 M HCl and 16 ml of 2 M HCl acid solutions, respectively.     

Detection of Radicals at the Photolysis of tert-Butyl Hydroperoxide in DMSO and water

The decomposition of tert-butyl hydroperoxide by photochemically induced reactions in DMSO

1 Abbreviations used: DMSO, dimethyl sulfoxide; DMSO-d₆, completely deuterium labelled dimethyl sulfoxide; cw-ESR, continuous-wave Electron Spin Resonance; u. v., ultra violet; DMPO, 5, 5-dimethyl-I-pyrroline N-oxide; TMPO, 3, 3, 5, 5-tetramethyl-l-pyrroline N-oxide.

and water was investigated by cw-e.s.r. spectroscopy. The products tert-butylperoxyl, methyl and sulfur-centered free radicals were identified. The tert-butoxyl free radical is involved in the primary process as shown by time-resolved e.s.r. technique. On the basis of directly identified radical species, a mechanism for the photochemically induced reactions of tert-butyl hydroperoxide in DMSO is proposed. At concentrations below 0.8 mol · l⁻¹ the radical formation from tert-butyl hydroperoxide proceeds by cleavage of the O O bond rather than by hydrogen abstraction.     

Synthesis and photodegradation of poly[1,4-bis(dimethylsilyl)naphthalene]

Summary Poly[1,4-bis(dimethylsilyl)naphthalene](I), a copolymer with alternating 1,4-naphthalene and disilyl units, has been prepared by the Wurtz coupling of 1,4-bis(dimethylchlorosilyl) naphthalene (II) or 1,4-bis(dimethylfluorosilyl)naphthalene (III) with sodium metal dispersion in toluene. The molecular weight distribution of I prepared from III is significantly higher than when I is prepared from II. I has been characterized by ¹H, ¹³C and ²⁹Si NMR, IR, UV, GPC, TGA and elemental analysis. Photolysis of I in benzene/methanol solution results in rapid degradation of I.     

Preparation of 2-Aroyl-3-methyl-1H-1,4-benzothiazines. ESR Study of 2-benzoyl-1,3-dimethyl-1H-1,4-benzothiazine

2-Aroyl-3-methyl-1 H-1,4-benzothiazine ylids ( 2a – k ) were prepared by alkylation of the corresponding 4H-benzothiazines 1 . The ylids 2 are labile at room temperature; proper analytical and ¹H-n.m.r. data were obtained for their picrates. E.s.r. studies of u. v. irradiated polycrystalline form of ( 2 ; R¹ = Me, R² = H) gave evidence for a long-lived benzothiazinyl radical with the odd electron residing on nitrogen 6 .     

Two d10 Coordination Polymers Based on the Substitutional Aromatic Multicarboxylate and N-donor Co-ligands: Syntheses, Structures and Luminescent Properties

Two new coordination polymers, formulated as Zn(3-NPA)(1,4-bimb) (1) and Cd(3-NPA)(1,2-bimb)(H₂O) (2) (3-NPAH₂?=?3-nitrophthalic acid, 1,4-bimb?=?1,4-bis(imidazol-1 -ylmethyl)benzene, 1,2-bimb?=?1,2-bis(imidazol-1-ylmethyl)-benzene) have been synthesized by hydrothermal reactions of the semirigid neutral ligand 1,4-bimb or 1,2-bimb with metal ions in the presence of 3-nitro phthalic acid. The two compounds were characterized by infrared spectroscopy, elemental analysis, thermo gravimetric analysis and single-crystal X-ray diffraction analysis. Polymer 1 possesses a new two-dimensional puckered rectangular grid architecture, with the 1,4-bimb ligands displaying a cis-conformation. In polymer 2, the 3-NPA^2? anions coordinate the Cd(II) ions in a tetra dentate mode to form a dimer unit, which is connected by the 1,2-bimb ligands resulting in a single layer. Intra layer hydrogen bond interactions are found between the water molecule and carboxylate oxygen atoms. Weak π···π interactions are observed between the layers through the benzene rings from the adjacent 3-NPA^2? and 1,2-bimb ligands. In addition, the luminescent properties of the two compounds were also investigated in this paper.     

Reductive silylation of chloroprene

Summary Copolymers made up of 1,4-(2-trimethylsilyl-1,3-butadiene) (I) and 1,4-(2-chloro-1,3-butadiene) (II) units have been prepared by reaction of chloroprene with trimethylchlorosilane and sodium dispersion in THF. The ratio of III units in the copolymers have been determined by IR,¹H NMR and elemental analysis. The EZ ratio of these units has been determined by¹H NMR.¹³C and²⁹Si NMR of these copolymers is discussed.     

Osmium(VIII) catalyzed oxidation of a sulfur containing amino acid—a kinetics and mechanistic approach

The kinetics of osmium (VIII) catalyzed oxidation of DL-methionine by hexacyanoferrate(III) (HCF) in aqueous alkaline medium at a constant ionic strength of 0.50 mol dm^?3 was studied spectrophoto-metrically. The reaction between hexacyanoferrate(III) and DL-methionine in alkaline medium exhibits 2:1 stoichiometry (2HCF:DL-methionine). The reaction is of first order each in [HCF] and [Os(VIII)], less than unit order in [alkali] and zero order for [DL-methionine]. The decrease in dielectric constant of the medium increases the rate of the reaction. The added products have no effect on the rate of reaction. The main products were identified by spot test. A free radical mechanism has been proposed. In a prior equilibrium step Os(VIII) binds to OH^? species to form a hydroxide species and reacts with [Fe(CN)₆]^3? in slow step to form an intermediate species(C₁). This reacts with a molecule of DL-methionine in a fast step to give the sulfur radical cation of methionine and yields the sulfoxide product by reacting with another molecule of [Fe(CN)₆]^3?. The rate constant of the slow step of the mechanism is calculated. The activation parameters with respect to slow step of the mechanism are evaluated and discussed.