Wojciech M. Wolf

Heavy Metal Uptake by Herbs. IV. Influence of Soil pH on the Content of Heavy Metals in Valeriana officinalis L.

The aim of the study was to estimate the influence of soil pH on the uptake of copper, zinc, and manganese by Valeriana officinalis. Preliminary studies involved soil analyses to determine acidity, organic matter content, and copper, zinc, and manganese total and bioavailable forms. The study involved atomic absorption spectrometry to determine the concentration of the elements, and mineral soil of pH = 5.1 was used in the study, as being typical for central Poland. The copper, zinc, and manganese contents were determined in plants grown in soils which had been modified to cover a wide range of pH values 3÷13. The intensity of germination was strongly pH dependent with the highest yield obtained in original, unmodified soil. Surprisingly, high soil alkalinity stimulated copper and manganese uptake while at the same time resulting in a decrease in zinc content.

Synthesis and cytotoxic evaluation of β-alkyl or β-aryl-δ-methyl-α-methylene-δ-lactones. Comparison with the corresponding γ-lactones

We present a simple and general strategy for the synthesis of beta,delta-disubstituted-alpha-methylene-delta-lactones starting from easily available tert-butyl 2-(diethoxyphosphoryl)alk-2-enoates. The elaborated synthetic protocol includes pyrrolidine-catalyzed Michael addition of acetone, diastereoselective reduction of the carbonyl group, lactonization and finally the Horner-Wadsworth-Emmons reaction with formaldehyde. All alpha-methylene-delta-lactones were evaluated in vitro against mouse leukemia cell line L-1210 and two human leukemia cell lines HL-60 and NALM-6. Comparison of cytotoxic activity with corresponding alpha-methylene-gamma-lactones is also discussed.

Synthesis, Characterization, and Antimicrobial Activity of Silver(I) and Copper(II) Complexes of Phosphate Derivatives of Pyridine And Benzimidazole

Two silver(I) complexes—{[Ag(4‐pmOpe)]NO3}n and [Ag(2‐bimOpe)2]NO3—and three copper(II) complexes—[Cu4Cl6O(2‐bimOpe)4], [CuCl2(4‐pmOpe)2], and [CuCl2(2‐bis(pm)Ope]—were synthesized by reaction of silver(I) nitrate or copper(II) chloride with phosphate derivatives of pyridine and benzimidazole, namely diethyl (pyridin‐4‐ylmethyl)phosphate (4‐pmOpe), 1H‐benzimidazol‐2‐ylmethyl diethyl phosphate (2‐bimOpe), and ethyl bis(pyridin‐2‐ylmethyl)phosphate (2‐bis(pm)Ope). These compounds were characterized by 1H, 13C, and 31P NMR as well as IR spectroscopy, elemental analysis, and ESIMS spectrometry. Additionally, molecular and crystal structures of {[Ag(4‐pmOpe)]NO3}n and [Cu4Cl6O(2‐bimOpe)4] were determined by single‐crystal X‐ray diffraction analysis. The antimicrobial profiles of synthesized complexes and free ligands against test organisms from the ATCC and clinical sources were determined. Silver(I) complexes showed good antimicrobial activities against Candida albicans strains (MIC values of ∼19 μM). [Ag(2‐bimOpe)2]NO3 was particularly active against Pseudomonas aeruginosa and methicillin‐resistant Staphylococcus epidermidis, with MIC values of ∼5 and ∼10 μM, respectively. Neither copper(II) complexes nor the free ligands inhibited the growth of test organisms at concentrations below 500 μg mL−1.

Nitroalkanes as nucleophiles in a self-catalytic Michael reaction

A simple, effective procedure for the preparation of 4-nitroalkanoates 6–9 by the Michael reaction of nitroalkanes 2–5 with the acrylate 1 is described. The primary nitro adduct 6 undergoes isomerization to hydroxamic acid 10 while heated in boiling nitromethane. Consecutive reactions of the latter compound lead to the formation of N-hydroxysuccinimide 11 and its N-ethoxy derivative 12. The spontaneous Nef reaction of the mother 4-nitrobutanoic acid 15 gives N-hydroxysuccinimide 14. The analogous reaction of secondary nitroalkanoic acids 16 and 17 provides 4-oxoalkanoic acids 18 and 19, respectively. Intramolecular participation by the carboxylic acid group in the Nef reaction is proposed.

X-ray investigations of sulfur-containing fungicides. III. Intramolecular forces governing the conformation of a novel orthorhombic polymorph of benzoylmethyl phenyl sulfone, benzoylmethyl 4-chlorophenyl sulfone and benzoylphenylmethyl phenyl sulfone

The crystal and molecular structures of three beta-ketosulfones: benzoylmethyl phenyl sulfone (I), benzoylmethyl 4-chlorophenyl sulfone (II) and benzoylphenylmethyl phenyl sulfone (III) have been investigated using X-ray analysis and quantum mechanics ab initio calculations. Compound (I) crystallizes in the monoclinic and orthorhombic crystal systems. The crystal structure of the orthorhombic polymorph has not been reported previously. At room temperature and in the presence of daylight the pale yellow orthorhombic crystals undergo transformation to the stable colourless monoclinic polymorph. Hyperconjugative sigma(S-C1) - pi(*)(C2=O3) and sigma(*)(S-C1) - pi(C2=O3) stabilization energies in benzoylmethyl phenyl sulfones are highly dependent on the central dihedral angle alpha: S-C1-C2=O3 and are largest for a gauche arrangement, as found in both crystal forms of (I). The electron density distribution in all compounds (I), (II) and (III) is significantly affected by interactions of oxygen lone pairs with non-bonding orbitals of the adjacent S-C1 and C1-C2 bonds. The latter effect is responsible for back-donation of the electron density from O atoms towards the central part of the molecule.

Three-component reaction of 3-(diethoxyphosphoryl)coumarin, enolizable ketones and primary amines: Simple, stereoselective synthesis of benzo[1,3]oxazocine skeletons

The synthesis of benzoxazocine phosphonates was accomplished by means of the three-component reaction of 3-(diethoxyphosphoryl)coumarin, enolizable ketones and benzylamine. An asymmetric version of this reaction was also developed. Treatment of the coumarin with cyclopentanone and (R)- or (S)-1-phenylethylamine afforded enantiomerically pure benzoxazocine phosphonates in a 2.5:1 diastereoisomeric ratio. In contrast, similar reaction with cyclohexanone provided α-phosphono-δ-enamides as single diastereoisomers. The mechanistic features of the reaction were discussed. A transition state model rationalizing its stereochemical outcome was proposed. The α-phosphono-δ-lactams obtained were transformed into the corresponding α-methylene-δ-lactams. The cytotoxicity of these compounds was evaluated.

X-ray investigations of bicyclic α-methylene-δ-valerolactones. V. (4aS,7R,8aR)-7-Isopropenyl-4a-methyl-3-methyleneperhydrochromen-2-one

The title compound, C(14)H(20)O(2), adopts a conformation in which the delta-valerolactone and cyclohexane rings are almost coplanar with one another. The gamma-methyl substituent occupies an axial position with respect to the cyclohexane ring. The delta-valerolactone moiety adopts an envelope arrangement, while the cyclohexane ring exists in a chair conformation.

The stereochemistry of the phosphorus-selenium bond. VII. Structure of 5,5-dimethyl-2-(o-nitrophenyl)amino-1,3,2-dioxaphosphorinane 2-selenide.

C11H15N2O4PSe, Mr = 349.2, monoclinic, P2(1)/c, a = 10.204(3), b = 19.891 (3), c = 6.823 (3) A, beta = 94.41 (3) degrees, U = 1380.8 A3, Z = 4, Dm = 1.66, Dx = 1.68 Mg m-3, Mo K alpha, lambda = 0.71069 A, mu = 3.05 mm-1, F(000) = 704, room temperature, R = 0.026 for 1755 observed reflections [I greater than 3 sigma (I)]. The dioxaphosphorinane ring adopts a flattened chair conformation with P = Se and P-N bonds in equatorial and axial positions respectively. The properties of the molecule are mainly governed by anomeric interactions between endocyclic oxygen lone pairs and antibonding orbitals of the axial P-N bond.

Studies of substituted quinoxaline-di-N-oxides. Part 1. Crystal structure and molecular conformation of 2-[N-(2-hydroxyethyl)carboxamide]-3-methylquinoxaline 1,4-dioxide

A single crystal X-ray investigation of the yellow 2-[N-(2-hydroxyethyl) carboxamide]-3-methylquinoxaline 1,4-dioxide, a commercially available growth promoter used in agricultural stock farming, shows that the molecule is planar. The dihedral angle between the benzene and heterocyclic rings is 0.5°. The N(1)-O(1) and N(2)-O(2) distances are: 1.286(1) and 1.304(1) Å. The C(1)-C(2) bond of the pyrazine ring is not lengthened by substitution at the C(1) and C(2) atoms and is 1.421(2) Å. The atoms O(1) and O(2) deviate by 0.036(2) and 0.123(2) Å from the least-squares plane through the heterocyclic ring. The deviation of the C(12) atom is −0.012(2) Å. The plane through the atoms C(1), C(9), N(3), and O(3) makes an angle of 100.5(2)° with the heterocyclic ring plane. Intermolecular hydrogen bonds O(4)-HO(4)⋯O(3) between the hydroxyl and carbonyl groups generated alternating, antiparalled chains extending in thea direction. The crystals are triclinic,P¯1 (No. 2), witha=7.469(2),b=8.111(2),c=10.357(3) Å,α=80.11(2),β=88.90(2), γ=67.73(2)°, andV=571.3(2) Å3. The structure was solved by direct phase determination guided by negative quartets and refined by full-matrix least squares to anR value of 0.041 for 2159 observed reflections.

X-ray investigations of bicyclic alpha-methylene-delta-valerolactones. III. trans-(4aR,8aR)-4a-Methoxy-3-methyleneperhydrochromen-2-one.

The title compound, C11H16O3, adopts a conformation in which the delta-valerolactone and cyclohexane rings are almost coplanar with one another. The beta-methoxy substituent occupies an axial position with respect to the cyclohexane ring. The delta-valerolactone moiety adopts a half-chair arrangement, while the cyclohexane ring exists in a chair conformation.