Si-Containing Amides of Phosphoric Acid

Summary. The first representative of the N-silylmethylamides of phosphoric acid O=P[NMe(CH₂SiMe _n (OEt)_3-n ]₃ have been synthesized by interaction of MeNHCH₂SiMe _n (OEt)_3-n (n = 2, 3) with POCl₃. The interaction of the N,N′,N″-trimethyl-N,N′,N″-tris[(ethoxydimethyl- silyl)methyl]triamide phosphoric acid with BF₃·Et₂O or BCl₃ results in the formation of the N,N′,N″-trimethyl-N,N′,N″-tris[(fluorodimethyl-silyl)methyl]triamide phosphoric acid or N,N′,N″-trimethyl-N,N′,N″-tris[(chlorodimethylsilyl)methyl]triamide phosphoric acid. NMR data show on the tetracoordinate state of silicon in these products. Professor Vadim Aleksandrovich Pestunovich, our chief, teacher and friend died on July 4^th, 2004     

The Synthesis of Novel Methotrexate-like Compounds

Summary. Methotrexate (MTX) is a folate antagonist used in treatment of several chronic inflammatory and neoplastic conditions. In this study, new MTX-like compounds that may-be potential anticancer agents were synthesized and their structures were determined by IR, UV, GC-MS, ¹H NMR, and ¹³C NMR spectra. Also, in this study, a series structurally related to MTX or folate analogous compounds were evaluated whether they have inhibitory properties on the dihydrofolate reductase activity (DHFR).     

An Efficient Method for the Synthesis of N-Acylsulfonamides: One-pot Sulfonylation and Acylation of Primary Arylamines under Solvent-Free Conditions

Summary. The preparation of N-acylsulfonamides is described using primary amines, arylsulfonyl chlorides and acyl chlorides. Reaction of primary aryl amines with arylsulfonyl chlorides in the presence of NaHCO₃ produced N-arylsulfonamides, which reacted in situ with benzoyl chloride furnishing the corresponding N-benzoyl-N-arylsulfonamides in 72–96% yields. Accordingly, 4-nitrobenzoyl chloride and 3,5-dinitrobenzoyl chloride were used as acylating agents. All the reactions were carried out under solvent-free conditions at room temperature and the products were isolated after simple work-up in high yields and purity.     

High-Yield Syntheses of Tetra-O-benzyl-α-D-glucopyranosyl bromide and Tetra-O-pivaloyl-α-D-glucopyranosyl bromide and their Advantage in the Koenigs-Knorr Reaction

Summary. Several improved approaches for the preparation of tetra-O-benzyl-α-D-glucopyranosyl bromide and tetra-O-pivaloyl-α-D-glucopyranosyl bromide are discussed. The importance of these compounds, which are useful glycosyl donors, was demonstrated by successful preparation of cholesteryl glucopyranosides in an almost neutral medium without the formation of orthoesters. In addition, accurate ¹H and ¹³C NMR resonance assignments of the synthesized cholesteryl glycosides were performed by 2D NMR spectroscopy.     

Fatty acid composition of Viscum album subspecies from Turkey

The lipophylic extracts of three Viscum album subspecies growing on different host plants in Turkey were comparatively analyzed for derived methyl esters of their fatty acids by capillary gas chromatography-mass spectrometry (GC-MS). The sample of V. album ssp. album growing on apricot trees was remarkably rich in palmitic acid (11.47%). Arachidic acid was found in only ssp. austriacum and ssp. abietis samples. The unsaturated fatty acids, mainly oleic and linoleic acids, were identified in nine lipophylic extracts obtained from V. album samples belonging to ssp. album. The amounts of linoleic and oleic acid were the highest in the sample of ssp. album growing on apricot trees (12.18 and 9.19%, respectively). Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 523–525, November–December, 2006.     

Fatty Acid Compositions of Seed Oils of Three Turkish <Emphasis Type="Italic">Salvia</Emphasis> Species and Biological Activities

The fatty acid composition of seed extracts of Salvia bracteata, S. aethiopis, and S. candidissima ssp. candidissima were analyzed by GC/MS. The main compound of S. bracteata, S. aethiopis, and S. candidissima ssp. candissima was found to be 9,12-octadecenoic acid at 64.3%, 73.4%, and 20.8%, respectively. The seed extracts of S. bracteata showed activity against S. aureus E. coli, M. smegmatis, and C. albicans with MIC values of 1.1, 0.5, 1.1, and 1.1 mg/mL, respectively, while the seeds extract of S. aethiopis showed activity against the same microorganisms with MIC values of 2.2, 2.2, 1.1, and 1.1 mg/mL, respectively. However, the seed extract of S. candidissima ssp. candidissima showed activity only against M. smegmatis with a MIC value of 0.25 mg/mL.__________Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 223–225, No. 3, May–June 2005.     

Synthesis and Stereostructure of Saturated Isoindolone-Fused Hetero Tri-, Tetra-, and Pentacyclic Compounds

Summary. t-2-Benzoyl-t-4-phenylcyclohexane-r-1-carboxylic acid reacts with hydrazine to give the saturated 1,7-diphenyl-trans-phthalazin-4(3H)-one. The reaction of the acid with ethylenediamine yields diastereomeric trans-imidazo[2,3-a]isoindoles, which differ in their C-1 configuration. The cyclizations of the acid with cis-2-aminocyclohexane- or 4-cyclohexenemethanol result in trans-isoindolo[2,1-a][3,1]benzoxazines, while in its reactions with the analogous di-endo- and di-exo-norbornane- and -norborneneamino alcohols, the acid gives methylene-bridged isomeric di-endo-norbornanes or a norbornene derivative; the corresponding diastereomeric di-exo derivatives have also been prepared. After isolation, the structures were established by means of ¹H and ¹³C NMR spectroscopy, with application of DIFFNOE, DEPT, HMQC, HMBC, and 2D-COSY techniques.     

Effects of <Emphasis Type="Italic">L</Emphasis>-Carnitine Supplementation in Sows

Summary. In recent years L-carnitine has been used increasingly in animals. This review gives an overview of the effects of dietary L-carnitine supplementation during pregnancy and lactation on the reproductive performance of sows. In one investigation L-carnitine supplementation during pregnancy increased the number of piglets born to sows. Other studies showed heavier litters in sows supplemented with L-carnitine compared with control sows, and litters of L-carnitine supplemented sows gained more weight during the suckling period than litters of control sows. This effect might be due to more vigorous suckling by piglets of L-carnitine supplemented sows, causing the sows’ milk production to rise. At negative energy balance during lactation L-carnitine supplemented sows are able to mobilize more energy from adipose tissue, which can be used for the production of surplus milk. In conclusion, recent studies clearly show that dietary L-carnitine supplementation increases the reproductive performance of sows. This finding suggests that the amount of L-carnitine synthesized endogenously does not cover the requirement for maximum sow performance during pregnancy and lactation.     

Ion-Pair Solvent Extraction of EDTA Anions with Tetraalkylammonium Ions in Various Organic Solvents

Summary.  The ion-pair solvent extraction behavior of ethylenediaminetetraacetate (EDTA) anion by various tetraalkylammonium ions was investigated at 25.0 ± 0.1°C. The extraction of EDTA exceeded 90% from the basic aqueous solution into the organic solvents such as n-hexane and benzene derivatives containing tri-n-octylmethylammonium chloride, but EDTA was hardly extracted from acidic solution. Among the chemical species of EDTA in aqueous solution, edta ⁴⁻ is the most extractable one. On the other hand, the extraction of EDTA was less than 1% into chloroform and 1,2-dichloroethane even from the basic aqueous solution. The effect of the structure of alkylammonium ion was also examined. Tetra-n-hexylammonium and tetra-n-octylammonium ions could not extract EDTA even from the basic aqueous solution, while the use of tri-n-octylmethylammonium and di-n-lauryldimethylammonium ions enhances the extraction of EDTA. These results suggest that the steric hindrance in the ion-pair of alkylammonium and EDTA anion in the organic phase affects the extractability of EDTA containing ion-pair. The solution structure of ion-pair in the organic phase was calculated by MMFF force field and the steric effect in the ion-pair was also suggested. From the extraction constants obtained, the possibility of the extraction separation of EDTA has been shown. Present address: Chemistry Department, Heilongjiang University, Harbin, China     

Essential Oil Composition of Four <Emphasis Type="Italic">Achillea</Emphasis> Species from the Balkans and Its Chemotaxonomic Significance

The chemical composition of the essential oils of Achillea clavennae L., Achillea holosericea Sibth. & Sm., Achillea lingulata W. & K., and Achillea millefolium L. from the Balkans was determined by GC and GC/MS analyses. The main components were 1,8-cineole in A. holosericea, camphor in A. clavennae, β-pinene in A. millefolium, and τ-cadinol in A. lingulata. A detailed chemotaxonomic discussion is presented. __________ Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 555–558, November–December, 2005.     

Preparation and Characterization of a Stable Semiquinone-Iron Complex

Summary. Dopamine oxidation by iron oxide (Fe₂O₃) was studied in the presence and absence of sodium thiosulfate in aqueous medium around pH 7 by UV-Vis spectroscopy. The pH changes from 6 to 8 indicate that the dopamine oxidation process has occurred producing an anionic semiquinone radical which appears after ca. 100 hours presenting bands at 309 and 337nm. It forms a stable compound with Fe(III) released by the iron oxide. The complex [CTA][Fe(SQ)₂(CAT)], where SQ=semiquinone, CAT=catecholate, and CTA=cetyltrimethylammonium cation, was isolated by precipitation with cetyltrimethylammonium bromide and was characterized through EPR, Raman and IR spectroscopies. The EPR spectrum presented two intense bands, one with g=2.003 assigned to o-semiquinone and the other with g=4.274 characteristic for high spin Fe(III) approaching an octahedral symmetry. The most intense Raman resonance band occurs at 1360cm^–1 assigned to (C₁–C₂) and at 1575cm^–1 to (C–C)ring of the o-semiquinone. The O₂ dissolved in solution is mainly responsible for the dopamine oxidation when sodium thiosulfate is present. A thermal decomposition mechanism based on the thermogravimetric curves (TG) was proposed. These results suggest that iron can participate in the degenerative process of the dopaminergic nigral neurons. Its role seems to be its coordination with the dopamine oxidation products as o-semiquinone and catecholate which could damage neurons giving rise to parkinsonism.     

A Green Synthesis of Tetrahydrobenzo[b]pyran Derivatives through Three-Component Condensation Using N-Methylimidazole as Organocatalyst

Summary. An efficient and convenient approach to the synthesis of 2-amino-3-cyano-4-aryl-7,7-dimethyl-5-oxo-4H-5,6,7,8-tetrahydrobenzo[b]pyran derivatives using N-methylimidazole as the organocatalyst (20 mol%) is described. This method has several advantages, such as mild conditions, high yields, and simple work-up procedure.     

A group theoretical study of f n systems in an environment of approximately icosahedral symmetry

Group theoretical methods are developed to determine in a generalised format for an f ⁿ ion in a crystal field environment of icosahedral symmetry, the effect on the energy level scheme when a crystal field distortion is considered parallel to any direction. As an illustration, the effect on the g-tensor components are examined as a function of the magnitude and the direction of the crystal field distortion. All appropriate reduced matrix elements in group theoretical terminology are evaluated for the f ⁿ -ion ground states. Specific results are given for the f ³-ion case and compared with electron paramagnetic resonance, optical, and magnetic susceptibility data.     

Stereodivergent <Emphasis Type="Italic">Baylis-Hillman</Emphasis> Reaction of a Chiral Acryloyl Imide Exploiting Ion-Chelation Effect: Mechanistic Insight on the Rearrangement of Trichloroacetimidates of the <Emphasis Type="Italic">Baylis-Hillman</Emphasis> Adducts to Trichloroacetamides

Summary. In the presence of DABCO, ethyl glyoxalate and (4S,5R)-1,5-dimethyl-3-acryloyl-4-phenylimidazolidin-2-one gave mixtures of the corresponding Baylis-Hillman adducts enriched in either isomer, depending on the absence or the presence of LiClO₄ in the reaction mixture. A diastereomeric mixture in 10:90 dr allowed to definitively establish the mechanism of the reaction leading to trichloroacetamides starting from trichloroacetimidates of the Baylis-Hillman adducts.     

Reaction of N-Heterocycles with Acetylenedicarboxylates in the Presence of N-Alkylisatins or Ninhydrin. Efficient Synthesis of Spiro Compounds

Summary. The 1,3-dipolar intermediates generated by addition of isoquinoline, to dialkyl acetylenedicaboxylates are trapped by N-alkylisatins to produce dialkyl 1,2-dihydro-2-oxo-1-alkylspiro[3H-indol-3,2′-[2H,11bH][1,3]oxazino[2,3-a]isoquinoline]-3′,4′-dicarboxylates in excellent yields. The reaction of isoquinoline, quinoline, or pyridine with dimethyl acetylenedicarboxylate in the presence of ninhydrin led to dimethyl 1,2-dihydro-1,3-dioxospiro[3H-indene-3,2′-[2H,11bH][1,3]oxazino[2,3-a]isoquinoline]-3′,4′-dicarboxylate, dimethyl 1,2-dihydro-1,3-dioxospiro[3H-indene-3,3′[3H,4aH][1,3]oxazino[3,2-a]quinoline]-1,2-dicarboxylate, or dimethyl 1,2-dihydro-1,3-dioxospiro[3H-indene-3,2′-[2H,9aH]pyrido[2,1-b][1,3]oxazino]-3,4-dicarboxylate.     

The <Emphasis Type="Italic">Willgerodt-Kindler</Emphasis> Reaction in Water: High Chemoselectivity of Benzaldehydes over Acetophenones

Summary. Water has been found for the first time as a useful solvent in the Willgerodt-Kindler (WK) reaction for the synthesis of benzothiomorpholides in high yield at 80°C for 3 h. This novel approach confronts the WK protocol with a new situation in which water not only is not regarded as a serious disadvantage but also is applied in this case as a useful solvent in the reaction. The basis of this finding is the presence of a methylene chain in the carbonyl substrates, which leads to the high reaction selectivity of benzaldehydes over acetophenones.     

Stereoselective Michael Addition of Carbonyl Compounds to ( E )-β-Nitrostyrene Catalysed by N -Toluensulfonyl-l -proline Amide in Ionic Liquids

Summary. N-Toluensulfonyl-l-prolin amide was tested as catalyst in the enantioselective Michael addition of carbonyl compounds to (E)-β-nitrostyrene in nine ionic liquids under different reaction conditions. The reaction rates and enantioselectivities were strongly dependent on the ionic liquids. Change of enantioselectivity was observed too and it is attributed to both the cation and the anion of ionic liquid. The best yields (up to 98%) and enantioselectivity (70% ee) of product were obtained in a basic ionic liquid [bmim]BF₄ at room temperature.     

The Synthesis of Cyclopenta[<Emphasis Type="Italic">c</Emphasis>]pyridine (2-Pyrindene) Derivatives

Summary. Ethyl 2-(N-morpholinyl)cyclopent-1-ene-1-carboxylate reacted smoothly with cyanothioacetamide to give morpholinium 4-cyano-1-oxo-2,5,6,7-tetrahydro-1H-cyclopenta[c]pyridine-3-thiolate; the former when treated with N-benzyl-α-chloroacetamide gave either a S-alkyl derivative or cyclopenta[d]thieno[2,3-b]pyridine, depending on the reaction conditions. Under Mannich-type aminomethylation with primary amines and formaldehyde the above thiolate afforded derivatives of the previously unknown heterocyclic system, cyclopenta[g]pyrido[2,1-b][1,3,5]thiadiazine in 81–90% yields. Victor P. Litvinov, was Deceased Victor P. Litvinov, This paper is dedicated to the blessed memory of our colleague, Prof. Victor Petrovich Litvinov (Dec 24, 1932–Feb 26, 2007)     

Magnetic Orbitals and Mechanisms of Exchange II. Superexchange

Summary. In a first step, we examine the concept of magnetic orbital which is very useful to treat the mechanism of superexchange. After that, we recall the general broad lines of the first historical model proposed by Anderson. In a second step, we develop a new general treatment for superexchange, in the case of the centrosymmetrical model AXB, where A and B are metal cations and X a common bridging ligand (with here, for simplification, A = B, without transfer between cations). It allows one to retrieve the expression of exchange energy J vs. key molecular integrals, as respectively proposed by several authors such as Anderson on the one hand, Hay, Thibeault, and Hoffmann on the other one, and, finally, Kahn and Briat. This model may be easily generalized to the case where a transfer does exist between both cations, with A = B or A ≠ B. An erratum to this article is available at .     

The Stannides YNi x Sn2 ( x = 0, 0.14, 0.21, 1) – Syntheses, Structure, and 119Sn M?ssbauer Spectroscopy

Summary. The stannides YNi _x Sn₂ (x = 0, 0.14, 0.21, 1) were prepared by arc-melting of the pure elements. They were characterized through X-ray powder and single crystal data: ZrSi₂ type, space group Cmcm, a = 438.09(6), b = 1629.6(4), c = 430.34(7) pm, wR2 = 0.0607, 386 F ² values, 14 variables for YSn₂, CeNiSi₂ type, Cmcm, a = 440.6(1), b = 1640.3(1), c = 433.0(1) pm, wR2 = 0.0632, 416 F ² values, 19 variables for YNi_0.142(7)Sn₂, a = 441.0(1), b = 1646.3(1), c = 434.6(1) pm, wR2 = 0.0491, 287 F ² values, 19 variables for YNi_0.207(7)Sn₂, and LuNiSn₂ type, space group Pnma, a = 1599.3(3), b = 440.89(5), c = 1456.9(2) pm, wR2 = 0.0375, 1538 F ² values, 74 variables for YNiSn₂. The YSn₂ structure contains Sn1–Sn1 zig-zag chains (297 pm) and planar Sn2 networks (307 pm). The stannides YNi_0.142(7)Sn₂ and YNi_0.207(7)Sn₂ are nickel filled versions of YSn₂. The nickel atoms have a distorted pyramidal tin coordination with Ni–Sn distances ranging from 220 to 239 pm. New stannide YNiSn₂ adopts the LuNiSn₂ type. The nickel and tin atoms build up a complex three-dimensional [NiSn₂] network in which the yttrium atoms fill distorted pentagonal and hexagonal channels. Within the network all nickel atoms have a distorted square pyramidal tin coordination with Ni–Sn distances ranging from 247 to 276 pm. Except the Sn4 atoms which are located in a tricapped trigonal Y₆ prism, all tin atoms have between 4 and 5 tin neighbors between 297 and 350 pm. ¹¹⁹Sn M?ssbauer spectroscopic data of YNi _x Sn₂ show a decreasing isomer shift (from 2.26 to 2.11 mm/s) from YSn₂ to YNiSn₂, indicating decrease of the s electron density at the tin nuclei.