Quantum Chemistry Studies on the Fe-Cu Interactions and 31p NMR in Fe（CO）3（Ph2Ppy）2（CuXn） （Xn = Cl2^2-, Cl-, Br-）

In order to study the Fe-Cu interactions and their effects on 31p NMR, the structures of mononuclear complex Fe（CO）3fPhzPpy）a 1 and binuclear complexes Fe（CO）3（PhEPpy）z（CuXn） （2： Xn = Cl2^2-, 3： Xn = Cl-, 4： Xn = Br-） are calculated by density functional theory （DFT） PBE0 method. For complexes 1, 3 and 4, the 31p NMR chemical shifts calculated by PBE0-GIAO method are in good agreement with experimental results. The 31p chemical shift is 82.10 ppm in the designed complex 2. The Fe-Cu interactions （including Fe→Cu and Fe←Cu charge transfer） mainly exhibit the indirect interactions. Moreover, the Fe-Cu（I） interactions （mostly acting as σFe-p→4Scu and aFe-C→4Scu charge transfer） in complexes 3 and 4 are stronger than Fe-Cu（Ⅱ） interactions （mostly acting as σFe-p→4Scu and σFe-p←4Sc,） in complex 2. In complex 2, the stronger Fe←Cu interac- tions, acting as σFe-p←44SCu charge transfer, increase the electron density on P nucleus, which causes the upfield 31p chemical shift compared with mononuclear complex 1. For 3 and 4, although a little deshielding for P nucleus is derived from the delocalization of σFe-p→4Scu due to the Fe→Cu interactions, the stronger σFe-c→np charge-transfer finally increases the electron density on P nucleus. As a result, an upfield 31p chemical shift is observed compared with 1. The stability follows the order of 2〉3=4, indicating that Fe（CO）3（PhzPpy）2（CuCl2） is stable and could be synthesized experimentally. The N-Cu（Ⅱ） interaction plays an important role in the stability of 2. Because the delocalization of σFe-p→4SCu and σFe-c→πc-o weakens the a bonds of Fe-C and ~r bonds of CO, it is favorable for increasing the catalytic activity of binuclear complexes. Complexes 3 and 4 are expected to show higher catalytic activity compared to 2.     

甘薯象鼻虫信息素(E)-2-丁烯酸-(Z)-3-十二烯基酯的全合成

性信息素;甘薯象鼻虫信息素(E)-2-丁烯酸-(Z)-3-十二烯基酯的全合成     

Theoretical and Experimental Conformational Studies of Oligoglucosides Structurally Related to Fragments of Fungal Cell Wall β-(1→3)-D-Glucan

The conformational behavior of linear oligo-β-(1→3)-D-glucosides was studied using NMR experiments and molecular modeling. The explicit solvent model in calculations yielded the best coincidence between experimental and theoretical values of NOE and spin-spin coupling constants to evidence the strong influence of solvation upon the conformations of the oligoglucosides. Long-range coupling constants calculated for di- and trimeric clusters of the studied glucosides fit the experimental data much better than the single-molecule approach. It was shown that conformational properties of disaccharide fragments in studied oligoglucosides depended on neither their position in the chain nor the length of the chain.     

4-氟苯甲醛、β-萘胺和Meldrum酸-锅反应生成1-(4-氟苯基)-1,2-二氢苯并[f]喹啉-3(4H)-酮的反应机理理论研究

采用密度泛函理论(DFT)研究了4-氟苯甲醛、β-萘胺和Meldrum酸一锅反应生成1-(4-氟苯基)-1,2-二氢苯并[f]喹啉-3(4H)-酮的微观反应机理.在B3LYP/6-311G*基组水平上优化了反应物、过渡态、中间体及产物的几何构型,通过振动分析确认了过渡态的结构,并用内禀反应坐标(IRC)确认反应途径.应用分子中的原子理论(AIM)分析了这些物质的成键特征.采用SCRF(PCM)方法研究了反应体系的溶剂化效应.报道了可能的反应路径,其中Re→TS1→IM1→TS2→IM2→TS3→IM3→TS4→IM5→TS7→IM9→TS13→IM10→TS14→P3具有相对较低的活化能,是反应的主要通道,理论预测的主要产物与实验吻合.     

Synthesis of 3-aminopropyl glycosides of branched β-(1→3)-glucooligosaccharides

Russian Chemical Bulletin - The synthesis of branched β-(1→3)-glucooligosaccharides bearing a β-d-glucose residue at position 6 of one of the monosaccharides of the linear chain at...     

Synthesen des Analgetikums 2-[1-(m-Methoxyphenyl)-2-cyclohexen-1-yl]-N,N -dimethyl-äthylamin

Syntheses of the Analgesic 2-[1-(m-Methoxyphenyl)-2-cyclohexen-1-yl] -N,N-dimethyl-ethylamine Three principal routes to 2-[1-(m-methoxyphenyl)-2-cyclohexen-1-yl]- N,N-dimethyl-ethylamine (13) , a compound with interesting analgesic properties, are described. In the first, derivatives of [1-(m-methoxyphenyl)-2-cyclohexen-1-yl]acetic acid (10) (alternatively the ethyl ester 29 , the dimethylamide 32 or the nitrile 34 ) serve as crucial intermediates. All three can be synthesized from 2-(m-methoxyphenyl)cyclohexanone (1) by sequences comprising successively C-alkylation ( 1→2,4,5; Scheme 1), reduction of the ketone carbonyl group ( 2→6;4→18;5→19; Scheme 1 and 2) and elimination ( 16→29; 18→32; 19→34; Scheme 2). The relative configuration of the cyclohexanols 16, 18, 19 and of a series of related compounds is established by chemical correlation with the lactone 30 the structure of which follows from ¹H-NMR. data (Scheme 2). The second route creates the intermediates 29 and 32 by ester- or amide-enolate-Claisen-type-rearrangement reactions starting from 3-(m-methoxyphenyl)-2-cyclohexen-1-ol ( 39; Scheme 3). Compounds 29, 32 and 34 are transformed into the target molecule 13 by standard reactions. A Hofmann elimination of the quaternary ammonium fluoride 50 (X=F), derived from the known cis-perhydroindoline 48 , is the essential step in the third approach to 13 (Scheme 4).     

Halodemetallation of (Z)-1-[2-(Triarylstannyl)vinyl]-cyclooctanol and Correlation of Proton Chemical Shift with Electronegativity

IntroductionOrganotin compounds have attracted attentionas an optimal model for antitumour agents due tothe function of the interesting intramolecularO→Sn coordination[1,2 ] . Our recent concern hasbeen focused on the preparation of ( Z) - 1 - [2 -( triarylstannyl) vinyl]- cyclooctanol[3 ] .In order tofind more appropriate compounds used asanticancer agents and explore the effect of thecoordinate O→ Sn interaction to the antitumoractivity,the new compounds werehalodemetallated and characte…     

Electrochemical, catalytic and antimicrobial activity of N-functionalized tetraazamacrocyclic binuclear nickel(II) complexes

The five binuclear nickel(II) complexes have been synthesized by the Schiff base condensation of 1,8-[bis(3-formyl-2-hydroxy-5-methyl)benzyl]-l,4,8,11-tetraazacyclo-tetradecane (PC) with appropriate aliphatic diamines and nickel(II) perchlorate. All the five complexes were characterized by elemental and spectral analysis. The electronic spectra of the complexes show three d-d transition in the range of 550-1055 nm due to 3A2g→3T2g(F), 3A2g→3T1g(F) and 3A2g→3T1g(P). These spin allowed electronic transitions are characteristic of an octahedral Ni2+ center. Electrochemical studies of the complexes show two irreversible one electron reduction waves at cathodic region. The reduction potential of the complexes shifts towards anodically upon increasing the chain length of the macrocyclic ring. All the nickel(II) complexes show two irreversible one electron oxidation waves at anodic region. The oxidation potential of the complexes shift towards anodically upon increasing the chain length of the macrocyclic ring. The catalytic activities of the complexes were observed to be increase with increase the macrocyclic ring size. The observed rate constant values for the catalytic hydrolysis of 4-nitrophenyl phosphate are in the range of 5.85×10(-3) to 9.14×10(-3) min(-1). All the complexes were screened for antimicrobial activity.     

Aromatization of 1-Benzyltetrahydroisoquinolines: Racemization of (−)-(S)-(N-nor)-Reticuline

Aromatization in the series of optically active 1-benzyltetrahydroisoquinolines has been accomplished with (—)-(S)?(N-nor)-reticuline ( 1b ) and analogs. Direct catalytic or chemical reduction of the isoquinoline 4 obtained could not be achieved in a practical way but 4 was converted into 1 in three steps ( 4 → 8 → 9 → 1 ), in 55% overall yield. Partial O-methylation of the isoquinoline 4 gave the isoquinoline alkaloid palaudine ( 5 ), before papaverine ( 6 ) was formed.     

Synthesis of propyl O-(α-L-rhamnopyranosyl)-(1→3)-[2,4-di-O-(2s-methylbutyryl)-α-L-rhamnopyranosyl]-(1→2)=(3-O-acetyl-β-D-glucopyranosyl)-(1→2)-βp-D-fucopyranoside,the tetrasaccharide moiety of Tricolorin A

Propyl O-(α-L-rhamnopyranosyl)-(1→3)-[2,4di-O-(2s-methylbutyryl)-α-L-rhamnopyranosyl]-(1→2)-(3-O-acetyl-β-glucopyranosyl)-(1→2)-β-D-fucopyranoside (1), the tetrasaccharide moiety of Ricolorin A, was synthesized in total 23 steps with a longest linear sequence of 10 steps, and overall yield of 3.7% from D-Glucose. The isomerization of the dioxolane-type benzylidene in the prance of NIS/AgOTf was observed. Tetrasaccharide 1 exhibited no activity against the cultured P388 cell as Tricolorin A did.     

Notiz zur Synthese des optisch aktiven (—)-(2R,3R,6S,8S)-Nonactinsäure-methylesters

Using optically active propylene oxide (from lactic acid) methyl (?)-nonactate is prepared by way2→3→4→5→6→1.     

Synthesis of highly active corticotropic (1-D-serine,17,18-dilysine)-beta-corticotropin-(1-18)-octadecapeptide amide

A synthesis is described of [1-D -serine, 17, 18-dilysine]-β-corticotropin-(1–18)-octadecapeptide amide (I), a short chain ACTH analogue which has been found to possess in animals and also in man high and prolonged corticotropic activity. Synthesis was carried out by the fragment condensation approach involving, in the last build-up step, coupling of the protected sequences 1–10 and 11–18. From the protected octadecapeptide derivative 1–18 the free peptide was obtained in high yield by acidolysis.     

Structure-activity relationships (SAR) of [D-Arg(2)]dermorphin(1-4) analogues,N(alpha)-amidino-Tyr-D-Arg-Phe-X

In investigating the development of compounds with potent analgesic effects after oral administration, 74 C-terminal analogues (N(alpha)-amidino-Tyr-D-Arg-Phe-X), based on the structure of N(alpha)-amidino-Tyr-D-Arg-Phe-Me beta Ala-OH (ADAMB), were synthesized. Their analgesic activity was evaluated using the mouse-tail pressure test after both subcutaneous and oral administration, and the structure-activity relationships (SAR) were examined in detail. The results clearly indicated that compounds containing beta-amino acid without a side chain at the X position are preferable for expression of potent analgesic activity, and that the free carboxyl group is superior in its analgesic activity to that of the esterified or amidated carboxy group at the C-terminal. In addition, N-methylation of the amide bond at the 4th position contributed to improved analgesic activity. These results indicated that the strong and long-lasting analgesic effect of ADAMB is expressed by the synergistic effects of N(alpha)-amidination, the N-methylation of the amide bond at the 4th position and the carbon chain length (beta-Ala) of the residue at the 4th position, and that this is the most suitable structure.     

Calculation and comparative analysis of IR spectra of (22S,23S)-24-epibrassinolide and (22S,23S)-28-homobrassinolide

A consistent calculation of frequencies and intensities of normal vibrations of some steroid phytohormones having biological activity ( (22S,23S)-24-epibrassinolide and (22S,23S)-28-homobrassinolide molecules) is performed within an original approach combining a classical normal mode vibration analysis by the molecular mechanics method and a quantum chemical estimation of absolute intensities. Based on a comparison of the experimental and theoretical spectral absorption curves the interpretation of IR spectral absorption bands is given for the first time and the effect of structural differences within the side chain of these molecules on the formation of their IR spectra in the range 1500-950 cm^?1 is estimated.     

Structural-dynamic approach and path analysis of the intramolecular electron transfer in the bridged complexes [(NH3)5Ru-py-(C2H2) n -py-Ru(NH3)5]5+ withn = 0,1,2,3

The electron interaction transfer paths in the mixed-valence complexes[(NH₃)₅Ru-py-(C₂H₂)_n-py-Ru(NH₃)₅]⁵⁺ are analyzed in the framework of perturbation theory. A structural-dynamic approach to treatment of the intramolecular electron transfer is proposed. This approach is based on the solution of the nonstationary Schrödinger equation in a basis of many-electron functions describing separate structural sites of the electron-transport chain Ry^II→pyridyl→ C₂H₂)_n→pyridyl→Ru^III.     

Intramolecular diels-alder reaction with furan-diene: Total synthesis of (±)-11-ketotestosterone and (±)-adrenosterone

A novel D → BCD → ABCD route to 11 -keto steroids is reported involving a high yield stereoselective intramolecular Diels-Alder reaction of furan-diene $\text{12}$ in water as a key-step. The dienophilic side chain is readily introduced starting from $\text{8}$ via a sequence involving alkylation with ethyl ($\text{E}$)-3-ethoxy-4-iodo-2-butenoate, reduction and acid hydrolysis. The reduced adduct $\text{14}$ is further converted into (±)-adrenosterone ($\text{6}$) via $\text{24}$, the dienediolate equivalent of which is a known intermediate in corticosteroid synthesis.     

Crystal and molecular structure of 1-(3-ammoniopropyl)silatrane chloride

By single crystal X-ray diffraction the crystal and molecular structure of 1-(3-ammoniopropyl)silatrane chloride (I) is determined. One of three cations in the asymmetric unit of the crystal of I differs from the other two by the length of the coordination N → Si bond. The opposite electronic effects in two geometrically similar cations are transferred inductively through a three-carbon chain.     

Synthesis,Crystal Structure,Characterizationand Quantum Chemical Studies on 1N-Acetyl-3-（2,4-dichloro-5-fluorophenyl）-5-（p-methyl-phenyl）-2-pyrazoline

1N-Acetyl-3-（2,4-dichloro-5-fluoro-phenyl）-5-（p-methyl-phenyl）-2-pyrazoline has been synthesized and characterized by elemental analysis, IR, UV-Vis and X-ray single-crystal diffraction. Ab intio calculations have been carded out for the compound by using both B3LYP and HF methods at the 6-31G^＊ basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. The electronic absorption spectra calculated by B3LYP/6-31G^＊ method are approximate to the experiments and the Natural Bond Orbital （NBO） analyses suggest that the above electronic transitions are mainly assigned to n→π^＊ and π→π^＊ transitions. CIS-HF/6-31G^＊ method is not suitable to predict the electronic spectra for the title compound. The calculation of the second order optical nonlinearity was carded out, giving the value of molecular hyperpolarizability equal to 2.194^＋ 10^-30 esu. On the basis of vibrational analyses, the thermodynamic properties of the compound at different temperature have been calculated, revealing the correlation between C p, m^0, S m^0, H m^0 and temperature.     

Stereospecific synthesis of (+)- and (-)-sesbanimide A

Starting from L-xylose and D-xylose derivatives, (-)-sesbanimide A and (+)-sesbanimide A, respectively, have been synthesized. The carbohydrate templates constitute ring B of the alkaloid on which the remaining two rings are constructed in the sequence B → AB → ABC.     

Totalsynthese von natürlichem α-Tocopherol. 2. Mitteilung. Aufbau der Seitenkette aus (−)-(S)-3-Methyl-γ-butyrolacton

Total Synthesis of Natural α-Tocopherol A short and efficient route to optically pure (+)-(3 R, 7 R)-trimethyldodecanol ( 14 ) is demonstrated, 14 serving as side chain unit in the preparation of natural vitamin E. The synthesis of 14 is based on the concept of using a single optically active C₅-synthon of suitable configuration and functionalization to introduce both asymmetric centres in 14 . (?)-(S)-3-Methyl-γ-butyrolacton ( 1 ) and ethyl (?)-(S)-4-bromo-3-methylbutyrate ( 2 ), respectively, is used in a sequence of either two Grignard C,C-coupling reactions 5 → 8 and 12 → 13 or two Wittig reactions 17a → 18 and 20 → 21 to achieve this goal. 14 is converted to (2 R, 4′R, 8′R)-α-tocopherol (= vitamin E) by coupling with a chroman unit in known manner. Optical purity of products and intermediates is established.