bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoisomerization of Ethyl 2–(3–Acylselenoureido)thiophene– 3–carboxylates and Their Benzoanalogues
Authors: Pazdera Pavel , Sibor Jiri , Marek Radek , Kuty Michal , Marek Jaromir
Published: October 2008

Synthesis, isomerisation and structure elucidation of the title compounds 1–6 and its isomers 7–12 by FTIR, 1H, 13C, 15N, 77Se NMR spectroscopy is reported. Ethyl 2–(3–acylselenoureido)thiophene–3–carboxylates and their benzoanalogues (where acyl is benzoyl and pivaloyl) were prepared by addition of ethyl 2–aminothiophene–3–carboxylates and ethyl 2–aminobenzoate on benzoyl– or pivaloylisoselenocyanate in acetone solution. An isomerization of 1–6 to the corresponding 3–acylisoselenoureas 7–12 was obtained. The isomerisation proceeds either by irradiation with light (340–400 nm) or in the case of benzoylderivatives 1, 3, 5 by treatment with acetic acid. On the other hand the acid action in the pivaloyl set inhibited this isomerisation and evoked the retroisomerisation reaction of 8, 10, 12 to 2, 4, 6. Thermal analyses showed that isomerisation can be initiated also by heating. These changes proceed in the solid phase as an exothermic process at an elevated temperature but always below the temperature of melting. The structure 2 was supported by X–ray analysis. Molecular design of 2 and 8 was modeled during application of ab initio quantum chemistry calculation.
Purification of Laboratory Chemicals, Fourth Edition. By W. L. F. Armarego
Authors: Read R.
Published: October 2008

n/a
Alkaloids: Chemical & Biological Perspectives. Vol. 10. By S.W. Pelletier
Authors: Peerzada N.
Published: October 2008

This volume provides four excellent reviews refereed at least by one expert in the field.[...]
Guidebook on Molecular Modeling in Drug Design. By N. C. Cohen
Authors: Craik D.
Published: October 2008

This book is intended as a "guide for advanced students and chemists entering the field of molecular modeling".[...]
Online Searching: A Scientist's Perspective. Damon D. Ridley
Authors: Savage G.
Published: October 2008

In order to be of any use computer software must be either easy to use or be supported by very well written manuals. Unfortunately, STN (previously CAS-Online) is neither.[...]
Advances in Chemistry of Insect Control, Vol 3. By G.G. Briggs
Authors: Peerzada N.
Published: October 2008

This monograph contains 18 lectures given by the experts in their field at the Symposium Advances in the Chemistry of Insect Control", held at Queens, College Cambridge, on 18-21 July 1993.[...]
Comprehensive Polymer Science. By S. L. Aggarwal
Authors: Busfield Ken
Published: October 2008

This final supplement to the excellent series of Comprehensive Polymer Science books is fully up to the high standard set by the originals.[...]
Some Terpenes and Related Derivatives Synthesized in Cold Plasma Systems
Authors: Manolache Sorin , Romanescu Constantin , Cobileac Gheorghe , Simionescu Cristofor  I.
Published: October 2008

The synthesis of bicyclo-[2.2.1]-heptane and bicyclo-[7.2.0]-undec-4-ene derivatives under cold plasma conditions are reported. The reaction systems involve gaseous mixtures at an interface with ice surfaces. The reactions are sensitive to the feed mixture and the ice trapped compounds.
Chemical Composition of the Essential Oil of Hyptis Suaveolens
Authors: Peerzada N.
Published: October 2008

The chemical composition of Hyptis suaveolens was investigated and twenty three compounds were abundant enough to be identified by GC-MS.
Experimental Studies on the UV-Spectra of Several Substituted Pyridine N-Oxides and Conjugated Cationic Acids in Acetonitrile
Authors: Chmurzynski Lech
Published: October 2008

The ultraviolet spectra of heterocyclic N-oxides of pyridine N-oxide series and the conjugated cationic acids (simple cations of protonated N-oxides) in acetonitrile as the representative of polar aprotic solvents, were determined. The obtained spectra of N-oxides studied (mainly tri-substituted pyridine N-oxides) and their cations obtained by the protonation of free N-oxides by the excess of perchloric acid, have been collected and discussed. Taking into account the spectroscopic results, a scheme of acid-base equilibria in polar aprotic solvents has been discussed. The influence of the traces of water on acid-base equilibria in nonaqueous media has been stressed.
Dehydration of Aromatic Heterocyclic Carboxamides to Aromatic Heterocyclic Carbonitriles
Authors: Aquino Fabrice , Karge Reinhard , Pauling Horst , Bonrath Werner
Published: October 2008

Phosphorus pentoxide is commonly used for the dehydration of heterocyclic carboxamides to the corresponding nitriles. In this report, the use of cyanuric chloride/N,N-disubstituted formamide for this reaction is described. The advantages of this procedure are mild reaction conditions and good yields. Depending on the reaction conditions and the structures of the amides, the nitriles are obtained in yields from 51% to 99%. Several of the oxazole carbonitriles synthesized by this procedure have not yet been described.
Synthesis and Neurotropic Activity of Novel Quinoline Derivatives
Authors: Lukevics Edmunds , Segal Izolda , Zablotskaya Alla , Germane Skaidrite
Published: October 2008

Hydroxyalkyl and carboxyalkyl derivatives of silatetrahydroisoquinoline, tetrahydroisoquinoline and tetrahydroquinoline have been synthesized. Their neurotropic activity has been investigated.
Preparation of α,β-Unsaturated Ketones Bearing a Trifluoromethyl Group and Their Application in Organic Synthesis
Authors: Nenajdenko Valentine G. , Sanin Andrei V. , Balenkova Elizabeth S.
Published: October 2008

The approaches to the synthesis of α,β-unsaturated CF3-containing ketones and their use in organic chemistry are reviewed. The synthetic applications of these ketones are discussed. The formation of 4-, 5-, 6- and 7-membered heterocycles bearing a CF3 group based on reactions of α,β-unsaturated CF3-containing ketones with different nucleophiles are discussed.
4-Aryldihydropyrimidines via the Biginelli Condensation: Aza-Analogs of Nifedipine-Type Calcium Channel Modulators
Authors: Kappe C.  Oliver
Published: October 2008

Recent results from the author's laboratory in the area of dihydropyrimidine chemistry are summarized.
Synthesis and Intramolecular [4+2] Cycloaddition Reactions of 4-Pyridazinecarbonitriles with Alkyne Side Chains
Authors: Fülep Günther , Haider Norbert
Published: October 2008

The preparation of a series of new 3-(alkynyl-X)-substituted 4-pyridazinecarbonitriles 2-5 (X = O, NH) is described. The compounds are shown to undergo thermally induced intramolecular Diels-Alder reactions with inverse electron demand, affording the fused benzonitriles 6-8. Incorporation of a 1,2-phenylene unit into the side chain, as in the case of compounds 10 and 13, results in a more favorable conformation of the dienophilic substructure and thus to a pronounced acceleration of the [4+2] cycloaddition reaction.
Review of the Molecule of the Month Website in 1997
Authors: May Paul
Published: October 2008

This review describes the history of the "Molecule of the Month" Website, along with a short summary of some of the molecules which featured during 1997.
Synthesis and Biological Evaluation of 14 -Methoxy Digitalis Derivatives
Authors: Gobbini M. , Almirante N. , Cerri A. , Padoani G. , Melloni P.
Published: October 2008

The synthesis and biological evaluation of 14β-methoxy derivatives of digitoxigenin and of other digitalis-like compounds are reported. These compounds have a 14β-oxygen, which can be a hydrogen bonding acceptor, as is the case of 14β,15β-epoxide derivatives, but not a hydrogen bonding donor as is the case of 14β-hydroxy derivatives. All the new 14β-methoxy derivatives show a considerable reduced binding affinity on Na+,K+-ATPase when compared with the 14β-hydroxy analogues and also with the 14β,15β-epoxy derivatives. These results could mean that the digitalis receptor does not permit the presence of a bulky substituent in the 14β region, even of relatively small volume like the methyl group
Nucleophilic Additions of 2-Furyllithium to Carbonyl Derivatives of L-Serine. Formal Synthesis of (2R,3R)-β-Hydroxy Aspartic Acid
Authors: Merino P. , Franco S. , Merchan F.  L. , Tejero T.
Published: October 2008

The nucleophilic addition of 2-furyllithium to esters derived from L-serine is described. The obtained furyl ketone 5 is stereoselectively reduced (ds≥95%) with sodium borohydride to afford the corresponding syn aminoalcohol 12 in enantiomerically pure form. Compound 12 was further converted into valuable α-hydroxy-β-amino acids by means of the furan-to-acid equivalence.
An Improved Synthesis of Homocitrate
Authors: Li Zeng-Chun , Xu Ji-Qing
Published: October 2008

Monoethyl malonate (1) and tert-butyl alcohol are esterified by catalysis with dicyclohexylcarbodiimide and 4-dimethylaminopyridine to yield ethyl t-butyl malonate (2). The ethoxymagnesio derivative (3) of the ester is condensed with b-carbomethoxypropionyl chloride to give the triester (4), which is decomposed by heating under vacuum in the presence of b-naphthalensulfonic acid to give ethyl methyl β-ketoadipate (5). Compound 5 is reacted with hydrogen cyanide,followed by hydrolysis of the cyanohydrin to give the free acid (6). Compound 6 is converted to homocitrate (7) by the use of an improved procedure.
An Expedient Synthesis of the Sugarcane Borer Pheromone Components
Authors: Subbaraman Ayalur  S. , Mithran Sethuram , Mamdapur Vasant  R.
Published: October 2008

A practical synthesis of the title compounds has been developed. The salient features of the synthesis were i) use of easily accessible starting materials viz. aleuritic acid, 10-undecenoic acid, cyclohexanone etc. and ii) fixation of the required olefinic geometry via Wittig and acetylenic routes.
A Three Step Synthesis of 11-Cycloheptylundecanoic Acid, a Component of the Thermoacidophile Alicyclobacillus cycloheptanicus
Authors: Hassarajani Sham  A. , Mamdapur Vasant  R.
Published: October 2008

A simple synthesis of the methyl ester of 11-cycloheptylundecanoic acid (1), isolated from the lipid fraction of the thermoacidofile, Alicyclobacillus cycloheptanicus has been developed. This involved regioselective Grignard coupling between cycloheptylmagnesium bromide and methyl 11-bromoundecanoate (2), prepared from 10- undecanoic acid.
A Short and Efficient Synthesis of (R)-Phoracantholide I
Authors: Sharma A. , Chattopadhyay S.
Published: October 2008

A short and efficient chemoenzymatic synthesis of the title compound has been developed. The salient features of the synthesis were i) preparation of the required chiron via a porcine pancreatic lipase (PPL) catalyzed esterification of a ω-functionalized 2-alkanol and ii) use of easily accessible and inexpensive materials/ reagents.
Polymer Syntheses, Vol. 3, 2nd Edition. By Stanley R. Sandler
Authors: Chiefari John
Published: October 2008

This is the latest volume in the Polymer Syntheses series which sets out to describe the most current methods of preparing olefin-sulfur dioxide copolymers, polythioesters, sulfide polymers, polyisocyanates, polyoxyalkylhydroxy compounds, polyvinylcarbazoles, polyvinyl acetates, polyally esters and polyvinyl fluorides.[...]
Classics in Total Synthesis. By K.C. Nicolaou and E. J. Sorensen
Authors: Peerzada N.
Published: October 2008

This book is essential for any synthetic organic chemist.[...]
NMR of Polymers. By F. A. Bovey Frank Bovey
Authors: Amiet R.
Published: October 2008

This comprehensive book on all aspects of modern NMR techniques as applied to synthetic polymers (not natural) is divided into five chapters.[...]
Efficient Polymer-Supported Sharpless Alkene Epoxidation Catalyst
Authors: Karjalainen Jaana  K. , Hormi Osmo  E.O. , Sherrington David  C.
Published: October 2008

Homogeneous linear poly(tartrate ester) ligands provide high chemical yields and enantiomeric excesses in the epoxidation of trans-hex-2-en-1-ol using Ti(OPri)4-tert-butyl hydroperoxide. Branched poly(tartrate ester) can be use as heterogeneous ligands in the epoxidation of trans-hex-2-en-1-ol using Ti(OPri)4-tert-butyl hydroperoxide. Removal and recovery of the polymer catalyst is a simple filtration at the end of reactions.
Intramolecular Cycloaddition of Imines of Cysteine Derivatives
Authors: Cabral Ana M. T. D. P. V. , D'A Rocha Gonsalves António M. , Pinho e Melo Teresa  M. V. D.
Published: October 2008

Azomethine ylides were generated from Schiffs bases of S-allylcysteine methyl ester and their intramolecular 1,3-dipolar cycloadditions were studied. These reactions led to the synthesis of thieno[3,4-b]pyrrole derivatives in good yield.
An Asymmetric Synthetic Approach to the A-ring of the Taxol Family of Anti-Cancer Compounds
Authors: Craig D. , Marin M.  L.
Published: October 2008

A synthetic route developed for the preparation of the A-ring of Taxol family of molecules is reported. By means of an intramolecular Diels-Alder reaction an asymmetric approach to this ring has been accomplished. Also, initial studies to prepare the A ring using an intramolecular Diels-Alder reaction have been successful.
Synthesis of Novel Fused Heterocycles Based on Pyrano[2,3-c]pyrazole
Authors: Zaki M.  E. A.
Published: October 2008

3-Substituted 1,2,4-triazole derivatives (5, 9, 13, 16b, 19), pyrimidinium salts (21), triazines (24), and aryl methylene hydrazono pyrazolopyrano-pyrimidine (27a,b) which are rearranged in basic medium to 30a,b, were afforded via the reaction of 6-amino 1,4,5,6-tetrahydro-5-imino-3-methyl-1-phenyl-4 (pchlorophenyl) pyrazolo [4', 3' : 5,6]-pyrano [2,3-d] pyrimidine (3) with different reagents.
Synthesis of (2R,5R)-2-Amino-5-Hydroxyhexanoic Acid by Intramolecular Cycloaddition
Authors: Sheradsky Tuvia , Silcoff Elliad  R.
Published: October 2008

The title compound was synthesized from sorbic acid by an eight step sequence. The key step was the stereospecific intramolecular Diels-Alder reaction of the acylnitroso derivative of N-sorbyl-L-proline (5). L-Proline served as a temporary tether which directed both the stereochemistry and the regiochemistry of the cycloaddition.
Application of Microwave in Organic Synthesis. Dry Synthesis of 2-Arylmethylene-3(2)-naphthofuranones
Authors: Villemin Didier , Martin Benoit , Bar Nathalie
Published: October 2008

3(2)-Naphthofuranone (1) was condensed in the presence of Al2O3-KF with aromatic aldehydes (4) to give arylidenenaphthofuranones (5a-f) without solvent under focused microwave irradiation.
Elemental and Molecular Heritage: An Internet-based Display
Authors: Rzepa Henry  S.
Published: October 2008

The background to a Web page describing elemental and molecular heritage at Imperial College chemistry department is described. Photographs are shown of the original samples of elemental bromine and crystalline silicon, and molecular ferrocene and mauveine. 3D "Hyperactive" models of these systems are shown, together with a recently discovered heterocyclic systems scorpionine, which like mauveine is made by a deceptively simple chemical synthesis.
A New Convenient Synthesis of 5-Acyl-1,2,3,4-tetrahydropyrimidine-2-thiones/ones
Authors: Shutalev Anatoly  D. , Kishko Ekaterina  A. , Sivova Natalie  V. , Kuznetsov Aleksei  Yu.
Published: October 2008

An efficient one-pot synthesis of 5-acyl-1,2,3,4-tetrahydropyrimidine-2-thiones/ones is described. The synthesis is based on the reaction of readily available α-tosyl substituted thioureas or ureas with enolates of β-oxoesters or 1,3-dicarbonyl compounds followed by acid-catalyzed dehydration of the obtained 5-acyl-4-hydroxyhexahydropyrimidine-2-thiones/ones.
Enantiodivergent Synthesis of (R)- and (S)-Rolipram
Authors: Demnitz Joachim , LaVecchia Luigi , Bacher Edmond , Keller Thomas , Müller Thomas , Schürch Friedrich , Weber Hans-Peter , Pombo-Villar Esteban
Published: October 2008

Both enantiomers of rolipram (1) have been prepared in large quantity from a common intermediate rac-3-(3’-cyclopentyloxy-4’-methoxy)phenyl-4-nitro butyric acid (6), which was resolved by way of the two readily separable diastereoisomeric amides obtained with (S)-(-)-phenylethylamine. Reduction of the nitro group and intramolecular transamidation gave (R)-(-)-1 and (S)-(+)-1, respectively. CD spectra of both enantiomers of rolipram are reported and discussed. Both enantiomers of rolipram presented the same potency of inhibitory activity against recombinant cyclic-AMP-selective phosphodiesterase (PDE4) subtypes.
Evaluation of Effect of Microwave Irradiation on Syntheses and Reactions of Some New 3-Acyl-methylchromones
Authors: Lacova Margita , El-Shaaer Hafez  M. , Loos Dusan , Matulova Maria , Chovancova Jarmila , Furdik Mikulas
Published: October 2008

The 3-Acyl-2-R-methylchromones (R = H, ArO, C6H4(CO)2N) were prepared in good yields by different methods from 2-hydroxyaroylacetone derivatives. Some subsequent reactions of these compounds with hydroxylamine and 3-formylchromones are described. The effect of microwave irradation on some condensation reactions was studied.
Professor Sir Derek H. R. Barton (1918-1998)
Authors: Lin Shu-Kun
Published: October 2008

With great sadness I just learned that Professor Sir Derek H. R. Barton died in the evening of 16 March 1998, at age 80.[...]
Synthesis of 2-(6-Acetamidobenzothiazolethio)acetic Acid Esters as Photosynthesis Inhibitors
Authors: Sidoova Eva , Kralova Katarina , Loos Dusan
Published: October 2008

The synthesis and photosynthesis-inhibiting activity of 13 new 2-(6-acetamidobenzothiazolethio)acetic acid esters are reported. The new compounds were prepared by acetylation of 2-(alkoxycarbonylmethylthio)-6-aminobenzothiazoles with acetic anhydride. The structure of the compounds was verified by 1H NMR spectra. The compounds inhibit photosynthetic electron transfer in spinach chloroplasts. The structure - activity relation was studied. Lipophilicity was found to influence substantially photosynthetic electron transfer.
Chemistry and Chemical Reactivity. By John C. Kotz
Authors: Tariq Shabbir , Yamin B.
Published: October 2008

This is a textbook for an introductory university courses in chemistry for students of subjects such as biology, engineering, geology, physics, agriculture, etc.[...]
Giant Molecules: Here, There, & Everywhere. By Alexander Yu Grosberg
Authors: Biggs Simon
Published: October 2008

As a scientific text it is without doubt one of the easiest to read I have ever encountered.[...]
Organic Chemistry. By M. Jones, Jr.
Authors: Peerzada N.
Published: October 2008

This text is without doubt one of the easiest to read I have ever encountered.[...]
Organic Chemistry, A Comprehensive Degree Text and Sourcebook. By H. Beyer and W. Walter, Translator and Editor
Authors: Read Roger
Published: October 2008

This book has few counterparts.[...]
A New Isoflavone from Smilax glabra
Authors: Yi Yijun , Cao Zhengzhong , Yang Dalong , Cao Yuan , Wu Yongping , Zhao Shouxun
Published: October 2008

A new isoflavone, 7,6’-dihydroxy-3’-methoxyisoflavone, has been isolated from the roots of Smilax glabra. The structure was determined by 2D-NMR techniques.
Second Annual Conference on Strategies and Techniques for Identification of Novel Bioactive Compounds. October 8-9, 1998 Zurich, Switzerland
Authors: Lin Shu-Kun
Published: October 2008

n/a
Synthesis and Reactions of New 4-Oxo-4H-benzopyran-3-carboxaldehydes Containing Hydroxy Groups or 2-Oxopyran Cycles
Authors: Lacova Margita , Loos Dusan , Furdik Mikulas , Matulova Maria , El-Shaaer Hafez  M.
Published: October 2008

The synthesis of eight hydroxy- and 2-oxopyranochromone-3-carboxaldehydes 3, 5 and their reactions with 2-hydroxyaniline, 2,4-dinitrophenylhydrazine and 2-benzothiazolylhydrazine were investigated. Products were confirmed by IR, NMR spectral and elemental analysis data. The semi-empirical AM1 quantum-chemical method has been used to study optimal geometries and heats of formation of synthesized 3-formylchromones.
Syntheses of 1,5-Benzothiazepines. Part 20. Syntheses of 8-Substituted-2,5-dihydro-2-(4-N-dimethylaminophenyl)-4-(4-methoxyphenyl)-1,5-benzothiazepines
Authors: Pant Seema , Singhal Babita , Upreti Mani , Pant Umesh  C.
Published: October 2008

8-Substituted-2,5-dihydro-2-(4-N-dimethylaminophenyl)-4-(4-methoxyphenyl)-1,5-benzothiazepines (5a-e) have been synthesized by reacting 5-substituted-2-aminobenzene-thiols (1a-e) with 4-Ndimethylaminobenzal-4-methoxy acetophenone (2) in dry ethanol saturated with hydrogen chloride gas. The products were tested for purity by tlc and characterized by elemental analysis for carbon, hydrogen and nitrogen and IR, 1H NMR and mass spectral studies.
Glutathione Peroxidase-like Activities of Oxygen-Containing Diselenides
Authors: Wirth Thomas
Published: October 2008

Various diselenides 1 – 8 have been examined with respect to their glutathione peroxidase-like activities (GPx-activities) as an index of their antioxidant properties. The glutathione oxidase activities of these compounds have also been reviewed reflecting the pro-oxidant properties (GOx-activities) and could be used as an index of cell toxicity. Based on a qualitative structure-activity relationship some trends are suggested.
A Straightforward Route to Enantiopure Pyrrolizidines and Indolizidines by Cycloaddition to Pyrroline N-Oxides Derived from the Chiral Pool
Authors: Goti Andrea , Cicchi Stefano , Cordero Franca M. , Fedi Valentina , Brandi Alberto
Published: October 2008

Enantiomerically pure, five membered cyclic nitrones, easily obtained in large amounts from protected hydroxyacids and aminoacids such as D- and L-tartaric, L-malic, and L-aspartic acids, give cycloaddition reactions with a good diastereocontrol. The adducts of L-malic and L-aspartic acids derived from addition of nitrones to dimethyl maleate and g-crotonolactone were easily converted into enantiopure pyrrolizidinones, which can be transformed into polyhydroxypyrrolidines or polyhydroxypyrrolizidines, both interesting compounds as potential glycosidase inhibitors. The method is suitable for natural products synthesis as exemplified by a straightforward and convenient access to the pyrrolizidine alkaloid necine base (–)-hastanecine, as well as to indolizidine alkaloids, i.e. (+)- lentiginosine.
An Efficient, Self-Protecting Route to Dimethyl 4-Amino-4-[2-(methoxycarbonyl)ethyl]-heptanedioate HCl
Authors: Henrie Sally , Majerle Rita  S. K.
Published: October 2008

A method to reduce the nitro moiety in dimethyl 4-nitro-4-[1-[2(methoxycarbonyl)ethyl]]heptanedioate using a T-1 Raney nickel catalyst in an acidic environment is reported. The method avoids facile lactam formation.
Chemical Property Calculation through JavaScript and Applications in QSAR
Authors: Wu Hanqing
Published: October 2008

The inorganic property (I) and organic property (O) values of general organic groups are re-proposed here. Both I and O values of drug and biological molecules or groups can be calculated based on their common group values. The calculation can be performed easily on-line through JavaScript. Similar calculation can be done for the drug and biological molecular group electronegativity (X) according to the author's published paper. The calculation of lipophilicity (π or logP) parameter of (macro)molecules (like proteins) can also be performed on-line through JavaScript. Two equations expressed with I and O are provided here to define the hydrophobicity of each amino acid. The correlations of inorganic property and organic property values with other parameters are also discussed. These calculated parameters combined with other parameters can be used for QSAR studies in some drug molecules.
Polarization by the effect of a small torsional change in the benzothiazole (A)-benzobisthiazole (B) oligomer A-B13-A
Authors: Torrens Francisco , Sánchez-Marín José , Nebot-Gil Ignacio
Published: October 2008

We use a method for the calculation of the molecular dipole ( μ ) and quadrupole (θ ) moments and dipole-dipole (α ), dipole-quadrupole ( A) and quadrupole-quadrupole (C ) polarizabilities which we have successfully applied to the benzothiazole (A)-benzobisthiazole (B) linear oligomer A-B13-A. Two model rotational isomers have been characterized: (1) the fully-planar (000) conformation; and (2) a rotational isomer with each unit rotated in the range 1 - 10° in the same direction (+++). For isomer 000, μ is smaller than for +++. The calculation of α, A and C has been carried out by the interacting induced dipoles polarization model that calculates tensor effective anisotropic point polarizabilities (method of Applequist et al.). The values of A are specially sensitive to μ which varies under rotation. This fact explains the great values of Ax,xx for the +++ polar isomer. It is found that small torsional changes can enhance solubility by a clear increasing of the hydrophilic accessible surface area. However, the torsion of the oligomer varies the value of μ and so modifies α, C , and, specially, A. For conformer +++, polarization effects occur even when each unit is rotated only f = 1°. The observed effect is an increase in μ and, hence, in α , C , and, specially, A.
Acid Catalyzed Reactions of Substituted Salicylaldehydes with 2-Methylfuran
Authors: Butin Alexander  V. , Gutnov Andrey  V. , Abaev Vladimir  T. , Krapivin Gennadij  D.
Published: October 2008

Data, concerning condensation reactions of salicylaldehydes and 2-methylfuran are generalized. During the course of investigation a sequence of proceeding transformations is established. It is shown that it is possible to obtain 2-hydroxyarylbis(5-methylfur-2-yl)methane, benzofuran or oxazulene derivatives selectively by simple changing of the reaction conditions.
Mass Spectra of 2-Substituted Diethyl Malonate Derivatives
Authors: Kwon Tae  Woo , Chung Sung  Kee , Smith Michael  B.
Published: October 2008

Addition of Grignard derivatives to diethyl ethoxymethylene malonate generates 2-substituted diethyl malonate derivatives. This paper reports the mass spectral data for these derivatives.
Novel Carbon-Carbon Bond Oxidative Cleavage of Hexabenzylhexaazaisowurtzitane by n-BuONO and (NH4)2Ce(NO3)6
Authors: Guan Xiao-Pei , Yan Hong , Sun Jian-Guang , Yu Yong-Zhong
Published: October 2008

Treatment of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo-[5.5.0.05,9.03,11]dodecane (1) with n-butyl nitrite or ammonium cerium nitrate results in novel C(1)-C(7) oxidative cleavage to give 1,3,4,5,7,8-hexabenzyl-cis-cisoid-cis-hexahydro-1H,5H-diimidazolinium[4,5-b:4',5'-e]pyrazine dinitrate (2).
3-(2-Alkylsulfanyl-6-benzothiazolylaminomethyl)-2-benzoxazolethiones - Synthesis and Photosynthesis-Inhibiting Activity in Spinach Chloropasts
Authors: Sidoova Eva , Kralova Katarina , Loos Dusan
Published: October 2008

The synthesis and photosynthesis-inhibiting activity of 14 new 3-(2-alkylsulfanyl-6-benzothiazolylaminomethyl)-2-benzoxazolethiones are reported. The new compounds were prepared by the reaction of 2-alkylsulfanyl-6-aminobenzothiazoles with 3-hydroxymethyl-2-benzoxazolethione. The structures of the compounds were verified by 1H NMR spectra. The compounds inhibit photosynthetic electron transport in spinach chloroplasts. The photosynthetic activity was found to depend on the calculated lipophilicity of the new compounds. Some structure characteristics and quantum chemical parameters were calculated by AM1 method.
Benzothiazole Derivatives. 48. Synthesis of 3-Alkoxycarbonylmethyl-6-bromo-2-benzothiazolones and 3-Alkoxycarbonylmethyl-6-nitro-2-benzothiazolones as Potential Plant Growth Regulators
Authors: Loos Dusan , Sidoova Eva , Sutoris Viktor
Published: October 2008

3-Alkoxycarbonylmethyl-6-bromo- and 3-alkoxycarbonylmethyl-6-nitro-2-benzothiazolones were synthesized by reaction of alkylesters of halogenoacetic acids with 6-bromo-2-benzothiazolones and 6-nitro-2-benzothiazolones respectively. The compounds were tested for plant growth stimulating activity on wheat (Triticum aestivum). The bromo derivatives manifested 25.4 % average stimulating activity in comparison with the control. The stimulation activity of the nitro derivatives was not significant. Optimal structures of the compounds were obtained by a MMPI method, atomic charges and dipole moments were calculated by a semiempirical AM1 method. On the basis of molecular electrostatic potential it has been found that the biological activity of synthesized compounds depends on charge distribution in the molecules.
A Study of Acid-Base Equilibria in Acetonitrile Systems of 2-Halo(Cl,Br,I)-4-nitropicoline(3,5,6) N-oxides
Authors: Kaczmarczyk Ewa , Puszko Aniela , Lorenc Jadwiga , Chmurzynski Lech
Published: October 2008

An attempt has been made to determine potentiometrically (1) acid dissociation constants of cations obtained by protonation of nine trisubstituted pyridine N-oxides, namely 2-halo(Cl, Br and I)-4-nitropicoline N-oxides with the methyl group at positions 3, 5, and 6, as well as (2) the cationic homoconjugation constants of these cationic acids with conjugated N-oxides in acetonitrile. On the basis of the substitution effect, variations of the acid dissociation constants of the trisubstituted pyridine N-oxide cations are discussed. The determined pKa values of the protonated 2-halo-4-nitropicoline N-oxides are compared with the previously determined equilibrium constants of the cationic acids conjugated with the mono- and disubstituted pyridine N-oxides in acetonitrile. Further, based on the pKa values of the protonated 2-halo-4-nitropicoline N-oxides in acetonitrile, supplemented with correlations between pKa’s of the protonated mono- and disubstituted pyridine N-oxides in acetonitrile and water, the pKa's of the acids conjugated with the trisubstituted N-oxides studied in aqueous solutions have been estimated. Moreover, it has been concluded that the cationic homoconjugation constants cannot be determined by potentiometric titration in acetonitrile solutions of the 2-halo-4-nitropicoline N-oxide systems.
X-ray Crystallography at 170 K of Racemic 2,2'-Dimethoxy-9,9'-biacridine and 1H NMR Study of 2,2'-Diacetoxy-9,9'-biacridine
Authors: Boyer Gérard , Lormier Tuan , Galy Jean-Pierre , Llamas-Saiz Antonio  L. , Foces- Foces Concepción , Fierros Marta , Elguero José , Virgili Albert
Published: October 2008

Three derivatives of 9,9'-biacridine, 2,2'-dihydroxy, 2,2'-dimethoxy and 2,2'-diacetoxy have been prepared. The crystal structure of racemic 2,2'-dimethoxy-9,9'-biacridine CHCl3 1:1 complex has been determined and shows an almost perpendicular conformation of both acridine rings. 1H NMR experiments using the diacetoxy derivative and both Eu(tfc)3 and R-Pirkle's alcohol show the splitting of some signals characteristic of a racemic compound.
Professor Ta-shue Chou (1950-1999)
Authors: Lin Shu-Kun
Published: October 2008

Professor Ta-shue Chou, who died of cancer on 25 February 1999 at the age of 50 and spent much of his academic career as Research Professor of Organic Chemistry, at the Institute of Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China, was an editorial board member of the international chemistry journal Molecules.[...]
Regioselectivity of Arylation of 2,3’-Biquinolyl Dianion
Authors: Aksenov A. V. , Aksenova I. V. , Borovlev I. V. , Smushkevich Yu. I.
Published: October 2008

The dianion of 2,3’-biquinolyl with aryl- and hetaryl halides forms the products of arylation to 4’-position, which on treatment with alkyl halides or water yield 1’-alkyl-1’,4’dihydro-2,3’-biquinolyls or 4’-aryl-1’,4’-dihydro-2,3’-biquinolyls respectively. The oxidation of the latter leads to 4’-aryl-2,3’-biquinolyls. The cation dependence of the arylation is shown.
Synthesis of Aromatic Vinyl Esters by Exchange Reaction Catalyzed with Pd(II)
Authors: Rashidi-Ranjbar Parviz , Piri Farideh
Published: October 2008

Pd(II) catalyzed the exchange reaction of vinyl acetate with aromatic acids to produce the corresponding vinyl esters in good yields.
BC Conferences: Exploiting The Promise of Combinatorial Chemistry: Successful Strategies & Proof of Concept Case Studies. The Merchant Centre, London. 25 June 1999. Combinatorial Chemistry 99: Novel Strategies, Chemistry, Purification & Chemoinformatics. An IBC Conference. The Merchant Centre, London. 23-24 June 1999
Authors: Lin Shu-Kun
Published: October 2008

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IBC Conferences: Developing Effective Assays for High Throughput ADME/Toxicology Studies. The Café Royal, London. 9 July 1999. Effective Assay Development: Optimising Technologies & Methodologies to Accelerate & Enhance Drug Discovery. The Café Royal, London. 7-8 July 1999
Authors: Lin Shu-Kun
Published: October 2008

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Synthesis of N-Phenylpyrrole Carboximides
Authors: Hubmann Dieter , Liechti Christoph , Trinks Uwe , Traxler Peter , Séquin Urs
Published: October 2008

Several N-phenylpyrrole carboximides were synthesised using acyl isocyanates as intermediates.
Synthesis of (3Z)-Dodecenyl-(E)-2-butenoate, the Pheromone of Sweet Potato Weevil
Authors: Mithran S. , Subbaraman A.  S.
Published: October 2008

A practical synthesis of the title pheromone has been developed. The key feature of the synthesis was the fixation of the required olefin geometry via a cis-selective Wittig reaction and use of commercially available starting materials to prepare the required synthons.
Principles and Applications of Stereochemistry. By M. North
Authors: Lin Shu-Kun
Published: October 2008

Stereochemistry is about the shape and change of shape of molecules.[...]
Polyalkoxy Nitrones as Chiral Building Blocks in Asymmetric Synthesis
Authors: Merino Pedro , Tejero Tomás
Published: October 2008

Optically active nitrones derived from both aldoses and dialdoses add metallated heterocycles in a stereocontrolled way depending on the nature of the Lewis acid used as a precomplexing agent of the nitrone. Further elaborations of the resulting hydroxylamines lead to the development of new synthetic methodologies for the preparation of polyalkoxy α-amino aldehydes and α-amino acids. These compounds can be used as key advanced intermediates in the synthesis of a wide range of natural products and derivatives including amino sugars, aza sugars, and complex nucleosides.
Supramolecular Bioorganic Chemistry: Nucleic Acids Recognition and Synthetic Vectors for Gene Transfer
Authors: Vigneron Jean-Pierre
Published: October 2008

Our works on nucleic acids recognition and synthetic vectors for gene transfer have been reviewed.
Furyl(aryl)alkanes and Their Derivatives. 19. Synthesis of Benzofuran Derivatives via 2-Hydroxyaryl-R-(5-methylfur-2-yl)methanes. Reaction of Furan Ring Opening - Benzofuran Ring Closure Type
Authors: Gutnov Andrey V. , Butin Alexander V. , Abaev Vladimir T. , Krapivin Gennadij D. , Zavodnik Valerij E.
Published: October 2008

2-Hydroxyaryl(5-methylfur-2-yl)alkanes synthesized by alkylation of 2-methylfuran with various 2-hydroxybenzylic alcohols, were rearranged into corresponding 3-R-benzo[b]furan derivatives by treatment with ethanolic HCl solution. These compounds can not be transformed into dibenzoxazulenium salts.
Reactivity of a-Oxophosphonium Ylides: A Contribution to the Mechanistics
Authors: Pinho e Melo Teresa  M.V.D. , D’A. Rocha Gonsalves António  M. , Carrapato Sara  M. S. , Taborda Ana  M. O. M. P.
Published: October 2008

Ylides 1f and 1g react with chlorine, with bromine and with N-chlorosuccinimide in the presence of a range of nucleophiles. The 2,3-disubstitutedbutenedioates obtained in this way allow us to gather more information about the mechanism involved. Ylide 1c was also studied showing similar reactivity and leading to the highly selective synthesis of 2,3-disubstituted-3-phenylpropenoates.
Bifunctional Derivative of p,p'-Dichlorochalcone. Part II. Synthesis of a Novel Compound 2-[2-Carboxymethylthio-2-(4-chlorophenyl)ethyl]-2-(4-chlorophenyl)-4-thiazolidinone
Authors: Mukhtar Sayeed , Rahman Mujeebur  V.P. , Ansari Wajid  Husain , Lemière Guy , De Groot Alex , Dommisse Roger
Published: October 2008

The synthesis of 2-[2-carboxymethylthio-2-(4-chlorophenyl) ethyl]-2-(4-chlorophenyl) - 4-thiazolidinone (1) from p, p'- dichlorochalcone using thioglycollic acid in the presence of ammonium carbonate is described. Structural assignment and stereochemistry are discussed.
A New Routine for the Synthesis of N-substituted-N-(sulfonyl) bromoacetamides with ZnCl2 as a Catalyst
Authors: Trávnícek Martin , Potácek Milan
Published: October 2008

A series of N-acylated N-substituted sulfonamides was prepared for the first time in good yields and with excellent conversion by the reaction of N-substituted-N-(p-toluene) sulfonamides (1) with acetyl chloride and bromoacetyl bromide (2), respectively, in the presence of a catalytic amount of anhydrous ZnCl2.
Convenient Synthesis of Two Mango Allergens
Authors: Trivedi Shyam  V. , Subbaraman Ayyulur S. , Chattopadhyay Subrata , Mamdapur Vasant  R.
Published: October 2008

The mango allergens, 5[2’(Z)-heptadecenyl]resorcinol (10) and 5[12’(Z)-heptadecenyl]resorcinol (20) have been synthesized by simple routes using easily accessible starting materials.
The Need for Systematic Naming Software Tools for Exchange of Chemical Information
Authors: Williams Antony , Yerin Andrey
Published: October 2008

The availability of systematic names can enable the simple textual exchange of chemical structure information. The exchange of molecular structures in graphical format or connection tables has become well established in the field of cheminformatics and many structure drawing tools exist to enable this exchange. However, even with the availability of systematic naming rules, software tools to allow the generation of names from structures, and hopefully the reversal of these systematic names back to the original chemical structure, have been sorely lacking in capability and quality. Here we review the need for systematic naming as well as some of the tools and approaches being taken today in this area.
Fluorescent 2,7-Dialkylamino-[1,8]-Naphthyridines: Preparation and Spectroscopic Properties
Authors: Hoock Christoph , Reichert Jörg , Schmidtke M.
Published: October 2008

Substitution of 4-methyl-[1,8]-naphthyridine in 2 and 7 position by alkylamines leads to highly fluorescent compounds. The arrangement of hydrogen donor and acceptor groups of these naphthyridines allows interactions with guanine and guanine cytosine base pairs. The described synthesis offers easy access to these small and stable fluorescent probes.
Stereoselective Transformation of Cyclodecene-1,4-dione Systems, Derived from Steroids, to the Corresponding spiro-γ-lactones. A Semiempirical MO Study
Authors: Lorenc Ljubinka , Pavlovich Vladimir , Juranich Ivan , Mihailovich Mihailo  Lj. , Bondarenko- Gheorghiu Lidija , Krstich Natalija , Dabovich Milan
Published: October 2008

The thermal and acid-catalyzed intramolecular rearrangement of the (Z)- and (E)-cyclodecene-1,4-dione compounds deriving from steroids, 2a,b and 3a,b, respectively, proceeds stereoselectively to give the corresponding configurationally different spiro-γ-lactone derivatives, the (5R,9R)-isomers 4a,b (from the (Z)-cyclodecenediones 2a,b) and the (5R,9S)-isomers 5a,b (from the (E)-cyclodecenediones 3a,b). The semiempirical MNDOAM1 and PM3 molecular orbital methods were applied to elucidate the possible mechanistic pathway of the observed intramolecular process leading to the spiro-γ-lactone structures.
Synthetical Application of Alkyl 2-isothiocyanatocarboxylates. A Simple Synthesis of 5-Substituted-3-amino-2-thioxo-4-imidazolidinones (3-Amino-2-thiohydantoins)
Authors: Floch Lubomir , Oremus Vladimir , Kovac Martin
Published: October 2008

The title 3-amino-2-thiohydantoins 3 has been prepared in very good yields by the reaction of alkyl isothiocynatocarboxylates 1 with hydrazine hydrate.The synthesis of starting isothiocyanates as well as spectral data of 3-aminothiohydantoins and alkyl isothiocyanatocarboxylates has been presented.
Synthesis of N-7-Substituted Purines from Imidazole Precursors
Authors: Ostrowski Stanislaw
Published: October 2008

Synthesis of purines and purine mono-1-oxides from the respective 5-substituted 4-nitroimidazole derivatives is described. The commercially available 4-nitroimidazole, in a few simple steps (including Vicarious Nucleophilic Substitution of Hydrogen), was transformed into: 4-aminoimidazoyl-5-carboximes, N-[1-(4-amino-1H-imidazol-5-yl)methylidene]-N-(aryl)amine derivatives or into 4-amino-5-aminomethyl-imidazole. These intermediates were cyclized to the final products.
Trimethylcyanosilane as a Convenient Reagent for the Preparation of Trimethylsilyl Enol Ethers of 1,3-Diketones
Authors: Zhuo Jin-Cong
Published: October 2008

Trimethylsilyl enol ethers of 1,3-diketones are generated “in situ” or obtained in high isolated yield by the reaction of 1,3-diketones with trimethylcyanosilane in various solvents such as cyclohexane, hexane, benzene, methylene chloride, chloroform, carbon tetrachloride, and acetonitrile.
Organic Chemistry: Structure and Function. By K. Peter C. Vollhardt
Authors: Patiny Luc
Published: October 2008

Teaching organic chemistry is a challenging task and tools which allow students to understand what is happening during an organic reaction are really difficult to find.[...]
The Weak Hydrogen Bond: Applications to Structural Chemistry and Biology(International Union of Crystallography Monographs on Crystallography, 9). By Gautam R. Desiraju
Authors: Lin Shu-Kun
Published: October 2008

This book is an important monograph for those working on the related structural chemistry of the weak hydrogen bond.[...]
17O NMR Spectra of α,β-Unsaturated Carbonyl Compounds RCH=CHCOX: the Influence of Group X on the δ(17O) Value of the Carbonyl Oxygen and on the Shielding Effect of Group R
Authors: Zhuo Jin-Cong
Published: October 2008

17O NMR spectra of RCOX (R = Me, Ph), RCH=CHCOX (R = H, Ph, Me, CO2Et) and Me2C=CHCOX (X = H, Me, Et, i-Pr, t-Bu, Ph, PhCH=CH, OMe, OEt, Cl, CN, CF3, CO2Et) are reported. The 17O shift values of these carbonyl compounds depend mainly on the electron donating power of X and correlate well with the resonance constants sR+ of X. This suggests that the d(17O) values can be used to reflect qualitatively the electrophilicity of the carbonyl group. The shielding effect of the substituent R in RCH=CHCOX is diminished with increasing the electronic donating power of X and correlates with s+ values of X.
8-Chloro-11-[4-(8-chloro-5H-dibenzo[b,e][1,4]diazepin-11-yl)piperazino]-5H-dibenzo[b,e][1,4]diazepine
Authors: Capuano Ben
Published: October 2008

A method to synthesize desmethylclozapine, 3, is reported. The procedure afforded the target compound in 69% yield. A by-product, isolated from the reaction mixture in 11% yield, proved to be the title compound, 4.
Fast Solvent-free Alkylation of Amides and Lactams under Microwave Irradiation
Authors: Bogdal Dariusz
Published: October 2008

N-Substituted amides and lactams are rapidly N-alkylated under solvent-free phase-transfer catalytic conditions using microwaves.
X-Ray Crystal Structure of 10β-Hydroxy-4β,5β-epoxyestr-1-en-3,17-dione and Antitumor Activity of its Congeners
Authors: Milić Dragana R. , Kapor Agneš , Markov Borislava , Ribar Bela , Strümpel Marianne , Juranić Zorica , Gašić Miroslav J. , Šolaja Bogdan A.
Published: October 2008

Based on the biological properties of epoxyquinols from natural sources, the title compound was synthesised as a potential antitumor agent. Its molecular structure was partially confirmed by NMR studies. The detailed structure was established by X-ray analysis revealing two symmetry independent molecules in the asymmetric unit each consisting of four fused rings with the C(10) β-oriented hydroxy group and β-oriented O atom bridging C(4) and C(5). The conformation of A ring in both conformers A and B is boat (B3,6), while rings B and C are chairs (1C4) and the five-membered D ring is in an envelope (E2) conformation. The in vitro antitumor activity of title compound and its 17b-acetoxy analogue against HeLa and Fem-x cells revealed IC50 values of 5.7 and 7.1 mM, and 2.25 and 1.58 mM, respectively. Corresponding quinols were tested on 47 cell lines with 10b-hydroxy-17β-acetoxyestra-1,4-dien-3-one being most active against leukemia SR cells (GI50 = 0.17 mM).
Teaching NMR Using Online Textbooks
Authors: Hornak Joseph  P.
Published: October 2008

Nuclear magnetic resonance (NMR) spectroscopy has almost become an essential analytical tool for the chemist. High-resolution one- and multi-dimensional NMR, timedomain NMR, and NMR microscopy are but a few of the NMR techniques at a chemist's disposal to determine chemical structure and dynamics. Consequently, even small chemistry departments are finding it necessary to provide students with NMR training and experience in at least some of these techniques. The hands-on experience is readily provided with access to state-of-the-art commercial spectrometers. Instruction in the principles of NMR is more difficult to achieve as most instructors try to teach NMR using single organic or analytical chemistry book chapters with static figures. This paper describes an online textbook on NMR spectroscopy called The Basics of NMR (http://www.cis.rit.edu/htbooks/nmr/) suitable for use in teaching the principles of NMR spectroscopy. The book utilizes hypertext and animations to present the principles of NMR spectroscopy. The book can be used as a textbook associated with a lecture or as a stand-alone teaching tool. Conference participants are encouraged to review the textbook and evaluate its suitability for us in teaching NMR spectroscopy to undergraduate chemistry majors.
Molecular Catenanes, Rotaxanes and Knots. A Journey Through the World of Molecular Topology. Edited by J.-P. Sauvage
Authors: Lin Shu-Kun
Published: October 2008

The parts of a molecule are connected by chemical bonds such as the covalent bond, the ionic bond, the hydrogen bond, etc.[...]
Ullmann’s Encyclopedia of Industrial Chemistry. CD-ROM. 6th Edition 1999 Electronic Release
Authors: Lin Shu-Kun
Published: October 2008

When I was being trained in dyestuff research, development and production at Ciba-Geigy in 1994, my supervisors as senior dyestuff chemists, brought to my attention the Ullmann’s Encyclopedia of Industrial Chemistry.[...]
Industrial Organic Chemicals. Starting Materials and Intermediates
Authors: Lin Shu-Kun
Published: October 2008

The encyclopedia of Industrial Organic Chemicals brings together around 200 detailed and thoroughly edited articles on organic starting materials and intermediates.[...]
Molecules, MolBank and ECSOC-4
Authors: Neier Reinhard
Published: October 2008

It is one of the great ironies of our information age that at the same time that we have the technical capability to make information freely available world-wide, budget problems are seriously endangering the free access to scientific information.[...]
Recent Developments in the Area of Asymmetric Transfer Hydrogenation
Authors: Wills Martin , Palmer Matthew , Smith Athene , Kenny Jennifer , Walsgrove Tim
Published: October 2008

The use of an enantiomerically pure amino alcohol, coupled to a transfer hydrogenation process, in the asymmetric catalysis of the reduction of ketones to alcohols, is described. The process works well for unfunctionalised ketones, affording e.e.s of up to 98%, and excellent conversions. We have recently extended, for the first time in this application, the scope of the methodology to the reductions of a-heteroatom substituted substrates, through the use of the appropriate protecting groups on each atom.
General Method for the Preparation of Substituted 2-Amino-4H,5H-pyrano[4,3-b]pyran-5-ones and 2-Amino-4H-pyrano[3,2-c]pyridine-5-ones
Authors: Stoyanov Edmont  V. , Ivanov Ivo  C. , Heber Dieter
Published: October 2008

Reaction of 4-hydroxy-6-methyl-2-pyrone (1a) as well as 4-hydroxy-6-methyl-2(1H)-pyridones (1b-d) with arylmethylene malononitriles or arylmethylene methyl cyanoacetates (2a-h) leads to the formation of the very stable 5,6-fused bicyclic 2-amino-4Hpyran derivatives 3a-3af.
On the Need for Multiple Lists of Chemical Information
Authors: Goodman Jonathan
Published: October 2008

Cambridge University Department of Chemistry has a list of University Chemistry Departments and Chemistry-related journals around the world: ChemSites (http://www.ch.cam.ac.uk/ChemSitesIndex.html). This article describes what makes it distinct from other lists, and justifies the existence of more than one such list.