bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of 1,5-Substituted Pyrrolin-2-ones with Dichlorocarbene under Phase Transfer Catalysis Conditions
Authors: Egorova Alevtina , Sedavkina Valentina , Timofeyeva Zlata
Published: October 2008

Treatment of 5-alkyl(aryl)-3H-pyrrolin-2-ones with dichlorocarbene under phase transfer catalysis conditions at 20-30ºC results in a cycloaddition of the carbene to the C=C bond followed by skeletal rearrangement.
Synthesis and Reactions of Substituted 3-amino-2-furyl(aryl)-thieno[2,3-b]pyridines
Authors: Kaigorodova Ye. A. , Vasilin V. K. , Konyushkin L.  D. , Usova Ye. B. , Krapivin G. D.
Published: October 2008

New substituted thieno[2,3-b]pyridines which contain 4-nitropehnyl and 5-nitro-, carboxy-, methoxycarbonyl-2-furyl groups in the 2 position have been obtained.
Synthesis of Regioselectively Protected Protocatechuic Acid Derivatives by Biomimetic Transformation of Quinic Acid
Authors: Bianco Armandodoriano , Bonadies Francesco , Melchioni Cristiana
Published: October 2008

3- and 4-monoesterified protocatechuic acid methyl ester (5 and 7 respectively) have been synthesised from quinic acid by a high yields biomimetic rearrangement.
Synthesis of Novel 1-Substituted and 1,9-Disubstituted-1,2,3,4-tetrahydro-9H-Carbazole Derivatives as Potential Anticancer Agents
Authors: Shmeiss N.  A. M. M. , Ismail M. M.F. , Soliman A.  M. , El-Diwani H.  I.
Published: October 2008

Condensation of 1-acetyl-1,2,3,4-tetrahydro-9H-carbazole (2) with some amino compounds furnished the corresponding imino derivatives 3a-e. Compound 3a reacted with chloroacetic acid and underwent cyclization to give the thiazolidine derivative 5. Also, treatment of 3c with thionyl chloride caused cyclization to yield the [1,2,6]thiadiazino derivative 6, which gave the corresponding N-formyl derivative 7 upon heating with ethyl formate. In addition, interaction of 3d with ethyl cyanoacetate yielded the monoamide of malonic acid derivative 8. Acylation of carbazole 1 with succinoyl chloride or phenylacetyl choride produced the corresponding azepine (11) and 1,9-diphenyl acetyl derivatives (14), respectively. Compounds 11, 14 were further reacted to give the carbazole derivatives 12, 13 and 15a,b. The cytotoxic activity for some of the prepared compounds against breast cancer B20 is discussed.
Crystal Structure of Methyl 4-amino-4-cyano-4,6-dideoxy-2,3-O-isopropylidene-α-L-talopyranoside
Authors: Koóš Miroslav , Steiner Bohumil , Mičová Júlia , Langer Vratislav , Ďurík Marián , Gyepesová Dalma , Smrčok Ľubomír
Published: October 2008

The structure of methyl 4-amino-4-cyano-4,6-dideoxy-2,3-O-isopropylidene-α-Ltalopyranoside was established by X-ray analysis confirming a talo configuration at C-4 and suggesting a 1C4 conformation of the pyranose ring. The values of relevant torsion angles and calculated puckering parameters revealed a distortion into the direction of 5E conformation, thus indicating a flattening at C-2.
Studies On Some Acid Divalent-Metal Nitrilotriacetate Complexes
Authors: Souaya E. R. , Hanna W. G. , Ismail E. H. , Milad N. E.
Published: October 2008

IR and 1H-NMR studies on nitrilotriacetic acid (H3NTA) suggest that the acid exists in the zwitterion form, which allows the existence of intermolecular hydrogen bonding. A tetrahedral structure is established for eleven (1:1) anhydrous acid-metal (II) nitrilotriacetates complexes. The ten Dq values for the colored complexes were determined spectrophotometrically. The pKa values for the eleven acid metal complexes [M(HNTA)].(OH2)3] were determined and compared with the corresponding pKa values of the [M(OH2)n]+2 ions and also with the log β1 values of the corresponding [M(NTA)]- complexes. X-ray diffraction studies on the ligand and on eight of these complexes are described.
Application of Flow Thermolysis in Organic Synthesis: Easy Access to α,ω-Bis Thienyl- and Bis Pyrrolyl- Alkanes from Methylene Derivatives of Meldrum's Acid
Authors: Pommelet Jean  Claude , Jourdain Fanck , Dhimane Hamid
Published: October 2008

Thermal decomposition of Meldrum's acid derivatives and rearrangement of (alkylsulfanyl) or (propargylamino)methylene ketene intermediates leads in one step to bis thienyl- or bis pyrrolyl-alkanes.
Synthesis of New Bis-Alkylated Phosphono Alkenyl Acyclonucleosides : (Z) and (E)-Diethyl-2-(3-alkyl pyrimidin-1-yl)ethylen-1-yl Phosphonate
Authors: Rochdi A. , Taourirte M. , Lazrek H. B. , Barascut J. L. , Imbach J. L.
Published: October 2008

The E- and Z- phosphonoalkenyl acyclonucleosides of uracil and thymine were synthesized under Michael addition conditions. Introduction of an alkyl, alkenyl or alkynyl group at the N-3 position of the pyrimidine moiety was accomplished using potassium carbonate in DMF.
A New Pathway to 3-Hetaryl-2-oxo-2H-chromenes: On the Proposed Mechanisms for the Reaction of 3-Carbamoyl-2-iminochromenes with Dinucleophiles
Authors: Kovalenko Sergiy M. , Bylov Igor E. , Sytnik Konstantyn M. , Chernykh Valentyn P. , Bilokin Yaroslav V.
Published: October 2008

The present account summarizes the author's studies to elucidate the mechanisms of the recently reported rearrangements resulting from inter- and/or intramolecular reactions of 2-imino-2H-chromene-3-carboxamides with different dinucleophiles.
One-pot Syntheses of Fused Quinazolines by Reaction of N-(2-Cyanophenyl)chloromethanimidoyl Chloride. I. A New Synthesis of 1,3-Oxazolo- and 1,3-Oxazino[2,3-b]quinazolines
Authors: Divišová Hana , Havlišová Helena , Borek Petr , Pazdera Pavel
Published: October 2008

12H-Benzo[1,3]oxazolo[2,3-b]quinazolin-12-imine (5a), 9-chloro-12Hbenzo[1,3]oxazolo[2,3-b]quinazolin-12-imine (5b), 2,3-dihydro-5H-[1,3]oxazolo[2,3-b]quinazolin-5-imine (5c), 2,3-dihydro-3,3-dimethyl-5H-[1,3]oxazolo[2,3-b]quinazolin-5-imine (5d) and 3,4--dihydro-2H,6H-[1,3]oxazino[2,3-b]quinazolin-6-imine (5e) were synthesized in a one-pot reaction of N-(2-cyanophenyl)chloromethanimidoyl chloride (1) with 2-aminophenols, 2-aminoethanol, and 3-aminopropanol in the presence of a base. The course of the reaction was controlled by the temperature and the amount of base used. N-(2-Cyanophenyl)-(2-hydroxyanilino)methanimidoyl chloride (3a), 2-chloro-3-(2-hydroxyphenyl)-3,4-dihydroquinazolin-4-imine (4a) and 6-imino-2H, 3H, 4H, 6H, 11H-1,3-oxazino[2,3-b]-5-quinazolinium chloride (6) were identified as intermediates of the one-pot process.
Regioselective Oxidation of 3-Substituted Pyridinium Salts
Authors: Terán Joel  L. , Gnecco Dino , Galindo Alberto , Juárez Jorge  R. , Enríquez Raúl  G. , Soriano Manuel , Reynolds W. F.
Published: October 2008

(1'R)-(+)-3-Hydroxymethyl-1-(1'-phenyl-ethyl)-pyridinium chloride (1), 1-benzyl-3-[1', 3']-dioxolan-2'-yl-pyridinium chloride (2) and (2'S, 4'S, 5'R)-(-)-1-benzyl-3-(3',4'-dimethyl-5'-phenyl-oxazolidin-2'-yl)-pyridinium bromide (3), were transformed by oxidation with potassium ferricyanide into the corresponding 1H-pyridin-2-ones in excellent yields with high regioselectivity.
The Reaction of Trimethylsilylethynyl(phenyl)iodonium Triflate with Some Phenolates: Formation of Substitution and sp2 C-H Insertion Products
Authors: Nikas Spyros , Rodios Nestor , Varvoglis Anastasios
Published: October 2008

Treatment of trimethylsilylethynyl(phenyl)iodonium triflate with the potassium salts of some acidic phenols results in the formation of substitution products (O-trimethylsilylethynylphenols and/or O-ethynylphenols), along with sp2C-H insertion products which afford eventually 2-aroxybenzo[b]furans.
Synthesis of 1-(2'-Deoxy-ß-D-ribofuranosyl)-1H-imidazo[4,5-d]-pyridazine-4,7(5H,6H)-dione: A Potential Building Block for Antisense Applications
Authors: Chen Huan-Ming , Hosmane Ramachandra  S.
Published: October 2008

Synthesis of the title compound,1-(2'-deoxy-b-D-ribofuranosyl)-1H-imidazo[4,5-d]pyridazine-4,7(5H,6H)-dione (1), is reported. It was synthesized in five steps, commencing with methyl 1-(b-D-ribofuranosyl)imidazo-4,5-dicarboxylate (2). The 3',5'-hydroxyl groups of 2 were protected with a bis-silylating agent to form 3, which was then converted into the corresponding 2'-thionocarbonate derivative 5. The reduction of the latter with tri-n-butyltin hydride (to form 6), followed by silyl deprotection with tetra-nbutylammonium fluoride, afforded 7. Treatment of the latter with hydrazine hydrate yielded the target nucleoside 1.
Synthesis Of Some Novel Silver-Cysteamine Complexes
Authors: Habibi Davood , Ghaemi Ezat , Nematollahi Davood
Published: October 2008

The aim of this research was to synthesize some new silver-cysteamine complexes of potential biological interest. Reactions were carried out between silver nitrate and cysteamine (2-aminoethanethiol hydrochloride) under different conditions of pH and mole ratios of the metal (silver) to the ligand (cysteamine). Some novel silver-cysteamine complexes were made, and after characterization of the complexes by cyclic voltammetry, pH measurements, and microanalysis, it is now obvious that the mole ratio of the metal to the ligand in complexes is about four to three.
Synthesis of Jasmonoides from Furan Derivatives
Authors: Nowicki Janusz
Published: October 2008

This paper presents applicability of commonly available furan derivatives, like 2-methyl furan, furaldehyde and 5-methylfuraldehyde in syntheses of jasmanoides.
Regioselectivity of Electrophilic Attack on 4-Methyl-1-Thioxo-1,2,4,5-Tetrahydro[1,2,4]Triazolo[4,3-A]Quinazolin-5-One Part 2: Reactions on Nitrogen Atom
Authors: Fathalla W. , Čajan M. , Pazdera P.
Published: October 2008

The regioselectivity on a cyclic thioamide group towards different electrophiles was studied on the model compound 4-methyl-1-thioxo-1,2,4,5-tetrahydro[1,2,4]triazolo [4,3-a]quinazolin-5-one 1. The examined compound 1 reacts with alkyl halides, amines in the presence of formaldehyde, acyl halides and compounds having activated double bonds to afford the N-substituted derivatives 2, 3 and 6. The regioselective reactions on nitrogen atom are due to strong Coulombic attraction. The reaction of 1 with amines in the presence of hydrogen peroxide afforded the aminolysis product 4. Compounds 1-6 were identified by FTIR, 1H NMR, 13C NMR, and mass spectroscopy.
Chemistry of Substituted Quinolinones. Part VI. Synthesis and Nucleophilic Reactions of 4-Chloro-8-methylquinolin-2(1H)-one and its Thione Analogue
Authors: Ismail Mostafa  M. , Abass Mohamed , Hassan Mohamed  M.
Published: October 2008

The synthesis of 4-chloro-8-methylquinolin-2(1H)-one and its thione analogue is described. Some nucleophilic substitution reactions of the 4-chloro group were carried out to get new 4-substituted 2-quinolinones and quinolinethiones, such as 4-sulfanyl, hydrazino, azido and amino derivatives, which are of important synthetic use. The structure of the new compounds was established by their elemental analysis, IR and 1H-NMR spectra. Also the mass fragmentation pattern of some products is discussed.
An Efficient Synthesis of 5-Alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones Catalyzed by KSF Montmorillonite
Authors: Lin Haixia , Ding Jinchang , Chen Xianten , Zhang Ziyi
Published: October 2008

A mild and efficient catalytic method for synthesis of 5-alkoxycarbonyl-4-aryl-3,4- dihydropyrimidin-2(1H)-ones using KSF montmorillonite as catalyst is described.
Improvement of a Critical Intermediate Step in the Synthesis of a Nitroxide-Based Spin-Labeled Deoxythymidine Analog
Authors: Powell Jeannine  H. , Johnson Edward  M. , Gannett Peter  M.
Published: October 2008

Methods to reduce the carboxylic acid moiety in 3-carboxy-2,2,5,5-tetramethylpyrrolin-1-oxyl to an alcohol as an intermediate toward the corresponding aldehyde have been explored and an improved method has been developed.
Facile and Stereoselective Synthesis of Non-Racemic 3,3,3-Trifluoroalanine
Authors: Crucianelli Marcello , Battista Natalia , Bravo Pierfrancesco , Volonterio Alessandro , Zanda Matteo
Published: October 2008

A highly stereoselective enantiodivergent synthesis of non-racemic 3,3,3-trifluoroalanine 7 is reported. The methodology is based on the reduction, by 9-BBN or DIBAH, of the chiral sulfinimine 3 derived from ethyl trifluoropyruvate, followed by acidic hydrolysis of the resulting diastereomeric sulfinamides 4 and 5.
An Efficient Synthetic Strategy for the Preparation of Nucleic Acid-Encoded Peptide and Protein Libraries for In Vitro Evolution Protocols
Authors: Kurz Markus , Kuang Guannan , Lohse Peter  A.
Published: October 2008

We describe an improved synthetic strategy for the preparation of nucleic acid encoded peptide and protein libraries. A solid-phase format was used to prepare and purify a novel type of mRNA-template for in vitro mRNA-protein fusion synthesis. The present protocol simplifies and accelerates the preparation of fusion libraries and should prove most useful for in vitro protein evolution procedures which involve repetitive cycles of fusion library preparation and selection.
Relative Reactivities of Activated Carboxylic Acids in Amide-Forming Reactions Employed for the Synthesis of Tetraphenylporphyrin Libraries
Authors: Dombi Kendra  L. , Richert Clemens
Published: October 2008

Presented here is a method for rapidly testing the reactivity of carboxylic acids in amide-forming reactions. For this, a mixture of two acids, one a reference compound, and one acid whose reactivity is unknown, are coupled to an aminoacylated tetrakis(paminophenyl) porphyrin under typical peptide coupling conditions. The product distribution in the resulting library is analyzed via MALDI-TOF mass spectrometry to reveal the relative reactivity. This rapid reactivity test requires sub-nanomole quantities of acids, does not involve cleavage from a support or any potentially biasing work-up, and is automatable. Thus, it is well suited for testing building blocks for combinatorial syntheses. Further, it is demonstrated that step-wise coupling can produce near-statistically distributed libraries of porphyrins when acids of very different reactivity are employed.
Synthesis of Some Fused Pyrazoles and Isoxazoles
Authors: Padmavathi Venkatapuram , Reddy Boggu  Jagan Mohan , Balaiah Akula , Reddy Katta  Venugopal , Reddy Dandu  Bhaskar
Published: October 2008

The α-keto methylene group in 3,5-diaryl-2-cyclohexenones 2 and 3,5-diarylcyclohexanones 8 have been used to obtain fused pyrazoles and isoxazoles. The new compounds were characterized by IR and 1H-NMR spectral data.
Synthesis of α-Hydroxyacetosyringone
Authors: Echeverri Fernando , Quiñones Winston , Torres Fernando , Duque Mario , Archbold Rosendo
Published: October 2008

A phytoalexin from papaya fruit has been synthesized in four steps; this procedure involved a Pummerer- type reaction.
Hydroxyquinones: Synthesis and Reactivity
Authors: Spyroudis Spyros
Published: October 2008

Quinones having hydroxy groups directly attached to the quinone ring constitute a very interesting class of quinoid compounds. A great number of hydroxyquinones are found in nature and the majority of them exhibit unique biological activity. Their syntheses and their main reactivity patterns are reviewed in this paper.
Organic Iodine(I, III, and V) Chemistry: 10 Years of Development at the Medical University of Warsaw, Poland
Authors: Skulski Lech
Published: October 2008

This review reports some novel (or considerably improved) methods for the synthesis of aromatic iodides, (dichloroiodo)arenes, (diacetoxyiodo)arenes, iodylarenes and diaryliodonium salts, as well as some facile, oxidative anion metatheses in crude diaryliodonium halides and, for comparison, potassium halides. All these new results were obtained in our laboratory over the past decade (1990-2000). A full list of our papers dealing with the organic iodine(I, III and V) chemistry, covering exlusively the aromatic derivatives, is also provided.
Synthesis and Photochemical Cyclization of a Novel Enyne-Carbodiimide
Authors: Schmittel Michael , Rodríguez David , Steffen Jens-Peter
Published: October 2008

The triplet sensitized cyclization of enyne-carbodiimide 4 leads to efficient formation of indoloquinoline 5 with concomittant loss of a methyl group. The efficient loss of the methyl group was explained using AM1 semiempirical calculations.
The Relationship between Redox Potentials and Torsional Angles in 4,4’-Dimethyl N, N’-Alkylidene 2,2’-Bipyridinium Salts
Authors: Wang Yijun , Zhao Wenyuan
Published: October 2008

The redox potentials of 4,4’-dimethyl-N’N’-alkylidene bridged 2,2’-bipyridinium salts derivatives (DBPAs) can be controlled by changing the N, N’-alkylidene bridge length which changes the conformation of the DBPAs.. In this paper, the torsional angles between the two pyridine rings and the molecular energy of DBPAs are calculated using a PC based software package (AccuModel 1.2). The relationship between torsional angle and N, N’-alkylidene bridge length is discussed. The molecular energy of DBPAs can also be related to the torsional angles (or N, N’-alkylidene bridge size). Some DBPAs had been synthesized and their redox potentials measured. The difference in potential between ethylene and propylene bridged DBPAs is large enough to make a organic diode through bilayer modified electrode.
Study of Stereoselectivity in Organometallic Additions to 1,2-O-Isopropylidene-O-R-α-D-xylopentodialdo-1,4-furanose
Authors: Gracza Tibor , Szolcsányi Peter
Published: October 2008

Diastereofacial selectivity of the addition of organometallic reagents to 1,2-Oisopropylidene-O-R-α-D-xylopentodialdo-1,4-furanoses (6) was studied.
Substitution Effects on Reactivity of N-Acyl-2-amino-2-desoxyglucopyranoses. Quantum Chemical Study
Authors: Vektariene Aušra , Juodviršis Arvydas , Vektaris Gytis
Published: October 2008

Quantum mechanical calculations were carried out to study the molecular geometry and electronic structure of 2-amino-2-desoxyglucopyranose (AG) and the Nacetyl-, N-ethanoyl-, series of N-phthalimidoalkanoyl-AG. The total charge density, electrostatic potential, spatial distribution and positions of HOMO and LUMO of N-acyl-AGs with respect to their substitutes yield information on the reactivity of the molecules.
Halogeno Aldol Reaction of Ethyl Vinyl Ketone and Aldehydes Mediated by Titanium Tetrachloride
Authors: Wei Han-Xun , Karur Subramanian , Li Guigen
Published: October 2008

A three-component halogeno aldol reaction has been developed by using titanium tetrachloride as the halogen source as well as the Lewis acid mediator. The dehydration and elimination of hydrogen chloride were inhibited by conducting the reaction at 0 °C in dichloromethane or at room temperature with a shortened reaction time. Seven examples were examined, giving good to high yields (61 - 92%) and modest stereoselectivity (syn/anti: 2.2/1.0 - 8.4/1.0).
High-level Computational Study of the Site-, Facial- and Stereoselectivities for the Diels-Alder Reaction Between o-Benzoquinone and Norbornadiene
Authors: Margetic Davor , Johnston Martin  R. , Warrener Ronald  N.
Published: October 2008

Ab initio and DFT quantum chemical calculations have been applied to a study of the Diels-Alder reaction of o-benzoquinone as diene and norbornadiene as dienophile. Transition states for the different reactions are located and activation energies estimated. The prefered exo-π-facial selectivity and exo,endo-stereoselectivity exhibited in this cycloaddition are readily predicted using RHF/3-21G or higher levels of calculations. Differences between experimentally observed results and calculations may be explained by the postulation of a second, nonconcerted biradical mechanism leading to formation of hetero Diels-Alder products.
Synthesis and Antimicrobial Activity of Some New Benzimidazole Derivatives
Authors: El-masry Afaf  H. , Fahmy H.  H. , Ali Abdelwahed S.  H.
Published: October 2008

Reaction of 3-(2-methylbenzimidazol-1-yl)propanoic acid hydrazide (1) with CS2/KOH gave oxadiazole 2 which underwent Mannich reaction to give 3. Compound 2 was treated with hydrazine hydrate to give triazole 4 which was treated with both aldehydes and acetic anhydride to give 5 and 6, respectively. Carbohydrazide 1 was reacted with ethyl acetoacetate, acetylacetone and aldehydes to give 7, 8 and 9, respectively. Cyclocondensation of 9 with thioglycolic and thiolactic acids gave 10 and 11, respectively. Some of these compounds showed potential antimicrobial activities.
Cyclohexenonic Long-Chain Fatty Alcohols as Neuronal Growth Stimulators
Authors: Luu Bang , De Aguilar José-Luis González , Girlanda-Junges Céline
Published: October 2008

Neurotrophic factors play an important role in the development and maintenance of neurons, thus providing a suitable therapeutic approach for the treatment of neurodegenerative diseases. However, their clinical use has revealed problematic because of a number of technical and biological disadvantages. Among the different strategies proposed to overcome such difficulties, the search for non-peptide substances with neurotrophic potential is giving promising results. Here we will expose major findings in this field, drawing special attention to cyclohexenonic long-chain fatty alcohols, a novel family of compounds that promote neuronal survival and neurite outgrowth.
Meeting Reports and Abstracts: Symposium on Applications of Porphyrins in Medicine and the Fourth School for Young Scientists on the Chemistry of Porphyrins and Related Compounds Ivanovo 2000
Authors: Golubchikov Oleg A. , Ageeva Tatjana A.
Published: October 2008

The Fourth School for Young Scientists on Chemistry of Porphyrins and Related Compounds Ivanovo 2000 and the Symposium "Application of Porphyrins in Medicine" were held at the facilities of Ivanovo State University of Chemistry and Technology and the Institute of the Solution Chemistry of the Russian Academy of Sciences in Ples (Ivanovo region, Russia) from August 21 to August 27, 2000. About a hundred lecturers and young scientists from Russia, Belarus, Ukraine, Italy and Poland took part in the various sessions of the School and Symposium. The main centers (Moscow, Ivanovo, St-Petersburg, etc.) and directions of porphyrin investigation were well represented by Russian lecturers. The School program included lectures on synthesis, physico-chemical, coordination and application properties of porphyrins, phthalocyanines and related macroheterocyclic compounds. [...]
Thermodynamics and Kinetics for the Biological Sciences. By Gordon G. Hammes
Authors: Lin Shu-Kun
Published: October 2008

Gain a working knowledge of thermodynamics and kinetics with a minimum of mathematics—a guide for individuals in the biological sciences[...]
Physical Biochemistry: Principles and Applications. By David Sheehan
Authors: Lin Shu-Kun
Published: October 2008

An accessible and easy-to-read text for students requiring a broad overview of the key techniques used to characterise the structure and function of complex biomacromolecules such as proteins and DNA.[...]
Combinatorial Chemistry. By Willi Bannwarth and Eduard Felder
Authors: Lin Shu-Kun
Published: October 2008

As we enter the new millennium, combinatorial chemistry is providing significant impetus to new innovations in synthetic chemistry.[...]
Carbohydrates in Chemistry and Biology. By Ernst, Beat / Hart, Gerald W. / Sinaÿ, Pierre
Authors: Lin Shu-Kun
Published: October 2008

Carbohydrate Chemistry and Glycobiology have witnessed a rapid expansion during the last few years with the development of numerous new, imaginative and efficient syntheses which provide further insight into structures and biological interactions of glycoconjugates.[...]
Lewis Acids in Organic Synthesis. By Yamamoto, Hisashi
Authors: Lin Shu-Kun
Published: October 2008

The use of Lewis acids in organic synthesis, especially in catalysis is one of the most rapidly developing fields in synthetic organic chemistry.[...]
Pharmaceuticals: Classes, Therapeutic Agents, Areas of Application. By McGuire, John L.
Authors: Lin Shu-Kun
Published: October 2008

The pharmaceutical industry - an important segment of the chemical industry - is technologically prolific.[...]
Molecular Diversity in Drug Design. Edited by Philip M. Dean
Authors: Lin Shu-Kun
Published: October 2008

This book focuses on the theoretical problems associated with molecular diversity as it is being applied in the pharmaceutical industry.[...]
Advanced Organic Chemistry. Part A: Structure and Mechanisms. Fourth Edition. by Francis A. Carey
Authors: Lin Shu-Kun
Published: October 2008

Since its original appearance in 1977, Advanced Organic Chemistry has found wide use as a text providing broad coverage of the structure, reactivity and synthesis of organic compounds.[...]
Synthetic Organic Sonochemistry. Jean-Louis Luche
Authors: Lin Shu-Kun
Published: October 2008

The use of ultrasound in chemistry – sonochemistry – has grown spectacularly in recent years, resulting in a significant body of empirical research.[...]
Progress in Drug Research. By Jucker, E.
Authors: Lin Shu-Kun
Published: October 2008

*Editor's Note: The brief summary and the contents of the books are reported as provided by the author or the publishers.[...]
Synthesis of Polycyclic Ring Systems Using Transition Metal Catalyzed Cyclizations of Diazo Alkynyl Ketones
Authors: Padwa Albert
Published: October 2008

The rhodium(II)-catalyzed reaction of α-diazo ketones bearing tethered alkyne units represents a new and useful method for the construction of a variety of substituted cyclopentenones. The process proceeds by addition of the rhodium-stabilized carbenoid onto the acetylenic π-bond to give a vinyl carbenoid intermediate. The resulting rhodium complex undergoes a wide assortment of reactions including cyclopropanation, 1,2-hydrogen migration, CH-insertion, addition to tethered alkynes and ylide formation. When 2-alkynyl-2-diazo-3-oxobutanoates were treated with a Rh(II)-catalyst, furo[3,4-c]furans were formed in excellent yield.
Invitation: High Quality Papers with Extensive Literature Review and Full Experimental Details
Authors: McPhee Derek , Lin Shu-Kun
Published: October 2008

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Tricarbonyl(h6-Arene)Chromium(0) Complexes as Chiral Auxiliaries: Asymmetric Synthesis of b-Lactones
Authors: Buttero Paola  Del , Montrasio Deborah
Published: October 2008

The optically pure tricarbonyl(h6-2-substituted benzaldehydes)chromium are used as chiral auxiliaries in the condensation with a series of doubly lithiated carboxylic acids. The intramolecular ring closure of the obtained Cr(CO)3 complexed b-hydroxyacids affords the optically pure b-lactones in satisfactory yield.
Bile Acids as Building Blocks of Supramolecular Hosts
Authors: Tamminen Jari , Kolehmainen Erkki
Published: October 2008

A review of the use of bile acid-based compounds as building blocks for designing novel supramolecular hosts for molecular recognition is presented. Pharmacological applications and the newest spectroscopic and computational studies of bile acid derivatives are also shortly considered.
A Simple Method for Synthesis of Active Esters of Isonicotinic and Picolinic Acids
Authors: Christensen Jørn  B.
Published: October 2008

A method for preparation of the p-nitrophenyl-, N-hydroxysuccinimidyl- and pentafluorophenyl esters of isonicotinic and picolinic acids from the corresponding acids is reported.
Sensitized Photooxygenation of Cholesterol and Pseudocholesterol Derivatives via Singlet Oxygen
Authors: Shuping Wu , Zhiqin Jiang , Heting Li , Li Yang , Daixun Zeng
Published: October 2008

3-Substituted cholesterols and 7-substituted pseudocholesterols undergo a facile photooxygenation sensitized by 9, 10-dicyanoanthracene (DCA) and lumiflavin (LF) to give similar, oppositely-positioned enol derivatives. Both steroids showed the same reaction pattern associated with the endocyclic 5- and 4-olefin units, respectively. The reaction was proposed to proceed via the ene reaction of singlet oxygen and subsequent rearrangement of the initially formed 5a-hydroperoxides.
Cohalogenation of Allyl and Vinylsilanes using Polymer-bound Haloate(I)-Reagents
Authors: Domann Silvie , Sourkouni-Argirusi Georgia , Merayo Nuria , Schönberger Andreas , Kirschning Andreas
Published: October 2008

Polymer-supported electrophilic halogenate(I) complexes 2 and 3 promote smooth addition to vinyl and allylsilanes without loss of the silyl group. In conjunction with Amberlyst A26 (OH− -form) vinyl silanes are converted into epoxysilanes.
RACI Natural Products Group Symposium
Authors: Karuso Peter
Published: October 2008

This special section of Molecules is dedicated to the Royal Australian Chemical Institute’s Natural Products Group.[...]
Indole Derivatives from the Egg Masses of Muricid Molluscs
Authors: Benkendorff Kirsten , Bremner John  B. , Davis Andrew R.
Published: October 2008

A range of brominated indole derivatives were found in the egg masses of six species of muricid molluscs. Several non-brominated indoles were also present in the eggs of two Mediterranean Muricidae, although these were not found in the Australian species. Tyrindoleninone (3), was the only compound found in all six species and is likely to be responsible for the observed antimicrobial activity of these muricid egg masses [1,2]. These bioactive indoles appear to be characteristic of muricid egg masses and were not found in the egg masses from 17 species in different families of marine molluscs.
The Effect of Mechanical Wounding on the Composition of Essential Oil from Ocimum Minimum L. Leaves
Authors: Zabaras Dimitrios , Wyllie S.  Grant
Published: October 2008

The effect of mechanical damage on the composition of the essential oil obtained from eugenol-rich Ocimum minimum leaves was determined over 48 hours. Changes in the levels of five oil-constituents were detected in the first post-wounding day but only one of those components (camphor) exhibited the same behaviour the day after. The levels of eugenol (-4.8%) and linalool (+2.5%) were affected the most by the wounding process. Principal component analysis (PCA) showed the post-wounding response to be independent from the pre-wounding levels of the particular compounds expressing the response and from the overall leaf oil-composition.
Determining the Antimicrobial Actions of Tea Tree Oil
Authors: Cox Sean  D. , Mann Cindy  M. , Markham Julie  L. , Gustafson John E. , Warmington John  R. , Wyllie S.  Grant
Published: October 2008

Research into the mode of action of the essential oil of Melaleuca alternifolia (Tea tree oil) is briefly reviewed. Its mode of action is interpreted in terms of the membrane-toxicity of its monoterpenoid components and different approaches for determining cell membrane damage are discussed.
Supercritical Fluid Extraction (SFE) of Monoterpenes from the Leaves of Melaleuca alternifolia (Tea Tree)
Authors: Wong Victor , Wyllie S.  Grant , Cornwell Charles  P. , Tronson Deidre
Published: October 2008

The technique of supercritical fluid extraction (SFE) was applied to various sample matrices under a range of supercritical carbon dioxide (scCO2) densities and chamber temperatures. The purpose was to develop an effective extraction condition for the removal of eight target monoterpenes from Australian tea tree (Melaleuca alternifolia Cheel) leaves. The optimum conditions for extraction were found to be 0.25 g/mL scCO2 density at a chamber temperature of 110oC. These condition were most effective when applied to whole fresh and rehydrated whole dried leaves, where it yielded maximum recovery of target analytes with minimum change in oil composition for the extractor system employed. This study demonstrates the importance of the type of sample matrix used in SFE work, and that a different extraction protocol would need to be developed for each matrix.
The Odour, the Animal and the Plant
Authors: Tronson Deidre
Published: October 2008

A review of the literature is presented that gives a background to the human sense of smell, then the importance of learnt and innate olfactory cues in animal behaviour. Some possible roles for natural products chemists interested in the interaction between animals and plants are discussed.
Initial Studies on Alkaloids from Lombok Medicinal Plants
Authors: Hadi Surya , Bremner John  B.
Published: October 2008

Initial investigation of medicinal plants from Lombok has resulted in the collection of 100 plant species predicted to have antimicrobial, including antimalarial, properties according to local medicinal uses. These plants represent 49 families and 80 genera; 23% of the plants tested positively for alkaloids. Among the plants testing positive, five have been selected for further investigation involving structure elucidation and antimicrobial testing on the extracted alkaloids. Initial work on structural elucidation of some of the alkaloids is reported briefly.
Natural Products From Sponges of the Genus Agelas - on the Trail of a [2+2]-Photoaddition Enzyme
Authors: Hao Eleanor , Fromont Jane , Jardine Daniel , Karuso Peter
Published: October 2008

By specifically targeting sponges likely to contain oroidin derivatives, we have, for the first time, identified Australian sponges that contain sceptrin (2) and related compounds. Using a simple extraction technique and HPLC (with a photodiode array detector) in combination with LC-MS and MS-MS we have been able to quickly identify known compounds and flag the presence of some new compounds in the extracts. Further work will entail isolation and structure elucidation of the new compounds and collection of fresh Agelas sp.1 with the aim of isolating the enzyme that catalyses the [2 + 2] dimerisation or oroidin to sceptrin
Muscarinic Receptor Agonists and Antagonists
Authors: Broadley Kenneth J. , Kelly David R.
Published: October 2008

A comprehensive review of pharmacological and medical aspects of the muscarinic class of acetylcholine agonists and antagonists is presented. The therapeutic benefits of achieving receptor subtype selectivity are outlined and applications in the treatment of Alzheimer’s disease are discussed. A selection of chemical routes are described, which illustrate contemporary methodology for the synthesis of chiral medicinal compounds (asymmetric synthesis, chiral pool, enzymes). Routes to bicyclic intrannular amines and intramolecular Diels-Alder reactions are highlighted.
7-(1-Acetoxymethylidene)Benzonorbornadiene: A Versatile Reagent for the Synthesis of 7-Formyl and 7-Hydroxymethyl Benzonorbornadienes
Authors: Warrener Ronald N. , Collin Geoffrey J. , Foley Patrick J.
Published: October 2008

7-(1-Acetoxymethylidene)benzonorbornadiene 3, prepared in one step by the addition of benzyne to 6-acetoxyfulvene 2, is hydrolysed in acid solution to form a 3:2-epimeric mixture of syn- and anti- 7-formylbenzonorbornadienes 4 and 5, respectively; the corresponding 7-hydroxymethylbenzonorbornadienes 6 and 9 were produced by reduction of the formyl isomers with sodium borohydride.
Synthesis of 1-(2'-O-Methyl-ß-D-ribofuranosyl)-1H-imidazo[4,5-d]pyridazine-4,7(5H,6H)-dione: An Attractive Building Block for Antisense and Triple-helical Applications
Authors: Chen Huan-Ming , Hosmane Ramachandra  S.
Published: October 2008

Synthesis of the title compound,1-(2'-O-methyl-ß-D-ribofuranosyl)-1H-imidazo-[4,5-d]pyridazine-4,7(5H,6H)-dione (1), is reported. It was synthesized in four steps, starting from methyl 1-(ß-D-ribofuranosyl)imidazo-4,5-dicarboxylate (2). The 3',5'-hydroxyl groups of 2 was protected with a bis-silylating agent to form 3, which was then methylated to form the corresponding 2'-O-methyl derivative 5. The silyl deprotection of the latter (to form 6), followed by treatment with hydrazine afforded the target nucleoside 1. The reported nucleoside has potentially beneficial applications in biomedicine based on antisense and triple-helical nucleic acid technologies.
Crystal and Molecular Structures of N-benzyl-C-(2-pyridyl) nitrone and its ZnBr2 Complex. A Study of Their Reactivity
Authors: Merino Pedro , Anoro Sonia , Cerrada Elena , Laguna Mariano , Moreno Ana , Tejero Tomas
Published: October 2008

The ZnBr2 complex of the title compound has been studied by both structural and theoretical methods. Similar reactivities have been observed for the nitrone alone and the complex in 1,3-dipolar cycloadditions and nucleophilic additions.
Comparison of Association Constants of Cyclodextrins and Their tert-Butyl Derivatives With Halogenbenzoic Acids and Acridine Derivatives
Authors: Pumera Martin , Matalová Radka , Jelínek Ivan , Jindřich Jindřich , Jůza Josef
Published: October 2008

Association constants of complexes of a new class of cyclodextrin alkyl derivatives - randomly susbstituted tert-butyl derivatives (TB-CDs) with complete set of mono-halobenzoic acids and acridine derivatives were measured using capillary electrophoresis and compared with association constants of natural cyclodextrins. In most cases the association constants of natural cyclodextrin and its corresponding tert-butyl derivative were comparable. Strong dependence of association constants on actual cyclodextrin concentration was observed for complexes of tert-butyl-α-cyclodextrin with acridine derivatives. Significant increase of the association constant occurred below the critical micelle concentration of the cyclodextrin derivative, while an increase above this value was less significant.
Synthesis of Acridine-based DNA Bis-intercalating Agents
Authors: Moloney Gerard  P. , Kelly David  P. , Mack P.
Published: October 2008

Methods for the synthesis of N1, N8-bis(9-acridinyl)-N4-(4-hydroxybenzyl)-spermidine and N1, N7-(hydroxybenzyl)-bis-(3-aminopropyl)amine were investigated. Thus monocyanoethylation of 4-methoxybenzylamine followed by treatment with 4-chlorobutyronitrile gave the dinitrile N-(2-cyanoethyl)-N-(3-cyanopropyl)-4-methoxybenzylamine. Subsequent in situ reduction with lithium aluminium hydride gave the corresponding diamine. Biscyanoethylation of 4-methoxybenzylamine with 2 mole of acrylonitrile followed by reduction yielded the diamine N, N-bis-(3-aminopropyl)-4-methoxybenzylamine. Both diamines reacted smoothly with 9-methoxyacridine to give the bis-(9-acridinyl) compounds 11 and 15 but with 4,5-dimethyl-9-methoxyacridine, the bis compound 16 was produced in only low yields. Demethylation of the dinitriles by a variety of approaches all failed to give the corresponding hydroxybenzyl derivatives. These studies yielded useful methylated tyrosine derivatives which could also be iodinated. This study has been useful for elucidating chemical methods needed for the synthesis of the desired tyrosine-based bis acridine compound and for alerting us to the need to synthesise a more labile protected tyrosine intermediate which will be easily deprotected to afford the desired tyrosine-based bis acridine compound.
Synthesis of (±)-trans-2,5-Diisopropylborolane
Authors: Laschober Gerhard , Zorzi Massimo , Hodgetts Kevin  J.
Published: October 2008

The cyclic hydroboration of 2,7-dimethyl-2,6-octadiene (6) was studied. It was found that the stereochemical outcome of the reaction was dependent upon the solvent, temperature, time and the nature of the borane reagent. Pure racemic trans-2,5-diisopropylborolane (14) was isolated following selective complexation of the cis-2,5-diisopropylborolane (15) with 1-(2-hydroxyethyl)-pyrrolidine.
Preparation of Arylthiocyanates Using N,N′-Dibromo-N,N′-bis(2,5-dimethylbenzenesulphonyl) ethylenediamine and N,NDibromo-2,5-dimethylbenzenesulphonamide in the Presence of KSCN as a Novel Thiocyanating Reagent
Authors: Khazaei Ardeshir , Alizadeh Abdolhamid , Vaghei Ramin Ghorbani
Published: October 2008

N-Bromosulphonamides, synthesized via direct bromination of sulphonamides, react with several types of arene substrates in the presence of KSCN to afford aryl thiocyanates. The method appears to be generally applicable to benzenoid substrates with a wide range of substituents, such as N,N-dimethylaniline, p-xylene, anisole, mesitylene and cumene.
Enantioselective Intramolecular CH-Insertions upon Cu-Catalyzed Decomposition of Phenyliodonium Ylides
Authors: Müller Paul , Boléa Christelle
Published: October 2008

The Cu-catalyzed intramolecular CH insertion of phenyliodonium ylide 5b has been investigated at 0° C in the presence of several chiral ligands. Enantioselectivities vary in the range of 38–72 %, and are higher than those resulting from reaction of the diazo compound 5c at 65° C. The results are consistent with a carbenoid mechanism for Cu-catalyzed decomposition of phenyliodonium ylides.
Aminoacids in the Synthesis of Heterocyclic Systems: The Synthesis of Triazinoquinazolinones, Triazepinoquinazolinones and Triazocinoquinazolinones of Potential Biological Interest
Authors: El-Sharief A. M.Sh. , Ammar Y.  A. , Zahran M.  A. , Ali A. H. , El-Gaby M. S.A.
Published: October 2008

A number of novel triazinoquinazolinones (5b,c and 8), triazepinoquinazolinones(5a, 6b, 7 and 9) and triazocinoquinazolinones (6a and 10) were obtained via nucleophilic interaction of 3-aminoquinazolinone derivatives 3 with different reagents.
Intramolecular Acylation of Aryl- and Aroyl-Aliphatic Acids by the Action of Pyrophosphoryl Chloride and Phosphorus Oxychloride
Authors: El-Sayrafi Sami , Rayyan Saleh
Published: October 2008

Both pyrophosphoryl chloride and phosphorus oxychloride react with aryl aliphatic acids to form mixed anhydrides which undergo intramolecular acylation to afford cyclic ketones without the addition of a Friedel-Crafts catalyst. Aryl and aroylbenzoic acids could be cyclized to the corresponding anthrones and anthraquinones respectively.
Photooxidation of n-Hexanal in Air
Authors: Tadić Jovan , Juranić Ivan , Moortgat Geert K.
Published: October 2008

Dilute mixtures of hexanal in synthetic air (up to 100 ppm) were photolyzed with fluorescent UV lamps (275-380 nm) in air at 298 K. The main photooxidation products, identified and quantitatively analyzed by FTIR spectroscopy, were butene, CO, vinylalcohol and ethanal. The photolysis rates and the absolute quantum yield Φ were found to be slightly dependent on the total pressure. At 100 Torr, Φ100 = 0.43 ± 0.02, whereas at 700 Torr the total quantum yield was Φ700 = 0.38 ± 0.02. These results may be explained by the collisional deactivations of photoexcited molecules. Two decomposition channels were identified: the radical channel C5H11CHO → C5H11 + HCO, and the molecular channel C5H11CHO → C4H8 + CH2=CHOH, having the relative yields of 27 and 73 % at 700 Torr. The product CH2=CHOH tautomerizes to ethanal.
Synthesis and Electrophilic Substitution of Pyrido[2,3,4-kl]-acridines
Authors: Koller Avi , Rudi Amira , Gravalos Marta  Garcia , Kashman Yoel
Published: October 2008

Several new pyrido[2,3,4-kl]acridines were synthesized by reacting naphthoquinone, juglone or cyclohexan-1,3-dione with β,β’-diaminoketones in a biomimetic reaction. The structure of all new compounds was elucidated by NMR and MS spectroscopy. Electrophilic substitution, mainly nitration, of the various compounds was undertaken and the substitution positions determined. A series of derivatives was prepared and their cytotoxicity towards P-388 mouse lymphoma cells analysed. The most cytotoxic derivatives were found to have IC50’s of 0.05 and 0.1 ug/ml.
Synthesis of Substituted 2-Benzoylaminothiobenzamides and Their Ring Closure to Substituted 2-Phenylquinazoline-4-thiones
Authors: Hanusek Jiří , Hejtmánková Ludmila , Kubicová Lenka , Sedlák Miloš
Published: October 2008

Acylation of 2-aminothiobenzamide or 2-methylaminothiobenzamide with substituted benzoyl chlorides has been used to synthesise the corresponding 2-benzoylaminothiobenzamides whose subsequent sodium methoxide-catalysed ring closure gives the corresponding quinazoline-4-thiones. These compounds were characterised by means of their 1H- and 13C-NMR spectra. The preferred tautomeric form of selected compounds has been discussed on the basis of their 13C-NMR, IR and Raman spectra. It has been found that in the given medium 1-methyl-quinazoline-4-thiones undergo a replacement of the sulphur substituent by oxygen giving 1-methyl-quinazoline-4-ones. In strong acid media, 2-benzoylaminothiobenzamide is cyclised through its sulphur atom to give 2-phenylbenzo[d-1,3]thiazin-4-one.
Malonates in Cyclocondensation Reactions
Authors: Stadlbauer Wolfgang , Badawey El-Sayed , Hojas Gerhard , Roschger Peter , Kappe Thomas
Published: October 2008

The use of malonates such as diethyl malonates 9, (chlorocarbonyl)ketenes 15 and bis(2,4,6-trichlorophenyl) malonates 18 as reagents for cyclocondensation with 1,3-dinucleophiles to give six-membered heterocycles is described. Further attempts to use malonates such as bis(trimethylsilyl) malonates 19 and bis(carbamimidoyl) malonates 29 as new cyclocondensation agents are described .
π-Bond Screening in Benzonorbornadienes: The Role of 7-Substituents in Governing the Facial Selectivity for the Diels-Alder Reaction of Benzonorbornadienes with 3,6-Di(2-pyridyl)-s-Tetrazine
Authors: Warrener Ronald  N. , Harrison Peter  A.
Published: October 2008

Benzonorbornadiene 21, 7-spirocyclopropylbenzonorbornadiene 23, 7,7-dimethylbenzonorbornadiene 25, and 7-spirocyclopentylbenzonorbornadiene 27 have been reacted with 3,6-di(2-pyridyl)-s-tetrazine (rate: 21>23>25=27) to form symmetrical 4,5-dihydropyridazines which are stable towards fragmentation but rearrange with varying facility to their 1,4 isomers. The facial selectivity of attack on the π-bond changes from exo-attack for 21 and 23 to endo-attack for 25 and 27. The 7-spirocyclopropyl benzonorbornadiene 23 typically forms a mixture of dihydropyridazines with exo-stereochemistry, which undergo further stereochemical isomerisation to an exo-fused product upon acetylation (acetyl chloride in hot pyridine). Oxidation with DDQ of the dihydropyridazines individually or as mixtures gives the corresponding fused 3,6-di(2-pyridyl)pyridazines.
Predicting Vapour Pressures of Organic Compounds from Their Chemical Structure for Classification According to the VOCDirective and Risk Assessment in General
Authors: Olsen Erik , Nielsen Frands
Published: October 2008

The use of organic compounds in the European Union will in the future be regulated in accordance with the Council Directive 1999/13/EC of 11 March 1999 [1]. In this directive, any organic compound is considered to be a volatile organic compound (VOC) if it has a vapour pressure of 10 Pa or more at 20oC, or has a corresponding volatility under the particular condition of use. Introduction of such a limit will sometimes create problems, because vapour pressures cannot be determined with an infinite accuracy. Published data on vapour pressures for a true VOC will sometimes be found to be below 10 Pa and vice versa. When the same limit was introduced in the USA, a considerable amount of time and money were spent in vain on comparing incommensurable data [2]. In this paper, a model is presented for prediction of the vapour pressures of VOCs at 20oC from their chemical (UNIFAC) structure. The model is implemented in a computer program, named P_PREDICT, which has larger prediction power close to 10 Pa at 20oC than the other models tested. The main advantage of the model, however, is that no experimental data, which will introduce uncertainty in the predictions, is needed. Classification using P_PREDICT, which only predicts one value for a given UNIFAC structure, is proposed. Organic compounds, which can be described by the UNIFAC groups in the present version of P_PREDICT, therefore, can be classified unambiguously as either VOCs or non-VOCs. Most people, including the present authors, feel uneasy about prioritising precision above accuracy. Modelling vapour pressures, however, could save a lot of money and the errors introduced are not large enough to have any substantial adverse effects for neither human beings nor the environment. A method for calculating vapour pressures at other temperatures than 20oC is tested with a dubious result. This method is used for EU risk assessment of new and existing chemicals.
Synthesis of the New Type of Water-Soluble Ligand N,N-Bis-(diphenylphosphinomethyl)-2-aminoethylphosphonic Acid (Ph2PCH2)2NCH2CH2PO3H2 and Its Sodium Salt
Authors: Ma Xuebing , Fu Xiangkai , Li Longqin , Chen Jingrong
Published: October 2008

The novel water-soluble ligand, N,N-bis(diphenylphosphinomethyl)-2-aminoethylphosphonic acid, (Ph2PCH2)2NCH2CH2PO3H2, had been synthesized in quantitative yield by reaction of 2-aminoethylphosphonic acid with bis(hydroxymethyl)-diphenylphosphonium chloride in water. Its mono- and disodium salts, which can be used as water-soluble ligands for transition metal complex catalysts, were also easily prepared under mild conditions.