bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetic Support for the Generation of a Phenylsulfenium Ion Intermediate
Authors: Takeuchi Hiroshi , Tateiwa Jun-ichi , Moriguchi Shintaro
Published: October 2008

In the reaction of N-methylbenzenesulfenamide (1) with thioanisole (4) in the presence of trifluoroacetic acid (TFA), the initial rate υ0 of total appearance of 2- and 4-(methylthio)phenyl phenyl sulfides (5) is first and zero order with respect to the initial concentrations of 1 and 4, respectively: υ0=kobs[1]0. The pseudo-first order rate constant kobs is evaluated as 5.2×10-4 sec-1 with varying concentrations of 4 (0.72 to 5.0 M) in a mixture of 4 and CH2Cl2 in the presence of TFA at 10 °C. This data supports the notion that a phenylsulfenium ion intermediate 3 interacting with both the counter ion and the unshared electron-pair of amine is generated by heterolytic N-S scission of the protonated sulfenamide 2, leading to the observed formation of 5.
Dipolar Cycloaddition Reactions with Quinazolinones: A New Route for the Synthesis of Several Annelated Pyrrolo- and Pyridazinoquinazoline Derivatives
Authors: Ghabrial Sami  S. , Gaber Hatem  M.
Published: October 2008

The novel 2-aryl-3a,4,12,12a-tetrahydropyrrolo[3',4':4,3]-pyridazino[6,1-b]-quinazoline-1,3,6-triones (6a–d), 2-aryl-10-oxopyridazino[6,1-b]-quinazoline-3-thio-carboxamides (10a–d) and 2-aryl-3-nitro-1,2,3,4-tetrahydro-pyridazino[6,1-b]quinazolin-10-ones (12a–d) were synthesized via a new, facile one step route involving the reactions of the zwitterion 4, formed in situ, with a variety of N-arylmaleimides 5, 3-aryl-2-cyano-thioacrylamides 8 and ω-nitrostyrenes 11. Dehydrogenation of the tetrahydro derivatives 6a–d and 12a–d in nitrobenzene resulted in the formation of 2-arylpyrrolo[3',4':4,3]-pyridazino[6,1-b]quinazoline-1,3,6-triones (7a–d) and 2-aryl-3-nitropyridazino[6,1-b]quinazolin-10-ones (13a–d), respectively. The structures of the products were confirmed by elemental analysis and spectral data.
Synthesis and Structure of bis(Dibutyldithiocarbamate)zinc(II): Zn2[(n-Bu)2NCSS]4
Authors: Zhang Weiguang , Zhong Yun , Tan Minyu , Tang Ning , Yu Kaibei
Published: October 2008

The binuclear zinc (II) complex Zn2[(n-Bu)2NCSS]4 has been prepared, and its crystal and molecular structure have been determined by x-ray diffraction. The crystal is monoclinic, space group C2/c, with a=23.329(3)Å, b=17.090(2)Å, c=16.115(2)Å, α =90°, β=127.560(10)°, γ=90°, z=4, V=5039.1(11)Å3, F(000)=2016, R=0.0450, and Rw=0.1192. The crystal structure shows that two S-N-S atom chains, belonging to the different dibutyldithiocarbamate ligands, bridge two zinc (II) ions. Each zinc (II) ion coordinates to four S atoms. The coordination geometry around the zinc (II) is a tetrahedron, however, the coordination sphere of two zinc ions in the dimer is best described as a distorted octagon. The X-ray photoelectron spectra, IR and UV data have been used to study the structure and spectra properties of the complex.
Theoretical Study on the Interaction of o-Tetrafluorophenylene Mercury with Ethylene and Acetylene
Authors: Castro Eduardo  A.
Published: October 2008

The results of a theoretical study on the interaction of o-tetrafluorophenylene mercury with ethylene and acetylene are reported. The AM1 molecular orbital semiempirical method is applied through a complete optimization procedure without any restrictions to find the optimal equilibrium geometries. The comparative capabilities of ethylene and acetylene molecules to form stable complexes with o-tetrafluorophenylene mercury are analyzed and their corresponding bonding features are discussed. Ethylene seems to be capable of forming a molecular complex while acetylene is predicted to be incapable of doing so.
Structures and Chemical Equilibria of Some N-Heterocycles Containing Amide Linkages
Authors: Masoud M.  S. , Abd El Zaher Mostafa M. , Ahmed R.  H. , Abd El Moneim N.   H.
Published: October 2008

Structures and chemical equilibria of 5-carboxy-2-thiouracil (1), 5,6-diphenyl-3-hydroxy-1,2,4-triazine (2), 1-phenyl-3-methyl-5-pyrazolone (3) and 2-mercapto-4,6-dimethylpyrimidine hydrochloride (4) are reported. Their electronic transitions are assigned and pK values are evaluated and discussed.
Synthesis of Some Transition Metal Complexes of a Novel Schiff Base Ligand Derived from 2,2'-bis(p-Methoxyphenylamine) and Salicylicaldehyde
Authors: Tai Xishi , Yin Xianhong , Chen Qiang , Tan Minyu
Published: October 2008

A novel Schiff base ligand derived from 2,2'-bis(p-methoxyphenylamine) and salicylicaldehyde and its transition metal complexes with Cu (Ⅱ), Co (Ⅱ) and Mn (Ⅱ) have been synthesized. Their spectral properties and electrochemical behavior were investigated.
Synthesis of New Pyrazole and Pyrimidine Steroidal Derivatives
Authors: Rivera Daniel  G. , Peseke Klaus , Jomarrón Isabel , Montero Alina , Molina Reinaldo , Coll Francisco
Published: October 2008

The synthesis of steroidal heterocycles containing the pyrazole and pyrimidine ring fused to the 16,17-position of the steroid nucleus is reported. Androstenolone acetate (1) reacted with carbon disulfide, iodomethane and sodium hydride to furnish 3β-acetoxy-16-[bis(methylthio)methylene]-5-androst-5-en-17-one (2). The reactions of 2 with hydrazine hydrate and methylhydrazine afforded the 5’-methylthio- pyrazolo[4’,3’:16,17]androst-5-en-3β-ols 3a and 3b, respectively. Treatment of 2 with amidinium, guanidinium, and isothiuronium salts in the presence of sodium methoxide yielded the 6’-methoxy-pyrimido[5’,4’:16,17]androst-5-en-3β-ols (4a-4e).
Synthesis and Catalytic Activity of Two New Cyclic Tetraaza Ligands
Authors: Fonseca María Hechavarría , Hjelmgaard Thomas , König Burkhard
Published: October 2008

Two new chiral cyclic tetraaza ligands were synthesized and characterized. Their catalytic activity was tested in the asymmetric addition of diethylzinc to benzaldehyde. The expected secondary alcohol was obtained in moderate yields, but with very low enantioselectivity.
Special Issue: Selected Papers from the Second Eurasian Meeting on Heterocyclic Chemistry: Heterocycles in Organic and Combinatorial Chemistry
Authors: Babaev Eugene V.
Published: October 2008

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Synthesis of 6-Nitroderivatives of Oxazolo[3,2-a]-pyridines and Their Reactions with Nucleophiles
Authors: Bush Alexander  A. , Babaev Eugene V.
Published: October 2008

5-Nitro-2-pyridone can be selectively N-phenacylated, and the resulting phenacylpyridones I undergo cyclization to 6-nitrooxazolo[3,2-a]pyridinium salts II. These salts II readily react with ammonia and aliphatic amines leading to the products of pyridine ring opening - previously unknown 1-amino-2-nitro-4-(oxazole-2-yl)butadienes-1,3. Reaction of salts II with water lead to hydrolytic cleavage of the oxazole fragment.
Solid-Phase Synthesis of Methyl N-(pyrimidin-2-yl)glycinate
Authors: Ermolat'ev Denis S. , Babaev Eugene V.
Published: October 2008

A versatile method for the preparation of N-heteroaryl substituted aminoacid derivatives is suggested. The method avoids facile diketopiperazine formation.
Synthesis and Biological Evaluation of New 4,5-Disubstituted-Thiazolyl Amides, Derivatives of 4-Hydroxy-Piperidine or of 4-N-Methyl Piperazine
Authors: Geronikaki A. , Hadjipavlou-Litina D. , Chatziopoulos C. , Soloupis G.
Published: October 2008

4,5-disubstituted-thizolyl amides, derivatives of 4-hydroxy-piperidine and of 4-N-methyl piperazine, were synthesized and tested as anti-inflammatory agents. Log P values were theoretically calculated and experimentally determined. These compounds were tested for antioxidant activity, as hydroxyl radical scavengers and for their ability to interact with stable 1,1-diphenyl-2-picryl hydrazyl free radical (DPPH). The effect of the synthesized compounds on inflammation, using the carrageenin induced mice paw edema model was studied. Both anti-inflammatory and antioxidant activities depended on some structural characteristics of the synthesized compounds.
Synthesis of New Polyfused Heterocycles of Biological Importance by Means of Pd(0) Catalysis
Authors: Hajós Gy. , Riedl Zs. , Timári G. , Mátyus P. , Maes B.  U. W. , Lemière G.  L. F.
Published: October 2008

A general synthetic methodology employing heteroaryl-aryl Suzuki coupling is reviewed, by which 15 heteroaromatic ring systems of biological interest have been prepared.
Novel Heteroatom-containing Vitamin D3 Analogs: Efficient Synthesis of 1α,25-Dihydroxyvitamin D3-26,23-lactam
Authors: Kato Yuko , Hashimoto Yuichi , Nagasawa Kazuo
Published: October 2008

Vitamin D3 and its synthetic analogs are promising compounds for controlling various types of cell differentiation. In this article, we describe the synthesis of novel vitamin D3 analogs containing heteroatoms in their side chains – so-called vitamin D3 lactam analogs – via 1,3-dipolar cycloaddition reaction as a key step.
The Ring Transformation of 3-Methyl-5-nitropyrimidin-4(3H)-one
Authors: Nishiwaki Nagatoshi , Tamura Mina , Hori Kazushige , Tohda Yasuo , Ariga Masahiro
Published: October 2008

3-Methyl-5-nitropyrimidin-4(3H)-one readily reacts with carbonyl compounds to produce three kinds of ring transformations. The nitropyrimidinone behaves as the synthetic equivalent of activated diformylamine affording 3,5-difunctionalized 4-pyridones, 4,5-disubstituted pyrimidines and functionalized 4-aminopyridines. It also behaves like α-nitro-formylacetic acid to give 5,6-disubstituted 3-nitro-2-pyridones.
New Synthetic Approaches to Multifunctional Phenazinium Salt Derivatives
Authors: Garipova Inna  Yu. , Silnikov Vladimir N.
Published: October 2008

Two different approaches are offered for the synthesis under mild conditions of disubstituted phenazinium and benzo[a]phenazinium salts. Direct nucleophilic substitutions by primary and secondary amines in quaternary phenazinium salts containing an additional positive charge in the aliphatic part of the molecule were carried out. The substitution proceeds successively in positions 2 and 7, which allows selective introduction of different substituents into the heterocycle. Direct nucleophilic substitution in quaternary 2-N-alkyl-acetamidophenazinium and 5-alkoxy-benzo[a]phenazinium salts with different amines can also serve as a convenient method for the introduction of two different substituents.
Withdrawn Paper: Molecules 2001, 6, 647-654 [1]
Authors: McPhee Derek
Published: October 2008

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Synthesis and Characterization of Acyclic and Cyclic Azabridged Ligands Incorporating 2,2'-Bipyridine Subunits and Their Complexes With Copper(II), Cobalt(II), and Nickel(II)
Authors: Mamo Antonino , Pappalardo Andrea
Published: October 2008

The synthesis of a series of N,N'-disubstituted acyclic (AL) and cyclic (CL) aza-bridged ligands incorporating 2,2-pipryidine subunits is described. 1H-NMR and IR spectral data support the proposed ligand structures. Dynamic 1H-NMR studies on diurea and diamide derivatives point to the presence of slowly interconverting conformers on the 1H-NMR time-scale, owing to N−H···N hydrogen bonding and/or a restricted rotation around the amide bonds. The ligands synthesized form 1:1 complexes with divalent transition metal ions. Upon complexation, bis-ester derivatives AL5 and CL5 undergo a metal-induced hydrolysis of the ester groups to carboxyl functions, which act as additional binding sites for the metal ion, as well as hydrogen-bonding donor-acceptor binding site to produce dimeric complexes.
Synthesis and Reactivity of New 1-Pentafluorophenyl-1Hpyrrole Derivatives
Authors: Hrnčariková Katarína , Végh Daniel
Published: October 2008

We present 1-pentafluorophenyl-1H-pyrrole and some of its electrophilic substitution reactions: formylation and acetylations. The 2-substituted products formed in these reactions are selectively and in high yield converted into 3-substituted products by treatment with trifluoromethanesulfonic acid. A general synthesis of 3-acylpyrroles was developed by the trifluoromethanesulfonic acid-mediated rearrangement of the corresponding 2-acylpyrroles.
Microwave Assisted Synthesis, Part 1: Rapid Solventless Synthesis of 3-Substituted Coumarins and Benzocoumarins by Microwave Irradiation of the Corresponding Enaminones
Authors: Al-Zaydi Khadijah  M.
Published: October 2008

The reactivity of enaminones toward a variety of reagents under microwave irradiation is reported. The results are compared with traditional solution methods.
Synthesis of Plasmepsin II Inhibitors – Potential Antimalarial Agents
Authors: Mueller Reto , Huerzeler Marianne , Boss Christoph
Published: October 2008

A new series of plasmepsin II (PM II) inhibitors has been prepared based on 4-aminopiperidine-tert-butyl-carbamate (1). These compounds might be useful as antimalarial drugs acting via a new mechanism, and therefore be less susceptible to parasite resistance now often observed with current antimalarial therapies. Some of the final compounds prepared exhibited encouraging inhibitory activity towards PM II.
Selective Nitration of Aromatic Compounds with Bismuth Subnitrate and Thionyl Chloride
Authors: Muathen Hussni  A.
Published: October 2008

Bismuth subnitrate/thionyl chloride have been found to be an efficient combination of reagents for nitration of a wide range of aromatic compounds in dichloromethane. Phenols, in particular, were easily mononitrated and dinitrated with the reagents by controlling the stoichiometry,
Preparation and Crystal Structure of (1S, 5S, 7S, 8R)-8-Hydroxy-7-phenyl-2,6-dioxabicyclo[3.3.0]octan-3-one
Authors: Langer Vratislav , Gyepesová Dalma , Koman Marian , Kapitán Peter , Babjak Matej , Gracza Tibor , Koóš Miroslav
Published: October 2008

The absolute configuration at two newly formed stereogenic centres (5S, 7S) during the key steps of the total synthesis of naturally occuring goniothalesdiol was established by single-crystal X-ray diffraction analysis relative to stereocentres (1S, 8R) of the title compound (alternatively named 3,6-anhydro-2-deoxy-6-phenyl-L-ido-1,4-hexonolactone, C12H12O4). The conformation of both 5-membered lactone and furanose fused rings is also discussed.
Peter Karuso and Paul J. Scheuer, Natural Products from Three Nudibranchs: Nembrotha kubaryana, Hypselodoris infucata and Chromodoris petechialis, Molecules, 2002, 7, 1-6
Authors: Karuso Peter
Published: October 2008

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A Facile Procedure for the Generation of Dichlorocarbene from the Reaction of Carbon Tetrachloride and Magnesium using Ultrasonic Irradiation
Authors: Lin Haixia , Yang Mingfa , Huang Peigang , Cao Weiguo
Published: October 2008

An improved method for the generation of dichlorocarbene was developed that utilizes ultrasound in the reaction of carbon tetrachloride with magnesium. High yields of gem-dichlorocyclopropane derivatives can be obtained in the presence of olefins by this method.
Constituents from Moghat, the Roots of Glossostemon bruguieri (Desf.)
Authors: Meselhy Meselhy R.
Published: October 2008

The new biflavone moghatin (3″′-hydroxycupressuflavone) was isolated from Moghat, the dried peeled roots of Glossostemon bruguieri (Desf.), together with five known compounds: 4′-methoxyisoscutellargin, sesamin, chrysophanol, emodin and methoxyemodin (physcion). The structures of these compounds were assigned on the basis of spectroscopic data. Occurrence of these compounds in Moghat is reported here for the first time.
Syntheses of New Unsymmetrical and Symmetrical Diarylsulphides and Diarylsulphones Containing Thiazolinyl and Thiazolidinonyl Moieties Using 4,4'-Diacetyldiphenylsulphide
Authors: Abbady M. A. , Abdel-Hafez Sh. H. , Kandeel M. M. , Abdel-Monem M. I.
Published: October 2008

Condensation of 4,4’-diacetyldiphenyl sulphide (2) with variable amounts of thiosemicarbazide (3) in refluxing ethanol and in the presence of catalytic amounts of dry piperidine afforded only 4-acetylthiosemicarbazone-4’-acetyldiphenyl sulphide (5). Condensation of 2 with excess semicarbazide hydrochloride (4) in the presence of fused sodium acetate and/or piperidine yielded 4,4’-diacetylsemicarbazone diphenyl sulphide (6), whereas use of equimolar amounts of 2 and 4 afforded 4-acetyl-semicarbazone-4’-acetyldiphenyl sulphide (7). 4-Acetylsemicarbazone-4’-acetylthiosemicarbazone diphenyl sulphide (8) was also obtained via two different routes. The effect of tautomeric structure 5d is discussed. 4-(4"-phenyl-Δ3-thiazoline-2"-acetylazino)-4’-acetyldiphenyl sulphide (9), 4-(5"-carboxyethyl-4"-thiazolidinone-2"-acetylazino)-4’-acetyldiphenyl sulphide (10), 4-(4"-thiazolidinone-2’-acetylazino)-4’-acetyldiphenyl sulphide (11) and 4-(4"-methyl-Δ3-thiazoline-2"-acetylazino)-4’-acetyldiphenyl sulphide (12) were prepared by interaction of 5 with phenacylbromide, bromodiethylmalonate, chloro ethylacetate and chloroacetone, respectively. Sulphides 9-12 were easily condensed with 3 to afford the corresponding 4-(heterocyclic moiety-2"-acetylazino)-4’-acetylthiosemicarbazone diphenyl sulphides 23-26. Oxidation of the prepared sulphides 5-7, 9-12, 23 and 25-26 using H2O2/glacial AcOH mixtures yielded only 4,4’-diacetyldiphenyl sulphone (13) as the main product in every case, besides 3 and 4 in certain cases. Unsymmetrical and symmetrical sulphones 14-22 were obtained starting from 13. The structures of the synthesized compounds are based on IR, 1H-NMR, 13C-NMR and mass spectral data. A theoretical study on some of the prepared compounds using molecular modeling was carried out.
Microwave-Assisted Synthesis of Some 3,5-Arylated 2-Pyrazolines
Authors: Azarifar Davood , Ghasemnejad Hassan
Published: October 2008

Condensation of 2-acetylnaphthalene with benzaldehydes under microwave irradiation affords chalcones which undergo facile and clean cyclizations with hydrazines RNHNH2 (R= H, Ph, Ac) to afford 3,5-arylated 2-pyrazolines in quantitative yields, also under microwave irradiation and in the presence of dry AcOH as cyclizing agent. The results obtained indicate that, unlike classical heating, microwave irradiation results in higher yields, shorter reaction times (2-12 min.) and cleaner reactions.
An Attempt to Assign the NMR Spectra in 7-Methyl-and 7-Benzyl-substituted 7H-Purine 1-Oxides Using the ACD/Labs Software Package
Authors: Ostrowski Stanisław
Published: October 2008

Commercially available 4-nitroimidazole can be transformed in a few simple steps into 4-aminoimidazoyl-5-carboximes, from which the respective purine mono-1-oxides may be synthesized. The N→O functionality in these products significantly changes the electron density in the purine skeleton and consequently, the determination of the 1H- and 13C-NMR spectra of these simple compounds is somewhat troublesome. The use of the ACD/Labs software package for this purpose is discussed.
Solvent and Substituent Effects on the Thermolysis of Antimalarial Fluorophenyl Substituted 1,2.4-Trioxanes
Authors: Cafferata Lazaro  F. R. , Rimada Ruben  S.
Published: October 2008

The kinetics and mechanism of the thermal decomposition reaction of cis-6-(4-fluoropheny1)-5,6-[2-(4-fluorophenyl)-propylidene]-3,3-tetramethylene-l,2,4-trioxacyclohexane (I) were investigated separately in n-hexane and in methanol solutions over the temperature and concentration ranges of 393.2-443.2 K and 2.7-54 x l0-5 M, respectively. The values of the activation parameters for both reactions were compared with the corresponding ones for the thermolysis of cis-6-(4-fluorophenyl-5,6-[2-(4-fluorophenyl)-3-hydroxypropylidene]-3,3-tetramethylene-1,2,4-trioxacyclohexane (II), investigated in the same solvents and temperature range. Substituent and solvent effects on the initial homolytic rupture of the O-O peroxydic bonds of those molecules were evaluated.
Highly Efficient, and Fast Solid State Deprotection of 1,3-Dithianes and 1,3-Dithiolanes using Mercury(II) Nitrate Trihydrate
Authors: Habibi Mohammad H. , Tangestaninejad Shahram , Montazerozohori Morteza , Mohamadpoor-Baltork Iraj
Published: October 2008

A variety of 1,3-dithianes and 1,3-dithiolanes are deprotected in the solid state to the corresponding parent carbonyl compounds in excellent yields using mercury(II) nitrate trihydrate in a mild, efficient and fast method.
Sesquiterpenes from Cymbopogon proximus
Authors: El-Askary Hesham  I. , Meselhy Meselhy  R. , Galal Ahmed  M.
Published: October 2008

In addition to four previously reported compounds: proximadiol (1), 5α-hydroxy-β-eudesmol (2), 1β-hydroxy-β-eudesmol (4) and 1β-hydroxy-α-eudesmol (5), two new sesquiterpenes, 5α-hydroperoxy-β-eudesmol (3) and 7α,11-dihydroxycadin-10(14)-ene (6) were isolated from the unsaponifiable fraction of the petroleum ether extract of Cymbopogon proximus STAPF. Isolation of compounds 2, 4 and 5 from the genus Cymbopogon is reported for the first time. The structure elucidation of these compounds was based primarily on 1D and 2D-NMR analyses.
Synthesis of 2-(4-Methoxyphenyl)pyrrolo[2,1-d]pyrido[2,3-c]-[1,5]-thiazepin-3(2H)-one
Authors: Ma Eunsook
Published: October 2008

2-(4-Methoxyphenyl)pyrrolo[2,1-d]pyrido[2,3-c][1,5]thiazepin-3(2H)-one, a key intermediate in the synthesis of pyrrolopyridothiazepine derivatives, was synthesized from bis(4H-pyrrolo-3-pyridyl)disulfide and α-bromo-(4-methoxyphenyl) acetic acid ethyl ester in order to develop a novel calcium channel antagonist.
Policy Change Concerning Sample Submission
Authors: McPhee Derek
Published: October 2008

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2-(p-Hydroxybenzyl)indoles - Side Products Formed Upon Cleavage of Indole Derivatives from Carboxylated Wang Polymer - an NMR Study
Authors: Mutulis Felikss , Erdélyi Máté , Mutule Ilze , Kreicberga Jana , Yahorava Sviatlana , Yahorau Aleh , Borisova-Jan Larisa , Wikberg Jarl  E.S.
Published: October 2008

Treatment of carboxylated Wang polymer attached to a 2-unsubstituted indole derivative with a trifluoroacetic acid based mixture resulted in a side reaction: p-hydroxybenzylation at the 2-position of the indole ring. The structure of the resulting N-3-aminopropyl)-N-benzyl-4-[2-(4-hydroxybenzyl)-1H-indol-3-yl]-butyramide trifluoroacetate was ascertained by a full assignment of its 1H- and 13C-NMR spectra. The side reaction could be suppressed by the use of 1,2-ethanedithiol in high concentrations (16 %).
Novel 4-Aroyl-3-alkoxy-2(5H)-furanones as Precursors for the Preparation of Furo[3,4-b][1,4]-diazepine Ring System
Authors: Zimmer Hans , Librera Christian  P. , Hausner Sven , Bauer Jeanette , Amer Adel
Published: October 2008

A general synthesis of tetronic acid derivatives, namely 4-aroyl-3-alkoxy-2(5H)-furanones, is achieved via the treatment of an anhydrous dimethylformamide (DMF) solution of 4-aroyl-3-hydroxy-2(5H)-furanones with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as base at -10-0°C, followed by the addition of alkyl iodide. Their structural assignments are based on spectroscopic data and confirmed by X-ray crystallography. These furanones were used as starting materials for the preparation of furodiazepines.
Synthesis and Reactions of Some New Heterocyclic Carbohydrazides and Related Compounds as Potential Anticancer Agents
Authors: Mansour Abdel  Kader , Eid Mohga  M. , Khalil Nasser  S. A. M.
Published: October 2008

Acylation of 3-hydrazino-5,6-diphenyl-1,2,4-triazine (2) and hydrazine hydrate (7) with 4-aryl-1,3,7-triphenyl-8-oxa-1,2,6-triazaspiro[4.4]nona-2,6-dien-9-ones 5a,b gave the corresponding heterocyclic carbohydrazides 6a,b and 8a,b respectively. Conversion of compounds 8a,b into the versatile carbohydrazide derivatives 9a-g, 10, 13 and the related oxadiazoles 11, 12a,b was undertaken. A primary in vitro test of compound 8a (concentration 10-4 M) showed activity against leukemia cell lines (CCRFCEM, K-256, MOLT-4, PRMI-8226, SR).
Synthesis and Biological Evaluation of Quinazoline-4-thiones
Authors: Kubicová Lenka , Šustr Martin , Kráľová Katarína , Chobot Vladimír , Vytlačilová Jitka , Jahodář Luděk , Vuorela Pia , Macháček Miloš , Kaustová Jarmila
Published: October 2008

Several 2,2-dimethyl-3-phenyl-1,2-dihydroquinazoline-4(3H)-thiones and 2-methyl-3-phenylquinazoline-4(3H)-thiones were synthesized and tested for their antimycobacterial, photosynthesis-inhibiting, and antialgal activity. Antimycobacterially active compounds were found among the 6-chloro substituted compounds. 6-Chloro-3-(4-isopropylphenyl)-2-methylquinazoline-4(3H)-thione exhibited higher activity than the isoniazid standard against Mycobacterium avium and M. kansasii. Most of the compounds possessed photosynthesis-inhibiting activity. 6-Chloro-2,2-dimethyl-3-phenyl-1,2-dihydroquinazoline-4(3H)-thione and its 3´-chloro- and 3´,4´-dichloro analogs were most effective in the inhibition of oxygen evolution rate in spinach chloroplasts. Of compounds selected for toxicological screening, 6-chloro-3-(4-isopropylphenyl)-2-methyl-quinazoline-4(3H)-thione was the only one active in the brine shrimp bioassay.
Structure of Sulfated Monosaccharides Studied by Quantum Chemical Methods
Authors: Scholtzová Eva , Mach Pavel , Hricovíni Miloš
Published: October 2008

Ab initio and DFT analysis have been used to study of geometry of sulfated monosaccharides GlcN,6-SO3- and IdoA 2-SO3- in solvent. The computed low conformational barrier between the interconverting conformers of the IdoA 2-SO3- residue is in agreement with experimental data.
Synthesis and X-Ray Structure of [N,N-Bis(3,5-dimethylpyrazol-1-ylmethyl)-1-hydroxy-2-aminoethane](3,5-dimethylpyrazole) copper(II) dinitrate
Authors: El Kodadi Mohamed , Malek Fouad , Touzani Rachid , Ramdani Abdelkrim , El Kadiri Sghir , Eddike Driss
Published: October 2008

The tridentate ligand N,N-Bis(3,5-dimethylpyrazol-1-ylmethyl)-1-hydroxy-2-aminoethane (L) has been prepared in one step by condensation of two equivalents of 1-hydroxymethyl-3,5-dimethylpyrazole with one equivalent of 2-aminoethanol. This reaction is carried out under microwave irradiation (60 W) in the absence of solvent for 20 min [1]. Using this ligand L a new Cu(II) dinitrate complex has been prepared. The singlecrystal X-ray structure of the title compound, [N,N-bis(3,5-dimethylpyrazol-1-ylmethyl)-1-hydroxy-2-aminoethane] (3,5-dimethylpyrazole)copper(II) dinitrate, revels that the copper (II) ion is coordinated to two pyrazole nitrogens, one tertiary amine nitrogen of the ligand L and 3,5-dimethylpyrazole, and in the apical position by an alcohol O atom.
Synthesis and Characterization of Chiral Nitrobenzaldehyde - Schiff Base Ligands
Authors: Gao Wen  Tao , Zheng Zhuo
Published: October 2008

Three chiral nitrobenzaldehyde/Schiff base ligands (2a-c) were prepared by the reaction of ortho, meta, and para-NO2 substituted benzaldehydes (1a-c) with (1R,2R)-(-)-1,2-diaminocyclohexane. The structures of ligands 2a-c were characterized by IR, 1H-NMR, 13C-NMR and elemental analysis.
The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis
Authors: Erian Ayman  W. , Sherif Sherif  M. , Gaber Hatem  M.
Published: October 2008

The molecular structures and spectral properties of α-haloketones as well as their syntheses are analyzed and reviewed. Their reactivity towards oxygen, nitrogen, and sulfur nucleophiles, carboxylic acids, carbon nucleophiles, alkenes, and alkynes are discussed.
Synthesis and Crystal Structure of Hexakis(imidazole) nickel (II) O,O′-diphenyldithiophosphate [Ni(Im)6](Ph2O2PS2)2
Authors: Zhang Shusheng , Wang Shiying , Wen Yonghong , Jiao Kui
Published: October 2008

The crystal and molecular structures of [Ni(Im)6](dtp)2 (Im = imidazole, dtp = O,O′-diphenyldithiophosphate) have been determined by X-ray crystallography. It crystallizes in the triclinic system, space group Pī, with cell parameters a = 9.375 (2), b = 12.324(3), c = 13.285(3) Å, α = 107.86(3), β = 102.28(3), γ = 109.24(3), and Z = 1. The crystal structure of the title compound is built up of discrete monomeric molecules of [Ni(Im)6](dtp)2. The nickel (II) ion is hexacoordinated by six imidazole molecules and the coordination environment of Ni (II) is of octahedral geometry. In the solid state, a network of N-H···S intermolecular hydrogen bonds connect the Ni(Im)6 moieties and O,O′-diphenyldithiophosphate molecules, forming a three-dimensional structure.
Silane Reduction of 5-Hydroxy-6-methyl-pyridine-3,4-dicarboxylic Acid Diethyl Ester: Synthesis of Vitamin B6
Authors: Dumond Yves  René , Gum Andrew  G.
Published: October 2008

Alternative methods for the synthesis of pyridoxine have been investigated. The key intermediate, 5-hydroxy-6-methyl-pyridine-3,4-dicarboxylic acid diethyl ester (5), was reduced with either a silane monomer (MeSiH(OEt)2) or a polysiloxane (polymethylhydrosiloxane, PMHS) to afford crude pyridoxine. An isolation technique utilizing a commercially available resin was devised, affording the desired product, vitamin B6, in an overall yield of 38-54 % and a purity of 76%.
A Carboxylic Acid from Ilex integra
Authors: Tori Motoo , Mukai Yoshie , Nakashima Katsuyuki , Sono Masakazu
Published: October 2008

(12E,14E,17E)-11-Hydroxy-12,14,17-dodecatrienoic acid was isolated from the stems of Ilex integra and its structure was determined on the basis of the spectroscopic data of its methyl ester.
Epoxidation of Diosgenin, 25(R)-1,4,6-Spirostatrien-3-one and 25(R)-4,6-Spirostadien-3β-ol
Authors: Ma Eunsook , Kim Jongwon
Published: October 2008

Upon treatment of 25(R)-spirost-5-en-3β-ol (diosgenin), 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with 30% H2O2 and 5% NaOH in methanol, diosgenin did not react, 25(R)-1,4,6-spirostatrien-3-one was converted to 25(R)-1α,2α-epoxy-4,6-spirostadien-3-one and 25(R)-4,6-spirostadien-3β-ol was oxidized to give a small amount of 25(R)-4,6-spirostadien-3-one, while most of the original starting material remained unchanged. On the other hand, reactions of diosgenin, 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with m-chloroperoxybenzoic acid in chloroform yielded 25(R)-5α,6α-epoxyspirostan-3β-ol, 25(R)-6α,7α-epoxy-1,4-spirostadien-3-one and 25(R)-4β,5β-epoxy-6-spirosten-3β-ol, respectively.
Synthesis and Characterization of Benzo-15-Crown-5 Ethers with Appended N2O Schiff Bases
Authors: Sousa Carla , Freire Cristina , De Castro Baltazar
Published: October 2008

New derivatives of benzo-15-crown-5 with flexible appended N2O unsymmetrical Schiff bases were prepared by a two step procedure which involves: (i) preparation of N2O Schiff bases by condensation of hydrazine with salicylaldehyde, 3-methoxysalicylaldehyde or 2-hydroxy-1-naphtaldehyde and (ii) reaction of the resulting NH2 functionalized compounds with 4-formyl-benzo-15-crown-5.
New Bioactive Azaartemisinin Derivatives
Authors: Al-Oqail Mai  M. , Galal Ahmed  M. , Ahmad Mohamed  S. , Al-Fishawi Ahlam  M. , El-Feraly Farouk  S.
Published: October 2008

Reaction of artemisinin (1) with ethanolamine, followed by acid treatment produced the lactam (4S,8S,9S,13S,1R,5R,12R)-11-aza-11-(2-hydroxyethyl)-1,5,9-trimethyl-14,15-dioxatetracyclo [10.2.1.0.0]pentadecan-10-one (4) and the diol (1S,2S,6S,7S,5R,8R)-4-aza-5,6-dihydroxy-4-(2-hydroxyethyl)-2,8-dimethyl-7-(3-oxobutyl) bicyclo[4.4.0]decan-3-one (7). When ethylenediamine was used instead of the ethanolamine, the dimeric lactam (1S,4S,8S,9S,13S,5R,12R)-11-[2-((1S,4S,8S,9S,13S,5R,12R)-11-aza-1,5,9-trimethyl-14,15-dioxa-10-oxotetracyclo[10.2.1.0.0] pentadec-11-yl)ethyl]-11-aza-1,5,9-tri-methyl-14,15-dioxatetracyclo-[10.2.1.0.0]-pentadecan-10-one (8) was obtained. All compounds are new azaartemisinin derivatives lacking the peroxide functionality. These compounds were evaluated for antimalarial and cytotoxic activities. Only the dimer 8 was found to possess antimalarial activity, while only the diol 7 exhibited cytotoxic activity against human breast ductal carcinoma.
2-Arylhydrazonopropanals as Building Blocks in Heterocyclic Chemistry: Microwave Assisted Condensation of 2-Arylhydrazonopropanals with Amines and Active Methylene Reagents
Authors: Al-Zaydi Khadijah  M. , Borik Rita  M. , Elnagdi Mohamed  H.
Published: October 2008

Utilization of 2-arylhydrazonopropanals for the synthesis of 2-arylhydrazonoimino propanones, 1,2,4-trizolo[4,3-a]pyrimidines, pyridopyridazine hydrazones, 3-oxaloalkanonitriles and 1,2,3-trizole derivatives by conventional heating and under microwave irradiation is described. Structural assignments are based on spectroscopic data and confirmed in some cases by X-ray crystallography.
Hexachloroacetone as a Precursor for a Tetrachloro-substituted Oxyallyl Intermediate: [4+3] Cycloaddition to Cyclic 1,3-Dienes
Authors: Föhlisch Baldur , Reiner Stefan
Published: October 2008

The enol phosphate 2,2-dichloro-1-(trichloromethyl)ethenyl diethyl phosphate (1), easily available by a Perkow reaction between hexachloroacetone and triethyl phosphite, reacts with sodium trifluoroethoxide/trifluoroethanol in the presence of cyclic 5-membered 1,3-dienes to furnish α,α,α',α'-tetrachloro-substituted[3.2.1]bicyclic ketones 2. A [4+3] cycloaddition of a tetrachloro-oxyallyl intermediate is postulated.
Reaction of Substituted Furan-2-carboxaldehydes and Furo[b]pyrrole Type Aldehydes with Hippuric Acid
Authors: Puterová Zita , Sterk Heinz , Krutošíková Alžbeta
Published: October 2008

4-Heteroarylidene-2-phenyl-1,3-oxazol-5(4H)-ones were prepared by reactions of hippuric acid with substituted furan-2-carboxaldehydes or furo[b]pyrrole type aldehydes. The reactivity of various furan-2-carboxaldehyde derivatives in this reaction is discussed. The effect of microwave irradiation on some condensation reactions was compared with “classical” conditions. The results show that microwave irradiation shortens the reaction times while affording comparable yields. Elementary analysis, UV, IR and 1D NMR proved the structure of new synthesised compounds. 2D NMR spectroscopic measurements confirmed that the configuration at the carbon-carbon double bond corresponds to the pure E isomers of the products.
Addition of Organochromium Reagents to Heteroaryl Aldehydes. Synthesis of Heteroaryl Substituted bis-Allyl Ethers and Homoallyl Ethers
Authors: Servi S. , Topaloglu C.
Published: October 2008

Heteroaryl substituted allyl and homoallyl alcohols were synthesised with two different method. Synthesis of bis-allyl ethers and homoallyl ethers were carried out via reaction of allyl bromide with allyl alcohols and homoallyl alcohols, respectively. [2.3]-Wittig Rearrangement reactions of heteroaryl substituted bis-allyl ethers were investigated using GC/MS techniques. In these reactions two unexpected products were isolated in high yield.
Synthesis and Antimicrobial Activity of Some New Sugar-Based Monocyclic β-Lactams
Authors: Jarrahpour A.  A. , Shekarriz M. , Taslimi A.
Published: October 2008

The syntheses of some new sugar-based monocyclic β-lactams possessing several other functionalities in addition to the carbohydrate moiety are described. The key step was the Staudinger [2+2] cycloaddition of chiral carbohydrate Schiff base 5 with phthalimidoacetyl chloride to yield the sugar-based monocyclic β-lactam 6 as a single isomer. Treatment of protected β-lactams 6 and 8 with methylhydrazine afforded the free amino β-lactams 9 and 10. Acylation of these free amino β-lactams with benzoyl, phenoxyacetyl, cinnamoyl and phenylacetyl chloride in the presence of pyridine afforded β-lactams 11a-d and 12a-d. Some of these novel β-lactams were found to be active against Staphilococcus citrus, Klebsiella pneumoniae, Escherichia coli and Bacillus subtilis.
Biologically Relevant Heterocyclic Compounds
Authors: Strekowski Lucjan
Published: October 2008

Heterocyclic chemistry is a rapidly growing branch of organic chemistry. [...]
Noncovalent Labeling of Biomolecules with Red and Near- Infrared Dyes
Authors: Patonay Gabor , Salon Jozef , Sowell John , Strekowski Lucjan
Published: October 2008

Biopolymers such as proteins and nucleic acids can be labeled with a fluorescent marker to allow for their detection. Covalent labeling is achieved by the reaction of an appropriately functionalized dye marker with a reactive group on a biomolecule. The recent trend, however, is the use of noncovalent labeling that results from strong hydrophobic and/or ionic interactions between the marker and biomolecule of interest. The main advantage of noncovalent labeling is that it affects the functional activity of the biomolecule to a lesser extent. The applications of luminescent cyanine and squarylium dyes are reviewed.
New Synthetic Routes to Furocoumarins and Their Analogs: A Review
Authors: Traven Valery F.
Published: October 2008

Many furocoumarins and their analogs possess a prominent photobiological activity. Some of them are successfully used as drugs in phototherapy of skin diseases. Fries rearrangement of acyloxyheteroarenes, condensation of acylhydroxyheteroarenes with α-carbonyl compounds under base catalysis and transformations of dihydrofurocoumarinones are new trends in synthesis of furocoumarins and their analogs.
Probing the Structure of DNA Aptamers with a Classic Heterocycle.
Authors: Wood IV Arthur E. , Bishop G. Reid
Published: October 2008

DNA aptamers are synthetic, single-stranded DNA oligonucleotides selectedby SELEX methods for their binding with specific ligands. Here we present ethidiumbinding results for three related DNA aptamers (PDB code: 1OLD, 1DB6, and 2ARG)that bind L-argininamide (L-Arm). The ligand bound form of each aptamer's structurehas been reported and each are found to be composed primarily of two domainsconsisting of a stem helical region and a loop domain that forms a binding pocket for thecognate ligand. Previous thermodynamic experiments demonstrated that the DNAaptamer 1OLD undergoes a large conformational ordering upon binding to L-Arm. Herewe extend those linkage binding studies by examining the binding of the heterocyclicintercalator ethidium to each of the three aptamers by fluorescence and absorptionspectrophotometric titrations. Our results reveal that ethidium binds to each aptamer with∆Go's in the range of -8.7 to -9.4 kcal/mol. The stoichiometry of binding is 2:1 for eachaptamer and is quantitatively diminished in the presence of L-Arm as is the overallfluorescence intensity of ethidium. Together, these results demonstrate that a portion ofthe bound ethidium is excluded from the aptamer in the presence of a saturating amountof L-Arm. These results demonstrate the utility of ethidium and related compounds forthe probing of non-conventional DNA structures and reveal an interesting fundamentalthermodynamic linkage in DNA aptamers. Results are discussed in the context of thethermodynamic stability and structure of each of the aptamers examined.
Synthesis, Molecular Structure and Reactivity of 5-Methylidene-1,2,3,5-tetrahydroimidazo[2,1-b]quinazolines
Authors: Kornicka Anita , Sączewski Franciszek , Gdaniec Maria
Published: October 2008

Synthesis of novel 5-methylidene-1,2,3,5-tetrahydro[2,1-b]-quinazolinederivatives 2-4 with potential biological activities mediated by α-adrenergic and/orimidazoline receptors was performed by reacting 2-chloro-4,5-dihydroimidazole (1) withthe corresponding 2-aminoacetophenones. Compound 2, which incorporates an enaminemoiety, underwent a 1,3-dipolar cycloaddition reaction with the appropriate nitrones 5-9to give 1,2,3,5-tetrahydro-imidazo[2,1-b]quinazolin-5,5'-spiro-2',3'-diphenylisoxazol-idines 10-14. Reactions of the title compounds 2 and 4 with dimethyl acetylene-dicarboxylate (DMAD) afforded dimethyl 2-(2,3-dihydroimidazo[2,1-b]quinazolin-5(1H)-ylidenemethyl)but-2-enedioates 15, 16. Imidazo[2,1-b]quinazoline 2 was furthertreated with acetyl chloride, benzoyl chloride and mesyl chloride to give the 1-substitutedderivatives 17, 18 and 19, respectively. The structures of all new compounds obtainedwere confirmed by elemental analysis and spectral data (IR, 1H- and 13C-NMR) as well asX-ray crystallographic analysis of 3 and 18.
Structure-Activity Relationships for the 9-(Pyridin-2’-yl)- aminoacridines
Authors: Mosher Michael D. , Holmes Kristi L. , Frost Katherine S.
Published: October 2008

A series of 9-(pyridin-2’-yl)-aminoacridines was prepared and analyzed for their ability to change the thermal denaturation temperature of genomic calf thymus DNA. Development of a QSAR equation indicated that electron withdrawing groups on the pyridine ring promoted the interaction with double stranded DNA.
Synthesis and Antitumor Activity of 5-Trifluoromethyl-2,4- dihydropyrazol-3-one Nucleosides
Authors: Abdou Ibrahim M. , Saleh Ayman M. , Zohdi Hussein F..
Published: October 2008

2,4-Dihydropyrazole glucosides 3a-3c were prepared and tested for theirantitumor activity. The structures of these compounds were established by 1H and 13C-NMR spectroscopy. Glucoside 3b shows an in vitro IC50 value of 16.4 μM againstproliferation of the human promyelotic leukemia (HL60) cell line.
Kinetics of the Epoxidation of Geraniol and Model Systems by Dimethyldioxirane
Authors: Baumstark A. L. , Franklin P. J. , Vasquez P. C. , Crow B. S.
Published: October 2008

The mono-epoxidation of geraniol by dimethyldioxirane was carried out invarious solvents. In all cases, the product ratios for the 2,3 and 6,7 mono-epoxides werein agreement with literature values. Kinetic studies were carried out at 23 oC in thefollowing dried solvent systems: acetone (k2 = 1.49 M-1s-1), carbon tetrachloride/acetone(9/1, k2=2.19 M-1s-1), and methanol/acetone (9/1, k2 = 17 M-1s-1). Individual k2 valueswere calculated for epoxidation of the 2,3 and 6,7 positions in geraniol. The non-conjugated diene system was modeled employing two simple independent alkenes:2-methyl-2-pentene and 3-methyl-2-buten-1-ol by determining the respective k2 valuesfor epoxidation in various solvents. The kinetic results for each independent alkeneshowed that the relative reactivity of the two epoxidation sites in geraniol as a function ofsolvent was not simply a summation of the independent alkene systems.
Unexpected Syntheses of seco-Cyclopropyltetrahydroquinolines >From a Radical 5-Exo-Trig Cyclization Reaction: Analogs of CC-1065 and the Duocarmycins
Authors: Pati Hari , Forrest Lori , Townes Heather , Lingerfelt Brian , McNulty LuAnne , Lee Moses
Published: October 2008

Analogs of the seco-cyclopyrroloindoline (seco-CPI), the DNA alkylation pharmacophore of CC-1065 and the duocarmycins, can be prepared through a 5-exo-trig radical cyclization of a free radical and a 3-chloro-2-allylic moiety. This manuscript reports an unexpected discovery that, depending on the structure and stability of the free radical, the cyclization process leads to the production of an appreciable amount of seco- cyclopropyltetrahydroquinolines 7a-d along with the seco-cyclopropoyltetra- hydroindoline products (6a-e). For instance, free radical reaction of the bromoallylic chloride 5a produced an equal amount of 6-benzyloxy-N-t-butoxycarbonyl-3- (chloromethyl)furano[e]indoline (6a), and 7-benzyloxy-N-t-butoxycarbonyl-3-chloro- 1,2,3,4-tetrahydrofurano[f]quinoline (7a). Three other examples that produced mixtures of indoline and quinoline products are provided. In only one of the examples reported in this manuscript, the 6-benzyloxy-N-t-butoxycarbonyl-3-(chloromethyl)benzo[e]indoline, was a seco-CBI precursor 6e formed exclusively, consistent with literature precedents.
Lipid-Lowering Effects of Ethyl 2-Phenacyl-3-aryl-1H-pyrrole- 4-carboxylates in Rodents
Authors: Holub Justin M. , O'Toole-Colin Kathy , Getzel Adam , Argenti Anthony , Evans Michael A. , Smith Daniel C. , Dalglish Gerard A. , Rifat Shahzad , Wilson Donna L. , Taylor Brett M. , Miott Ulander , Glersaye Josephine , Lam Kam Suet , McCranor Bryan J. , Berkowitz Joshua D. , Miller Robert B. , Lukens John R. , Krumpe Keith , Gupton John T. , Burnham Bruce S.
Published: October 2008

A series of substituted 2-phenacyl-3-phenyl-1H-pyrrole-4-carboxylates were prepared from substituted acetophenones in 6 steps. The final condensations between a chloroenal and an aminoketone were carried out under neutral conditions in parallel to yield the series listed below. Selected pyrrole derivatives proved to be potent hypolipidemic agents lowering serum triglyceride concentrations in CF-1 male mice after 14 days of I.P. administration. One agent orally lowered serum cholesterol in Sprague-Dawley male rats at 2mg/kg/day after 14 days. The agents demonstrated a lowering of mouse serum LDL- cholesterol levels and selected compounds showed an elevation of serum HDL-cholesterol levels. The cholesterol concentrations in the liver were raised while the cholesterol and triglyceride contents of the aorta were significantly lowered by the selected trisubstituted pyrrole.
The Synthesis of Dicationic Extended Bis-Benzimidazoles
Authors: Kang Zhijan , Dykstra Christine C. , Boykin David W.
Published: October 2008

The synthesis of extended dicationic bis-benzimidazoles starting from trans-1,2-bis(4-cyanophenyl)ethene and trans-1,2-bis(4-cyanophenyl)cyclopropane is reported. The target diamidines show significant in vitro activity against B. subtilis.
Phenoxydifluoromethyl Substituted Nitrogen Heterocycles. Synthesis and Heterocyclization Reactions of Ethyl 4,4-Difluoro- 4-phenoxyacetoacetate
Authors: Solodukhin S. Yu. , Peregudov A. S. , Vorontsov E. V. , Chkanikov N. D.
Published: October 2008

Ethyl 4,4-difluoro-4-phenoxyacetoacetate was obtained and studied as a precursor to new heterocyclic compounds. 6-Hydroxypyrimidine, 1,3-dihydro-1,5- benzodiazepin-2-one, quinolin-2-one and 6-hydroxypyrazolo[3,4-b]pyridine derivatives containing phenoxydifluoromethyl groups were synthesized. These results make it possible to introduce aryloxydifluoromethyl substituents for the design of biologically active heterocycles.
New Imide 5-HT1A Receptor Ligands – Modification of Terminal Fragment Geometry
Authors: Bojarski Andrzej J. , Mokrosz Maria J. , Duszyńska Beata , Kozioł Aneta , Bugno Ryszard
Published: October 2008

Two sets of new o-methoxyphenylpiperazine (MPP; series a) and 1,2,3,4-tetrahydroisoquinoline (THIQ; series b) derivatives, containing various imide moietiesderived from NAN190, were synthesized and evaluated in vitro for their ability to bind tothe serotonin 5-HT1A and 5-HT2A receptors. All new derivatives from series a demonstratedhigh 5-HT1A affinities, whereas THIQ analogues were much less active. With respect to5-HT2A receptors, three MPP derivatives presented moderate activity but the rest of theinvestigated compounds were practically inactive. The influence of changes in terminusgeometry on 5-HT1A receptor affinity was analyzed in regard to model compounds NAN190and MM199.
Biaryl Product Formation from Cross-coupling in Palladiumcatalyzed Borylation of a Boc Protected Aminobromoquinoline Compound
Authors: Fang Hao , Yan Jun , Wang Binghe
Published: October 2008

The palladium catalyzed borylation of a Boc protected aminobromoquinoline compound with bis(pinacolato)diboron yielded a biaryl compound, resulting from cross coupling, as the major product, instead of the intended boronate, even though no strong base was used. Such results indicate that under certain conditions and with certain substrates, cross coupling can be a major problem during borylation, leading to unintended consequences.
Mechanism-based Enzyme Inactivators of Phytosterol Biosynthesis
Authors: Zhou Wenxu , Song Zhihong , Kanagasabai Ragu , Liu Jialin , Jayasimha Pruthvi , Sinha Archana , Veeramachanemi Phani , Miller Mathew  B. , Nes W. David
Published: October 2008

Current progress on the mechanism and substrate recognition by sterol methyl transferase (SMT), the role of mechanism-based inactivators, other inhibitors of SMT action to probe catalysis and phytosterol synthesis is reported. SMT is a membrane-bound enzyme which catalyzes the coupled C-methylation-deprotonation reaction of sterol acceptor molecules generating the 24-alkyl sterol side chains of fungal ergosterol and plant sitosterol. This C-methylation step can be rate-limiting in the post-lanosterol (fungal) or post-cycloartenol (plant) pathways. A series of sterol analogs designed to impair SMT activity irreversibly have provided deep insight into the C-methylation reaction and topography of the SMT active site and as reviewed provide leads for the development of antifungal agents.