bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Precursors for the Oxidative Tandem Cyclization of Diphenols to Galanthamine Analogs
Authors: Treu Matthias , Jordis Ulrich
Published: October 2008

Methods for the preparation of 4-bromo-5-[2-(4-hydroxybenzyl)benzyl]-2-methoxyphenol and 4-bromo-5-[4-(4-hydroxyphenyl)butyl]-2-methoxyphenol are described.
Fractal Hybrid Orbitals Analysis of the Tertiary Structure of Protein Molecules
Authors: Torrens Francisco
Published: October 2008

The structure and shape of the polypeptide chains of proteins are determined by the hybridized states of the atomic orbitals in the molecular chain. The calculated s ratio in the spn hybrid orbitals is computed from the fractal dimension D of the tertiary structures of 43 proteins selected to cover the five structural classes of protein molecules. A brief introduction to fractal theory is given in the text. It is demonstrated that the principles dictating the folding of the local and global backbone structures are well characterized in terms of the representation given by fractal theory. Comparison of the fractal character of protein molecules with that of the ideal Gaussian chain revealed several features of these principles. It is also shown that proteins in the β type structural class are distinguished quantitatively from those in other classes with this representation. They show a higher s ratio (0.32) in sp2.20 hybrids, rather similar to planar sp2. Comparison of the proteins with a Gaussian chain is interpreted in terms of steric repulsion.
Thirteen New Xanthone Derivatives from Calophyllum caledonicum (Clusiaceae)
Authors: Morel Cécile , Hay Anne-Emmanuelle , Litaudon Marc , Sévenet Thierry , Séraphin Denis , Bruneton Jean , Richomme Pascal
Published: October 2008

An EtOAc extract of the stem bark of Calophyllum caledonicum (Clusiaceae) yielded thirteen new hydroxylated and/or prenylated xanthone derivatives, namely 5-hydroxy-8-methoxyxanthone (1), 3,5-dihydroxy-1,2-dimethoxyxanthone (2), 1,8-dihydroxy-6,7-dimethoxyxanthone (3), 5,7-dihydroxy-2,6-dimethoxyxanthone (4), 6,8-dihydroxy-3,7-dimethoxy-xanthone (5), 2,5,6,7,8-pentahydroxyxanthone (6), 1,3,8-trihydroxy-5,7-dimethoxyxanthone (7) and according to a previously adopted nomenclature [3], caledonixanthone G-L. (8-13). The structural elucidation of 1-13 were mainly established on the basis of 1D and 2D NMR and HRMS spectroscopic analysis.
Virtual Screening in Lead Discovery: A Viewpoint
Authors: Oprea Tudor  Ionel
Published: October 2008

Virtual screening (VS) methods have emerged as an adaptive response to massive throughput synthesis and screening technologies. Based on the structure-permeability paradigm, the Lipinski rule of five has become a standard property filtering protocol for VS. Three possible VS scenarios with respect to optimising binding affinity and pharmacokinetic properties are discussed. The parsimony principle for selecting candidate leads for further optimisation is advocated.
ElectronTransfer Induced Ring Opening of α-Epoxyketones: Spirodioxolane Formation
Authors: Memarian Hamid  R. , Nikpour Farzad
Published: October 2008

Stereospecific formation of spirodioxolanes has been observed on electron transfer induced ring opening of α-epoxyketones by 2,4,6-triphenylpyrylium tetrafluoroborate in the presence of cyclohexanone
Lithium Perchlorate Mediated Three-Component Preparation of Primary Aminoesters
Authors: Saidi Mohammad  R. , Azizi Najmoddin
Published: October 2008

A three-component reaction between an aldehyde, metallated hexamethyldisilazane and a functionalized organozinc compound proceeded smoothly in the presence of LiClO4 in diethyl ether to afford primary amino esters in good yields.
New Phenylpropanoid Glucosides from Eucalyptus maculata
Authors: Rashwan Omar  A.
Published: October 2008

Three compounds were isolated from the butanol soluble fraction of the resinous exudate from the stem of Eucalyptus maculata. In addition to p-coumaric acid two new compounds were identified. They were identified as 1-O-cinnamoyl 6-O-pcoumaroylglucose and 7-methyl-aromadendrin-4′-O-(6′′-trans-p-coumaroyl)-β-D-glucopyranoside by spectroscopic and chemical means.
The Behaviour of 1,2,3-Indantrione Towards Wittig-Horner Reagents
Authors: Abd El-Rahman N. M. , Boulos L. S.
Published: October 2008

Wittig-Horner reagents 1a,b react with 1,2,3-indantrione (2) to give the dimeric adducts 3a and 3b, respectively. Moreover, 2 reacts with tert-butyl diethylphosphonoacetate (1c) yielding the ethylenic compound 4. On the other hand, 2 reacts with 1d to yield the phosphonate adduct 5. Mechanisms accounting for the formation of the new products are discussed and the probable structures of the products are presented based on compatible analytical and spectral data.
Three-Component Halo Aldol Condensation of Thioacrylates with Aldehydes Mediated by Titanium (IV) Halide
Authors: Kim Sun  Hee , Wei Han-Xun , Gao Joe  J. , Li Guigen
Published: October 2008

a,b-Ethyl thioacrylate was difuctionalized by a tandem X-C/C=C bond formation reaction. The new system uses Ti (IV) halide as both the Lewis acidic promoter and the halogen source for the Michael-type addition onto the thioacrylate. The titanium enolate species resulting from Michael-type addition react with aldehydes followed by dehydration to afford trisubstituted olefin products. Complete geometric selectivity (>95%) and up to 72% yield have been obtained for 7 examples.
Synthesis of Heterocyclic Skeletons by the Reaction of N1-(2-Cyanophenyl)-benzimidoyl Chloride with Thioamides
Authors: Fathalla Walid  M. , Pazdera Pavel
Published: October 2008

The reaction of N-(2-cyanophenyl)benzimidoyl chloride with reagents containing a thioamide moiety, i.e. thioacetamide, benzylthiourea, symmetrical dialkyl- and diarylthioureas gave different cyclic products: 3,1-benzothiazine, 1,3,5-benzotriazocine and quinazoline. The reaction pathways of prepared compounds are discussed.
An Investigation of the Reactions of Substituted Homoallylic Alcohols with Various Oxidation Reagents
Authors: Servi S. , Acar A.
Published: October 2008

Substituted homoallylic alcohols have been synthesised both by [2,3]-Wittig rearrangement of unsymmetrical bis-allylic ethers and reaction of alkenyl chloromethyl oxiranes with Mg/THF. These substrates were then oxidized using four different oxidants. When the substituted homoallylic alcohols were oxidized with pyridinium chlorochromate or zinc chlorochromate nonahydrate the corresponding carbonyl compounds were produced. The same substrates formed the corresponding allylic oxidation products together with epoxidation products when oxidized with t-BuOOH. When and t-BuOOH and catalytic amounts of OsO4 were used the allylic oxidation reaction was prevented and the only products formed were those in which the substituted double bond was epoxidized.
Photooxygenation of Nimonol, a Tetranortriterpenoid from Azadirachta indica. A. Juss.
Authors: Gopalakrishnan Geetha , Pradeep Singh N.  D. , Kasinath V.
Published: October 2008

Nimonol (1), a tetranortriterpenoid isolated from the leaves of Azadirachta indica A. Juss (Meliaceae), upon photolysis undergoes both Diels-Alder and ene reactions with singlet oxygen at different sites leading to 14,15,20,21-diepoxy-23-nimonolactone (3), along with nimonolide (4), which have been well-characterised. The novelty of the reported reactions lies in hitherto unreported formation of an α-epoxide in the ring D in tetranortriterpenoids. The photoproduct 4 exhibited antifeedancy comparable to that of azadirachtin-A, the most potent antifeedant constituent isolated from neem.
Cyclization of N-(3-Oxoalkyl)chloroacetamides Under Basic Conditions. Synthesis of cis-3,4-Epoxypiperidin-2-ones
Authors: Fisyuk Alexander  S. , Poendaev Nikolai  V.
Published: October 2008

It has been shown that N-(3-oxoalkyl)chloroacetamides (1) can be converted into cis-3,4-epoxypiridin-2-ones (2) upon treatment with t-BuOK in a t-BuOH-C6H6 solution due to a resulting intramolecular Darzens reaction. It has been found that under kinetically controlled reaction conditions (NaOH/C6H6), besides the intramolecular Darzens reaction an intramolecular alkylation takes place.
Synthesis of 5,6-Dihydropyridin-2(1H)-ones, 1,5,6,8,8a-Hexahydroisoquinolin-3(2H)-ones and 4a,5,6,7,8,8a-Hexahydroquinolin-2(1H)-ones by Intramolecular Wittig Reaction
Authors: Fisyuk Alexander  S. , Poendaev Nikolai  V.
Published: October 2008

A new, universal and diastereospecific method has been developed for the synthesis of 5,6-dihydropyridin-2(1H)-ones, 1,5,6,8,8a-hexahydroisoquinolin-3(2H)-ones and 4a,5,6,7,8,8ahexahydroquinolin-2(1H)-ones (4) based on the intramolecular Wittig cyclization of the triphenyphosphonium salts 2 derived from the N-(3-oxoalkyl)–chloroacetamides 1.
An Improved Three Step Synthesis of (-)-3β-Hydroxycarvone from (-)-Carvone
Authors: Dos Santos Reginaldo  B. , Brocksom Timothy  J. , Zanotto Paulo R. , Brocksom Ursula
Published: October 2008

(-)-Carvone (3) has been efficiently transformed into (-)-3β-hydroxycarvone (1), which is expected to be a useful synthon or chiral template in the synthesis of natural molecules. This short and efficient synthesis of compound 1 involves regioselective and stereoselective α-hydroxylation of carvone via the trimethylsilyl-dienyl-ether derivative.
Silica gel Catalyzed Synthesis of Quinophthalone Pigments Under Solvent-Free Conditions Using Microwave Irradiation
Authors: Loghmani-Khouzani Hossein , Sadeghi Majid  M. , Safari J.
Published: October 2008

Condensations of anhydrides and quinaldine derivatives are accelerated by microwave irradiation under solvent free conditions in the presence of silica gel as catalyst.
Synthesis of Two Potentially Heptadentate (N4O3) Schiff-base Ligands Derived from Condensation of Tris(3-aminopropyl)-amine and Salicylaldehyde or 4-Hydroxysalicylaldehyde. Nickel(II) and Copper(II) Complexes of the Former Ligand
Authors: Keypour Hassan , Salehzadeh Sadegh , Parish R.  V.
Published: October 2008

Two potentially heptadentate (N4O3) tripodal Schiff-base ligands: tris(3-(salicylideneimino)propyl)amine (H3L1) and tris(3-(4’-hydroxysalicylideneimino)-propyl)amine (H3L2) have been prepared and characterized by various spectroscopic methods (IR, FAB-MS, NMR). They are derived from the condensation reactions of tris(3-aminopropyl)amine (tpt), with 3 equivalents of either salicylaldehyde or the ringsubstituted salicylaldehyde, 4-hydroxysalicylaldehyde. The nickel(II) and copper(II) complexes of H3L1 were obtained from the its reactions Ni(II) and Cu(II) salts in absolute methanol. These complexes were studied by IR and FAB-Mass spectrometry.
Synthesis of Thieno[2,3-d]-1,3-dithiol-2-thiones from Thieno[2,3-d]-1,2,3-thiadiazoles: Matryoshka-type autoclave for high-temperature, high-pressure thermolysis microscale reactions
Authors: Jordis Ulrich , Bhattacharya Kaberi , Boamah Philip  Y. , Lee Ving  J.
Published: October 2008

Thieno[2,3-d]-1,2,3-thiadiazoles (1) react with carbon disulfide in a "Matryoshkatype" double compartment autoclave [1] to yield thieno[2,3-d]-1,3-dithiol-2-thiones (2). With BH3/Me2S the cyclic trithiocarbonate (2d) is cleaved and the product characterized after methylation as 4b. Compounds 7a and 7b are prepared via the thieno[2,3-d]-1,3-dithiolium salts (6) followed by NaBH4-reduction.
Synthesis and Reactions of Acenaphthenequinones-Part-2. The Reactions of Acenaphthenequinones
Authors: El Ashry El Sayed H. , Hamid Hamida Abdel , Kassem Ahmed A. , Shoukry Mahmoud
Published: October 2008

The reactions of acenaphthenequinone and its derivatives with different nucleophiles, organic and inorganic reagents are reviewed. This survey also covers their oxidation and reduction reactions, in addition to many known reactions such as Friedel Crafts, Diels-Alder, bromination and thiolation.
Functionalization of Phenyl Rings by Imidoylnitrenes. 3 The Effects of Resonance, Steric, and Inductive Properties on the Reactivity or Selectivity of Nitrenes and the Stability of their Precursors
Authors: Dabbagh Hossein  A. , Karimzadeh Reza
Published: October 2008

The thermal decomposition of imidoyl azides (ArO-C=N-Z)-N3, (Ar = p-NO2-C6H4-, p-Br-C6H4-, p-Cl-C6H4-, p-C6H5-, p-CH3-C6H4-, 2,4-dimethyl-C6H3-, 2,4,6-trimethyl-C6H2-, p-CH3O-C6H4- and Z = p-CH3-C6H4-SO2-, 2,4,6-trimethyl-C6H2-SO2-,CN) in the solid phase and in anisole has been studied in detail. The sensitivity of nitrenes and nitrene precursors (imidoyl azides) towards substitution changes in the aryloxy (ArO) and Z moieties is examined.
Synthesis of Substituted Phenyl N-(2-hydroxybenzyl)-N-Methylcarbamates
Authors: Hrabík Oldřich , Šimůnek Petr , Mindl Jaromír , Kaválek Jaromír
Published: October 2008

Thirteen previously unreported substituted phenyl N-(2-hydroxybenzyl)-Nmethylcarbamates were prepared by the reaction of substituted 2-hydroxybenzyl-Nmethylamines with phenyl chlorocarbonates. They were identified by their 1H- and 13C-NMR spectra.
marvin: A Platform for Chemoinformatics Software Development
Authors: Dominik A. , Roth H.  J.
Published: October 2008

A strategy for a new type of platform for chemoinformatics software development and its first implementation are presented. The basic task of such a platform is to apply sequences of computational methods to high numbers of molecules. The implementation presented is based on four major components: (a) the application manager, responsible for running programs and for data management; (b) executable applications that supply limited pieces of functionality; (c) syntax definitions for data and control files and (d) the runtime library which comprises routines for data handling and user interface. This simple concept is implemented in the software package marvin. Different computational methods are available within marvin, including parts of commercial software packages (e.g. molecular modeling, bioinformatics, statistics, etc.) as well as newly developed and innovative algorithms. The basic layout of marvin is described and a simple example illustrates its application.
Synthesis of Some Aldoxime Derivatives of 4H-Pyran-4-ones
Authors: Abrishami Fateme , Teimuri-Mofrad Reza , Bayat Yadollah , Shahrisa Aziz
Published: October 2008

Aldoxime derivatives of 4H-pyran-4-ones 4-7a,b have been synthesized by the reaction of di(aminoxymethyl) pyranones 3a,b with aromatic aldehydes.
An Acylated Kaempferol Glycoside from Flowers of Foeniculum vulgare and F. Dulce
Authors: Soliman Fathy  M. , Shehata Afaf  H. , Khaleel Amal  E. , Ezzat Shahera  M.
Published: October 2008

An acylated kaempferol glycoside, namely kaempferol-3-O-α-L-(2,3-di-E-pcoumaroyl)-rhamnoside (1) was isolated from the flowers of Foeniculum vulgare Mill. and F. dulce DC. It is thus isolated for the first time from family Apiaceae. In addition, the different organs of both plants afforded six flavonoid glycosides - namely afzelin (kaempferol-3-O-α-L-rhamnoside) (2), quercitrin (3), isorhamnetin-3-O-β-D-glucoside (4), isoquercitrin (5), rutin (6), and miquelianin (quercetin-3-O-β-D-glucuronide) (7). Structure elucidation of the above mentioned flavonoids was achieved by UV, 1H- and 13C-NMR, 1H-1H COSY, HMQC and EI-MS.
Reactivity of 3-Ethoxycarbonyl Isoquinolinium Salts Towards Various Nucleophilic Reagents: Applications to the Synthesis of New 1,2-Dihydroisoquinoline-3-carboxylates
Authors: Meziane Mohamed   Ameziane Aït Amer , Bazureau Jean  Pierre
Published: October 2008

Different types of novel 1,2-disubstituted 1,2-dihydro isoquinolines were synthesized by addition reactions of organolithium, alcoholates and borohydride reagents with various isoquinolinium salts. The leaving group character of the isoquinoline moiety was also evidenced.
Mn (Br8TPPS) Supported on Amberlite IRA-400 as a Robust and Efficient Catalyst for Alkene Epoxidation and Alkane Hydroxylation
Authors: Tangestaninejad S. , Habibi M.  H. , Mirkhani V. , Moghadam M.
Published: October 2008

Manganese (III) meso-tetrakis(p-sulfonatophenyl)-β-octabromoporphyrin supported on Amberlite IRA-400 [Mn(Br8TPPS)-Ad-400] is a robust and efficient catalyst for epoxidation of alkenes and hydroxylation of alkanes with sodium periodate at room temperature.
Chemistry of the Genus Plectranthus
Authors: Abdel-Mogib M. , Albar H. A. , Batterjee S. M.
Published: October 2008

This review presents the phytochemical constituents of the genus Plectranthus reported up to 1999. Only a tetrameric derivative of caffeic acid was isolated from P. japonicus, but a group of long-chain alkylphenols, of possible taxonomic significance in the genus, was also isolated. As a genus of the subfamily Nepetoideae, Plectranthus is free from iridoid glycosides and rich in essential oil (i.e. > 0.5% volatile oil on a dry weight basis). Diterpenoids are the more common secondary metabolites in Plectranthus. The majority of them are highly modified abietanoids. This seems to be similar to the pattern of diterpenoids observed for Salvia, but no clerodane diterpenoids were found in Plectranthus.
1,3-Dipolar Cycloaddition Reactions of Substituted Benzyl Azides with Acetylenic Compounds
Authors: Abu-Orabi Sultan  T.
Published: October 2008

We review in this article some of our work which has been published over the last fifteen years in the area of 1,3-dipolar cycloaddition reactions of substituted benzyl azides with acetylenic compounds to form the corresponding 1,2-3-triazoles. Several triazole derivatives were transformed into triazolopyridazine and triazolo-1,3,4-oxadiazole derivatives upon their reactions with hydrazine.
Synthesis of 6-Methoxy-1-oxaspiro[4,5]deca-6,9-diene-8-one
Authors: Plourde Guy L. , Fisher Benjamin  B.
Published: October 2008

The synthesis of a new spirolactone is described. The title compound is obtained as a white solid in 46% yield from 3-(4-hydroxy-2-methoxyphenyl)propanoic acid using [Bis(trifluoroacetoxy)iodo]benzene (PIFA) as the oxidant.
Synthesis and Spectroscopic Characterisation of N-Alkyl Quaternary Ammonium Salts Typical Precursors of Cyanines
Authors: Pardal A.  C. , Ramos S.  S. , Santos P.  F. , Reis L.  V. , Almeida P.
Published: October 2008

The synthesis and spectroscopic characterisation of some representative N-alkylsubstituted quaternary ammonium salts derived from benzothiazole, benzoxazole, benzoselenazole, indole and quinoline are described. These heterocyclic salts, bearing an activated methyl group in the 2-position in relation to the nitrogen atom and N-methyl, -pentyl, -hexyl and -decyl chains, are typical precursors of cyanine dyes.
Correlation between Phenylphenalenone Phytoalexins and Phytopathological Properties in Musa and the Role of a Dihydrophenylphenalene Triol
Authors: Otálvaro Felipe , Echeverri Fernando , Quiñones Winston , Torres Fernando , Schneider Bernd
Published: October 2008

A correlation has been established between production of specific phenylphenalenones and resistance of various banana and plantain varieties towards certain pathogens. In addition a dihydrotrihydroxyphenylphenalene was isolated from the resistant 'Pelipita' plantain variety in relatively high concentrations and its structure and relative configuration were assigned on the basis of 1D and 2D NMR and NOE information. This compound is considered a key intermediate in the biosynthesis of phenylphenalenone phytoalexins.
Synthesis and Rearrangement of 3-Methyl-1,4-pentadiyne-3-ol
Authors: Buser Dominik , Pauling Horst , Thum Andreas , Bonrath Werner
Published: October 2008

An efficient synthesis and rearrangement of 3-methyl-1,4-pentadiyne-3-ol (1) using perrhenate- and Mo(VI)-catalysts is reported. The by-products 3,6-dimethyl-1,4,7-octatriyne-3,6-diol (2) and 3-ethynyl-5-methyl-1,6-heptadiyne-3,5-diol (3) were isolated and spectroscopically characterized. A possible reaction mechanism for the formation of the byproducts is discussed.
Synthesis of 2,3-Dimethoxy-7-methyl-7,12-dihydro-6H-[1]-benzofuro-[2,3-c]-[1]-benzazepin-6,12-dione
Authors: Jackson Yvette  A. , Marriott Karla-Sue  C.
Published: October 2008

Treatment of 5,6-dimethoxy-2-(methylphenylcarbamoyl)-benzofuran-3-carboxylic acid with PPA yielded 2,3-dimethoxy-7-methyl-7,12-dihydro-6H-[1]-benzofuro-[2,3-c]-[1]-benzazepin-6,12-dione. The analogous 2-[(5,6-dimethoxybenzofuran-2-carbonyl)methylamino]benzoic acid was resistant to cyclization, whereas 2-[(6-methoxybenzofuran-2-carbonyl)-amino]benzoic acid underwent cyclization to the corresponding 3,1-benzoxazin-4-one.
Substituted Amides of Pyrazine-2-carboxylic acids: Synthesis and Biological Activity
Authors: Dolezal Martin , Miletin Miroslav , Kunes Jiri , Kralova Katarina
Published: October 2008

Condensation of 6-chloro-, 5-tert-butyl- or 6-chloro-5-tert-butylpyrazine-2-carboxylic acid chloride with ring substituted anilines yielded a series of amides, which were tested for their in vitro antimycobacterial, antifungal and photosynthesis-inhibiting activities. The highest antituberculotic activity (72% inhibition) against Mycobacterium tuberculosis and the highest lipophilicity (log P = 6.85) were shown by the 3,5-bistrifluoromethylphenyl amide of 5-tert-butyl-6-chloropyrazine-2-carboxylic acid (2o). The 3-methylphenyl amides of 6-chloro- and 5-tert-butyl-6-chloro-pyrazine-2-carboxylic acid (2d and 2f) exhibited only a poor in vitro antifungal effect (MIC = 31.25-500 μmol·dm-3) against all strains tested, although the latter was the most active antialgal compound (IC50 = 0.063 mmol·dm-3). The most active inhibitor of oxygen evolution rate in spinach chloroplasts was the (3,5-bis-trifluoromethylphenyl)amide of 6-chloropyrazine-2-carboxylic acid (2m, IC50 = 0.026 mmol·dm-3).
4a,5,9,10,11,12-Hexahydro-6H-benzo[a]cyclohepta[hi]benzofuran - Synthesis of Unnatural Galanthamine Analogs
Authors: Treu Matthias , Jordis Ulrich
Published: October 2008

The synthesis of an unnatural galanthamine analog is reported
Synthesis of New Active Sulfones in the 5-Nitroimidazole Series
Authors: Benakli Kamel , Terme Thierry , Vanelle Patrice
Published: October 2008

We describe here the preparation of new 5-nitroimidazoles which are known to have an efficacy against metronidazole-susceptible and -resistant Giarda, Trichomonas, and Entamoeba spp. The multi-step synthesis uses electron transfer methodology.
Synthesis of Mixed Carbonates via a Three-Component Coupling of Alcohols, CO2, and Alkyl Halides in the Presence of K2CO3 and Tetrabutylammonium Iodide
Authors: Shi Min , Shen Yu-Mei
Published: October 2008

Various mixed carbonates can be conveniently prepared in good yields using the corresponding alcohols, alkyl halides under CO2 atmosphere in the presence of potassium carbonate or sodium carbonate and tetrabutylammonium iodide.
Synthesis of New Lipophilic Phosphonate and Phosphonamidate Analogues of N-Acetylmuramyl-L-alanyl-D-isoglutamine Related to LK 423
Authors: Gobec Stanislav , Urleb Uroš
Published: October 2008

A syntheses of three new muramyl dipeptide (MDP) analogues related to LK 423 as potential immunomodulators are presented. The dipeptide part of the lead compound was modified by introducing a phosphonamide isostere instead of the amide bond between Lalanine and D-glutamic acid (or D-isoglutamine), yielding new MDP analogues 5 and 9. Furthermore, the amide bond between L-Ala and D-Glu was replaced by a phosphonate isostere, giving peptidyl phosphonate 14. The scope and limitations of the synthetic strategies employed are discussed.
Synthesis of Platinum Complexes from N-Benzyl-1,3-Propanediamine Derivatives, Potential Antineoplastic Agents
Authors: De Almeida Mauro  Vieira , Fontes Ana  Paula Soares , Berg Richard  Nilton , César Eloi  Teixeira , De Castro Antunes Felício Emanoel , De Souza Filho José  Dias
Published: October 2008

This work describes the synthesis of seven new platinum complexes having Nbenzyl 1,3-propanediamine derivatives as ligands. They were prepared by the reaction of K2[PtCl4] with the appropriate ligand in water. These complexes are analogs of cisplatin, and are potential antineoplastic agents.
Microwave Assisted Regioselective Bromomethoxylation of Alkenes Using Polymer Supported Bromine Resins
Authors: Gopalakrishnan Geetha , Kasinath Viswanathan , Pradeep Singh N. D. , Santhana Krishnan V. P. , Solomon K. Anand , Rajan S. S.
Published: October 2008

A facile regio- and chemoselective bromomethoxylation of alkenes under microwave irradiation conditions employing a new polymer supported brominechloride resin is reported. The resin is prepared from the commercially available chloride resin by a simple one step procedure.
Regio- and Stereoselective [2+2] Photodimerization of 3-Substituted 2-Alkoxy-2-oxo-2H-1,2-benzoxaphosphorines
Authors: Nikolova Rositca D. , Vayssilov G. N. , Rodios Nestor , Bojilova Anka
Published: October 2008

Diethyl 1,2-benzoxaphosphorine-3-carboxylates 5 undergo a regio- and stereoselective [2+2] photodimerization reaction in methanol solution under the action of sunlight, giving in all cases the corresponding anti head-to-tail dimers 6 and 7. Concerning the stereogenic P atom, the photodimerization is also stereoselective, and the centrosymmetric stereoisomer 6 predominates over the non symmetric P-epimer 7.
A New Palladium-Catalyzed Phenyl-Alkene Bond Formation
Authors: Schmor Brad , Roy René
Published: October 2008

A new method of palladium-catalyzed phenyl-alkene bond formation is reported. This reaction involves transfer of all three phenyl groups from triphenylantimony onto alkenes containing allylic protons.
Synthesis, Crystal Structure, and Conformation of Methyl 5-Oacetyl-5-cyano-6-deoxy-2,3-O-isopropylidene-β-L-gulofuranoside
Authors: Mičová Júlia , Steiner Bohumil , Koóš Miroslav , Gajdoš Ján , Langer Vratislav , Gyepesová Dalma
Published: October 2008

Methyl 5-O-acetyl-5-cyano-6-deoxy-2,3-O-isopropylidene-β-L-gulofuranoside was prepared in high yield from methyl 6-deoxy-2,3-O-isopropylidene-α-D-lyxopentodialdo-1,4-furanoside. The configuration at the C5 atom was unambiguosly established by single crystal X-ray analysis of the corresponding 5-O-acetyl derivative. The conformation of the furanose and 1,3-dioxolane rings is also discussed.
Synthesis of “Acetylene-Expanded” Tridentate Ligands
Authors: Holmes Brian  T. , Pennington William  T. , Hanks T. W.
Published: October 2008

Synthetic routes to four new tridentate ligands with large cavities have been developed. Each ligand features two halides at the termini of the molecules that could be used for further elaboration of the system. Such compounds are ideal for encapsulating organoiodide guests using charge-transfer interactions.
Niobium Pentachloride Activation of Enone Derivatives: Diels-Alder and Conjugate Addition Products
Authors: Constantino Mauricio Gomes , Júnior Valdemar Lacerda , Da Silva Gil Valdo José
Published: October 2008

Niobium pentachloride has proven to be a powerful activating agent for Diels-Alder or conjugate addition reactions of cycloenones. The Diels-Alder product was obtained only with an unsubstituted enone (cyclohexenone) and the highly reactive diene cyclopentadiene; substituents in the b-position of enones seem to prevent Diels-Alder reaction: oxygenated substituents favor the formation of vinyl chlorides (ethyl ether or dichloromethane as solvents) or enol ethers (ethyl acetate as solvent), while a methyl substituent prevents any kind of transformation with NbCl5. Less reactive dienes, furan and 2-methylfuran gave the conjugate addition products of the furan ring to the enone system.
Microwave Assisted Facile Cleavage of 2,4-Dinitrophenylhydrazones to the Corresponding Carbonyl Compounds with N,N′-Dibromo-N,N′-1,2-ethanediylbis(p-toluenesulphonamide)
Authors: Khazaei Ardeshir , Vaghei Ramin  Ghorbani
Published: October 2008

Deprotections of 2,4-dinitrophenylhydrazones to their corresponding carbonyl compounds have been carried out in good yields by using N,N′-dibromo-N,N′-1,2-ethanediylbis(p-toluenesulphonamide) (BNBTS, 2) under microwave irradiation.
Toward a Library Synthesis of the Natural Dipeptide Antibiotic TAN 1057 A,B
Authors: Aguilar Nuria , Krüger Jochen
Published: October 2008

The natural dipeptide antibiotic TAN 1057 A,B represents a promising new antibiotic entity. In this communication we report a novel approach for the synthesis of TAN 1057 A,B analogs bearing variations in the β-arginine side chain. This approach involves a combination of liquid and solid phase methods and allows for a library synthesis of analogs of the natural product.
Synthetic Studies on Diels-Alder Adducts: Intramolecular Interactions Between Two Functions
Authors: Constantino Mauricio Gomes , De Souza Altamiro Xavier , Da Silva Gil Valdo José
Published: October 2008

In this paper we describe the synthesis of a γ,δ-unsaturated aldehyde from a bicyclic Diels-Alder adduct, to be used in future electrocyclic reaction studies. A number of reactions produced undesired materials resulting from the interaction between functions, forcing the use of partial protection to accomplish a synthesis that would be otherwise straightforward. Suggestions to account for the results are given.
An Efficient Preparation of 1,2-Diamino-1-phenylheptane
Authors: Thennarasu S. , Perumal P.  T.
Published: October 2008

A convenient four-step method for the preparation of the lipophilic vicinal diamine 1,2-diamino-1-phenylheptane is described. Condensation involving octan-2-one, benzaldehyde and ammonia is reported. Regioselective Schmidt rearrangement of 2,6-diphenyl-3-pentyl-piperidin-4-one (1) to 2,7-diphenyl-3-pentyl hexahydrodiazapin-5-one (3) is presented. Hydrolysis of 2,7-diphenyl-3-pentyl hexahydrodiazapin-5-one to 1,2-diamino-1-phenylheptane (4) is also reported for the first time.
A Novel Synthesis of 1,2,4-Triazolopteridines
Authors: Abdallah Tayseer  A. , Darwish Manal  A. , Hassaneen Hamdi  M.
Published: October 2008

Reaction of 1,2-dihydro-2-thioxopteridin-4(3H)-one, 6,7-dimethyl-1,2-dihydro-2-thioxopteridin-4(3H)-one and 6,7-diphenyl-1,2-dihydro-2-thioxopteridin-4(3H)-one with hydrazonoyl halides affords the title compounds in good yields.
Carotamine, a Unique Aromatic Amide from Daucus Carota L. Var Biossieri (Apiaceae)
Authors: Eldahshan Omayma  A. , Ayoub Nahla  A. , Singab Abd-El Naser  B. , El-Azizi Mohamed  M.
Published: October 2008

The unique aromatic peptide 4-(p-aminobenzoylamino)-2-aminobenzoic acid, carotamine, together with 2,4-diaminobenzoic acid, isolated for the first time from a plant source, were identified from the aqueous alcoholic extract of the aerial parts of Daucus carota L. var. boissieri (Apiaceae). The structures were determined through conventional methods of analysis and confirmed by LC-ESI/MS and NMR spectral analysis.
Synthesis of Novel Quinazoline Derivatives via Pyrimidine ortho-Quinodimethane
Authors: Chioua R. , Benabdelouahab F. , Chioua M. , Martínez-Alvarez R. , Fernández A.  Herrera
Published: October 2008

The [4+2] cycloaddition between 2,4-diphenylpyrimidine ortho-quinodimethane and dimethyl acetylenedicarboxylate leads to 2,4-diphenylquinazoline-6,7-dicarboxylate (6). 2,4-Diphenylfuro[3,4-g]quinazoline-6,8-dione (7) is also obtained by basic hydrolysis of compound 6, followed by the closure of the resulting diacid in acetic anhydride.
Synthetic Studies on Optically Active Schiff-base Ligands Derived from Condensation of 2-Hydroxyacetophenone and Chiral Diamines
Authors: Gao Wen  Tao , Zheng Zhuo
Published: October 2008

Three optically active Schiff-base ligands have been prepared by condensation of 2-hydroxyacetophenone with (1R,2R)-(-)-1,2-diaminocyclohexane, (1S,2S)-(-)-1,2-diphenylethylenediamine or R-(+)-2,2’-diamino-1,1’-binaphthalene, respectively. The products have been characterized by their IR, 1H- and 13C-NMR spectra.
Total Synthesis of (-)-(7S,10R)-Calamenene and (-)-(7S,10R)-2-Hydroxycalamenene by Use of a Ring-Closing Metathesis Reaction. A Comparison of the cis- and trans-Isomers
Authors: Nakashima Katsuyuki , Imoto Masashi , Sono Masakazu , Tori Motoo , Nagashima Fumihiro , Asakawa Yoshinori
Published: October 2008

The title compounds have been synthesized starting from l-menthone by application of a ring-closing metathesis reaction to confirm their reported absolute and relative stereochemistry. Comparisons of the NMR spectra and specific rotations are also discussed.
Hydrogen Transfer from Hantzsch 1,4-Dihydropyridines to Carbon-Carbon Double Bonds under Microwave Irradiation
Authors: Torchy Séverine , Cordonnier Guy , Barbry Didier , Vanden Eynde Jean Jacques
Published: October 2008

1,4-Dihydropyridines (DHPs) have been used in the reduction of carbon-carbon double bonds under microwave irradiation without solvent. The efficiency of the reactions is dramatically dependent on the steric effects in the DHPs and on the electronic effects in the olefins.
Synthesis and Theoretical Study of a New Type of Pentacyclic bis-Benzothiazolium Compound
Authors: Zahradnik Pavol , Buffa Radovan
Published: October 2008

The synthesis of a new type of pentacyclic benzothiazolium compound -6,13-dihydropyrazino[2,1-b:5,4-b´]bis(1,3-benzothiazole)-7,14-diiumdibromide (2), is reported. Compound 2 was prepared by dimerization of 2-(bromomethyl)benzothiazole. Quantum chemical calculation studies have been carried out on the structures of possible isomers of 2, as well as the products of its deprotonation reactions.
Michael Reactions of Arylidenesulfonylacetonitriles. A New Route to Polyfunctional Benzo[a]quinolizines
Authors: Abdallah Tayseer. A. , Abdelhadi Hyam. A. , Hassaneen Huwida M. , Hassaneen Hamdi M.
Published: October 2008

Arylidenesulfonylacetonitriles react in acetonitrile with 1-methylisoquinoline and isoquinolin-1-yl-acetonitrile in the presence of piperidine to give benzo[a]quinolizines 6,9 and 7,10, respectively. The structures of the products were established on the basis of elemental and spectral analyses and their chemical reactivity.
Synthesis and Structure of the Cadmium (II) Complex: [Cd(C5H5N)2(S2CO-n-C4H9)2]
Authors: Jiang Xu  Hong , Zhang Wei  Guang , Zhong Yun , Wang Sue  Lein
Published: October 2008

The [Cd(C5H5N)2(S2CO-n-C4H9)2] adduct of pyridine with [Cd(S2CO-n-C4H9)2]n was synthesized and characterized by IR, elemental analysis,1H-NMR and X-ray diffraction analysis. The crystasl belong to the monoclinic system, space group P2(1)/c with Z=2. Cell dimensions are a=1.1094(12), b=0.6152(6), c=1.7985(19) nm, • =96.148(2)°, V=1.2204(2)nm3. The structure was refined to R=0.0246 and wR=0.0645 for 2624 reflections with I>2•(I). The complex has a centrosymmetric molecule structure.
Annellation of Triazole and Tetrazole Systems onto Pyrrolo[2,3-d]pyrimidines: Synthesis of Tetrazolo[1,5-c]-pyrrolo[3,2-e]-pyrimidines and Triazolo[1,5-c]pyrrolo-[3,2-e]pyrimidines as Potential Antibacterial Agents
Authors: Dave Chaitanya  G. , Shah Rina  D.
Published: October 2008

Syntheses of several novel 4-chloropyrrolo[2,3-d]pyrimidines (1), 4-hydrazinopyrrolo[2,3-d]pyrimidines (2) and 3-amino-4-iminopyrrolo[2,3-d]pyrimidines (7) and their use in the synthesis of tetrazolo[1,5-c]pyrrolo[3,2-e]pyrimidines (3) and triazolo[1,5-c]pyrrolo[3,2-e]pyrimidines (4) required for biological screening are reported.
Chemoinformatics and Drug Discovery
Authors: Xu Jun , Hagler Arnold
Published: October 2008

This article reviews current achievements in the field of chemoinformatics and their impact on modern drug discovery processes. The main data mining approaches used in cheminformatics, such as descriptor computations, structural similarity matrices, and classification algorithms, are outlined. The applications of cheminformatics in drug discovery, such as compound selection, virtual library generation, virtual high throughput screening, HTS data mining, and in silico ADMET are discussed. At the conclusion, future directions of chemoinformatics are suggested.
Towards Highly Activating Leaving Groups: Studies on the Preparation of Some Halogenated Alkyl Sulfonates
Authors: Netscher Thomas , Bohrer Patrick
Published: October 2008

The trichloromethylsulfonyl-, dichloromethylsulfonyl-, chlorosulfonyl-, and fluorosulfonyl esters of a neopentyl-type alcohol have been prepared via sulfonylation or sulfinylation followed by oxidation. The preparative usefulness and potential of the transformations are discussed.
Synthesis of Substituted 2-Pyridyl-4-phenylquinolines
Authors: Mamo Antonino , Nicoletti Salvatore , Tat N.  Cam
Published: October 2008

The acid-catalyzed condensation of o-aminobenzophenones with aromatic acetyl derivatives, in a basic methanol/tetrahydrofuran medium, has been used to prepare a series of substituted 2-pyridyl-4-phenylquinolines. Derivatives having two aza binding sites can act as asymmetric bidendate ligands to complex transition metals such as ruthenium, osmium or iridium. All the compounds were characterized by elemental analysis, Ei or FAB (+) MS, 1H- and 13C-NMR spectroscopies. Complete assignments of the 1H spectra were accomplished by using a combination of one- and two-dimensional NMR techniques.
Novel Cytotoxic Oxopyridoindolizines: iso-Propyl-7,8,9-trichloro-6,7,8,9-tetrahydro-5-oxopyrido[2,3-a]-indolizine-10-carboxylates (OPIC)
Authors: Zunino Franco , Kotchevar Ann  T. , Waring Michael , Daoudi Maria , Larbi Najib  Ben , Mimouni Mostafa , Sam Najat , Zahidi Assou , Ben-Hadda Taibi
Published: October 2008

A series of eight new alkyl-7,8,9-trichloro-6,7,8,9-tetrahydro-5-oxopyrido[2,3-a]-indolizine-10-carboxylates (OPIC), analogues of camptothecin (CPT), were prepared in a one-pot reaction of 2,2'-bipyridine-3,3'-dicarboxylic acid (BPA) with a mixture of thionyl chloride/chlorine, followed by addition of the appropriate alcohol. This led to a mixture of OPIC compounds 3a-d, 4a-d and 3,3'-dialkoxycarbonyl-2,2'-bipyridines (BPE, 2a-d). The isopropyl OPIC 3c and its corresponding diastereoisomer 4c showed marked activity against three cancer cell lines compared to other analogs. These same diastereoisomers also displayed high cytotoxic activity against five leukemia cell lines, thus the presence of an isopropyl substituent on the carboxylic ester, as opposed to other alkyl substituents, appears to play a key role in the cytotoxic potency of this new class of compounds.
2,3-Bifunctionalized Quinoxalines: Synthesis, DNA Interactions and Evaluation of Anticancer, Anti-tuberculosis and Antifungal Activity
Authors: Waring Michael J. , Ben-Hadda Taibi , Kotchevar Ann T. , Ramdani Abdelkrim , Touzani Rachid , Elkadiri Sghir , Hakkou Abdelkader , Bouakka Mohamed , Ellis Tom
Published: October 2008

A variety of 2,3-bifunctionalized quinoxalines (6-14) have been prepared by the condensation of 1,6-disubstituted-hexan-1,3,4,6-tetraones (1-4) with o-phenylenediamine, (R,R)-1,2-diaminocyclohexane and p-nitro-o-phenylenediamine. It is concluded that strong intramolecular N-H----O bonds in the favoured keto-enamine form may be responsible for the minimal biological activities observed in DNA footprinting, antitubercular, anti-fungal and anticancer tests with these hyper π-conjugated quinoxaline derivatives. However, subtle alteration by addition of a nitro group affecting the charge distribution confers significant improvements in biological effects and binding to DNA.
DivCalc: A Utility for Diversity Analysis and Compound Sampling
Authors: Gangal Rajeev
Published: October 2008

Diversity, in the form of genetic diversity, chemical diversity etc, is a very important concept in several areas of scientific research, and calculation of diversity is one of the most important considerations in pre-clinical drug discovery research and, in particular, in design of diverse chemical libraries for combinatorial chemistry and compound selection for High Throughput Screening (HTS). DivCalc is a WindowsTM based software that implements a previously published method of diversity calculation [1]. This facilitates sampling of a given data matrix to obtain the most diverse compounds that span the entire descriptor space.
NMR Detection of Isomers Arising from Restricted Rotation of the C-N Amide Bond of N-Formyl-o-toluidine and N,N’-bis-Formyl-o-tolidine
Authors: Quintanilla-Licea Ramiro , Colunga-Valladares Juan  F. , Caballero-Quintero Adolfo , Rodríguez-Padilla Cristina , Tamez-Guerra Reyes , Gómez-Flores Ricardo , Waksman Noemí
Published: October 2008

Full and unambiguous assignment of all 1H- and 13C-NMR resonances of the isomers due to restricted C-N amide bond rotation of N-formyl-o-toluidine and N,N'-bis-formyl-o-tolidine in DMSO-d6 is reported. The cis-isomer predominates in the equilibrium mixture of both compounds as 1D-NOE difference experiments show.
Solid State Deprotection of Acetals and Thioacetals Using Benzyltriphenylphosphonium Peroxymonosulfate
Authors: Hajipour Abdol Reza , Mallakpour Shadpour E. , Mohammadpoor-Baltork Iraj , Adibi Hadi
Published: October 2008

A variety of acetals and thioacetals 2 are deprotected to the corresponding parent carbonyl compounds 3 under solvent-free conditions using benzyltriphenylphosphonium peroxymonosulfate (1) in the presence of aluminum chloride.
Synthesis and Biological Activity of 3-(2-Furanyl)-6-Aryl-1,2,4-Triazolo[3,4-b]-1,3,4 –Thiadiazoles
Authors: Zhang Li-Xue , Zhang An-Jiang , Chen Xian-Xing , Lei Xin-Xiang , Nan Xiang-Yun , Chen Dong-Yong , Zhang Zi-Yi
Published: October 2008

3-(2-Furanyl)-4-amino-5-mercapto-1,2,4-triazole (1) was prepared from 2-furoic acid through a multi-step reaction sequence. Compound 1 reacted with aromatic acids in the presence of phosphorus oxychloride to give 3-(2-furanyl)-6-aryl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles (2). The structures of all the newly synthesized compounds have been confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectra. The bioassay indicated most of the title compounds possess significant growth promoting effects on mung bean radicles.
Crystal Structure of N,N-bis-(3-Carbomethoxy-5-methyl-pyrazol-1-ylmethyl)aniline
Authors: Daoudi Maria , Larbi Najib  Ben , Benjelloun Driss , Kerbal Abdelali , Launay Jean  Pierre , Bonvoisin Jacques , Jaud Joël , Mimouni Mostafa , Ben-Hadda Taibi
Published: October 2008

The tripodal ligand N,N-bis-(3-carbomethoxy-5-methylpyrazol-1-yl)methyl aniline (2) has been prepared by the condensation of aniline with two equivalents of N-hydroxymethyl[3-carbomethoxy-5-methyl]pyrazole. The molecule consists of two structurally analogous 3-carbomethoxy-5-methylpyrazol-1-ylmethyl moieties, which adopt a transoidal conformation via a central aniline ring, suggesting that this tripodal ligand is highly flexible and could accommodate many metals by coordination.
Regioselective Protection of the 4-Hydroxyl of 3,4-Dihydroxy-benzaldehyde
Authors: Plourde Guy L. , Spaetzel Randy R.
Published: October 2008

The regioselective protection of the 4-hydroxyl group of 3,4-dihydroxy-benzaldehyde was accomplished with seven different protecting groups (benzyl, p-methoxybenzyl, o-nitrobenzyl, 2,6-dichlorobenzyl, 3,4-dichlorobenzyl, vinyl and propargyl) in yields ranging between 67-75%.
Diazoamino Coupling of a 4-Sulfobenzenediazonium Salt with Some Cyclic Amines
Authors: Kažemėkaitė Marytė , Talaikytė Zita , Niaura Gediminas , Butkus Eugenius
Published: October 2008

Preparation of several novel potassium salts of 4-substituted aminoazo-benzenesulfonic acids by the simple and convenient reaction of insoluble 4-sulfo-benzenediazonium chloride with some (hetero)cyclic amines of various ring sizes is reported. The compounds obtained have shown potential antiinflammatory activity in biological testing.
Chemical Composition of the Essential Oil of Psidium caudatum McVaugh
Authors: Yáñez Xiomara , Pinzón Martha  Lucía , Solano Fredy , Sánchez Luis  Roberto
Published: October 2008

The chemical composition of the essential oil of Psidium caudatum McVaugh was investigated and thirty-two compounds were identified by HRGC-MS. The main constituents were terpinen-4-ol (47.72%), γ-terpinene (11.58%) and α-terpinene (6.70%).
Different Reaction Patterns in the Baylis-Hillman Reaction of Aryl Aldehydes with Phenyl Vinyl Ketone, Phenyl Acrylate and Phenyl Thioacrylate
Authors: Shi Min , Li Chao-Qun , Jiang Jian-Kang
Published: October 2008

In the Baylis-Hillman reaction of aryl aldehydes with phenyl vinyl ketone we have observed exclusive formation of diadducts 4, and that the yields of diadduct can reach 80% with increasing amounts of phenyl vinyl ketone. On the other hand, for phenyl acrylate and phenyl thioacrylate, only the normal Baylis-Hillman adduct was obtained. The effects of substituents were also examined and a plausible reaction mechanism is proposed for the formation of compounds 4.
Silica Sulfuric Acid/ NaNO2 as a Novel Heterogeneous System for the Nitration of Phenols under Mild Conditions
Authors: Zolfigol Mohammad  Ali , Madrakian Elahe , Ghaemi Ezat
Published: October 2008

Nitrophenols can be obtained in moderate to high yields via nitrosationoxidation of phenols with silica sulfuric acid, NaNO2 and wet SiO2 at room temperature. In situ generation of HNO2 and a radical cation mechanism via the nitrous acid catalyzed (NAC) pathway appear to be applicable to phenol nitration using these reagents.
Preparation of Shortened Norbelladine Analogs
Authors: Treu Matthias , Fröhlich Johannes , Jordis Ulrich
Published: October 2008

The preparation of N-[(2-bromo-5-hydroxy-4-methoxyphenyl)methyl]-N-[(4-hydroxyphenyl)methyl]formamide (5) and 2-bromo-5-hydroxy-α-[(4-hydroxyphenyl)-methyl]-4-methoxypropaneamide (10) is reported.
Deprotection of Acetals and Ketals by Silica Sulfuric Acid and Wet SiO2
Authors: Mirjalili BiBi  Fathemeh , Zolfigol Mohamad  Ali , Bamoniri Abdolhamid
Published: October 2008

Neat chlorosulfonic acid reacts with silica gel to give silica sulfuric acid in which sulfuric acid is immobilized on the surface of silica gel via covalent bonds. A combination of silica sulfuric acid and wet SiO2 was used as an effective deacetalizating agent for the conversion of acetals to their corresponding carbonyl derivatives under thermal conditions.
A Simple Synthesis of Some New Thienopyridine and Thienopyrimidine Derivatives
Authors: El-Saghier Ahmed  M. M.
Published: October 2008

A number of pyridothienopyridine (2, 3), pyridothienopyrimidine (6, 10), pyridothienotriazine (13), pyrimidothienopyrimidine (15, 16, 17a,b) and thienoimidazo-triazines (18) were obtained via interaction of 3-amino-5-phenylamino-2,4-dicarbonitrile (1) with different reagents.
Amino Acid Based Synthesis of Chiral Long Chain Diamines and Tetramines
Authors: Loukas Vassilios , Markidis Theodoros , Kokotos George
Published: October 2008

A method for the synthesis of long chain diamines and tetramines starting from natural α-amino acids is reported. Diamines and tetramines were prepared through the Wittig olefination reaction of N-protected amino aldehydes obtained from phenylalanine and lysine. A 1,2,17,18-tetramine was synthesized using (2S)-1-azido-2-[bis(tert-butoxycarbonyl)-amino]-5-oxopentane as key-intermediate compound.
A Synthesis of 6-(2,5-Dimethoxy-4-(2-aminopropyl)phenyl)-hexylthiol. A Ligand for Conjugation with Fluorescent Cadmium Selenide/Zinc Sulfide Core/Shell Nanocrystals and Biological Imaging
Authors: Tomlinson Ian  D. , Grey Jesse  L. , Rosenthal Sandra  J.
Published: October 2008

The synthesis of 6-(2,5-dimethoxy-4-(2-aminopropyl)phenyl)hexylthiol, an agonist with a very high affinity for the 5HT2A serotonin receptor subtype is reported. This agonist was designed to be attached to highly fluorescent cadmium selenide/zinc sulfide core/shells via a thiol at the end of a linker arm. This conjugate has applications in biological assays and biological imaging.
Synthesis and Characterization of some New Mesoionic 1,3-Thiazolium-5-thiolates via Cyclodehydration and in situ 1,3-Dipolar Cycloaddition/Cycloreversion
Authors: Lira Bruno  Freitas , De Athayde Filho Petrônio  Filgueiras , Miller Joseph , Simas Alfredo  Mayall , De Farias Dias Aderson , Vieira Maria  Joaquina
Published: October 2008

The title compounds were synthesized from C-aryl-N-methylglycines by Naroylation followed by a cyclodehydration to form the corresponding 1,3-oxazolium-5-olates. These were not isolated but converted to the title compounds by an in situ 1,3-dipolar cycloaddition/cycloreversion sequence using carbon disulphide. We have studied the cyclodehydration step using acetic anhydride, trifluoroacetic anhydride and 1,3-dicyclohexylcarbodiimide (DCC) at temperatures not exceding 60oC. Trifluroacetic anhydride proved to be the best reagent, giving a better yield and more easily purified products, although yields were also acceptable with the other two reagents.