Showing papers in "Molecules in 1999"
TL;DR: In this paper, 3-Alkoxycarbonylmethyl-6-bromo and 3-alkoxy carbonyl methyl 6-nitro-2-benzothiazolone derivatives were synthesized by reaction of alkylesters of halogenoacetic acids with 6-Bromo-2.
Abstract: 3-Alkoxycarbonylmethyl-6-bromo- and 3-alkoxycarbonylmethyl-6-nitro-2-benzothiazolones were synthesized by reaction of alkylesters of halogenoacetic acids with 6-bromo-2-benzothiazolones and 6-nitro-2-benzothiazolones respectively. The compounds were tested for plant growth stimulating activity on wheat (Triticum aestivum). The bromo derivatives manifested 25.4 % average stimulating activity in comparison with the control. The stimulation activity of the nitro derivatives was not significant. Optimal structures of the compounds were obtained by a MMPI method, atomic charges and dipole moments were calculated by a semiempirical AM1 method. On the basis of molecular electrostatic potential it has been found that the biological activity of synthesized compounds depends on charge distribution in the molecules.
26 citations
TL;DR: In this article, N-substituted amides and lactams are rapidly N-alkylated under solvent-free phase-transfer catalytic conditions using microwaves.
Abstract: N-Substituted amides and lactams are rapidly N-alkylated under solvent-free phase-transfer catalytic conditions using microwaves.
23 citations
TL;DR: The encyclopedia of industrial organic chemicals as discussed by the authors brings together around 200 detailed and thoroughly edited articles on organic starting materials and intermediates, including starting materials, starting compounds, and their derivatives.
Abstract: The encyclopedia of Industrial Organic Chemicals brings together around 200 detailed and thoroughly edited articles on organic starting materials and intermediates.[...]
19 citations
TL;DR: In this paper, the arrangement of hydrogen donor and acceptor groups of naphthyridines allows interactions with guanine and cytosine base pairs, and the described synthesis offers easy access to these small and stable fluorescent probes.
Abstract: Substitution of 4-methyl-[1,8]-naphthyridine in 2 and 7 position by alkylamines leads to highly fluorescent compounds. The arrangement of hydrogen donor and acceptor groups of these naphthyridines allows interactions with guanine and guanine cytosine base pairs. The described synthesis offers easy access to these small and stable fluorescent probes.
18 citations
TL;DR: In this article, 2-hydroxyaryl(5-methylfur-2-yl)alkanes were synthesized by alkylation of 2-Methylfuran with various 2hydroxybenzylic alcohols, were rearranged into corresponding 3-R-benzo[b]furan derivatives by treatment with ethanolic HCl solution.
Abstract: 2-Hydroxyaryl(5-methylfur-2-yl)alkanes synthesized by alkylation of 2-methylfuran with various 2-hydroxybenzylic alcohols, were rearranged into corresponding 3-R-benzo[b]furan derivatives by treatment with ethanolic HCl solution. These compounds can not be transformed into dibenzoxazulenium salts.
18 citations
TL;DR: Optically active nitrones derived from both aldoses and dialdoses add metallated heterocycles in a stereocontrolled way depending on the nature of the Lewis acid used as a pre-complexing agent of the nitrone as discussed by the authors.
Abstract: Optically active nitrones derived from both aldoses and dialdoses add metallated heterocycles in a stereocontrolled way depending on the nature of the Lewis acid used as a precomplexing agent of the nitrone. Further elaborations of the resulting hydroxylamines lead to the development of new synthetic methodologies for the preparation of polyalkoxy α-amino aldehydes and α-amino acids. These compounds can be used as key advanced intermediates in the synthesis of a wide range of natural products and derivatives including amino sugars, aza sugars, and complex nucleosides.
17 citations
TL;DR: In this article, the synthesis of 2-[2-carboxymethylthio-2-(4-chlorophenyl) ethyl]-2-( 4-chlorophyl) -4-thiazolidinone (1) from p, p'- dichlorochalcone using thioglycollic acid inthe presence of ammonium carbonate is described.
Abstract: Department of Chemistry (Natural Products), University of Antwerp (RUCA), Groenenborgerlaan171, B-2020 Antwerp, BelgiumFax: (internet.) +32-3-2180233, E-mail: lemiere@ruca.ua.ac.be*Author to whom correspondence should be addressed.Received: 3 March 1999 / Accepted: 10 June 1999 / Published: 19 July 1999Abstract: The synthesis of 2-[2-carboxymethylthio-2-(4-chlorophenyl) ethyl]-2-(4-chlorophenyl) - 4-thiazolidinone (1) from p, p'- dichlorochalcone using thioglycollic acid inthe presence of ammonium carbonate is described. Structural assignment andstereochemistry are discussed.Keywords: Organic synthesis, chalcone, thiazolidinone,
16 citations
TL;DR: In this paper, the synthesis and photosynthesis-inhibiting activity of 14 new 3-(2-alkylsulfanyl-6-benzothiazolylaminomethyl)-2benzoxazolethiones are reported.
Abstract: Eva Sidoova, Katarina Kralova and Dusan Loos*Institute of Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska dolina CH-2, SK-842 15 Bratislava, Slovakia. Tel. +421 7 60296342, Fax +421 7 65429064, E-mail loos@fns.uniba.sk*Author to whom correspondence should be addressed.Received: 12 May 1998 / Accepted: 5 March 1999 / Published: 29 March 1999Abstract: The synthesis and photosynthesis-inhibiting activity of 14 new 3-(2-alkylsulfanyl-6-benzothiazolylaminomethyl)-2-benzoxazolethiones are reported. The new compounds wereprepared by the reaction of 2-alkylsulfanyl-6-aminobenzothiazoles with 3-hydroxymethyl-2-benzoxazolethione. The structures of the compounds were verified by
15 citations
TL;DR: In this paper, it is shown that it is possible to obtain 2-hydroxyarylbis(5-methylfur-2-yl)methane, benzofuran or oxazulene derivatives selectively by simple changing of the reaction conditions.
Abstract: Data, concerning condensation reactions of salicylaldehydes and 2-methylfuran are generalized. During the course of investigation a sequence of proceeding transformations is established. It is shown that it is possible to obtain 2-hydroxyarylbis(5-methylfur-2-yl)methane, benzofuran or oxazulene derivatives selectively by simple changing of the reaction conditions.
15 citations
TL;DR: Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) (CAS Reg. No. 481-42-5) was isolated from the bark of Diospyros olen (Ebenaceae) via an antibiotic guided biological assay using the bacterium Pseudomonas solanacearum as mentioned in this paper.
Abstract: Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) (CAS Reg. No. 481-42-5) was isolated from the bark of Diospyros olen (Ebenaceae) via an antibiotic guided biological assay using the bacterium Pseudomonas solanacearum. D. olen bark, collected in New Caledonia, was extracted with dichloromethane and components separated by flash chromatography on silica.[...]
14 citations
TL;DR: In this article, the synthesis of purines and purine mono-1-oxides from the respective 5-substituted 4-nitroimidazole derivatives is described.
Abstract: Synthesis of purines and purine mono-1-oxides from the respective 5-substituted 4-nitroimidazole derivatives is described. The commercially available 4-nitroimidazole, in a few simple steps (including Vicarious Nucleophilic Substitution of Hydrogen), was transformed into: 4-aminoimidazoyl-5-carboximes, N-[1-(4-amino-1H-imidazol-5-yl)methylidene]-N-(aryl)amine derivatives or into 4-amino-5-aminomethyl-imidazole. These intermediates were cyclized to the final products.
TL;DR: Wu et al. as discussed by the authors proposed the inorganic property (I) and organic property (O) values of general organic groups to calculate the hydrophobicity of each amino acid.
Abstract: Hanqing WuDepartment of Chemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA E-mail hanqing@csd.uwm.edu* This paper was presented at ecsoc-1 at URL of http://www.unibas.ch/mdpi/ecsoc/e0002/e0002.htmPart of this work was performed in the Department of Applied Chemistry, University of Science andTechnology of China, Hefei, Anhui, P. R. China (1984-90)Editor's note: http://www.unibas.ch/mdpi/ecsoc/e0002/e0002.htm file will be included in the CD-ROM edition.Received: 30 January 1998 / Accepted: 1 July 1998 / Published: 8 February 1999Abstract: The inorganic property (I) and organic property (O) values of general organicgroups are re-proposed here. Both I and O values of drug and biological molecules orgroups can be calculated based on their common group values. The calculation can beperformed easily on-line through JavaScript. Similar calculation can be done for the drugand biological molecular group electronegativity (X) according to the author's publishedpaper. The calculation of lipophilicity (π or logP) parameter of (macro)molecules (likeproteins) can also be performed on-line through JavaScript. Two equations expressed withI and O are provided here to define the hydrophobicity of each amino acid. Thecorrelations of inorganic property and organic property values with other parameters arealso discussed. These calculated parameters combined with other parameters can be usedfor QSAR studies in some drug molecules.Keywords: Inorganic property and organic property, logP, bio-active molecules,JavaScript, QSAR, drug design.IntroductionQuantitative structure-activity relationship (QSAR) correlation has been widely applied inbiological activities over several decades. Many new descriptors (parameters) have been developed
TL;DR: Based on the biological properties of epoxyquinols from natural sources, the title compound was synthesized as a potential antitumor agent as discussed by the authors, and its molecular structure was partially confirmed by NMR studies.
Abstract: Based on the biological properties of epoxyquinols from natural sources, the title compound was synthesised as a potential antitumor agent. Its molecular structure was partially confirmed by NMR studies. The detailed structure was established by X-ray analysis revealing two symmetry independent molecules in the asymmetric unit each consisting of four fused rings with the C(10) β-oriented hydroxy group and β-oriented O atom bridging C(4) and C(5). The conformation of A ring in both conformers A and B is boat (B3,6), while rings B and C are chairs (1C4) and the five-membered D ring is in an envelope (E2) conformation. The in vitro antitumor activity of title compound and its 17b-acetoxy analogue against HeLa and Fem-x cells revealed IC50 values of 5.7 and 7.1 mM, and 2.25 and 1.58 mM, respectively. Corresponding quinols were tested on 47 cell lines with 10b-hydroxy-17β-acetoxyestra-1,4-dien-3-one being most active against leukemia SR cells (GI50 = 0.17 mM).
TL;DR: Torrens et al. as discussed by the authors used a method for the calculation of the molecular dipole (µ ) and quadrupole(θ ) moments and dipole-dipole (α ), dipolequadrupole (
Abstract: Francisco Torrens, Jose Sanchez-Marin and Ignacio Nebot-GilDepartment of Chemistry and Biochemistry, South Dakota State University, Box 2202, Brookings,South Dakota 57007, USA, (605)-688-6260, FAX (605) 688-6364Departament de Quimica Fisica, Facultat de Quimica, Universitat de Valencia, Dr. Moliner 50,E -46100 -Burjassot (Valencia), Spain. http://www.uv.es/~anton/inicio.html. Tel. +34 96 398 3182, Fax+34 96 398 3156. Email Francisco.Torrens@uv.esReceived: 30 September 1998 / Accepted: 5 January 1999 / Published: 12 February 1999Abstract: We use a method for the calculation of the molecular dipole (µ ) and quadrupole(θ ) moments and dipole-dipole (α ), dipole-quadrupole (
TL;DR: In this article, a practical synthesis of the title pheromone has been developed using a cis-selective Wittig reaction and using commercially available starting materials to prepare the required synthons.
Abstract: A practical synthesis of the title pheromone has been developed. The key feature of the synthesis was the fixation of the required olefin geometry via a cis-selective Wittig reaction and use of commercially available starting materials to prepare the required synthons.
TL;DR: In this article, the acid dissociation constants of nine trisubstituted pyridine N-oxides with the methyl group were determined, namely 2-halo(Cl, Br and I) -4-nitropicoline Noxides.
Abstract: Department of Organic Chemistry, School of Economics, Wroclaw, Poland*Author to whom correspondence should be addressed.Received: 9 March 1998 / Accepted: 8 March 1999 / Published: 29 March 1999Abstract: An attempt has been made to determine potentiometrically (1) acid dissociationconstants of cations obtained by protonation of nine trisubstituted pyridine N-oxides, namely2-halo(Cl, Br and I) -4-nitropicoline N-oxides with the methyl group at positions 3, 5, and 6,as well as (2) the cationic homoconjugation constants of these cationic acids with conjugatedN-oxides in acetonitrile. On the basis of the substitution effect, variations of the acid diss o-ciation constants of the trisubstituted pyridine N-oxide cations are discussed. The determinedpK
TL;DR: Virgili et al. as discussed by the authors presented the crystal structure of racemic 2,2'-dimethoxy-9,9'-biacridine-CHCl.
Abstract: Departament de Quimica, Facultat de Ciencies, Universitat Autonoma de Barcelona, E-08193Bellaterra, SpainFax: (internat.) +34(3)5811265 , E-mail : albert.virgili@uab.es*Author to whom correspondence should be addressed.Received: 16 March 1998 / Accepted: 5 May 1998 / Published: 16 April 1999Abstract: Three derivatives of 9,9'-biacridine, 2,2'-dihydroxy, 2,2'-dimethoxy and 2,2'-diacetoxy have been prepared. The crystal structure of racemic 2,2'-dimethoxy-9,9'-biacridineCHCl
TL;DR: A series of N-acylated N-substituted sulfonamides was prepared for the first time in good yields and with excellent conversion by the reaction of N+1-toluene with acetyl chloride and bromoacetyl bromide in the presence of a catalytic amount of anhydrous ZnCl2.
Abstract: Martin Travnicek and Milan Potacek*Department of Organic Chemistry, Masaryk University, 611 37 Brno, Czech RepublicE-mails: martint @ chemi.muni.cz, potacek@chemi.muni.cz*Author to whom correspondence should be addressed.This paper is dedicated to Professor Milan Kratochvil on the occasion of his 75th birthday.Received: 28 June 1999 / Accepted: 7 July 1999 / Published: 13 August 1999Abstract: A series of N-acylated N-substituted sulfonamides was prepared for the first timein good yields and with excellent conversion by the reaction of N-substituted-N-(p-toluene)sulfonamides (1) with acetyl chloride and bromoacetyl bromide (2), respectively, in thepresence of a catalytic amount of anhydrous ZnCl
TL;DR: From leaves and flowers of Ageratina vacciniaefolia, the authors isolated several compounds: a flavonoid, a diterpene and a new compound identified as (-)-b-D-18−glucopiranosyl-9,15-dihydroxy kaurenoate (see the formula).
Abstract: From leaves and flowers of Ageratina vacciniaefolia we have isolated several compounds: a flavonoid, a diterpene and a new compound identified as (-)-b-D-18–glucopiranosyl-9,15-dihydroxy kaurenoate (see the formula).[...]
TL;DR: When I was being trained in dyestuff research, development and production at Ciba-Geigy in 1994, my supervisors as senior dyestuffs chemists, brought to my attention the Ullmann's Encyclopedia of Industrial Chemistry as mentioned in this paper.
Abstract: When I was being trained in dyestuff research, development and production at Ciba-Geigy in 1994, my supervisors as senior dyestuff chemists, brought to my attention the Ullmann’s Encyclopedia of Industrial Chemistry.[...]
TL;DR: Hongyan et al. as mentioned in this paper treated 2,4,6,8,10,12-hexabenzyl-2.5.0 and 2.4, 6, 8, 10, 12-hexaazatetracyclo.
Abstract: Current address: Department of Chemistry and Environmental Engineering, Beijing PolytechnicUniversity, Beijing 100022, P. R. China, e-mail: hongyan@bj.col.com.cn*Author to whom correspondence should be addressed.Received: 12 May 1998 / Accepted: 5 March 1999 / Published: 16 March 1999Abstract: Treatment of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo-[5.5.0.0
TL;DR: The product 2 was prepared by the addition of formalin (CH2O) to 1 [1] according to the reported procedure [2] as discussed by the authors, according to which the product
Abstract: The product 2 was prepared by the addition of formalin (CH2O) to 1 [1] according to the reported procedure [2].[...]
TL;DR: The need for systematic naming is reviewed as well as some of the tools and approaches being taken today in this area.
Abstract: The availability of systematic names can enable the simple textual exchange of chemical structure information The exchange of molecular structures in graphical format or connection tables has become well established in the field of cheminformatics and many structure drawing tools exist to enable this exchange However, even with the availability of systematic naming rules, software tools to allow the generation of names from structures, and hopefully the reversal of these systematic names back to the original chemical structure, have been sorely lacking in capability and quality Here we review the need for systematic naming as well as some of the tools and approaches being taken today in this area
TL;DR: From leaves and flowers of Ageratina vacciniaefolia, this article isolated several compounds: a flavonoid, a diterpene, and a new compound identified as b-D-glucopyranosil ester of (-)17-(bglocopiranosyloxyl)- 16-hydroxy-kauran-19-oic acid (see the formula).
Abstract: From leaves and flowers of Ageratina vacciniaefolia [1-7] we have isolated several compounds: a flavonoid, a diterpene [8] and a new compound identified as b-D-glucopyranosil ester of (-)17-(bglucopiranosyloxyl)- 16-hydroxy-kauran-19-oic acid (see the formula).[...]
TL;DR: To a solution of 1-vinyl-2-pyrrolidinone (1, 11.1 g, 100 mmol) in CH2Cl2 (100 ml) was added a drop of CF3CO2H at room temperature.
Abstract: To a solution of 1-vinyl-2-pyrrolidinone (1, 11.1 g, 100 mmol) in CH2Cl2 (100 ml) was added a drop of CF3CO2H at room temperature.
TL;DR: Several N-phenylpyrrole carboximides were synthesized using acyl isocyanates as intermediates as discussed by the authors, using acyclic acid as the intermediate.
Abstract: Several N-phenylpyrrole carboximides were synthesised using acyl isocyanates as intermediates.
TL;DR: The authors' works on nucleic acids recognition and synthetic vectors for gene transfer have been reviewed and recommendations for further studies are made.
Abstract: Our works on nucleic acids recognition and synthetic vectors for gene transfer have been reviewed.
TL;DR: In this article, it was shown that the activity of the electrophilic carbonyl group, diminished by electron donating groups X, can be qualitatively re-flected by the electron donating power of X group.
Abstract: O NMR spectroscopy is a particularly useful tool for investigating the electronic state of carbonylgroups, including their electrophilicity [1, 2]. In RCOX derivatives, the shielding of O atom is in-creased with increasing the donating power of X group [2]. It has been shown by Dahn that the activityof the electrophilic carbonyl group, diminished by electron donating groups X, can be qualitatively re-flected by the
TL;DR: Pd(II) catalyzed the exchange reaction of vinyl acetate with aromatic acids to produce the corresponding vinyl esters in good yields as mentioned in this paper, but it was not used in the production of VE.
Abstract: Pd(II) catalyzed the exchange reaction of vinyl acetate with aromatic acids to produce the corresponding vinyl esters in good yields.
TL;DR: The history of the Molecule of the Month (MOMA) website is described in this paper, along with a short summary of some of the molecules which featured during 1997.
Abstract: This review describes the history of the "Molecule of the Month" Website, along with a short summary of some of the molecules which featured during 1997.