Showing papers on "Derivative (chemistry) published in 1999"

Total Synthesis of Spirotryprostatin A, Leading to the Discovery of Some Biologically Promising Analogues

Abstract: The total synthesis of the title compound has been accomplished. A key step involves the oxidative rearrangement of the β-carboline derivative to an oxindole via the action of N-bromosuccinimide. From this point, a diketopiperazine was introduced. A thiophenyl group served as a precursor of the isopropylidene function. Implementation of the same sort of chemistry starting with a methoxytryptophan derivative led to the parent structures. Furthermore, it was shown that the difficultly accessible isopropylidene side chain of spirotryprostatin A is not necessary for biological activity. Moreover, three analogues lacking the diketopiperazine system were shown to be quite active as cell cycle inhibitors.

Cyclomarins A−C, New Antiinflammatory Cyclic Peptides Produced by a Marine Bacterium (Streptomyces sp.)

Abstract: Three new cyclic heptapeptides, cyclomarins A−C (1−3), were isolated from extracts of a cultured marine bacterium collected in the vicinity of San Diego, CA. The major metabolite, cyclomarin A (1), contains three common and four unusual (or unique) amino acids. The structures of the new metabolites were determined using 1D and 2D NMR methods, and the stereochemistry was determined from an X-ray crystal structure of the diacetate derivative of 1. Cyclomarin A (1) displays significant antiinflammatory activity in both in vivo and in vitro assays.

Organic electroluminescence element

Abstract: PROBLEM TO BE SOLVED: To have high luminous efficiency and emit lights of various colors by setting the film thickness of a light emission layer including an organic substance causing concentration quenching to a specific value or less SOLUTION: It is preferable that the film thickness of a light emitting layer of an organic electroluminescence element is set to 4 nm or less Among light emitting materials used here and causing concentration quenching are quinacridone derivative, cumarin derivative, melocyanine derivative, oxazole derivative, thiazole derivative, styryl derivative, flavone derivative, and condensation polycyclic compound The organic electroluminescence element is prepared by vapor depositing a hole transport layer 3 for transporting a positive hole, a light emitting layer 4 inducing light emission phenomena, an electron transport layer 5 for transporting electrons, and a negative electrode on a material defining an ITO electrode beforehand as a transference electrode 2 on a glass substrate 1 in this order DCM (4-dicyanomethylene-2-methyl-6-(p- dimethylaminostyry)-4H-pyran), or an organic substance causing concentration quenching expressed by a formula is used for the light emitting layer 4

Conjugated 1,10-Phenanthrolines as Tunable Fluorophores.

Abstract: Multiple emission colors can be generated with the same compound from a novel family of highly emissive and visibly fluorescent 1,10-phenanthrolines 1. The emission wavelength of any derivative is dictated by the nature of its substituent and can be further modulated by exogenous additives such as protons or metal ions. R=H, Me, OMe, NMe(2).

Compounds containing a planar-tetracoordinate carbon atom as analogues of planar methane

Abstract: Over the past years the number of examples of compounds containing a planar-tetracoordinate carbon atom has increased. However, the presence of a carbon atom with a 360° sum of angles does not imply that the species is a derivative of planar methane; there must be an appropriate electronic stabilization. In the case of complexes 21a and 21b the central carbon atom is indeed stabilized by σ-donors and π-acceptors, as required for planar methane.

Investigation and Refinement of Palladium-Coupling Conditions for the Synthesis of Diarylethyne-Linked Multiporphyrin Arrays

Abstract: The synthesis of diarylethyne-linked multiporphyrin arrays requires Pd-mediated coupling conditions that are performed in dilute solution in the absence of copper and that give reaction mixtures that are easily purified. We previously developed copper-free Pd-mediated coupling conditions (Pd2(dba)3 and AsPh3 in toluene/triethylamine (5:1) at 35 °C) but extensive chromatography was required to remove unidentified porphyrinic byproducts. We have used laser-desorption mass spectrometry (LD-MS) and analytical size-exclusion chromatography (SEC) to assay the products from the coupling reaction of a zinc(II) iodophenylporphyrin (ZnI) and a zinc(II) ethynylphenylporphyrin (ZnU‘). Analysis of the crude reaction mixture revealed the diphenylethyne-linked dimer (Zn2U) as the major product, byproducts plausibly derived from phenyl−aryl exchange processes (a phenylated derivative of ZnU‘, a Ph2As-substituted derivative of ZnI), byproducts believed to originate from direct phenylation processes (a phenylated derivativ...

Enantioselective Single-Crystal-to-Single-Crystal Photodimerization of Coumarin and Thiocoumarin in Inclusion Complexes with Chiral Host Compounds.

Abstract: An intermolecular enantioselective photoreaction by a single-crystal-to-single-crystal transformation has been carried out for the first time, as is evident from X-ray structure analysis and X-ray powder diffractometric studies. This reaction, the dimerization of the title compound to cyclobutane derivative 1 (X=O, S), provides a good example for studying the mechanism of topochemical reactions in the crystal.

Inhibitor composition for (meth)acrylic acid stabilization comprises nitroxyl radical(s) (derivative) and a phenothiazine(s) and/or phenothiazine derivative(s)

Abstract: Inhibitor composition comprises a nitroxyl radical(s) (derivative) and a phenothiazine(s) and/or phenothiazine derivative(s). Inhibitor composition comprises a nitroxyl radical(s) (derivative) (N) and a phenothiazine(s) and/or phenothiazine derivative(s) (P) in a N/P weight ratio of at least 1. An Independent claim is included for a mixture comprising the above inhibitor composition and an ethylenically unsaturated compound(s).

New 3-aryl-2-hydroxypropionic acid derivative (i)

Abstract: A novel compound 3-{4-[2-(4-tert-Butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxy propanoic acid having formula (I) and pharmaceutically acceptable salts, solvates, and crystalline forms thereof, a process and intermediates for its manufacture, pharmaceutical preparations containing it and the use of the compound in clinical conditions associated with insulin resistance.

New ester compound, high polymer compound, resist material and pattern-forming method

Abstract: PROBLEM TO BE SOLVED: To provide a new ester compound easily decomposable with an acid, useful as a raw material for a polymer compound realizing the sensitivity, resolution and etching resistance highly exceeding those of conventional product and effective as a resist material. SOLUTION: The objective compound is expressed by formula I (R1 is H, methyl, CH2CO2R14 or the like; R2 is H, methyl or CO2R14; R3 is a 1-8C alkyl or a 6-20C aryl; R4 to R13 are each H, a univalent hydrocarbon group or the like; R14 is a 1-15C alkyl), e.g. the compound of formula II. The objective compound can be produced by carrying out the nucleophilic addition reaction to the carbonyl group of bicyclo[2.2.1]heptan-2-one and its derivative by Grignard reaction, etc., to obtain an endo-type alcohol, subjecting the endo-type alcohol to a substitution reaction with an acid accompanying the inversion of steric structure and further carrying out the procedure of an alkali hydrolysis to form an exo-type alcohol, etc.

Omega-cycloalkyl-prostaglandin e2 derivative

Abstract: PROBLEM TO BE SOLVED: To obtain the subject new compound having strong binding to EP2 which is a subtype of a prostaglandin E2 (hereinafter referred to as PGE2 ) receptor and useful for the prophylaxis and/or treatment of immunological diseases, asthma, osteodystrophia, etc. SOLUTION: This compound is an ω-cycloalkyl-prostaglandin E2 derivative represented by formula I [R is carboxy or the like; R is oxo, methylene or the like; R is H, hydroxyl group or the like; R is H, a 1-8C alkyl or the like; (n) is 0-4, with the proviso that the bond between the 13- and the 14-positions is not a triple bond when the bond between the 5- and the 6-positions is the triple bond; when the bond between the 13- and the 14-positions is a double bond, the double bond thereof is a mixture of the E-isomer with the Z-isomer and the EZ-isomer], e.g. (5Z,11α,13E)-11,16 dihydroxy-9-oxo-17,17- propanoprosta-5,13-dienoic acid. The compound represented by formula I in which the group R is carboxy is obtained by hydrolyzing a compound represented by formula II (R is a 1-6C alkyl) with an enzyme or under alkaline conditions.

Organic electroluminescent element

Abstract: PROBLEM TO BE SOLVED: To provide an organic electroluminescent element emitting yellow-red- colored light with stable light emitting property for long time SOLUTION: The organic electroluminescent element has a light emitting layer 3 in which, naphthacene derivative shown by the formula (1) is contained In the formula (1), X 1 , X 2 represent oxygen atom, sulfur atom, NH group, or the like, R 1 -R 18 represent hydrogen atom, halogen atom, or phenyl group COPYRIGHT: (C)2003,JPO

Polyamide chains of precise length

Abstract: Provided are chains of precise length and methods for their preparation. These chains are formed by the reaction of a derivative of a diacid and a diamine in a stepwise manner on a support. One of the reactants contains a water soluble oligomer, preferably polyethylene glycol. These chains are then used to chemically modify target macromolecules such as biologically important polypeptides.

A Diazoalkane Derivative of a Polyoxometalate: Preparation and Structure of [Mo6O18(NNC(C6H4OCH3)CH3)]2−

Abstract: A new metathetical route to diazoalkane complexes is described which allows the introduction of such ligands into previously inaccessible environments. The method, which involves the exchange of oxo and [N2 CR2 ] ligands, is illustrated by the preparation of the first diazoalkane-polyoxometalate complex 1.

Strong Hydrogen Bonding to the Amide Nitrogen Atom in an "Amide Proton Sponge": Consequences for Structure and Reactivity.

Abstract: N-Protonated amides have been proposed as intermediates in several biologically important reactions, but they have yet to be identified spectroscopically. The first step toward this goal is now reported in the form of spectroscopic and crystallographic proof of a strong intramolecular hydrogen bond between a charged proton donor and an amide nitrogen atom in the "proton sponge" derivative 1; novel reactivity results from this interaction. TfO-= trifluoromethanesulfonate.

Asymmetric polymerization via cycloaddition reactions

Abstract: The reaction of N-phthaloyl-L-leucine acid chloride (1) with isoeugenol (2) was carried out in chloroform, and novel optically active isoeugenol ester derivative 3 as a chiral monomer was obtained in high yield. Compound 3 was characterized by 1H-NMR, IR, and mass and elemental analysis and then was used for the preparation of model compound 5 and polymerization reactions. 4-Phenyl-1,2,4-triazoline-3,5-dione, PhTD (4), was allowed to react with compound 3. The reaction is very fast and gives only one diastereomer of 5 via Diels–Alder and ene pathways in quantitative yield. In order to explain this diastereoselectivity, a nonconcerted two-step mechanism involving benzylic cation (BC) and aziridinium (AI) have been proposed for the Diels–Alder and ene reactions, respectively. The polymerization reactions of novel monomer 3 with bis(triazolinedione)s [bis(p-3,5-dioxo-1,2,4-triazolin-4-ylphenyl)methane (8) and 1,6-bis(3,5-dioxo-1,2,4-triazolin-4-yl)hexane] (9)] were performed in N,N-dimethylacetamide (DMAc) at room temperature. The reactions are exothermic, fast, and gave novel optically active polymers 10 and 11 via repetitive Diels–Alder–ene polyaddition reactions. These polymers have inherent viscosities in a range about 0.18–0.22 dL/g. Some physical properties and structural characterizations of these new polymers have been studied and are reported. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1211–1219, 1999

Functional chitosan derivative

Abstract: A functional chitosan derivative which comprises a chitin/chitosan, which is a natural polysaccharide, and incorporated therein at least one of a saccharide, a photoreactive functional group, an amphipathic group, e.g., a polyoxyalkylene alkyl ether, and a glycosaminoglycan and which, due to the incorporation, has solubility in a neutral medium, self-crosslinkability, the property of highly containing water or healing wounds, and antithrombogenic properties. Namely, the derivative has various properties required of health care materials such as medical products and cosmetics.