Showing papers on "Derivative (chemistry) published in 1997"

Catalysis by Organic Solids. Stereoselective Diels−Alder Reactions Promoted by Microporous Molecular Crystals Having an Extensive Hydrogen-Bonded Network

Abstract: Anthracenebisresorcinol derivative 1 as an organic network material shows a novel catalysis in the solid state for the acrolein−cyclohexadiene Diels−Alder reaction. The suggested mechanism involves a catalytic cycle composed of sorption of the reactants in the cavities of polycrystalline host 1, preorganized intracavity reaction, and desorption of the product. The host also promotes stereoselective intracavity reactions for alkyl acrylates and cyclohexadiene but, in this case, not in a catalytic manner. Relevance of the present system as a functional organic analog of zeolites is discussed in light of the kinetics of respective elementary processes and the effects of pulverization of the catalyst thereupon as well as X-ray crystal structures.

Organic electroluminescent element material and organic electroluminescent element using the same

Abstract: PROBLEM TO BE SOLVED: To improve luminous efficiency as well as brightness, and extend service life by applying the constitution that a cyclic organic compound is contained in the hole injection layer or the luminous layer of an organic electroluminescent element having a plurality of layers of organic compound thin films, containing at least a luminous layer and a hole injection layer between a pair of electrodes. SOLUTION: A cyclic organic compound is expressed by the formula, and composed, for example, by the use of a naphthoquinone derivative, a Grignard's reagent and a lithiation reagent or diaryl benzoflane. Preferably, a hole injection layer is doped into an area formed with an anode, or the compound expressed by the formula is doped into the host substance of a luminous layer having an electron injection layer in an area formed with a cathode. As a result, carriers injected from the cathode are evenly recombined within the luminous layer. In the formula, (x) represents a halogen atom, a cyano group, an alkyl group, an aryl group, an alcoxy group, an aryloxy group, an alkylthio group, a cycloalkyl group, a heterocyclic group and an amino group, and (i) represents an integer between 1 and 28. COPYRIGHT: (C)1998,JPO

OB fusion protein compositions and methods

Abstract: The present invention relates to Fc-OB fusion protein compositions, methods of preparation of such compositions and uses thereof. In particular, the present invention relates to a genetic or chemical fusion protein comprising the Fc immunoglobulin region, derivative or analog fused to the N-terminal portion of the OB protein, derivative or analog.

Utilization of the Intramolecular Cycloaddition-Cationic pi-Cyclization of an Isomünchnone Derivative for the Synthesis of (+/-)-Lycopodine

Abstract: A new annulation sequence leading to the tetracyclic skeleton of the Lycopodium family of alkaloids is effected by using the tandem cycloaddition-cationic pi-cyclization reaction of an isomunchnone dipole as the key strategic element. Synthesis of the required alpha-diazo imide precursor involved treating 5-methylcyclohex-2-en-1-one with the organocopper reagent derived from 3-methoxybenzyl chloride in the presence of chlorotrimethylsilane. Ozonolysis of the resulting silyl enol ether followed by a Wittig reaction and conversion to the desired alpha-diazo imide was carried out using standard malonylacylation and diazotization procedures. Treatment of the alpha-diazo imide with rhodium(II) perfluorobutyrate afforded a transient 1,3-dipole which subsequently cycloadded across the tethered pi-bond. The resulting cycloadduct was treated with BF(3).2AcOH to give a rearranged tetracyclic compound derived from a Pictet-Spengler-type cyclization of an N-acyliminium ion. The rearranged product was subsequently converted into a key intermediate previously used for the synthesis of (+/-)-lycopodine.

The molecular basis of Celmer's rules: the stereochemistry of the condensation step in chain extension on the erythromycin polyketide synthase.

Abstract: Modular polyketide synthases (PKSs), for example, the 6-deoxyerythronolide B synthase (DEBS) responsible for synthesis of the aglycone core of the macrolide antibiotic erythromycin, generate an impressive diversity of asymmetric centers in their polyketide products. However, as noted by Celmer, macrolides have the same absolute configuration at all comparable stereocenters. Understanding how the stereochemistry of chain extension is controlled is therefore crucial to determining the common mechanism of action of these enzymes. We aimed to elucidate the molecular basis of Celmer's rules through in vitro studies with DEBS 1-TE, a bimodular derivative of DEBS from Saccharopolyspora erythraea, which uses (2S)-methylmalonyl-coenzyme A to produce both d- and l-methyl centers in its triketide lactone product. We show here that condensation of (2S)-methylmalonyl-CoA in module 2 proceeds with decarboxylative inversion without cleavage of the C−H bond adjacent to the methyl group; in contrast, in module 1 the chain...

Methanofullerene Molecular Scaffolding: Towards C60-substituted poly(triacetylenes) and expanded radialenes, preparation of a C60–C70 hybrid derivative, and a novel macrocyclization reaction

Abstract: The synthesis of (E)-hex-3-ene-l, 5-diynes and 3-methylidenepenta-1, 4-diynes with pendant methano[60]-fullerene moieties as precursors to C60-substituted poly(triacetylenes) (PTAs, Fig. 1) and expanded radialenes (Fig. 2) is described. The Bingel reaction of diethyl (E)-2, 3-dialkynylbut-2-ene-1, 4-diyl bis(2-bromopropane-dioates) 5 and 6 with two C60 molecules (Scheme 2) afforded the monomeric, silyl-protected PTA precursors 9 and 10 which, however, could not be effectively desilylated (Scheme 4). Also formed during the synthesis of 9 and 10, as well as during the reaction of C60 with thedesilylated analogue 16 (Scheme5), were the macrocyclic products 11, 12, and 17, respectively, resulting from double Bingel addition to one C-sphere. Rigorous analysis revealed that this novel macrocyclization reaction proceeds with complete regio- and diastereoselectivity. The second approach to a suitable PTA monomer attempted N, N′-dicyclohexylcarbodiimide(DCC)-mediated esterification of (E)-2, 3-diethynylbut-2-ene-l, 4-diol (18, Scheme 6) with mono-esterified methanofullerene-dicarboxylic acid 23; however, this synthesis yielded only the corresponding decarboxylated methanofullerene-carboxylic ester 27 (Scheme 7). To prevent decarboxylation, a spacer was inserted between the reacting carboxylic-acid moiety and the methane C-atom in carboxymethyl ethyl 1, 2-methano[60]fullerene-61, 61-dicarboxylate (28, Scheme 8), and DCC-mediated esterification with diol 18 afforded PTA monomer 32 in good yield. The formation of a suitable monomeric precursor 38 to C60-substituted expanded radialenes was achieved in 5 steps starting from dihydroxyacetone (Schemes 9 and 10), with the final step consisting of the DCC-mediated esterification of 28 with 2-[1-ethynyl(prop-2-ynylidene)]propane-1, 3-diol (33). The first mixed C60-C70 fullerene derivative 49, consisting of two methano[60]fullerenes attached to a methano[70]fullerene, was also prepared and fully characterized (Scheme 13). The Cs-symmetrical hybrid compound was obtained by DCC-mediated esterification of bis[2-(2-hydroxy-ethoxy)ethyl] 1, 2-methano[70]fullerene-71, 71-dicarboxylate (46) with an excess of the C60-carboxylic acid 28. The presence of two different fullerenes in the same molecule was reflected by its UV/VIS spectrum, which displayed the characteristic absorption bands of both the C70 and C60 mono-adducts, but at the same time indicated no electronic interaction between the different fullerene moieties. Cyclic voltammetry showed two reversible reduction steps for 49, and comparison with the corresponding C70 and C60 mono-adducts 46 and 30 indicated that the three fullerenes in the composite fullerene compound behave as independent redox centers.

Sharing the π-Bonding. An Iron Porphyrin Derivative with Trans, π-Accepting Axial Ligands. Synthesis, EPR and Mössbauer Spectra, and Molecular Structure of Two Forms of the Complex Nitronitrosyl(α,α,α,α-tetrakis(o-pivalamidophenyl)- porphinato)ferrate(II)

Abstract: The reaction of the iron(II) picket fence porphyrin derivative [Fe(TpivPP)(NO2)]- (Nasri et al. J. Am. Chem. Soc. 1991, 113, 717) with NO has been examined. The result is a new hexacoordinated iron...

Highly branched polyamidoamines and their preparation

Abstract: An intralinked polyamidoamine which is nonthermosetting and endcapped. This intralinked polyamidoamine is the reaction product of a dicarboxylic acid or dicarboxylic acid derivative, a polyamine, an endcapping agent, and an intralinker.

INSULIN PREPARATIONS CONTAINING NaCl

Abstract: Insulin preparations of superior chemical stability, comprising human insulin or an analogue or derivative thereof, glycerol and/or mannitol, and 5 to 100 mM of the halogenide are disclosed.

Asymmetric Total Synthesis of Taxol

Abstract: Asymmetric total syntheses of Taxol and of 8-demethyltaxoids 24-27 from the 8-membered ring compounds 29 and 12 respectively were completed via successive formation of the BC ring system by intramolecular aldol reaction, then the ABC ring system utilizing an intramolecular pinacol cyclization. The conversion of the tricyclic compound 43 to 7-TES baccatin III (49) was carried out by way of a newly devised method of constructing the oxetane ring. The dehydration condensation between a derivative of N- benzoylphenylisoserine and 49, followed by deprotection afforded the antitumor agent Taxol.

Isolation and chemical-structural determination of a novel aromatic amine mutagen in water from the Nishitakase River in Kyoto.

Abstract: Water samples from the Nishitakase River in Kyoto, Japan, especially taken at sites below sewage plants, show significantly high mutagenicity in the Ames test. In the present study, mutagens in the river water were adsorbed to 24 g of blue rayon, extracted, and separated by HPLC on ODS columns. Five mutagenic compounds (I-V) were isolated, and they accounted for 21%, 17%, 11%, 12%, and 6%, respectively, of the total mutagenicity of the blue rayon-adsorbed materials. With compound I obtained from adsorbate to 24 g of blue rayon as a marker, a large quantity (1.1 mg) of mutagenic compound I was isolated by Sephadex LH-20 column chromatography and HPLC on ODS columns from material adsorbed to 27 kg of blue cotton. X-ray crystal analysis was carried out with the debrominated derivative of compound I. Based on this X-ray crystallography data and the UV, mass, and 1H-NMR spectra of both the derivative and compound I, the structure of compound I was determined to be 2-[2-(acetylamino)-4-[bis(2-methoxyethyl)amino]-5-methoxyphenyl]-5-amino - 7-bromo-4-chloro-2H-benzotriazole (PBTA-1). PBTA-1 is a newly identified potent mutagen, inducing 1,200,000 revertants of Salmonella typhimurium YG1024 per microgram in the presence of S9 mix.

Total Synthesis of Archaeal 36-Membered Macrocyclic Diether Lipid

Abstract: Total synthesis of archaeal 36-membered macrocyclic diether lipid 2 is reported The synthesis is based upon stereoselective preparation of functionalized isoprenoid chains, ether-linkage formation between the isoprenoid chains with a glycerol derivative, and the ultimate intramolecular dicarbonyl coupling using low-valent titanium known as McMurry coupling This synthetic method has successfully provided the first practical route to chemically defined archaeal macrocyclic membrane lipids, which were not available because of the lack of synthetic access Also described is a highly stereoselective and convenient synthesis of stereochemically homogeneous archaeal biphytanyl glycerol lipid 1

Synthesis of 2'-o,3'-c-linked bicyclic nucleosides and bicyclic oligonucleotides

Abstract: The 3′-C-allyl furanose 4 has been used as a precursor for synthesis of the novel 2′-O,3′-C-linked bicyclic thymine nucleosides 15, 16, 20 and 25. The three bicyclic β-nucleosides 15, 20 and 25 have been incorporated into oligodeoxynucleotides. One of these nucleosides, dioxabicyclo[3.3.0]octane derivative 25, induces increased thermal stability of duplexes towards complementary RNA.

Photoelectrochemical Responses of Polymer Langmuir-Blodgett Films Containing Tris(2, 2'-bipyridine)ruthenium(II)Complex

Abstract: The tris(2,2‘-bipyridine)ruthenium(II) complex (Ru(bpy)32+) derivative monomer was copolymerized with N-tert-pentylacrylamide and N-dodecylacrylamide. These copolymers, p(tPA-Ru) and p(DDA-Ru), for...

Oral composition of fumagillol derivative

Abstract: The present invention relates to a pharmaceutical composition for oral administration in which a fumagillol derivative is stabilized and exhibits remarkable antiangiogenesis activity in oral administration.

Perfect on/off switching of emission of fluorescence by photochromic reaction of a binaphthol-condensed fulgide derivative

Abstract: While the colorless form of the propyl-substituted, binaphthol-condensed indolylfulgide did not emit fluorescence, its colored form, generated by the UV-light irradiation, emitted fluorescence in toluene at room temperature. Thus, a perfect on/off switching system of fluorescence controlled by the photochromic reaction has been exhibited.