- Palladium-catalyzed asymmetric hydrogenation of furan carboxylic acids
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Enantioselective hydrogenation of aromatic and heteroaromatic compounds is the field where chirally modified metal hydrogenation catalysts have the biggest potential compared to homogeneous chiral transition metal complexes. Here we report the hydrogenation of furan and benzofuran carboxylic acids over a cinchonidine-modified 5 wt% Pd/Al2O3 catalyst. (S)-Tetrahydrofuran-2-carboxylic acid was synthesized in 4 h at rt and 30 bar with 95% yield and 32% ee. The ee was lower in the hydrogenation of methylfuran carboxylic acids but up to 100% de was achieved. In the slow hydrogenation of benzofuran-2-carboxylic acid, the ee went up to 50% at 29% yield. The potential application of the method is limited by the competing hydrogenation of the quinoline rings of cinchonidine in the latter reaction, necessitating the feeding of small amounts of cinchonidine during reaction. Still, this simple method using an easily available chiral modifier and catalyst affords the highest rate and ee reported so far in the catalytic asymmetric hydrogenation of furan and benzofuran carboxylic acids, and it may be an attractive route in combination with optical resolution. We assume that the reaction mechanism is analogous to that described for α,β-unsaturated carboxylic acids over the same catalyst, involving a 1:2-type interaction between the cinchonidine and the acid dimer.
- Maris, Mihaela,Huck, Wolf-Ruediger,Mallat, Tamas,Baiker, Alfons
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Read Online
- Preparation method of tetrahydrofuranacetic acid and ester compounds thereof
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The invention provides a preparation method of tetrahydrofuranacetic acid and ester compounds thereof. The preparation method comprises the following steps: in a proper solvent, in a reducing atmosphere and under the action of a hydrogenation catalyst, carrying out a reduction reaction on furanacetic acid and ester compounds thereof under the conditions that a pressure is 0.1-10MPa and a temperature is 30-250 DEG C for 0.1-72 hours, separating out the catalyst, and distilling out the solvent to obtain the target products, namely tetrahydrofuranacetic acid and the ester compounds thereof. Under relatively mild and environment-friendly conditions, efficient conversion of bio-based furanacetic acid and esters thereof is achieved, industrial production of the reaction is facilitated, platform molecules can be converted into various important intermediates or terminal products through chemical catalysis upgrading to replace existing petrochemical products, dependence on fossil resources is reduced, and the application range of biomass is expanded.
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Paragraph 0018; 0022-0023; 0028
(2021/05/12)
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- Hydrogenolysis of tetrahydrofuran-2-carboxylic acid over tungsten-modified rhodium catalyst
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Catalysts for reduction of tetrahydrofuran-2-carboxylic acid (THFCA), which can be synthesized from furfural via oxidation and hydrogenation, were explored among the combinations of noble metal and reducible metal oxide supported on SiO2. Rh-WOx/SiO2 catalysts showed activity in C-O hydrogenolysis at 2-position of THFCA (to δ-valerolactone and 5-hydroxyvaleric acid) and higher yield ratio of these C-O hydrogenolysis products to carboxylic acid hydrogenation products than other bimetallic catalysts. The activity of Rh-WOx/SiO2 catalysts was highest at W/Rh = 0.25 mol/mol. XRD, TPR, CO adsorption and XAFS characterizations showed that the Rh-WOx/SiO2 (W/Rh = 0.25) catalyst contained Rh metal particles with surface modification with isolated W2+ oxide species. The mechanism that hydride-like species formed on Rh atom attacks the C atom at the α-position (2-position) of adsorbed carboxylate on W atom is proposed based on the similar kinetics and similar catalyst structure to Rh-MOx/SiO2 (M = Re, Mo) which is known to be active in THFA hydrogenolysis to 1,5-pentanediol.
- Asano, Takehiro,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
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- Selective hydrogenolysis of 2-furancarboxylic acid to 5-hydroxyvaleric acid derivatives over supported platinum catalysts
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The conversion of 2-furancarboxylic acid (FCA), which is produced by oxidation of furfural, to 5-hydroxyvaleric acid (5-HVA) and its ester/lactone derivatives with H2 was investigated. Monometallic Pt catalysts were effective, and other noble metals were not effective due to the formation of ring-hydrogenation products. Supports and solvents had a small effect on the performance; however, Pt/Al2O3 was the best catalyst and short chain alcohols such as methanol were better solvents. The optimum reaction temperature was about 373 K, and at higher temperature the catalyst was drastically deactivated by deposition of organic materials on the catalyst. The highest yield of target products (5-HVA, δ-valerolactone (DVL), and methyl 5-hydroxyvalerate) was 62%, mainly obtained as methyl 5-hydroxyvalerate (55% yield). The byproducts were mainly ring-hydrogenation compounds (tetrahydrofuran-2-carboxylic acid and its ester) and undetected ones (loss of carbon balance). The catalyst was gradually deactivated during reuses even at a reaction temperature of 373 K; however, the catalytic activity was recovered by calcination at 573 K. The reactions of various related substrates were carried out, and it was found that the O-C bond in the O-CC structure (1,2,3-position of the furan ring) is dissociated before CC hydrogenation while the presence and position of the carboxyl group (or methoxy carbonyl group) much affect the reactivity.
- Asano, Takehiro,Takagi, Hiroshi,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
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p. 6133 - 6145
(2019/11/20)
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- Molecular features of the prazosin molecule required for activation of Transport-P
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Closely related structural analogues of prazosin have been synthesised and tested for inhibition and activation of Transport-P in order to identify the structural features of the prazosin molecule that appear to be necessary for activation of Transport-P. So far, all the compounds tested are less active than prazosin. It is shown that the structure of prazosin appears to be very specific for the activation. Only quinazolines have been found to activate, and the presence of the 6,7-dimethoxy and 4-amino groups appears to be critically important.
- da Silva, Joaquim Fernando Mendes,Walters, Marcus,Al-Damluji, Saad,Ganellin, C. Robin
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p. 7254 - 7263
(2008/12/23)
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- NAPHTHALENONE COMPOUNDS EXHIBITING PROLYL HYDROXYLASE INHIBITORY ACTIVITY, COMPOSITIONS, AND USES THEREOF
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Compounds of Formula (I) and Formula (II) are useful as inhibitors of HIF prolyl hydroxylases. Compounds of Formula(I) and Formula (II) have the following structures, where the definitions of the variables are provided herein.
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Page/Page column 189-190
(2008/12/06)
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- Asymmetric hydrolysis of 2-hydroxy-carboxylic esters using recombinant Escherichia coli
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Optically active 2-hydroxy-carboxylates are important compounds for their use as intermediates in the synthesis of pharmaceuticals and stereoblock polymers. Enterobacter sp. DS-S-75 and the recombinant Escherichia coli harbouring the 4-chloro-3-hydroxybutyrate (CHB) hydrolase gene from the strain DS-S-75 showed asymmetric hydrolytic activity towards 2-hydroxy-carboxylates, as well as towards CHB. It was discussed that the hydroxyl group in the substrate was particularly important for the asymmetric hydrolytic activity of the CHB hydrolase, and as such, it was re-designated to EnHCH (hydroxy-carboxylic ester hydrolase derived from Enterobacter sp.). Using the recombinant cell, both the reaction rate and the concentration of the substrates were significantly improved upon when compared to that of DS-S-75. Optically active 2-hydroxy-carboxylates could be synthesized on a practical basis for industrial production in this report.
- Nakagawa, Atsushi,Kato, Ko,Shinmyo, Atsuhiko,Suzuki, Toshio
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p. 2394 - 2398
(2008/03/13)
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- PREPARATION OF ALFUZOSIN
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A process for preparing alfuzosin or a salt thereof, which minimizes the concentration of an N1-(4-amino-6,7-dimethoxyquinazolin-2-yl)-N1-methyl-N 2-(4-amino-6,7-dimethoxyquinazolin-2-yl)-propane-1,3-diamine impurity in the product.
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Page/Page column 6
(2008/06/13)
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- AN IMPROVED AND INDUSTRIAL PROCESS FOR THE PREPARATION OF ALFUZOSIN HYDROCHLORIDE AND ITS NOVEL POLYMORPHS
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An improved and industrial process for the preparation of Alfuzosin Hydrochloride and its novel polymorphs (Formula (I)).
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Page/Page column 11
(2008/06/13)
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- Bulky diarylammonium arenesulfonates as mild and extremely active dehydrative ester condensation catalysts
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More environmentally benign alternatives to current chemical processes, especially large-scale, fundamental reactions like ester condensations, are highly desirable for many reactions. Bulky diarylammonium pentafluorobenzenesulfonates and tosylates serve as extremely active dehydration catalysts for the ester condensation reaction of carboxylic acids with equimolar amounts of sterically demanding alcohols and acid-sensitive alcohols. Typically, the esterification reaction is performed in heptane by heating at 80°C in the presence of 1 mol% of the catalyst without removing water. Esterification with primary alcohols proceeds without solvents even at room temperature. Furthermore, 4-(N-mesitylamino)polystyrene resin-bound pentafluorobenzenesulfonate can be recycled more than 10 times without a loss of activity.
- Sakakura, Akira,Nakagawa, Shoko,Ishihara, Kazuaki
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p. 422 - 433
(2007/10/03)
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- METHOD FOR PRODUCING ESTER AND ESTERIFICATION CATALYST
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A process for producing an ester includes the step of allowing a carboxylic acid to react with an alcohol, wherein an ammonium sulfonate is used as an esterification catalyst, the ammonium sulfonate being composed of an ammonium cation having a basic skeleton represented by formula (1) (wherein n represents 1 or 2) in which hydrogen atoms in the benzene rings and hydrogen atoms bonded to bridge carbon may be substituted), and a sulfonic acid anion represented by RSO 3 - (wherein R represents an arene, a perfluoroalkane having 1 to 8 carbon atoms, or a bulky alkane).
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Page/Page column 22
(2008/06/13)
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- SALTS OF SUBSTITUTED ALLOPHANATES AND THEIR USE IN DRUGS
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The invention relates to salts of substituted allophanates, to methods for producing them, to drugs containing said compounds and to the use of said compounds for producing drugs.
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Page/Page column 51-52
(2008/06/13)
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- Electrochemical fluorination of several esters derived from oxolane-2-yl-carboxylic acid, oxolane-2-yl-methanol and oxane-2-yl-methanol
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Electrochemical fluorination (ECF) of the ester derivatives of oxolane-2-yl-carboxylic acid (1), oxolane-2-yl-methanol (2) and oxane-2-yl-methanol (3) were investigated. Perfluoro(oxolane-2-yl- carbonylfluoride) (4) was obtained from derivatives of 1 and 2, and perfluoro(oxane-2-yl-carbonylfluoride) (5) was obtained from derivatives of 3 as the desired compounds, respectively. From the ECF of acetates of 2 and 3, perfluorospiroethers having a dioxolane ring were also obtained as the cyclization product in low yield together with the desired perfluoroacid fluoride (4 and 5). The structure of these perfluorospiroethers was confirmed by analyzing the chlorinated products, which were obtained by the reaction with AlCl3.
- Abe, Takashi,Tamura, Masanori,Sekiya, Akira
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p. 325 - 332
(2007/10/03)
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- Bulky diarylammonium arenesulfonates as selective esterification catalysts
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More environmentally benign alternatives to current chemical processes, especially large-scale, fundamental reactions such as ester condensations, are highly desirable for many reactions. Bulky diarylammonium pentafluorobenzenesulfonates and tosylates serve as extremely active dehydration catalysts for the ester condensation reaction of carboxylic acids with equimolar amounts of sterically demanding alcohols and acid-sensitive alcohols. Typically, the esterification reaction is performed in heptane by heating at 80 °C in the presence of 1 mol % of the catalyst without removing water. Esterification with primary alcohols proceeds without solvents even at room temperature. Furthermore, 4-(N-mesitylamino)polystyrene resin-bound pentafluorobenzenesulfonate can be recycled more than 10 times without activity loss. Copyright
- Ishihara, Kazuaki,Nakagawa, Shoko,Sakakura, Akira
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p. 4168 - 4169
(2007/10/03)
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- A scalable chemoenzymatic preparation of (R)-tetrahydrofuran-2-carboxylic acid
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To develop a practical scalable approach to (R)-tetrahydrofuran-2-carboxylic acid (THFC) 1, a chiral building block for furopenem 2, enantioselective hydrolysis of its esters is explored: When ethyl (±)-tetrahydrofuran-2-carboxylate 3d (2 M, 288 g/L) is digested by an Aspergillus melleus protease {0.2% (w/v)} in a 1.5 M potassium phosphate buffer (pH 8) for 20 h, enantioselective hydrolysis proceeds with E=60 to give (R)-THFC 1 in 94.4% ee. On separation from the left-over antipodal ester (S)-3d by partition, (R)-THFC 1 is treated with N,N-dicyclohexylamine (DCHA) in methyl ethyl ketone/methanol (5:1) to precipitate the crystalline salt 4 that contains (R)-THFC 1 of >99% ee in 22% overall yield from (±)-3d.
- Fujima, Yoshito,Hirayama, Yoshihiro,Ikunaka, Masaya,Nishimoto, Yukifumi
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p. 1385 - 1391
(2007/10/03)
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- Asymmetric protonation of lithium enolate of α-amino acid derivatives using chiral Br?nsted acids
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Chiral alcohols possessing an asymmetric 2-oxazoline ring were synthesized as new chiral Br?nsted acids from tetrahydro-2-furoic acid and (1S, 2R)-2-amino-1,2-diphenylethanol. These alcohols were superior to (S,S)- or (R,R)-imide reported previously as a chiral proton source for enantioselective protonation of lithium enolate of an alanine derivative.
- Yanagisawa,Matsuzaki,Yamamoto
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p. 1855 - 1858
(2007/10/03)
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- Analytical Applications of Raman Spectroscopy in Organic Chemistry: Influence of the Position, Stereochemistry and Substitution Pattern of the Double Bond on the ν(C=C) and ν(sp2CH) Stretching Bands in the Raman Spectra of Alkenyl Methyl Ethers
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The Raman spectra of 29 alkenyl methyl ethers, CnH(2n-1)OCH3, of diverse structure containing up to seven carbon atoms are reported and discussed. All these spectra contain a strong band in the region 1640-1680 cm-1 associated with the stretching vibration of the C=C double bond. Reliable correlations are found between the wavenumber of this band and the position, stereochemistry and substitution pattern of the double bond the band is at higher wavenumber for ethers containing a di- or tri-substituted bond than for those with a monosubstituted bond and at higher wavenumber for trans than cis-stereoisomers. One or more bands in the range 2995-3080 cm-1 associated with the stretching vibration(s) of the sp2C-H bond(s) are also evident in the spectra of most of the ethers, but these bands are sometimes obscured by the stronger bands corresponding to stretching vibrations of the sp3C-H bonds at slightly lower wavenumber (generally below ca. 2950 cm-1). Correlations involving the number and position(s) of these band provide confirmatory evidence on the substitution pattern and stereochemistry of the C=C group. Unequivocal assignment of the symmetric and asymmetric C-H stretching vibrations of the important terminal C=CH2 entity is possible on the basis of these studies; these conclusions are supported by analysis of the Raman spectrum of the deuterium labelled ether CD2=CH(CH2)3OCH3.
- Bowen, Richard D.,Edwards, Howell G. M.,Farwell, Dennis W.,Rusike, Irene,Saunders, Darren M.
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p. 1901 - 1918
(2007/10/03)
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- Bicycloheptane substituted diamide and its congener prostaglandin analogs
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Bicycloheptane substituted amide prostaglandin analogs are provided having the structural formula STR1 wherein m is 0 to 4; A is --CH=CH-- or --CH2 --CH2 --; n is 1 to 5; Q is --CH=CH--, --CH2 --, STR2 or a single bond; R is CO2 H, CO2 alkyl, CO2 alkali metal, CO2 polyhydroxyamine salt, --CH2 OH, STR3 wherein R4 and R5 are the same or different and are H, lower alkyl, hydroxy, lower alkoxy or aryl, at least one of R4 and R5 being other than hydroxy and lower alkoxy; p is 1 to 4; R1 is H or lower alkyl; q is 1 to 12; R2 is H or lower alkyl; and R3 is H, lower alkyl, lower alkenyl, lower alkynyl, aryl, arylalkyl, lower alkoxy, aryloxy, arylalkyloxy, amino, alkylamino arylamino, arylalkylamino, lower alkyl-S-, aryl-S-, arylalkyl-S-, STR4 (wherein n' is 0, 1 or 2), alkylaminoalkyl, arylaminoalkyl, arylalkylaminoalkyl, alkoxyalkyl, aryloxyalkyl or arylalkoxyalkyl. The compounds are cardiovascular agents useful, for example, in the treatment of thrombotic disease.
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- 7-oxabicycloheptane α-substituted ketone prostaglandin analogs useful in the treatment of thrombotic disease
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7-Oxabicycloheptane α-substituted ketone prostaglandin analogs are provided having the structural formula STR1 wherein m is 0 to 4; A is --CH=CH-- or --CH2 --CH2 --; n is 1 to 5; X is halogen, alkanoyloxy or hydroxy; p is 1 to 4; R1 is H or lower alkyl; q is 1 to 12; R2 is H or lower alkyl; and R3 is H, lower alkyl, lower alkenyl, lower alkynyl, aryl, arylalkyl, lower alkoxy, aryloxy, amino, alkylamino, or arylamino. The compounds are cardiovascular agents useful, for example, in the treatment of thrombotic disease.
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- 7-oxabicycloheptane substituted amide-carbamate prostaglandin analogs
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7-Oxabicycloheptane substituted amide-carbamide prostaglandin analogs are provided having the structural formula STR1 wherein m is 0 to 4; A is --CH=CH-- or --CH2 --CH2 --; n is 1 to 5; Q is --CH=CH--, --CH2 --, STR2 or a single bond; R is CO2 H, CO2 alkyl, CO2 alkali metal, CO2 polyhydroxyamine salt, --CH2 OH, STR3 wherein R3 and R4 are the same or different and are H, lower alkyl, hydroxy, lower alkoxy or aryl, at least one of R3 and R4 being other than hydroxy and lower alkoxy; p is 1 to 5; R1 is H or lower alkyl; q is 1 to 12; and R2 is H, lower alkyl, lower alkenyl, lower alkynyl, aryl, or arylalkyl. The compounds are cardiovascular agents useful, for example, in the treatment of thrombotic disease.
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- 7-oxabicycloheptane substituted sulfonamide prostaglandin analogs
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7-Oxabicycloheptane substituted sulfonamide prostaglandin analogs are provided having the structural formula STR1 wherein m is 0 to 4; A is --CH=CH-- or --CH2 --CH2 --; n is 1 to 5; Q is --CH=CH--, --CH2 --, STR2 or a single bond; R is CO2 H, CO2 alkyl, CO2 alkali metal, CO2 polyhydroxyamine salt, --CH2 OH, STR3 wherein R3 and R4 are the same or different and are H, lower alkyl or aryl; p is 1 to 4; R1 is H or lower alkyl; and R2 is H, lower alkyl, lower alkenyl, lower alkynyl, aryl, arylalkyl, cycloalkyl or cycloalkylalkyl. The compounds are cardiovascular agents useful, for example, in the treatment of thrombotic disease.
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- 7-oxabicycloheptane substituted keto-amide prostaglandin analogs useful in the treatment of thrombotic disease
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7-Oxabicycloheptane substituted keto-amide prostaglandin analogs are provided having the structural formula STR1 wherein m is 0 to 4; A is --CH=CH-- or --CH2 --CH2 --; n is 1 to 5; Q is --CH=CH--, --CH2 --, STR2 or a single bond; R is CO2 H, CO2 alkyl, CO2 alkali metal, CO2 polyhydroxyamine salt, STR3 wherein R4 and R5 are the same or different and are H, lower alkyl, hydroxy, lower alkoxy or aryl, at least one of R4 and R5 being other than hydroxy and lower alkoxy; p is 1 to 4; R1 is H or lower alkyl; and R2 is H, lower alkyl, lower alkenyl, aryl, arylalkyl, cycloalkyl or cycloalkylalkyl. The compounds are cardiovascular agents useful, for example, in the treatment of thrombotic disease.
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- 7-oxabicycloheptane substituted thioamide-amide prostaglandin analogs
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7-Oxabicycloheptane substituted thioamideamide prostaglandin analogs are provided having the structural formula STR1 wherein m is 0 to 4; A is --CH=CH-- or --CH2 --CH2 --; n is 1 to 5; Q is --CH=CH--, --CH2 --, STR2 or a single bond; R is CO2 H, CO2 alkyl, CO2 alkali metal, CO2 polyhydroxyamine salt, --CH2 OH, wherein R4 and R5 are the same or different and are H, lower alkyl, hydroxy, lower alkoxy or aryl, at least one of R4 and R5 being other than hydroxy and lower alkoxy; p is 1 to 4; R1 is H or lower alkyl; q is 1 to 12; and R2 R3 are the same or different and are H, lower alkyl, lower alkenyl, lower alkynyl, aryl, arylalkyl, lower alkoxy, aralkyloxy, cycloalkyl or cycloalkylalkyl. The compounds are cardiovascular agents useful, for example, in the treatment of thrombotic disease.
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- 7-oxabicycloheptane substituted diacid diamide prostaglandin analogs
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7-Oxabicycloheptane substituted diacid diamide prostaglandin analogs are provided having the structural formula STR1 wherein m is 0 to 4; A is --CH=CH-- or --CH2 --CH2 --; n is 1 to 5; Q is --CH=CH--, --CH2 --, STR2 or a single bond; R is CO2 H, CO2 alkyl, CO2 alkali metal, CO2 polyhydroxyamine salt, --CH2 OH, STR3 wherein R4 and R5 are the same or different and are H, lower alkyl, hydroxy, lower alkoxy or aryl, at least one of R4 and R5 being other than hydroxy and lower alkoxy; p is 1 to 4; R1 is H or lower alkyl; q is 1 to 12; R2 and R3 are the same or different and are H, lower alkyl, lower alkenyl, lower alkynyl, aryl, arylalkyl, lower alkoxy, aralkyloxy or cycloalkyl. The compounds are cardiovascular agents useful, for example, in the treatment of thrombotic disease.
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- 7-OXABICYCLOHEPTANE SUBSTITUTED DIAMIDE AND ITS CONGENER PROSTAGLANDIN ANALOGS USEFUL IN THE TREATMENT OF THROMBOTIC DISEASE
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7-Oxabicycloheptane substituted amide prostaglandin analogs are provided having the structural formula STR1 wherein m is 0 to 4; A is--CH=CH--or--CH 2--CH 2--; n is 1 to 5; Q is--CH=CH--,--CH 2--, STR2 or a single bond; R is CO 2 H, CO 2 alkyl, CO 2 alkali metal, CO 2 polyhydroxyamine salt,--CH 2 OH, STR3 wherein R. sup.4 and R 5 are the same or different and are H, lower alkyl, hydroxy, lower alkoxy or aryl, at least one of R 4 and R 5 being other than hydroxy and lower alkoxy; p is 1 to 4; R. sup.1 is H or lower alkyl; q is 1 to 12; R 2 is H or lower alkyl; and R 3 is H, lower alkyl, lower alkenyl, lower alkynyl, aryl, arylalkyl, lower alkoxy, aryloxy, arylalkyloxy, amino, alkylamino arylamino, arylalkylamino, STR4 (wherein n' is 0, 1 or 2), alkylaminoalkyl, arylaminoalkyl, arylalkylaminoalkyl, alkoxyalkyl, aryloxyalkyl or arylalkoxyalkyl.The compounds are cardiovascular agents useful, for example, in the treatment of thrombotic disease.
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- 7-oxabicycloheptane substituted amide-sulfonamide prostaglandin analogs useful in the treatment of thrombotic disease
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7-Oxabicycloheptane substituted amide-sulfonamide prostaglandin analogs are provided having the structural formula STR1 wherein m is 0 to 4; A is --CH=CH-- or --CH2 --CH2 --; n is 1 to 5; Q is --CH=CH--, --CH2 --, STR2 or a single bond; R is CO2 H, CO2 alkyl, CO2 alkali metal, CO2 polyhydroxyamine salt, --CH2 OH, STR3 wherein R4 and R5 are the same or different and are H, lower alkyl, hydroxy, lower alkoxy or aryl, at least one of R4 and R5 being other than hydroxy and lower alkoxy; p is 1 to 4; R1 is H or lower alkyl; q is 1 to 12; R2 is H or lower alkyl; and R3 is lower alkyl, aryl, arylalkyl, cycloalkyl or cycloalkylalkyl. The compounds are cardiovascular agents useful, for example, in the treatment of thrombotic disease.
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