- RhCl3-catalyzed hydroboration of alkenyl nitriles
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RhCl3-promoted hydroboration-oxidation reactions of representative alkenyl nitriles have been carried out. Carbanion of acetonitrile is formed from the carbon-carbon heterolytic bond breaking in allyl cyanide during hydroboration. An unexpected process-trimerization of carbanion of acetonitrile has lead to the formation of 4-amino-2,6-dimethylpyrimidine.
- Buranov, Anvar U.,Morrill, Terence C.
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- Reductive metabolism of nabumetone by human liver microsomal and cytosolic fractions: Exploratory prediction using inhibitors and substrates as marker probes
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The metabolic reduction of nabumetone was examined by inhibition and correlation studies using human liver microsomes and cytosol. This reduction was observed in both fractions, with the Vmax values for reduction activity being approximately fourfold higher, and the Vmax/Km values approximately three-fold higher, in the microsomes than in the cytosol. The reduction of nabumetone was inhibited by 18β-glycyrrhetinic acid, an 11β-hydroxysteroid dehydrogenase (11β-HSD) inhibitor, in the microsomal fraction. The reduction activity was also inhibited by quercetin and menadione [carbonyl reductase (CBR) inhibitors], and by phenolphthalein and medroxyprogesterone acetate [potent inhibitors of aldo-keto reductase (AKR) 1C1, 1C2 and 1C4] in the cytosol. A good correlation (r2 = 0.93) was observed between the reduction of nabumetone and of cortisone, as a marker of 11β-HSD activity, in the microsomal fractions. There was also an excellent relationship between reduction of nabumetone and of the AKR1C substrates, acetohexamide, and ethacrynic acid (r2 = 0.92 and 0.93, respectively), in the cytosol fractions. However, a poor correlation was observed between the formation of 4-(6-methoxy-2-naphthyl)-butan-2-ol (MNBO) from nabumetone and CBR activity (with 4-benzoyl pyridine reduction as a CBR substrate) in the cytosol fractions (r2 = 0.24). These findings indicate that nabumetone may be metabolized by 11β-HSD in human liver microsomes, and primarily by AKR1C4 in human liver cytosol, although multiple enzymes in the AKR1C subfamily may be involved. It cannot be completely denied that CBR is involved to some extent in the formation of MNBO from nabumetone in the cytosol fraction.
- Matsumoto, Kaori,Hasegawa, Tetsuya,Kamei, Tomoyo,Koyanagi, Junichi,Takahashi, Tamiko,Akimoto, Masayuki,Sugibayashi, Kenji
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- A mild and facile synthesis of cyclic imides using pyridinium chlorochromate
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A mild and facile synthetic method of cyclic imides is presented. These compounds are widely used in the synthesis of novel medical, polymeric, photonic and electronic materials. Compared with traditional syntheses, the method reported has several advantages including mild conditions, simplified work-up and low cost.
- Yang, Yanyan,Wang, Ge,Cao, Xiaohui,Yan, Xilong,Chen, Ligong
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p. 657 - 658,2
(2020/07/30)
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- Palladium-catalyzed negishi cross-coupling reactions of unactivated alkyl iodides, bromides, chlorides, and tosylates
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A single method (2% Pd2(dba)3/8% PCyp 3/NMI in THF/NMP at 80°C; Cyp = cyclopentyl) achieves the cross-coupling of a range of β-hydrogen-containing primary alkyl iodides, bromides, chlorides, and tosylates with an array of alkyl-, alkenyl-, and arylzinc halides. The process is compatible with a variety of functional groups, including esters, amides, imides, nitriles, and heterocycles.
- Zhou, Jianrong,Fu, Gregory C.
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p. 12527 - 12530
(2007/10/03)
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- Processes for producing epsilon caprolactams
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This invention relates in part to processes for producing one or more substituted or unsubstituted epsilon caprolactams, e.g., epsilon caprolactam, which comprise (a) converting one or more substituted or unsubstituted hydroxyaldehydes, e.g., 6-hydroxyhexanal, optionally in the presence of a catalyst or a catalyst and promoter, to one or more substituted or unsubstituted hydroxyamides, e.g. 6-hydroxycaproamide, and/or one or more substituted or unsubstituted epsilon caprolactam precursors, e.g., 6-aminocaproamide, epsilon caprolactone, epsilon caprolactone oligomers and esters of 6-hydroxycaproic acid and mixtures thereof, and (b) converting said one or more substituted or unsubstituted hydroxyamides and/or said one or more substituted or unsubstituted epsilon caprolactam precursors, optionally in the presence of a catalyst or a catalyst and promoter, to said one or more substituted or unsubstituted epsilon caprolactams; wherein the amount of byproducts resulting from reduction and/or reductive amination of said one or more substituted or unsubstituted hydroxyaldehydes, e.g., 1,6-hexanediol, aminohexanol, and the like, is no greater than about 10 weight percent, preferably no greater than about 5 weight percent, and more preferably no greater than about 1 weight percent, of the total of said one or more substituted or unsubstituted hydroxyamides and/or one or more substituted or unsubstituted epsilon caprolactam precursors. This invention also relates in part to reaction mixtures containing one or more substituted or unsubstituted epsilon caprolactams as principal product(s) of reaction.
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- A mild hydration of nitriles into amides
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Stirring mixtures of β-hydroxynitriles with manganese dioxide, deposited onto silica gel for a few days at room temperature resulted in the formation of the corresponding amides in fair to good yields. The unprecedented conversion of 3-hydroxyglutarodinitrile into the corresponding monoamide has been performed by this methodology.
- Breuilles,Leclerc,Uguen
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p. 1401 - 1404
(2007/10/02)
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- Inhibition by carboxamides and sulfoxides of liver alcohol dehydrogenase and ethanol metabolism
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Sulfoxides and amides were tested as inhibitors of liver alcohol dehydrogenase and ethanol metabolism in rats. With both series of compounds, increasing the hydrophobicity resulted in better inhibition, and introduction of polar groups reduced inhibition. Of the cyclic sulfoxides, tetramethylene sulfoxide was the best inhibitor as compared to the tri- and pentamethylene analogue and other compounds, and it may be a transition-state analogue. The most promising compounds, tetramethylene sulfoxide and isovaleramide, were essentially uncompetitive inhibitors of purified horse and rat liver alcohol dehydrogenases with respect to ethanol as substrate. These compounds also were uncompetitive inhibitors in vivo, which is advantageous since the inhibition is not overcome at higher concentrations of ethanol, as it is with competitive inhibitors, such as pyrazole. The uncompetitive inhibition constants for tetramethylene sulfoxide and isovaleramide for rat liver alcohol dehydrogenase were 200 and 20 μM, respectively, in vitro, whereas in vivo the values were 340 and 180 μmol/kg. The differences in the values may be due to metabolism or distribution of the compounds. Further studies will be required to determine if isovaleramide or tetramethylene sulfoxide is suitable for therapeutic purposes.
- Chadha,Leidal,Plapp
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p. 916 - 922
(2007/10/02)
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