1119-16-0Relevant articles and documents
Oxidation of alcohols with tetramethylammonium fluorochromate in aceticoi acid
Sadeghy,Ghammami
, p. 1886 - 1888 (2005)
A number of alcohols were oxidized to the corresponding carbonyl compounds in excellent yields using tetramethylammonium fluorochromate in acetic acid. The oxidant takes up two electrons, the reaction follows first-order kinetics with respect to the oxidant under pseudofirst-order conditions, and the concentration of alcohols changes according to the Michaelis-Menten dependence.
The desA and desB genes from Clostridium scindens ATCC 35704 encode steroid-17,20-desmolase
Devendran, Saravanan,Mythen, Sean M.,Ridlon, Jason M.
, p. 1005 - 1014 (2018)
Clostridium scindens is a gut microbe capable of removing the side-chain of cortisol, forming 11?-hydroxyandrostenedione. A cortisol-inducible operon (desABCD) was previously identified in C. scindens ATCC 35704 by RNA-Seq. The desC gene was shown to encode a cortisol 20?-hydroxysteroid dehydrogenase (20?-HSDH). The desD encodes a protein annotated as a member of the major facilitator family, predicted to function as a cortisol transporter. The desA and desB genes are annotated as N-terminal and C-terminal transketolases, respectively. We hypothesized that the DesAB forms a complex and has steroid-17,20-desmolase activity. We cloned the desA and desB genes from C. scindens ATCC 35704 in pETDuet for overexpression in Escherichia coli. The purified recombinant DesAB was determined to be a 142 ± 5.4 kDa heterotetramer. We developed an enzyme-linked continuous spectrophotometric assay to quantify steroid- 17,20-desmolase. This was achieved by coupling DesABdependent formation of 11?-hydroxyandrostenedione with the NADPH-dependent reduction of the steroid 17-keto group by a recombinant 17?-HSDH from the filamentous fungus, Cochliobolus lunatus. The pH optimum for the coupled assay was 7.0 and kinetic constants using cortisol as substrate were Km of 4.96 ± 0.57 μM and kcat of 0.87 ± 0.076 min?1. Substrate- specificity studies revealed that rDesAB recognized substrates regardless of 11?-hydroxylation, but had an absolute requirement for 17,21-dihydroxy 20-ketosteroids.- Devendran, S., S. M. Mythen, and J. M. Ridlon. The desA and desB genes from Clostridium scindens ATCC 35704 encode steroid-17,20-desmolase.
Structural Determination of a Highly Branched C25 Sedimentary Isoprenoid Biomarker by NMR Spectroscopy and Mass Spectrometry
Belt, Simon T.,Cooke, David A.,Hird, Simon J.,Rowland, Steve
, p. 2077 - 2078 (1994)
The C25 diene 2,6,10,14-tetramethyl-7-(3-methylpent-4-enyl)pentadec-5-ene has been isolated from benthic sediments and characterised by 1H and 13C NMR spectroscopy together with mass spectrometry.
An organocatalytic enantioselective direct α-heteroarylation of aldehydes with isoquinoline: N -oxides
Bertuzzi, Giulio,Pecorari, Daniel,Bernardi, Luca,Fochi, Mariafrancesca
, p. 3977 - 3980 (2018)
A new protocol for the enantioselective direct α-heteroarylation of aldehydes with isoquinoline N-oxides, via chiral enamine catalysis, has been successfully developed. High enantiomeric excesses and moderate to good yields were achieved for a variety of α-heteroarylated aldehydes.
Nucleophilic Dearomatization of Pyridines under Enamine Catalysis: Regio-, Diastereo-, and Enantioselective Addition of Aldehydes to Activated N-Alkylpyridinium Salts
Bertuzzi, Giulio,Sinisi, Alessandro,Pecorari, Daniel,Caruana, Lorenzo,Mazzanti, Andrea,Bernardi, Luca,Fochi, Mariafrancesca
, p. 834 - 837 (2017)
Catalytic addition of chiral enamines to azinium salts is a powerful tool for the synthesis of enantioenriched heterocycles. An unprecedented asymmetric dearomative addition of aldehydes to activated N-alkylpyridinium salts is presented. The process exhibits complete C-4 regioselectivity along with high levels of diastereo- and enantiocontrol, achieving a high-yielding synthesis of a broad range of optically active 1,4-dihydropyridines. Moreover, the presented methodology enables the synthesis of functionalized octahydropyrrolo[2,3-c]pyridines, the core structure of anticancer peptidomimetics.
Activation of molecular hydrogen in cobalt-catalyzed hydroformylation
Pino, Piero,Major, Arpad,Spindler, Felix,Tannenbaum, Rina,Bor, Gyeorgy,Horvath, Istvan T.
, p. 65 - 76 (1991)
The mechanism of the activation of molecular hydrogen in cobalt-catalyzed hydroformylation of olefins has been studied by high pressure IR spectroscopy using HCo(CO)4 (1) under 100 bar H2 (or D2) in the absence or presence of CO at room temperature.The treatment of 1 with 100 bar H2 resulted in the formation of Co2(CO)8 (2) and a small amount of Co4(CO)12 (3), and the transient formation of HCo3(CO)9 (4).In the reaction of 1 with one equivalent of 3,3-dimethyl-butene-1 under 100 bar H2 both hydrogenation and hydroformylation occur, but the former is much faster.In the presence of large amounts of 1 the predominant path for the hydrogenation of the olefin involves the reaction of two equivalents of 1 with the olefin even under 100 bar of H2.Under a very low partial pressure of CO the stability of 1 is increased and the hydrogenation significant slowed down.The preferred path of the hydroformylation of the olefin involves the addition of H2 and CO from gas phase even in the presence of large amount of HCo(CO)4 (1) under 100 bar H2 and 2.3 bar CO at room temperature.The studies reveal that the mechanism of H2 activation in the presence of HCo(CO)4 (1) is highly dependent on the reaction conditions.Under 100 bar H2 and at rom temperature the activation of molecular hydrogen starts at a coordinatively unsaturated acyl cobalt carbonyl, yielding an aldehyde and an unknown cobalt species.It is believed that this species is a coordinatively unsaturated hydriodo cobalt carbonyl like (HCo(CO)3>, and can activate and catalytically hydroformylate the olefin.
ON THE CATALYTIC AMIDOCARBONYLATION OF SUBSTITUTED ALLYLIC ALCOHOLS
Yuan, Sun-Shine,Ajami, Alfred M.
, p. 255 - 258 (1986)
Substituted allylic alcohols (3-methyl-2-buten-1-ol and 2-methyl-3-buten-2-ol) were isomerized and amidocarbonylated.In addition to the expected product, N-acetylleucine, arising from their rearrengement to 3-methylbutanal and subsequent amidocarbonylation (22percent yield), we isolated two additional products (28percent yield).These were shown by spectroscopic methods and by syntheses, via amidocarbonylations of the respective aldehydes, to be 2-acetamido-5-methylhexanoic acid and 2-acetamido-4-methylhexanoic acid.Their formation is postulated to be the sequential result of (i) dehydration first to form isoprene, (ii) hydroformylation and hydrogenation of isoprene to give 3-methyl-1-pentanal and 4-methyl-1-pentanal, and (iii) aldehyde amidocarbonylation.Treatment of isoprene itself under the same conditions also gave these latter two acetylamino acids.
Isotope-Labeling Studies Support the Electrophilic Compound i Iron Active Species, FeO3+, for the Carbon-Carbon Bond Cleavage Reaction of the Cholesterol Side-Chain Cleavage Enzyme, Cytochrome P450 11A1
Yoshimoto, Francis K.,Jung, I-Ji,Goyal, Sandeep,Gonzalez, Eric,Guengerich, F. Peter
, p. 12124 - 12141 (2016)
The enzyme cytochrome P450 11A1 cleaves the C20-C22 carbon-carbon bond of cholesterol to form pregnenolone, the first 21-carbon precursor of all steroid hormones. Various reaction mechanisms are possible for the carbon-carbon bond cleavage step of P450 11A1, and most current proposals involve the oxoferryl active species, Compound I (FeO3+). Compound I can either (i) abstract an O-H hydrogen atom or (ii) be attacked by a nucleophilic hydroxy group of its substrate, 20R,22R-dihydroxycholesterol. The mechanism of this carbon-carbon bond cleavage step was tested using 18O-labeled molecular oxygen and purified P450 11A1. P450 11A1 was incubated with 20R,22R-dihydroxycholesterol in the presence of molecular oxygen (18O2), and coupled assays were used to trap the labile 18O atoms in the enzymatic products (i.e., isocaproaldehyde and pregnenolone). The resulting products were derivatized and the 18O content was analyzed by high-resolution mass spectrometry. P450 11A1 showed no incorporation of an 18O atom into either of its carbon-carbon bond cleavage products, pregnenolone and isocaproaldehyde. The positive control experiments established retention of the carbonyl oxygens in the enzymatic products during the trapping and derivatization processes. These results reveal a mechanism involving an electrophilic Compound I species that reacts with nucleophilic hydroxy groups in the 20R,22R-dihydroxycholesterol intermediate of the P450 11A1 reaction to produce the key steroid pregnenolone.
Synthesis and structural confirmation of calibagenin and saxosterol
Makino, Katsunori,Mizutani, Masaharu,Takaya, Hikaru,Watanabe, Bunta
supporting information, (2021/06/07)
Calibagenin and saxosterol are cholesterol-based plant steroids isolated from Calibanus hookerii and Narthecium ossifragum, respectively. To date, the configurations of their 16- and 22-hydroxy groups have not yet been determined. In this study, all the four 16,22-stereoisomers were chemically synthesized. The 1H and 13C NMR spectra were fully assigned using 2D NMR techniques, and the structures were determined unambiguously using X-ray crystallography. The H-18 and H-22 signals in the NMR spectra of the products are diagnostic for determining the configurations of the 16- and 22-hydroxy groups. A comparison of the NMR, [α]D, and mp data of the four isomers with those of natural calibagenin and saxosterol confirmed that the configurations of the 16- and 22-hydroxy groups of the former and the later are identical to 16β,22S and 16β,22R, respectively.
COMPOUND FOR TREATMENT OF RABIES AND METHOD FOR TREATMENT OF RABIES
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Paragraph 0299; 0304, (2021/06/25)
The present disclosure provides a compound that is useful for the treatment and prevention of rabies. The present disclosure provides a compound represented by formula IF or formula IB: wherein R1, R2, R3, and R4 are defined in the specification, a solvate, or a pharmaceutically acceptable salt thereof, use of such compound, solvate, or pharmaceutically acceptable salt thereof for the treatment or prevention of rabies, a pharmaceutical composition comprising such compound, solvate, or pharmaceutically acceptable salt thereof, and a method for treating or preventing rabies using the same.
