Disease relevance of Hydrogenation

• Trans isomers of fatty acids, formed by the partial hydrogenation of vegetable oils to produce margarine and vegetable shortening, increase the ratio of plasma low-density-lipoprotein to high-density-lipoprotein cholesterol, so it is possible that they adversely influence risk of coronary heart disease (CHD) [1].
• The primary signal in the biological perception of temperature: Pd-catalyzed hydrogenation of membrane lipids stimulated the expression of the desA gene in Synechocystis PCC6803 [2].
• Hydrogenation of cis-9,trans-11-octadecadienoic acid to yield trans-11-octadecenoic acid by cell-free preparations of Butyrivibrio fibrisolvens has been obtained under strictly anaerobic conditions [3].
• The formal dehydration of two vicinal phenol moieties of p-tert-butylcalix[6]arene was achieved in two steps by mild oxidation of the calixarene followed by treatment of the resulting monospirodienone derivative (9c) with an ionic hydrogenation mixture (Et(3)SiH/CF(3)COOH) [4].
• Initial hydrogenation during catabolism of picric acid by Rhodococcus erythropolis HL 24-2 [5].

Psychiatry related information on Hydrogenation

• The diastereoisomer of III (VII), obtained by hydrogenation of the methobromide of I (IV), extrusion of methyl bromide, and O-demethylation of the resultant free base (VIII), was almost inactive antinociceptively and did not suppress withdrawal symptoms in morphine-dependent monkeys [6].
• Platinum-oxide hydrogenation of 5-m-methoxyphenyl-2-methyl-9-oxomorphan (I) gave the 9 alpha-hydroxy racemate (II) whose phenolic analogue (III) is a strong antinociceptive agent, fully supportive of morphine dependence in rhesus monkeys [6].

High impact information on Hydrogenation

• Here we report direct observations of the structure of supported metal clusters consisting of four iridium atoms, and the identification of hydrocarbon ligands bound to them during propene hydrogenation [7].
• We propose a reaction mechanism whereby TrmE actively participates in the formylation reaction of uridine and regulates the ensuing hydrogenation reaction of a Schiff's base intermediate [8].
• Although catalytic hydrogenation has been practiced for over a century, use of hydrogen as a terminal reductant in catalytic C-C bond formation has been restricted to processes involving migratory insertion of carbon monoxide, e.g., alkene hydroformylation and related Fischer-Tropsch-type reactions [9].
• These catalysts have demonstrated their utility in the enantioselective hydrogenation of the tetrasubstituted cyclopentenone "dehydrodione", which leads to the commercially important perfume component Paradisone (Firmenich) [10].
• The selective hydrogenations of polyenes (such as 1,5,9-cyclododecatriene and 2,5-norbornadiene) are especially efficient [11].

Chemical compound and disease context of Hydrogenation

• 3beta-Hydroxyandrost-5-en-17-one acetate VII was converted to ethyl 3beta-acetoxypregn-5-en-21-oate XIIa via a Reformatsky reaction followed by dehydration of adduct VIIIa and selective hydrogenation of the diene X [12].
• The reduction of L-carnitine proceeded in two steps: (1) Dehydration of the L-carnitine to crotonobetaine, (2) hydrogenation of crotonobetaine to gamma-butyrobetaine [13].
• The diamine (+)-(1,3/2,6)-3,6-diamino-1-O-(beta-D-galactopyranosyl)-2-hydroxycycl ohexane, derived from compound 3 by catalytic hydrogenation, is stable against enzymic cleavage and competitively inhibits beta-D-galactosidase from Escherichia coli with a Ki-value of 5.5 mM [14].
• For this strain and for Clostridium kluyveri DSM 555 grown on ethanol/acetate/hydrogencarbonate, samples of 200-l batches were assayed to determine the hydrogenation activity for (E)-2-methyl-2-butenoate and (E)-2-buten-1-ol as a function of time during the exponential and stationary growth phases [15].
• To discover the specificity of Streptomyces beta-xylanase toward xylan having glucose stubs, glucoxylan was prepared by the hydrogenation of cotton-seed cake glucuronoxylan [16].

Biological context of Hydrogenation

• Reductive alkylation of proteins using iridium catalyzed transfer hydrogenation [17].
• Kinetics and mechanism of N2 hydrogenation in bis(cyclopentadienyl) zirconium complexes and dinitrogen functionalization by 1,2-addition of a saturated C-H bond [18].
• Similar one-pot esterifications and hydrogenations by sol-gel entrapped lipase and heterogenized rhodium complexes were carried out successfully with the saturated nonoic, undecanoic, and lauric acids together with several saturated and unsaturated alcohols [19].
• In the first phase metathesis-mediated dimerization of an aminodeoxymonosaccharide which was either allylated at the anomeric center or at C4 led to E/Z mixtures of C2-symmetric homodimers which were transformed into the corresponding 1,4-butanediol linked disaccharides by catalytic hydrogenation of the central olefinic double bond [20].
• [reaction: see text] A one-pot tandem cross-metathesis/hydrogenation/cyclization procedure was achieved at room temperature, under 1 atm of hydrogen, in the presence of a ruthenium catalyst and PtO(2) showing the compatibility of the two catalysts [21].

Anatomical context of Hydrogenation

• The Pd-catalyzed hydrogenation of plasma membrane lipids stimulated the expression of the desA gene [2].
• Relationship between lipid saturation and lipid-protein interaction in liver mitochondria modified by catalytic hydrogenation with reference to cardiolipin molecular species [22].
• We suggest that using Pd(QS)2 catalyst for thylakoid hydrogenation offers an excellent technique to study the role of various unsaturated fatty acids in the regulation of membrane fluidity and photosynthetic processes [23].
• The results demonstrated that when the 2'-position of (-)-dehydrogriseofulvin was substituted with a methyl group, its hydrogenation with the cell-free system occurred stereoselectively at the 5',6'-position [24].
• The fatty acyl chain composition of human normal and leukaemic lymphocytes and its modulation by specialised hydrogenation [25].

Associations of Hydrogenation with chemical compounds

• Hydrogen atoms emerging from the bulk of Ni metal to the surface are observed to be the reactive species in the hydrogenation of adsorbed methyl radical, ethylene, and acetylene to gas-phase products [26].
• Phase separation of the constituents of catalytic systems eliminated substrate inhibition (hydrogenation of aldehydes) and helped formation of catalytically active species ([RhH(PPh(3))(3)] from [RhCl(PPh(3))(3)] in hydrogenation of acetophenone) [27].
• Intradendrimer hydrogenation and carbon-carbon coupling reactions in water, organic solvents, biphasic fluorous/organic solvents, and supercritical CO2 are also described [28].
• The diphosphine ligand was found to be highly effective in the asymmetric hydrogenation of alpha- and beta-ketoesters, 2-(6'-methoxy-2'-naphthyl)propenoic acid, beta-(acylamino)acrylates, and enol acetates [29].
• (ii) The koff for NADH from its GPDH complex is 60 sec-1 rather than 9.4 sec-1 in Tris.HCl buffer (pH 7.4) at 25 degrees C. With this value one can explain kcat = 50 sec-1 for LDH-catalyzed hydrogenation of pyruvate with GPDH-bound NADH as coenzyme [30].

Gene context of Hydrogenation

• A chemoselective conversion of bastadin-4 to the important Ca2+ channel modulator bastadin-5 (1a) has been achieved using cationic hydrogenation (Et3SiH, TFA, 60%) [31].
• Sodium borohydride reduction of the antioxidant had no effect on the UV absorption, whereas platinum-catalyzed hydrogenation ablated all absorption peaks [32].
• The experimental heat of hydrogenation of 1, obtained from a thermochemical cycle, was found to be 91 +/- 9 kcal/mol [33].
• Asymmetric hydrogenation of tert-alkyl ketones [34].
• A solution containing mainly Delta/Lambda-c,c-3a reacts with acetophenone under Ar to give (S)-1-phenylethanol in 20% ee, whereas it is an active precatalyst for its hydrogenation under 5 atm H(2) to give 1-phenylethanol with an ee of 50-60% [35].

Analytical, diagnostic and therapeutic context of Hydrogenation

• The identities of HPLC peaks coinciding with unsaturated species of both phenacyl esters and methyl esters were confirmed by reanalyzing them after catalytic hydrogenation [36].
• Inhibition studies and gel filtration patterns reveal the presence of at least two hydrogenation systems, one of which is coupled through a flavin, possibly FMN [3].
• NMR imaging of the distribution of the liquid phase in a catalyst pellet during alpha-methylstyrene evaporation accompanied by its vapor-phase hydrogenation [37].
• Initial hydrogen transfer can take place from the metal to the carbene to give the imidazolium ring hydrogenation product, as shown by isotope labeling; this hydrogen transfer proves reversible on reflux when the abnormal aromatic carbene is obtained as final product [38].
• Structural analyses were undertaken after partial hydrogenation of their concentrates with hydrazine hydrate and subsequent isolation of the monoenoate products by argentation thin-layer chromatography [39].

References