7452-79-1Relevant articles and documents
PROCESSES FOR PREPARING A 2-(1,2,2-TRIMETHYL-3-CYCLOPENTENYL)-2-OXOETHYL CARBOXYLATE COMPOUND AND HYDROXYMETHYL 1,2,2-TRIMETHYL-3-CYCLOPENTENYL KETONE, AND A HALOMETHYL (1,2,2-TRIMETHYL-3-CYCLOPENTENYL) KETONE COMPOUND
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Paragraph 0026; 0328, (2021/04/23)
A process for preparing a 2-(1,2,2-trimethyl-3-cyclopentenyl)-2-oxoethyl carboxylate compound of the following general formula (6), wherein R represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, the process comprising esterifying a 2-(1,2,2-trimethyl-3-cyclopentenyl)-2-oxoethyl compound of the following general formula (5), wherein X represents a hydroxyl group or a halogen atom, to form the 2-(1,2,2-trimethyl-3-cyclopentenyl)-2-oxoethyl carboxylate compound (6).
Synthesis and mass spectra of rearrangement bio-signature metabolites of anaerobic alkane degradation via fumarate addition
Chen, Jing,Zhou, Lei,Liu, Yi-Fan,Hou, Zhao-Wei,Li, Wei,Mbadinga, Serge Maurice,Zhou, Jing,Yang, Tao,Liu, Jin-Feng,Yang, Shi-Zhong,Wu, Xiao-Lin,Gu, Ji-Dong,Mu, Bo-Zhong
, (2020/05/01)
Metabolite profiling in anaerobic alkane biodegradation plays an important role in revealing activation mechanisms. Apart from alkylsuccinates, which are considered to be the usual biomarkers via fumarate addition, the downstream metabolites of C-skeleton rearrangement can also be regarded as biomarkers. However, it is difficult to detect intermediate metabolites in both environmental samples and enrichment cultures, resulting in lacking direct evidence to prove the occurrence of fumarate addition pathway. In this work, a synthetic method of rearrangement metabolites was established. Four compounds, namely, propylmalonic acid, 2-(2-methylbutyl)malonic acid, 2-(2-methylpentyl)malonic acid and 2-(2-methyloctyl)malonic acid, were synthesized and determined by four derivatization approaches. Besides, their mass spectra were obtained. Four characteristic ions were observed at m/z 133 + 14n, 160 + 28n, 173 + 28n and [M - (45 + 14n)]+ (n = 0 and 2 for ethyl and n-butyl esters, respectively). For methyl esterification, mass spectral features were m/z 132, 145 and [M - 31]+, while for silylation, fragments were m/z 73, 147, 217, 248, 261 and [M - 15]+. These data provide basis on identification of potential rearrangement metabolites in anaerobic alkane biodegradation via fumarate addition.
Mononuclear ruthenium complex and organic synthesis reaction using same
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Page/Page column 42; 46, (2018/03/26)
A neutral or cationic mononuclear ruthenium divalent complex represented by formula (1) can actualize exceptional catalytic activity in at least one reaction among a hydrosilylation reaction, hydrogenation reaction, and carbonyl compound reduction reaction. (In the formula, R1-R6 each independently represent a hydrogen atom or an alkyl group, aryl group, aralkyl group, organooxy group, monoorganoamino group, diorganoamino group, monoorganophosphino group, diorganophosphino group, monoorganosilyl group, diorganosilyl group, triorganosilyl group, or organothio group optionally substituted by X; at least one pair comprising any of R1-R3 and any of R4-R6 together represents a crosslinkable substituent; X represents a halogen atom, organooxy group, monoorganoamino group, diorganoamino group, or organothio group; L each independently represent a two-electron ligand other than CO and thiourea ligands; two L may bond to each other; and m represents an integer of 3 or 4.)
Transfer Hydrogenation of Alkenes Using Ethanol Catalyzed by a NCP Pincer Iridium Complex: Scope and Mechanism
Wang, Yulei,Huang, Zhidao,Leng, Xuebing,Zhu, Huping,Liu, Guixia,Huang, Zheng
supporting information, p. 4417 - 4429 (2018/04/05)
The first general catalytic approach to effecting transfer hydrogenation (TH) of unactivated alkenes using ethanol as the hydrogen source is described. A new NCP-type pincer iridium complex (BQ-NCOP)IrHCl containing a rigid benzoquinoline backbone has been developed for efficient, mild TH of unactivated C-C multiple bonds with ethanol, forming ethyl acetate as the sole byproduct. A wide variety of alkenes, including multisubstituted alkyl alkenes, aryl alkenes, and heteroatom-substituted alkenes, as well as O- or N-containing heteroarenes and internal alkynes, are suitable substrates. Importantly, the (BQ-NCOP)Ir/EtOH system exhibits high chemoselectivity for alkene hydrogenation in the presence of reactive functional groups, such as ketones and carboxylic acids. Furthermore, the reaction with C2D5OD provides a convenient route to deuterium-labeled compounds. Detailed kinetic and mechanistic studies have revealed that monosubstituted alkenes (e.g., 1-octene, styrene) and multisubstituted alkenes (e.g., cyclooctene (COE)) exhibit fundamental mechanistic difference. The OH group of ethanol displays a normal kinetic isotope effect (KIE) in the reaction of styrene, but a substantial inverse KIE in the case of COE. The catalysis of styrene or 1-octene with relatively strong binding affinity to the Ir(I) center has (BQ-NCOP)IrI(alkene) adduct as an off-cycle catalyst resting state, and the rate law shows a positive order in EtOH, inverse first-order in styrene, and first-order in the catalyst. In contrast, the catalysis of COE has an off-cycle catalyst resting state of (BQ-NCOP)IrIII(H)[O(Et)···HO(Et)···HOEt] that features a six-membered iridacycle consisting of two hydrogen-bonds between one EtO ligand and two EtOH molecules, one of which is coordinated to the Ir(III) center. The rate law shows a negative order in EtOH, zeroth-order in COE, and first-order in the catalyst. The observed inverse KIE corresponds to an inverse equilibrium isotope effect for the pre-equilibrium formation of (BQ-NCOP)IrIII(H)(OEt) from the catalyst resting state via ethanol dissociation. Regardless of the substrate, ethanol dehydrogenation is the slow segment of the catalytic cycle, while alkene hydrogenation occurs readily following the rate-determining step, that is, β-hydride elimination of (BQ-NCOP)Ir(H)(OEt) to form (BQ-NCOP)Ir(H)2 and acetaldehyde. The latter is effectively converted to innocent ethyl acetate under the catalytic conditions, thus avoiding the catalyst poisoning via iridium-mediated decarbonylation of acetaldehyde.
Hepta-, hexa-, penta-, tetra-, and trisaccharide resin glycosides from three species of Ipomoea and their antiproliferative activity on two glioma cell lines
León-Rivera, Ismael,del Río-Portilla, Federico,Enríquez, Raúl G.,Rangel-López, Edgar,Villeda, Juana,Rios, María Yolanda,Navarrete-Vázquez, Gabriel,Hurtado-Días, Israel,Guzmán-Valdivieso, Ulises,Nú?ez-Urquiza, Verónica,Escobedo-Martínez, Carolina
, p. 214 - 223 (2017/03/05)
Six new partially acylated resin glycosides were isolated from convolvulin of Ipomoea purga, Ipomoea stans, and Ipomoea murucoides (Convolvulaceae). The structures of compounds 1–6 were elucidated by a combination of NMR spectroscopy and mass spectrometry. The structure of jalapinoside B (1) consists of a hexasaccharide core bonded to an 11-hydroxytetradecanoic (convolvulinic) acid forming a macrolactone acylated by a 2-methylbutanoyl, a 3-hydroxy-2-methylbutanoyl, and a quamoclinic acid B units. Purginoic acid A (2) contains a hexasaccharide core bonded to a convolvulinic acid acylated by a 3-hydroxy-2-methylbutanoyl unit. Stansin A (4) is an ester-type heterodimer, and consists of two stansoic acid A (3) units, acylated by 2-methylbutanoic and 3-hydroxy-2-methylbutanoic acids. The site of lactonization was located at C-3 of Rhamnose, and the position for the ester linkage of the monomeric unit B on the macrolactone unit A was established as C-4 of the terminal rhamnose. Compounds 5 and 6 are glycosidic acids. Murucinic acid II (5) is composed of a pentasaccharide core bonded to an 11-hydroxyhexadecanoic (jalapinolic) acid, acylated by an acetyl unit. Stansinic acid I (6) is a tetrasaccharide core bonded to a jalapinolic acid, acylated by 2-methylbutanoyl and 3-hydroxy-2-methylbutanoyl units. Preliminary testing showed the cytotoxicity of compounds 1–6 toward OVCAR and UISO-SQC-1 cancer cell lines. In addition, compound 1 showed an antiproliferative activity on glioma C6 and RG2 tumor cell lines. Copyright
Highly enantioselective iridium-catalyzed hydrogenation of α,β-unsaturated esters
Li, Jia-Qi,Quan, Xu,Andersson, Pher G.
, p. 10609 - 10616 (2012/11/07)
α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals. Asymmetric hydrogenation: A variety of α,β-unsaturated esters were hydrogenated with high enantioselectivities (see scheme). The hydrogenated products have been used in synthetic transformations as well as in formal total syntheses. Copyright
CONVERSION OF NITRILE COMPOUNDS INTO CORRESPONDING CARBOXYLIC ACIDS AND ESTERS
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Page/Page column 3, (2010/06/19)
Hydrocarbon compounds having at least one nitrile function are converted into compounds having at least one carboxylic function by hydrating the nitrile functions into amide functions by reaction with water in the presence of a strong inorganic acid, and then hydrolyzing the amide functions into carboxylic functions by reaction with water and a strong inorganic acid; the carboxylic compounds thus obtained can be esterified into diesters, advantageously diester solvents.
Hydrogenation Catalysis by an Iron Porphyrin and Its Application to α,β-Unsaturated Esters
Sakaki, Shigeyoshi,Kojima, Tatsuya,Arai, Toru
, p. 7 - 12 (2007/10/02)
Chloro(5,10,15,20-tetraphenylporphyrinato)iron(III) in tetrahydrofuran-methanol catalysed the hydrogenation of α,β-unsaturated esters by NaBH4 to the saturated esters; turnovers of up to 4580 h-1 have been attained for the hydrogenation of ethyl 2-methylbut-2-enoate.Deuterium labelling studies showed that the H(1-) of NaBH4 and the H(1+) of MeOH add to the β- and α-carbons of the double bond.A slower hydrogenation of oct-1-ene was accompanied by isomerization to oct-2-enes.Spectroscopy (UV/VIS, 1H NMR and ESR) suggests that hydrogenation proceeds via an iron(II) intermediate, and an alkyliron(II) species seems likely.
CHIRAL ACETYLENES AS SYNTHETIC INTERMEDIATES. V. A REINVESTIGATION ON THE SYNTHESIS OF OPTICALLY ACTIVE ISOXAZOLES
Falorni, Massimo,Lardicci, Luciano,Giacomelli, Giampaolo
, p. 7 - 10 (2007/10/02)
The synthesis of 3- or 5-alkyl isoxazoles and pyrazoles has been achieved starting from alkyl-substituted acetylenic ketones: the influence of the structure of the carbonyl compound on the isomeric composition of the heterocyclic compound has been studied.Some optically active monoalkyl-substituted isoxazoles have also been prepared: in this context, an investigation on the stereochemistry of the cyclization process has been carried out.
