39770-05-3Relevant articles and documents
2D NMR Nutation Analysis of Non-Thermal Polarization of Coupled Multi-Spin Systems
Ivanov,Miesel,Vieth,Yurkovskaya,Sagdeev
, p. 1641 - 1659 (2003)
A new, convenient method of analyzing the spin polarization of a non-equilibrium system of N coupled nuclei is described and applied to photo-reactions exhibiting chemically induced dynamic nuclear polarization (CIDNP). It is based on the Fourier analysis of the variation of NMR line intensities as a function of the radio frequency excitation pulse length. A relationship between the spectral components at various harmonic order and the alignment in the spin multiplet is established. In application to the Norrish type I photolysis of cyclodecanone we demonstrate that at low magnetic field the rate determining step in the reaction kinetics depends on the mutual orientation of at least four pairs of non-equivalent spins.
Convenient synthesis of novel macrocyclic urethanes: Alkoxycarbonylation of amines and ring-closing metathesis strategy
Ghosh, Arun K.,Hussain, Khaja Azhar
, p. 1881 - 1884 (1998)
Alkoxycarbonylation of amines followed by ring-closing metathesis of the resulting dienes with Grubbs catalyst (25-50 mol%) provided convenient access to 14-16 membered macrocyclic urethanes in very good yields.
The Effects of Material Properties on the Activity of Sol-Gel Entrapped Perruthenate under Supercritical Conditions
Ciriminna, Rosaria,Campestrini, Sandro,Pagliaro, Mario
, p. 1261 - 1267 (2003)
Silica gels organically modified and doped with the ruthenium species tetra-n-propylammonium perruthenate (TPAP) are leach-proof, selective catalysts for the aerobic oxidation of alcohols to carbonyl compounds with dioxygen at low pressure in compressed carbon dioxide. The catalytic sol-gels are recyclable and the correlation between the reactivity of the materials and their surface polarity and textural properties suggests valuable information on the chemical behaviour of sol-gel entrapped silica catalysts in oxidation catalysis which is of relevant interest considering the importance of heterogeneous oxidative dehydrogenation of alcohols in fine chemistry. An explanation of the structure-activity relationship is proposed to provide guidelines for the further development of efficient solid oxidation catalysts for conversions in supercritical carbon dioxide.
Highly efficient liquid-phase oxidation of primary alcohols to aldehydes with oxygen catalysed by Ru-Co oxide
Musawir, Mehdi,Davey, Paul N.,Kelly, Gordon,Kozhevnikov, Ivan V.
, p. 1414 - 1415 (2003)
RuIV-CoIII (1:1.5) binary oxide, prepared by co-precipitation, is a highly efficient solid catalyst for the oxidation of primary alcohols to aldehydes with O2 (76-95% selectivity at 54-100% conversion) in a liquid phase under atmospheric pressure.
Straightforward Synthesis of Fluorinated Enals via Photocatalytic α-Perfluoroalkenylation of Aldehydes
Wulkesch, Christian,Czekelius, Constantin
, p. 7425 - 7438 (2021/06/21)
(Per)fluorinated substances represent an important compound class with regard to drug design and material chemistry. We found a mild, operationally simple, and inexpensive photocatalytic perfluoroalkenylation reaction giving tetrasubstituted, highly electron-deficient enals straight from aldehydes. This one-step reaction tolerates various functional groups and can be applied to a wide range of substrates giving the products in yields of 52-84%.
Racemic or enantioselective osmium-catalyzed dihydroxylation of olefins under near-neutral conditions
Blumberg, Shawn,Martin, Stephen F.
, p. 7 - 14 (2020/10/08)
K3Fe(CN)6 and NaIO4 serve as catalytic co-oxidants for osmium-catalyzed dihydroxylations that are performed under near-neutral conditions with K2S2O8 as the stoichiometric oxidant and Na2HPO4 as the base. By using either quinuclidine or hydroquinidine 1,4-phthalazinediyl ether [(DHQD)2Phal], good yields of racemic or enantioenriched diols are obtained. This simple, biphasic procedure offers advantages over other neutral dihydroxylation protocols that use N-methylmorpholine oxide as the stoichiometric oxidant, by suppressing the secondary catalytic cycle that leads to reduced enantioselectivities. The utility of the procedure, which is nicely suited for base-labile starting materials or products, is demonstrated by performing the dihydroxylation in the presence of an aliphatic aldehyde moiety.
One-pot, two-step synthesis of unnatural α-amino acids involving the exhaustive aerobic oxidation of 1,2-diols
Inada, Haruki,Furukawa, Keisuke,Shibuya, Masatoshi,Yamamoto, Yoshihiko
supporting information, p. 15105 - 15108 (2019/12/26)
Herein, we report the nor-AZADO-catalyzed exhaustive aerobic oxidations of 1,2-diols to α-keto acids. Combining oxidation with transamination using dl-2-phenylglycine led to the synthesis of free α-amino acids (AAs) in one pot. This method enables the rapid and flexible preparation of a variety of valuable unnatural AAs, such as fluorescent AAs, photoactivatable AAs, and other functional AAs for bioorthogonal reactions.
Direct Synthesis of Free α-Amino Acids by Telescoping Three-Step Process from 1,2-Diols
Inada, Haruki,Shibuya, Masatoshi,Yamamoto, Yoshihiko
supporting information, p. 709 - 713 (2019/01/25)
A practical telescoping three-step process for the syntheses of α-amino acids from the corresponding 1,2-diols has been developed. This process enables the direct synthesis of free α-amino acids without any protection/deprotection step. This method was also effective for the preparation of a 15N-labeled α-amino acid. 1,2-Diols bearing α,β-unsaturated ester moieties afforded bicyclic α-amino acids through intramolecular [3 + 2] cycloadditions. A preliminary study suggests that the resultant α-amino acids are resolvable by aminoacylases with almost complete selectivity.
Copper(i)-catalysed stereoselective debromoborylation of aliphatic 1,1-dibromo-1-alkenes with bis(pinacolato)diboron
Pang, Yadong,Kojima, Ryoto,Ito, Hajime
supporting information, p. 6187 - 6190 (2018/09/10)
A stereoselective debromoborylation of aliphatic 1,1-dibromo-1-alkenes to prepare (Z)-1-bromo-1-alkenylboronate esters using copper(i) catalysts was developed. The debromoborylation of various aliphatic 1,1-dibromo-1-alkenes in the presence of a copper(i) catalyst and bis(pinacolato)diboron proceeded smoothly to produce (Z)-1-bromo-1-alkenylboronate esters in good yields with only Z geometry.
Resorcylic acid lactone biosynthesis relies on a stereotolerant macrocyclizing thioesterase
Heberlig, Graham W.,Wirz, Monica,Wang, Meng,Boddy, Christopher N.
supporting information, p. 5858 - 5861 (2015/02/19)
Zearalenone and radicicol are highly related resorcylic acid lactones with the rare property of having opposite stereochemical configurations of the secondary alcohol involved in lactone formation. The ability of the thioesterases from the zearalenone and radicicol biosynthetic pathways to macrocyclize both d and l configured synthetic substrate analogs was biochemically characterized and showed that both enzymes were highly stereotolerant, macrocyclizing both substrates with similar kinetic parameters. This observed stereotolerance is consistent with a proposed evolution of both natural products from a common ancestral resorcylic acid lactone.
