554-34-7Relevant academic research and scientific papers
Toward the oxidative deconstruction of lignin: Oxidation of β-1 and β-5 linkages
Fang, Zhen,Meier, Mark S.
, p. 2330 - 2341 (2018/04/05)
There have been numerous reports on methods for the oxidative cleavage of β-O-4 linkages in lignin model compounds, but relatively few reports of how those methods affect other linkages that are present in lignin. We have investigated the effect of several of these oxidation methods on the β-1 and the β-5 lignin linkages, using four β-1 and β-5 model compounds. We observed that direct oxidative cleavage of C-C bonds occurs in metal-catalyzed TEMPO oxidation systems and with iron porphyrin oxidations, neither of which had we observed in similar oxidations on β-O-4 models. The β-5 linkage proved to be largely resistant to all of these oxidative systems, but the dihydrofuran ring in the β-5 model 3 was opened when treated with KMnO4 at elevated temperature. Most promising was the oxidation of 2 with DDQ, which produced the benzylic ketone in high yield (84%), as it does in reactions with β-O-4 models. This reaction exhibits selectivity for the benzylic position as well as compatibility with phenols, characteristics that are highly desirable for a two-step, benzylic oxidation/Baeyer-Villiger route for cleavage of lignin.
Fluorogenic Diels-Alder reactions of novel phencyclone derivatives
Aydin, Engin Aytac,Altenbach, Hans-Josef
supporting information, p. 1832 - 1834 (2013/05/08)
With the aim of obtaining fluorogenic Diels-Alder reactions, novel phencyclone derivatives were synthesized. In a short time and under convenient reaction conditions, the formation of Diels-Alder adducts was observed by color-change and up to 33-fold enhancement of fluorescence. The modification of thymidine and deoxycytidine derivatives with a maleimide side chain and their usage in fluorogenic Diels-Alder reaction is also reported.
Synthesis of highly functionalized 9,10-phenanthrenequinones by oxidative coupling using MoCl5
Trosien, Simon,Waldvogel, Siegfried R.
, p. 2976 - 2979 (2012/07/27)
The strong oxidative power of molybdenum pentachloride gives rise to an efficient oxidative C-C bond formation of benzil derivatives to the corresponding 9,10-phenanthrenequinones. A highly complementary method to previous approaches was developed. The required derivatives are accessible in a modular fashion and in excellent yields. By this approach the orchid-derived natural product cypripediquinone A was synthesized for the first time.
Hexaphenylbenzene-based polymers of intrinsic microporosity
Short, Rhys,Carta, Mariolino,Bezzu, C. Grazia,Fritsch, Detlev,Kariuki, Benson M.,McKeown, Neil B.
, p. 6822 - 6824 (2011/08/08)
Microporous polymers derived from the 1,2- and 1,4-regioisomers of di(3′,4′-dihydroxyphenyl)tetraphenylbenzene have very different properties with the former being composed predominantly of cyclic oligomers whereas the latter is of high molar mass suitable for the formation of robust solvent-cast films of high gas permeability.
Heterocyclic analogs of combretastatin A-4
Vasilevsky,Davydova,Tolstikov
experimental part, p. 1257 - 1261 (2009/05/27)
A novel route is proposed for the synthesis of heterocyclic analogs of the naturally occurring combretastatin A-4 based on the reaction of α-acetylenic ketones with polyfunctional nucleophiles (hydroxylamine, hydrazine, guanidine). Previously unknown combretastatin A-4 analogs with azole and azine bridges were obtained.
Towards a facile synthesis of triarylethanones: Palladium-catalyzed arylation of ketone enolates under homogeneous and heterogeneous conditions
Churruca, Fátima,SanMartin, Raul,Carril, Mónica,Tellitu, Imanol,Domínguez, Esther
, p. 2393 - 2408 (2007/10/03)
The palladium-catalyzed regioselective α-monoarylation of deoxybenzoins and α,α-diarylation of acetophenones provides general, efficient access to 1,2,2-triarylethanones. After a comprehensive search for suitable experimental conditions to optimize such transformations, both reactions are alternatively conducted by means of either commercially available polymer-anchored catalysts or a very simple homogeneous catalytic system, thus avoiding the use of complex ligands. In addition, the synthesis of deoxybenzoins employing polymer-supported fibrous palladium catalysts is reported for the first time, and the excellent catalyst recycling properties suggest applicability to industrial purposes.
A New General Method for the Synthesis of 4-Hydroxylated 3-Aryltetrahydroisoquinolines
SanMartin, Raul,Olivera, Roberto,Marigorta, Eduardo Martinez de,Dominguez, Esther
, p. 5361 - 5368 (2007/10/02)
3-Aryl-4-hydroxytetrahydroisoquinolines have been prepared from deoxybenzoins.The nitrosation of the latter derivatives has been improved and the catalytic reduction of the obtained oximinoketones has been carried out with the help of ultrasounds.Heterocyclization to the isoquinoline moiety occurred on the unprotected 1,2-aminoalcohol to give stereoselectively the corresponding hydroxylated heterocycle with good yield.
Synthesis of Alkyl- and Alkoxy-Substituted Benzils and Oxidative Coupling to Tetraalkoxyphenanthrene-9,10-diones
Mohr, Bernhard,Enkelmann, Volker,Wegner, Gerhard
, p. 635 - 638 (2007/10/02)
Intermolecular Friedel-Crafts acylation of various substituted alkyl- or alkoxybenzenes with oxalyl chloride using carbon disulfide as solvent gave rise to the benzils 1a-k.Subsequent intramolecular oxidative coupling with either thallium(III) oxide/trifluoroacetic acid or vanadium(V) oxyfluoride/boron trifluoride diethyl etherate resulted in the corresponding phenanthrene-9,10-diones 2a-d.It has been shown that oxygen functionalities at the 3,3',4, and 4'positions are necessary for coupling to occur.These substituted benzils and phenanthrene-9,10-diones constitute precursors for ligands in the field of discotic metallomesogens or polymeric mesogens.
Synthesis of 1,2-Bis(3,4-dimethoxyphenyl)-1,3-propanediol Starting from trans-1,3-Bis(3,4-dimethoxyphenyl)-2,3-epoxy-1-propanone
Li, Shiming,Lundquist, Knut,Stomberg, Rolf
, p. 867 - 871 (2007/10/02)
erythro-1,2-Bis(3,4-dimethoxyphenyl)-1,3-propanediol has been synthesized (yield, 72percent) by acid-catalysed rearrangement of trans-2,3-bis(3,4-dimethoxyphenyl)-2,3-epoxy-1-propanone yielding 1,3-bis(3,4-dimethoxyphenyl)-3-oxopropanal (and its enol form) an subsequent reduction of this compound with sodium tetrahydridoborate. threo-1,2-Bis(3,4-dimethoxyphenyl)-1,3-propanediol (yield, 1-2percent), meso-hydroveratroin, 1,2-bis(3,4-dimethoxyphenyl)ethanol, 1,2-bis(3,4-dimethoxyphenyl)-1-propanol and 3,4-dimethoxybenzyl alcohol were also present in the reaction product.Reduction in alkaline solution lowered the yield notably owing to deformylation/reduction leading to the formation of substantial amounts of 1,2-bis(3,4-dimethoxyphenyl)ethanol.The general applicability of the synthetic method involving rearrangement of 1,3-diaryl-2,3-epoxy-1-propanones for the synthesis of lignin model compounds of the 1,2-diaryl-1,3-propanediol type is evaluated.
Discotic Liquid Crystals of Transition Metal Complexes 11: The First ?-Acceptor in Discotic Columnar Liquid Crystals Obtained from Octasubstituted Bis(diphenylethane-1,2-dithiolene)nickel Complexes
Ohta, Kazuchika,Hasebe, Hiroshi,Ema, Hiroshi,Moriya, Mitsuo,Fujimoto, Tetsuya,Yamamoto, Iwao
, p. 21 - 32 (2007/10/02)
Disk-like complexes, bisnickel (n-alkyl = n-hexyl, n-octyl) and bisnickel have been synthesized and characterized.It was found that n-decyloxy derivative exhibits a hexagonal discordered columnar (Dhd) mesophase while n-alkyl derivatives are not discotic liquid crystals but isotropic liquids at room temperature.The half-wave potentials for reduction of these complexes is -0.04 - -0.06 V. n-Decyloxy derivative is the first ?-acceptor in discotic columnar liquid crystals.
