- FLUORIDE MEDIATED REACTIONS OF LACTONES WITH SILYL KETENE ACETALS
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Aldolisation reactions of silyl ketene acetals with lactone carbonyls can be performed under very mild conditions in good yields in the presence of 5-10 mol-percent of TAS-TMSF2. - Key Words: aldolisation reactions; silyl ketene acetals; lactones; carbohydrates.
- Csuk, Rene,Schaade, Martina
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- Low-waste process for preparing ketopantolactone, with electrochemical recovery of bromine
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The process parameters of dehydrogenation of pantolactone with bromine in chloroform and the possibility of bromine recycling by electrolysis of hydrogen bromide formed in the synthesis of ketopanto-lactone were studied.
- Kaabak,Stepnova,Khudenko,Tomilov
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- Synthesis of dihydro-2,3-furandiones from diethyl oxalate and aldehydes through the action of sodium methoxide
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Dihydro-4,4-dimethyl-2,3-furandione (4e) was synthesized from diethyl oxalate, methylpropanal (1a) and formaldehyde in the presence of sodium methoxide. In a similar manner, analogs of dihydro-2,3-furandione 4 were prepared using other aldehydes.
- Hata,Morishita,Akutsu,Kawamura
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- Facile Synthesis of α-Ketocarbonyl Compounds from α-Hydroxycarbonyl Compounds
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Various α-ketocarbonyl compounds were obtained in excellent yields under mild condition from the reaction of the corresponding α-hydroxycarbonyl compounds with sodium hypobromite in the presence of HCl catalyst.
- Chang, Hae Sung,Woo, Jae Chun,Lee, Kyoung Mo,Ko, Young Kwan,Moon, Surk-Sik,Kim, Dae-Whang
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- Leveraging the n→π* Interaction in Alkene Isomerization by Selective Energy Transfer Catalysis
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Examples of geometric alkene isomerization in nature are often limited to the net exergonic direction (ΔG°0) comparatively under-represented. Inspired by the expansiveness of the maleate to fumarate (Z→E) isomerization in biochemistry, we investigated the inverse E→Z variant to validate nO→πC=O* interactions as a driving force for contra-thermodynamic isomerization. A general protocol involving selective energy transfer catalysis with inexpensive thioxanthone as a sensitizer (λmax=402 nm) is disclosed. Whilst in the enzymatic process nO→πC=O* interactions commonly manifest themselves in the substrate, these same interactions are shown to underpin directionality in the antipodal reaction by shortening the product alkene chromophore. The process was validated with diverse fumarate derivatives (>30 examples, up to Z:E>99:1), including the first examples of tetrasubstituted alkenes, and the involvement of nO→πC=O* interactions was confirmed by X-ray crystallography.
- Brüss, Linda,Daniliuc, Constantin G.,Gilmour, Ryan,McLaughlin, Calum,Molloy, John J.,Nevesely, Tomá?
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supporting information
(2021/11/30)
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- Synthesis process of D-pantolactone as D-calcium pantothenate intermediate
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The invention provides a synthesis process of D-pantolactone serving as a D-calcium pantothenate intermediate. The process is characterized by comprising the following steps: S1, adding isobutyraldehyde, dimethyl oxalate, formaldehyde and sodium hydroxide into a reaction kettle according to an equal molar mass ratio, raising the temperature to 120 DEG C from 30 DEG C, keeping the temperature for 4 hours, and distilling to remove methanol in the product to obtain an intermediate D-pantolactone. According to the method, a catalyst is generated in situ under the condition of adopting Ir (COD) Hpo3] 2, a ligand and an alkaline additive, and under the condition of the catalyst, hydrogen is introduced to carry out asymmetric catalytic hydrogenation reaction on ketopantolactone, so that the chiral D-pantolactone with high reaction activity and selectivity can be obtained. The synthesis method is mild in hydrogenation reaction condition, and is suitable for various ketopantolactone derivatives; the substrate is wide in application range; and the reaction process causes little pollution to the environment.
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Paragraph 0019
(2021/06/23)
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- Oxidation of secondary alcohols using solid-supported hypervalent iodine catalysts
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It is shown how secondary alcohols are oxidized to provide the corresponding ketones by use of Oxone and solid-supported hypervalent iodine catalysts. Under experimentally simple conditions with acetonitrile at elevated temperatures, excellent conversions were achieved with low catalyst loadings (0.2-5 mol%) when employing the conjugates 5 and 6 derived from IBX and IBS. The catalysts are broadly applicable to a range of alcohol substrates. Of primary importance with respect to sustainability issues, the metal-free catalysts are easily removed from the reaction mixture through filtration, and they can be re-used in oxidation processes for multiple times, without loss of catalytic activity.
- Ballaschk, Frederic,Kirsch, Stefan F.
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supporting information
p. 5896 - 5903
(2019/11/11)
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- Method for producing carbonyl compound
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[summary][PROBLEM TO BE SOLVED]: To provide a method for effectively producing carbonyl compound from alcohol using a ruthenium compound as an oxidation catalyst which can apply to various alcoholic compounds as starting materials, and to provide a method for effectively producing the carbonyl compound in high yield with decomposing neither the alcohol nor the produced carbonyl compound.[SOLUTION]: The method for producing carbonyl compound comprises the oxidative reaction process of alcohol using N-haloamide compound or N-haloimide compound in the presence of ruthenium compound of catalytic amount in the solvent containing organic solvent not substantially oxidized with the ruthenium compound The solvent used is solvent containing organic solvents other than the carboxylic acid; mixed solvent of pH5-14 containing organic solvent and water; or organic solvent containing base.
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Page/Page column 20-21; 24-25
(2008/06/13)
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- A practical RuCl3-catalyzed oxidation using trichlproisocyanuric acid as a stoichiometric oxidant under mild nonacidic conditions
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The combined use of catalytic RuCl3 (1.0 mol %) and stoichiometric trichloroisocyanuric acid (TCCA; 1.0 equiv) in the presence of n-Bu4NBr (2.0 mol %) and K2CO3 (3.0 equiv) in 1:1 MeCN/H2O at 25-45°C allows smooth oxidation of primary alcohols to carboxylic acids. Secondary alcohols can be oxidized to ketones when using the same set of the reagents in 1:1 MeCN/ H2O or 1:1 AcOEt/H2O. By proceeding under the nonacidic biphasic conditions dispensing with hazardous reagents, the oxidation reactions are applicable to structurally diverse alcohols, easy to work up, environmentally benign, and basically high-yielding.
- Yamaoka, Hidenori,Moriya, Narimasa,Ikunaka, Masaya
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p. 931 - 938
(2013/09/03)
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- MANUFACTURE OF KETOPANTOLACTONE
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A process for the oxidation of pantolactone to ketopantolactone comprises carrying out the oxidation with a periodate in the presence of a ruthenium catalyst, in an aqueous solvent system and in a microwave field. Ketopantolactone is a key intermediate in the manufacture of pantothenic acid, the latter being a member of the B complex vitamins and a constituent of coenzyme A. Asymmetric hydrogenation of ketopantolactone yields (D)(-)-pantolactone, from which pantothenic acid can then be manufactured.
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Page/Page column 4
(2008/06/13)
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- Process for the oxidation of alcohols
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A process for oxidizing primary and secondary alcohols to the corresponding aldehydes and ketones is disclosed. The oxidation is carried out by reacting the primary or secondary alcohol with an organic N-chloro compound oxidizing agent in the presence of a catalyst of the formula: STR1 wherein the substituent groups are as defined in the specification.
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- Synthesis of Dimethylbutatrienone, (CH3)2C=C=C=C=O, by a Rearrangement-Fragmentation Process and by Direct Elimination
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4-Methylpenta-1,2,3-trien-1-one (dimethylbutatrienone, Me2C=C=C=C=O) was generated by flash vacuum pyrolysis of precursors derived from 4,4-dimethyl-2-oxotetrahydrofuran-3-ylideneacetic acid (6) and from 4-methylpenta-2,3-dienoic acid (14).Pyrolysis of the mixed trifluoroacetic anhydride and of the acid chloride of (6) and, in poorer yield, of (14) gave 4-methylpenta-1,2,3-trien-1-one which was detected by argon matrix infrared spectroscopy (νmax 2224, 2216 cm-1) and by reaction with methanol to form methyl 4-methylpenta-2,3-dienoate.The fragmentation pathway forthe derivatives of (6) was established by detection of the initially formed propadienone, 4,4-dimethyl-2-oxotetrahydrofuran-3-ylideneethenone, and also by pyrolysis of the trifluoroacetic mixed anhydride (7-L) and the acid chloride (8-L) of 4,4-dimethyl-2-oxotetrahydro(2-13C)furan-3-ylideneacetic acid.The argon matrix spectra of pyrolysates from (7-L) and (8-L) showed bands at 2182 and 2177 cm-1 attributed to 4-methyl(1-13C)penta-1,2,3-trien-1-one. 4,4-Dimethyl-3-methylenedihydrofuran-2-one was prepared in 67percent yield by flash vacuum pyrolysis of the acid (6).
- Brown, Roger F. C.,Coulston, Karen J.,Eastwood, Frank W.,Irvine, Margaret J.
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- Novel Enzymatic Production of D-(-)-Pantoyl Lactone through the Stereospecific Reduction of Ketopantoic Acid
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The high yield stereoselective reduction of ketopantoic acid to D-(-)-pantoic acid with microbial cells as a catalyst is described .High activity was found in several bacteria belonging to the genus Agrobacterium.On incubation with a soil isolate, Agrobacterium sp.S-246, the yield of D-(-)-pantoic acid reached 119 mg/ml, with high molar conversion (90percent) and high stereoselectivity (>98percent enantiomeric excess).Ketopantoic acid reductase (EC 1.1.1.169) was suggested to be the enzyme responsible for this conversion.
- Kataoka, Michihiko,Shimizu, Sakayu,Yamada, Hideaki
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p. 177 - 182
(2007/10/02)
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- Process for producing intermediate furanones from diol derivative and thionyl chloride
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A novel process for the manufacture of the furanone of the formula STR1 is described. In this process, a diol is firstly reacted with thionyl chloride, then the sulphite formed, optionally after oxidation to the corresponding sulphate, is treated with sodium cyanide and the resulting hydroxynitrile is hydrolyzed. The furanone of formula I can be used as a starting material for the manufacture of R-(-)-pantolactone.
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- Preparation of dihydro-4,4-dimethylfuran-2,3-dione
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Dihydro-4,4-dimethylfuran-2,3-dione is prepared by oxidation of racemic dihydro-3-hydroxy-4,4-dimethyl-2(3H)-furanone by a process in which the oxidation is carried out by gradually adding powdered calcium oxide to a solution of racemic dihydro-3-hydroxy-4,4-dimethyl-2(3H)-furanone and chlorine in the inert organic solvent.
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- RUTHENIUM-CATALYZED AEROBIC OXIDATION OF PANTOYL LACTONE TO KETOPANTOYL LACTONE
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Pantoyl lactone was selectively oxidized into ketopantoyl lactone with molecular oxygen by the catalysis of ruthenium.
- Matsumoto, Masakatsu,Ito, Satoru
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p. 697 - 700
(2007/10/02)
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- Process for manufacturing a diketone
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A process for producing dihydro-4,4-dimethyl-2,3-furandione by oxidizing dihydro-3-hydroxy-4,4-dimethyl-2(3H)-furanone with a solid alkali metal hypochlorite or alkaline earth metal hypochlorite in an organic phase is disclosed.
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- THE DEGRADATION OF CARBOXYLIC ACIDS INTO ALDEHYDES. REGIOSELECTIVE α-ACETOXYLATION OF 1,2,4-TRIAZOLIUM SALTS WITH DIACETOXYIODATE(1)ANION
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A novel method was developed for degradation of carboxylic acid into aldehydes containing one C atom less whose key step consists in α-acetoxylation of 5-alkyl-3-methylthio-1,4-diphenyl-1,2,4-triazolium iodides by (diacetoxyiodo)benzene.The mechanism of the regioselective α-acetoxylation was studied and the diacetoxy-iodate(1)anion was shown to be the actual oxidising agent.Further oxidation reactions of tetraethylammonium diacetoxyiodate(1) were investigated.A novel method was developed for the oxidation of primary alkyl amines into aldehydes by the novel heterocyclic reagent 5-bromo-3-methylthio-1,4-diphenyl-1,2,4-triazolium bromide and diethyl azodicarboxylate.
- Doleschall, Gabor,Toth, Gabor
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p. 1649 - 1666
(2007/10/02)
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