541-50-4Relevant articles and documents
Flash photolysis of 2,2,6-trimethyl-4H-1,3-dioxin-4-one in aqueous solution: Hydration of acetylketene and ketonization of acetoacetic acid enol
Chiang,Guo,Kresge,Tee
, p. 3386 - 3391 (1996)
Acetylketene was produced by flash photolysis of 2,2,6-trimethyl-4H-1,3-dioxin-4-one in aqueous solution, and rates of hydration of the ketene to acetoacetic acid enol and subsequent ketonization of the enol were measured in this solvent across the acidity range [H+] = 1-10-13 M. Acetylketene proved to be a remarkably reactive substance, undergoing uncatalyzed hydration with the rate constant k = 1.5 x 106 s-1, some 104 times more rapidly than ketene itself: the acetylketene hydration reaction was also catalyzed weakly by hydroxide ion but not by hydrogen ion. Ketonization of acetoacetic acid enol was much slower with rates in the millisecond to second range. The reaction showed a complex rate profile that could be interpreted in terms of rate-determining carbon protonaton of the carboxylate-ionized form of the enol in the acid region and rate-determining carbon protonation of the doubly ionized carboxylate-enolate form in the basic region. Analysis of the data provided the acidity constant pQ(a) = 4.05 for the carboxylic acid group of the enol and pQ(a)(E) = 13.18 for its enolic hydroxyl group. (These acidity constants are concentration quotients referring to an ionic strength of 0.10 M). Combination of the present results with information on the enolization of acetoacetic acid available from the literature gave K(E) = 5.6 x 10-3, pK(E) = 2.25, as an estimate of the keto-enol equilibrium constant.
Kinetic study of the neutral and base hydrolysis of diketene
Goemez-Bombarelli, Rafael,Gonzalez-Perez, Marina,Perez-Prior, Maria Teresa,Manso, Jose A.,Calle, Emilio,Casado, Julio
, p. 438 - 442 (2009)
Diketene (4-methylene-2-oxetanone) is inactive as a carcinogen, although it is more reactive toward nucleophiles than the analogs b-propiolactone and b-butyrolactone, both of which are alkylating agents of known carcinogenicity. In the literature the lack of carcinogenic effects has been ascribed to the rapid hydrolysis of diketene, which could preclude its in vivo alkylating capacity. In this work, the kinetics of the neutral and alkaline hydrolysis of diketene in aqueous and different water-dioxane media have been studied. The following conclusions can be drawn: (i) The neutral hydrolysis of diketene is slightly faster than that of β-propiolactone and β-butyrolactone. (ii) The hydrolysis reaction of diketene is very slow when compared to its alkylation reaction of a DNA-model carcinogenicity. (iii) The diketene neutral hydrolysis rate constant increases with the water/dioxane ratio, the opposite occurring in base hydrolysis. Copyright
Tautomeric Equilibria in Acetoacetic Acid
Grande, Karen D.,Rosenfeld, Stuart M.
, p. 1626 - 1628 (1980)
Tautomeric equilibria in acetoacetic acid have been examined by 1H NMR and found to be strongly solvent dependent.Values for enol tautomer range from less than 2percent in deuterium oxide to 49percent in carbon tetrachloride.Chemical shift data suggest that the enol tautomer is internally hydrogen bonded in the less polar solvents and that internal hydrogen bonding is unimportant for the keto tautomer.The acid probably exists in the keto form in the solid state.
Discrepancies in the reactivity pattern of azaenamines towards cinnamonitriles: Synthesis of novel aza-steroid analogues
Ghozlan, Said A.S.,Abdelmoniem, Amr M.,Butensch?n, Holger,Abdelhamid, Ismail A.
, p. 1413 - 1418 (2015)
Azaenamine incorporating pyrazole-4-carboxylate is prepared and allowed to react with α,β-substituted nitriles. A new reactivity pattern was observed leading to the formation of substituted pyrazolo[4′,3′-5,6]pyrimido[2,1-a]phthalazine-9-carbonitriles, which can be considered as aromatic aza-steroid analogues.
Synthesis, characterization & biological studies of Mn(II), Fe(III) and Co(II) complexes of (Z)-1, 5-dimethyl-4-(2-(2-oxopropylidene) hydrazinyl)-2-phenyl-1H-pyrazol-3(2H)-one
Sreepriya,Kumar, Shubha S.,V, Sadasivan,S, Biju,Meena, Sher Singh
, (2020)
Mn(II), Fe(III) and Co(II) complexes of the hydrazone derived from 4-aminoantipyrine and ethylacetoacetate has been synthesized and characterized by elemental analysis, electrical conductance in non-aqueous solvents, spectroscopic data including FT-IR, electronic, Electrospray ionization mass and M?ssbauer as well as by thermogravimetric analysis. In all the complexes, the compound acts as neutral bidentate ligand, coordinating through the pyrazolone oxygen and azomethine nitrogen. A high spin octahedral geometry assigned to the Mn(II), Fe(III) and Co(II) complexes were further confirmed by magnetic moment data. Elemental analysis showed that Fe(III) complex composed of metal and ligand in a molar ratio of 1:1 whereas metal to ligand ratio in Mn(II) and Co(II) complexes were found to be 1:2. The complexes have also been screened for their antimicrobial and antioxidant activity. The MTT assay of the Co(II) complex was also carried out. Antiviral docking studies of the ligand was done against the native and mutant HIV-1 Reverse Transcriptase protein (PDB ID: 1RT2 and 1FK9) and the ligand showed significant inhibitory activity against both forms of the protein.
3,4-DIHYDROXYPHENETHYL 3-HYDROXYBUTANOATE, PREPARATION AND USE THEREOF
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Paragraph 0108, (2021/03/19)
The present disclosure discloses a novel compound, 3,4-dihydroxyphenethyl 3-hydroxybutanoate, a method for preparing the same and use of the same, and in particular, a compound of formula I, use of the compound of formula I, optically pure isomers of the compound, a mixture of enantiomers in any ratio, or pharmaceutically acceptable salts thereof in preparing health food and drug for relieving brain fatigue, improving learning and memory abilities, and ameliorating mania mood related to brain fatigue.
Synthesis method for preparing 3,5-dichloro-2-pentanone from methyl acetoacetate
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Paragraph 0023-0027; 0031-0035; 0039-0043; 0047-0051; 0055, (2020/10/30)
The invention discloses a synthesis method for preparing 3,5-dichloro-2-pentanone from methyl acetoacetate. The method comprises the following steps: S1: reactor preparation: preparing two reactors, namely a first reactor and a second reactor; S2, reactor cleaning: putting the first reactor and the second reactor into clear water for cleaning, flushing the first reactor and the second reactor after cleaning is completed, and drying the first reactor and the second reactor after flushing is completed; and S3, hydrolysis for salt formation: adding methyl acetoacetate into the first reactor, dropwise adding 30% caustic soda liquid under cooling of circulating water, and continuing to conducting a reaction for 6 hours after dropwise adding so as to obtain a hydrolyzed material. According to the synthesis method for preparing 3,5-dichloro-2-pentanone from methyl acetoacetate, working steps are rigorous, flammable and explosive materials are prevented from being used, safety is improved, reaction operations are reduced, reaction efficiency is improved, and cost is effectively reduced.
Structural design, synthesis and substituent effect of hydrazone-N-acylhydrazones reveal potent immunomodulatory agents
Meira, Cássio S.,dos Santos Filho, José Maurício,Sousa, Caroline C.,Anjos, Pamela S.,Cerqueira, Jéssica V.,Dias Neto, Humberto A.,da Silveira, Rafael G.,Russo, Helena M.,Wolfender, Jean-Luc,Queiroz, Emerson F.,Moreira, Diogo R.M.,Soares, Milena B.P.
, p. 1971 - 1985 (2018/03/12)
4-(Nitrophenyl)hydrazone derivatives of N-acylhydrazone were synthesized and screened for suppress lymphocyte proliferation and nitrite inhibition in macrophages. Compared to an unsubstituted N-acylhydrazone, active compounds were identified within initial series when hydroxyl, chloride and nitro substituents were employed. Structure-activity relationship was further developed by varying the position of these substituents as well as attaching structurally-related substituents. Changing substituent position revealed a more promising compound series of anti-inflammatory agents. In contrast, an N-methyl group appended to the 4-(nitrophenyl)hydrazone moiety reduced activity. Anti-inflammatory activity of compounds is achieved by modulating IL-1β secretion and prostaglandin E2 synthesis in macrophages and by inhibiting calcineurin phosphatase activity in lymphocytes. Compound SintMed65 was advanced into an acute model of peritonitis in mice, where it inhibited the neutrophil infiltration after being orally administered. In summary, we demonstrated in great details the structural requirements and the underlying mechanism for anti-inflammatory activity of a new family of hydrazone-N-acylhydrazone, which may represent a valuable medicinal chemistry direction for the anti-inflammatory drug development in general.
MULTIBIOTIC AGENTS AND METHODS OF USING THE SAME
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Page/Page column 84; 85, (2019/01/06)
Multibiotic agents are disclosed. The multibiotic agents may contain two or more moieties linked through bonds cleavable in vivo. The bonds cleavable in vivo can be ester bonds, amide bonds, azo bonds, glycosidic bonds, carbonate linkers, or carbamate linkers. The moieties can be alcohol cores, amine cores, and/or acyls. Also disclosed are compositions containing multibiotic agents and methods of using the multibiotic agents.
Stereoselective Coupling of N-tert-Butanesulfinyl Aldimines and β-Keto Acids: Access to β-Amino Ketones
Lahosa, Alejandro,Soler, Tatiana,Arrieta, Ana,Cossío, Fernando P.,Foubelo, Francisco,Yus, Miguel
, p. 7481 - 7491 (2017/07/26)
The reaction of chiral N-tert-butanesulfinyl aldimines with β-keto acids under basic conditions at room temperature proceeds with high levels of diastereocontrol, leading to β-amino ketones in high yields. Based on DFT calculations, an eight-membered cyclic transition state involving coordination of the lithium atom to the oxygens of carboxylate and sulfinyl units was proposed, being in agreement with the observed experimental diastereomeric ratios. The synthesis of the piperidine alkaloid (-)-pelletierine was successfully undertaken in order to demonstrate the utility of this methodology.
