4388-57-2Relevant academic research and scientific papers
Acid Catalyzed Competitive Esterification and Ketalization of Levulinic Acid with 1,2 and 1,3-Diols: The Effect of Heterogeneous and Homogeneous Catalysts
Amarasekara, Ananda S.,Animashaun, Moriam A.
, p. 1819 - 1824 (2016)
Abstract: Condensation reactions of levulinic acid (LA) with 1,2-ethanediol (1,2-ED), 1,2-propanediol (1,2-PD), and 1,3-propanediol (1,3-PD) were studied using Amberlyst-15 as well as p-toluenesulfonic acid catalysts in benzene under Dean–Stark conditions. In Amberlyst-15 catalyzed reactions the products are ketals and ketal-esters, whereas p-toluenesulfonic acid catalyzed reactions produce esters and ketal-esters as products. In p-toluenesulfonic acid catalyzed reactions with 1,2-ED and 1,3-PD, LA monoester product is formed as the major product after 180?min in 75 and 97?% yields respectively. Unlike the previously reported acid catalyzed ketalization of ethyl levulinate with diols, combined ketalization–esterification of LA with diols is a complex process. Graphical Abstract: [Figure not available: see fulltext.]
Organocatalytic enantioselective total synthesis of (-)-arboricine
Wanner, Martin J.,Boots, Rowan N.A.,Eradus, Bram,De Gelder, Rene,Van Maarseveen, Jan H.,Hiemstra, Henk
supporting information; scheme or table, p. 2579 - 2581 (2009/10/23)
The tetracyclic indole alkaloid (-)-arboricine has been prepared using an asymmetric organocatalytic Pictet - Spengler reaction as the key step followed by a diastereoselective Pd-catalyzed iodoalkene/enolate cyclization. The absolute stereochemistry was unequivocally proven by X-ray crystallographic analysis and appeared to be opposite to the published structure in the original paper.
SUBSTITUTED FUSED[1,2]IMIDAZO[4,5-C] RING COMPOUNDS AND METHODS
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Page/Page column 104, (2008/06/13)
[1,2]Imidazo[4,5-c] ring compounds (e.g., imidazo[4,5-c]quinolines, imidazo[4,5-c]naphthyridines, and imidazo[4,5-c]pyridines) substituted with a fused ring containing an oxygen and/or nitrogen atom attached at the 1- and/or 2-position, pharmaceutical compositions containing the compounds, intermediates, methods of making the compounds, and methods of use of these compounds as immunomodulators, for inducing cytokine biosynthesis in animals and in the treatment of diseases including viral and neoplastic diseases, are disclosed.
OXIME AND HYDROXYLAMINE SUBSTITUTED IMIDAZO[4,5-C] RING COMPOUNDS AND METHODS
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Page/Page column 84-85, (2008/06/13)
Imidazo[4,5-c] ring compounds, (e.g. imidazo[4,5-c]pyridines, imidazo[4,5-c]quinolines, 6,7,8,9-tetrahydro imidazo[4,5-c]quinolines, imidazo[4,5-c]naphthyridine, and 6,7,8,9-tetrahydro imidazo[4,5-c]naphthyridine compounds) having an oxime or hydroxylamine substituent at the 2-position, pharmaceutical compositions containing the compounds, intermediates, and methods of making and methods of use of these compounds as immunomodulators, for modulating cytokine biosynthesis in animals and in the treatment of diseases including viral and neoplastic diseases are disclosed.
Three- and Four-Carbon Elongating Ring Expansion of Cyclic Acetals to Medium-Sized Dioxacycloalkenones. Use of the Intramolecular Formation of Oxonium Ylides
Oku, Akira,Murai, Nobuhito,Baird, Julia
, p. 2123 - 2129 (2007/10/03)
The Rh(II)-catalyzed reaction of 2-(3′-diazo-2′-oxopropyl)-2-methyldioxolane (1) in the presence of a protic nucleophile (NuH) such as AcOH resulted in effective ring enlargement to give the 8-membered 3-acetoxydioxocanone 4a (41%) and dioxocan-2-en-1-one 3 (46%). Similar treatment of 2-(4′-diazo-3′-oxobutyl)-2-methyldioxolane (9) with AcOH gave 4-acetoxydioxonanone 10 (67%), which was readily hydrolyzed on silica gel to a tautomeric mixture of hydrolysis products 16a and 16b (total yield 46%). In contrast, similar treatment of 2-(5′-diazo-4′-oxopentyl)-2-methyldioxolane (19) gave 2,5-dioxa-1-methyldecalin-7-one (20, 24%), and the yield increased to 61% in the absence of AcOH, by Stevens rearrangement. The reaction of 1,3-dioxane homologues 26 and 31 gave similar results. All of these reactions can be explained in terms of the intermediacy of bicyclooxonium ylides, which undergo either a Stevens rearrangement or, after protonation by a NuH, ring enlargement through release of the strain of the bicyclic ylides. Evidence of the reversible formation of oxonium ylides is also provided.
Synthesis of labelled [13C6]testosterone and [13C5]19-nortestosterone
Joubert,Beney,Marsura,Luu-Duc
, p. 745 - 754 (2007/10/02)
The condensation of ethyl acetoacetate-13C4 and ethyl bromoacetate-13C2 afforded, in seven steps, (1,2,3,4,5-13C5) 5-(diethylphosphono)-2-pentanone ethylene ketal 9. The reaction of this labelled compound with 7-[[(1,1-dimethylethyl)-dimethylsilyl]oxy]-1,6,6a,7,8, 9, 9a, 9b-octahydro-6a-methyl-[6aS-(6aa,7a,9aβ,9ba)] cyclopenta[f][1]benzopyran-3 (2H)-one 13 gave the benzindenone 14 which was converted to (1,2,3,4,10,19-13C6)testosterone 17 then, into (1,2,3,4,10-13C5)19-nortestosterone 18 by a reductive alkylation method.
Synthesis and Application of Imidazole Derivatives. Synthesis and Acyl Activation of 2-Acyl-1-methyl-1H-imidazoles
Ohta, Shunsaku,Hayakawa, Satoshi,Moriwaki, Hiroki,Harada, Suzumi,Okamoto, Masao
, p. 4916 - 4926 (2007/10/02)
2-Acyl-1-methyl-1H-imidazoles (3) were prepared in good yields by treating 1-acylpyrrolidines (5) with 2-lithio-1-methyl-1H-imidazole (2) at -78 deg C.The acyl group of 3 was very stable under various severe conditions, but 2-benzoylimidazole (3a) was gradually hydrolyzed by heating with 1.3 N NaOH to produce benzoic acid and 1-methyl-1H-imidazole.Acyl activation of 3 was performed by direct quaternization of 3 with iodomethane or dimethyl sulfate or more successfully by quaternization of the corresponding O-trimethylsilylated gem-cyanohydrin (11) with dimethyl sulfate.Keywords- acylimidazole; 2-acylimidazole; imidazolium salt; acyl group activation; acylation; C-C bond fission; protecting group; latent functionality
PREPARATION ET REACTIVITE DU DERIVE LITHIE ISSU DU DIOXOLANNE DU -CETO PENTANOATE DE TRIMETHYLSILYLE.
Moreau, Jean Louis,Couffignal, Rene
, p. 5271 - 5274 (2007/10/02)
The organolithium reagent 4 issued from trimethylsilyl 4,4-ethylendioxypentanoate 3 reacts with ketones ; it affords β-hydroxy-acids 7 and β-ethylenic ketones 8.This reaction is an efficient route for carbonyl olefination. 4 also acts towards mixed carboxylic and carbonic anhydrides as a homoenolate equivalent.
SYNTHESE DE MONODIOXOLANNES DE DICETONES-1,4 ET DE DICETONES-1,4 AU MOYEN DES ANHYDRIDES MIXTES CARBOXYLIQUES ET CARBONIQUES: APPLICATION A LA PREPARATION DE LA DIHYDROJASMONE, DE LA Z-JASMONE ET DE LA DEHYDROJASMONE
Moreau, J.-L.,Couffignal, R.,Arous-Chtara, R.
, p. 307 - 310 (2007/10/02)
Levulinic acid 1 is easily converted by two steps into mixed carboxylic and carbonic anhydride 3 which reacts with the organolithium reagent issued from trimethylsilyl esters.Monoethylene acetal of 1,4-diketones 4 can be prepared; it is also possible to obtain 1,4-diketones 5 in one step by hot acid hydrolysis.The preparation of the dihydrojasmone 6d, Z-jasmone 6e and dehydrojasmone 6f shows the efficiency of the process.
