- Carboxylation of Ketones Using Triethylamine and Magnesium Halides
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Procedures for the carboxylation of ketones with carbon dioxide at atmospheric pressure in the presence of magnesium halides and triethylamine are described.A variety of ketones are converted to the corresponding β-keto acids in satisfactory yields by using magnesium chloride-sodium iodide mixtures in acetonitrile.This carboxylation reaction exhibits little regioselectivity with 2-butanone.
- Tirpak, Robin E.,Olsen, Richard, S.,Rathke, Michael W.
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- Discovery and Engineering of Pathways for Production of α-Branched Organic Acids
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Cell-based synthesis offers many opportunities for preparing small molecules from simple renewable carbon sources by telescoping multiple reactions into a single fermentation step. One challenge in this area is the development of enzymatic carbon-carbon bond forming cycles that enable a modular disconnection of a target structure into cellular building blocks. In this regard, synthetic pathways based on thiolase enzymes to catalyze the initial carbon-carbon bond forming step between acyl coenzyme A (CoA) substrates offer a versatile route for biological synthesis, but the substrate diversity of such pathways is currently limited. In this report, we describe the identification and biochemical characterization of a thiolase-ketoreductase pair involved in production of branched acids in the roundworm, Ascaris suum, that demonstrates selectivity for forming products with an α-methyl branch using a propionyl-CoA extender unit. Engineering synthetic pathways for production of α-methyl acids in Escherichia coli using these enzymes allows the construction of microbial strains that produce either chiral 2-methyl-3-hydroxy acids (1.1 ± 0.2 g L-1) or branched enoic acids (1.12 ± 0.06 g L-1) in the presence of a dehydratase at 44% and 87% yield of fed propionate, respectively. In vitro characterization along with in vivo analysis indicates that the ketoreductase is the key driver for selectivity, forming predominantly α-branched products even when paired with a thiolase that highly prefers unbranched linear products. Our results expand the utility of thiolase-based pathways and provide biosynthetic access to α-branched compounds as precursors for polymers and other chemicals.
- Blaisse, Michael R.,Dong, Hongjun,Fu, Beverly,Chang, Michelle C. Y.
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- A new protocol for a regioselective aldol condensation as an alternative convenient synthesis of β-ketols and α,β-unsaturated ketones
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A general and convenient synthesis of β-ketols and α,β-alkenones has been achieved by a Knoevenagel condensation of a β-ketoacid with an aldehyde in aqueous medium. Saponification of a β-ketoester by an aqueous KOH 10% solution gives the potassium salt of the β-ketoacid, which is condensed in situ with an aldehyde at pH 7.8-8.0, at 60 °C for 5-6 h. The intermediate β-ketocarboxylate is smoothly decarboxylated in the reaction medium, giving the β-ketol in high yield (75-90%). Acidification of the reaction mixture at pH 1 and heating at 70 °C under vigorous stirring for 6 h, leads directly to the corresponding α,β-unsaturated ketone in good yield (65-75%).
- Kourouli, Therapia,Kefalas, Panagiotis,Ragoussis, Nikitas,Ragoussis, Valentine
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- SYNTHESIS OF BOTH THE ENANTIOMERS OF THE HETEROCYCLIC PHEROMONES ISOLATED FROM THE MALE SWIFT MOTH HEPIALUS HECTA L.
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Both the enantiomers of the following three main components of the pheromone blend of the male swift moth Hepialus hecta L. were synthesized in highly optically pure state starting from chiral building blocks of microbial origin: (i) 6-ethyl-2-methyl-2,3-dihydro-4H-pyran-4-one, (ii) 1,8-dimethyl-3-ethyl-2,9-dioxabicyclonon-7-en-6-one and (iii) 1,8-dimethyl-3-ethyl-2,9-dioxabicyclonon-7-ene.
- Mori, Kenji,Kisida, Hirosi
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- Antibacterial agents: high-potency myxopyronin derivatives
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The invention provides compounds of Formula (I) and pharmaceutically acceptable salts thereof, wherein Ya, Yb, R1, R2, and G are as described in the specification, as well as compositions comprising a compound of formula (I). The compounds are useful as inhibitors of bacterial RNA polymerase and as antibacterial agents.
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Page/Page column 25-26; 37
(2016/03/12)
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- Organocatalyzed asymmetric synthesis of morphans
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A general effective organocatalyzed synthesis of enantioenriched morphans with up to 92% ee was developed. The morphan scaffold was constructed in a one-pot tandem asymmetric organocatalyzed Michael addition followed by a domino Robinson annulation/aza-Michael intramolecular reaction sequence from easily available starting materials.
- Bradshaw, Ben,Parra, Claudio,Bonjoch, Josep
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supporting information
p. 2458 - 2461
(2013/06/27)
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- ANTIBACTERIAL AGENTS: SIDECHAIN-FLUORINATED MYXOPYRONIN DERIVATIVES
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The invention provides compounds of Formula I: and pharmaceutically acceptable salts thereof, wherein R1, R2, R3, R4, R5, and G are as described in the specification, as well as compositions comprising a compound of formula I, methods of making such compounds, and methods of using such compounds, e.g., as inhibitors of bacterial RNA polymerase and as antibacterial agents.
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Page/Page column 16
(2013/10/08)
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- Synthesis of a new pyranoanthocyanin dimer linked through a methyl-methine bridge
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Two new anthocyanin-derived compounds corresponding to the ethylpyranomalvidin-3-glucoside and the pyranomalvidin-3-glucoside dimer linked through a methyl-methine bridge were synthesized for the first time and their structure characterized by LC-DAD/MS a
- Oliveira, Joana,Mateus, Nuno,Rodriguez-Borges, José E.,Cabrita, Eurico J.,Silva, Artur M.S.,De Freitas, Victor
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experimental part
p. 2957 - 2960
(2011/06/23)
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- Studies with pyridazines and condensed pyridazines: Routes for synthesis of 3-amino-5-aryl-2,5-dihydro-pyridazine, 10aH-pyridazino[1,6-a]quinazoline and thieno[3,4-d]pyridazinone
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(Chemical Equation Presented) Novel routes to 3-aminopyridazines, 10aH-pyridazino[1,6-a]quinazoline and, thieno[3,4-d]pyridazine utilizing the reaction of 2-oxobutanal-1-arylhydrazones 3a,b with α,β-unsaturated nitriles are described. Condensation of 3 wi
- Aziz, Suzan Ibrahim,Anwar, Hany Fakhry,El-Apasery, Morsy Ahmed,Elnagdi, Mohamed Hilmy
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p. 877 - 881
(2008/03/29)
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- SILVER β-KETOCARBOXYLATE, MATERIAL COMPRISING THE SAME FOR FORMING SILVER METAL, AND USE THEREOF
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A new material from which silver metal can be rapidly formed even at a temperature as low as about 210°C or below. The material for silver metal formation comprises a silver β-ketocarboxylate. Heating this forming material can rapidly form silver metal even at a temperature as low as about 210°C or below. Examples of the silver β-ketocarboxylate include silver isobutyrylacetate, silver benzoylacetate, silver acetoacetate, silver propionylacetate, silver α-methylacetoacetate, and silver α-ethylacetoacetate.
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(2008/06/13)
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- Synthesis of hetero atom modified pyrromethenones
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A series of six heteroaromatic compounds, ethyl-/methyl-and dimethylfuranones, thiophenones, and cyclopentenones, was synthesized and condensed with a methyl methylpropionate substituted pyrrole, yielding the "right" half of open-chain tetrapyrroles. These compounds serve as light-inducible chromophores in the plant photoreceptor phytochrome. Three-dimensional structure analysis of the 10-oxapyrromethen-1-one 25 revealed a planar conformation, similar to the dipyrromethenone parent compound, stabilized by a hydrogen bond formed between the pyrrole proton and the furanone oxygen atom. All six pyrrole-substituted heteroaromatic derivatives 25-30 show absorbances in the visible spectrum with high molar extinction coefficients. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Bongards, Christian,Gaertner, Wolfgang
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p. 5749 - 5758
(2008/09/17)
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- Pyrazole derivatives
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This invention relates to pyrazole derivatives of formula (I) or pharmaceutically acceptable salts, solvates or derivative thereof, wherein R1 to R4 are defined in the description, and to processes for the preparation thereof, intermediates used in their preparation of, compositions containing them and the uses of such derivatives. The compounds of the present invention bind to the enzyme reverse transcriptase and are modulators, especially inhibitors thereof. As such the compounds of the present invention are useful in the treatment of a variety of disorders including those in which the inhibition of reverse transcriptase is implicated. Disorders of interest include those caused by Human Immunodificiency Virus (HIV) and genetically related retroviruses, such as Acquired Immune Deficiency Syndrome (AIDS).
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Page/Page column 12
(2010/02/11)
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- PYRAZOLE DERIVATIVES AND THEIR USE AS THERAPEUTIC AGENTS FOR HIV MEDIATED DISEASES
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This invention relates to pyrazole derivatives of formula (I)or pharmaceutically acceptable salts, solvates or derivative thereof, wherein R' to R4; ;ark defined in the description, and to processes for the preparation thereof, intermediates used in their preparation of, compositions containing them and the uses of such derivatives. The compounds of the present invention bind to the enzyme reverse transcriptase and are modulators, especially inhibitors thereof. As such the compounds of the present invention are useful in the treatment of a variety of disorders including those in which the inhibition' of reverse transcriptase is implicated. Disorders of interest include those caused by Human Immunodificiency Virus (HIV) and genetically related retroviruses, such as Acquired Immune Deficiency Syndrome (AIDS).
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- Pyrazole derivatives
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This invention relates to pyrazole derivatives of formula (I) or pharmaceutically acceptable salts, solvates or derivatives thereof, and to processes for the preparation thereof, intermediates used in their preparation of, compositions containing them and the uses of such derivatives. The compounds of the present invention bind to the enzyme reverse transcriptase and are modulators, especially inhibitors thereof. As such, the compounds of the present invention are useful in the treatment of a variety of disorders including those in which the inhibition of reverse transcriptase is implicated. Disorders of interest include those caused by Human Immunodificiency Virus (HIV) and genetically related retroviruses, such as Acquired Immune Deficiency Syndrome (AIDS).
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- Antihypertensive dihydropyridine derivatives
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Compound of formula 1 are calcium entry antagonists useful for treating hypertension, congestive heart failure, angina, and vasospastic disorders: STR1 wherein n is an integer from 1 to 4; R1 and R2 are lower alkyl; R3 is lower alkyl or alkoxyalkyl; A is alkylene of two to eight carbon atoms; X1 and X2 are each independently --NO2, --CF3, CH3 O--, --CN, --H, lower alkyl or halo; Y is --O--, --S--, --S(O)--, or --S(O)2 --; and R is H, lower alkyl, cycloalkyl, alkoxyalkyl, cycloalkyloxy-alkyl, alkoxycycloalkyl, acyl, or saturated or unsaturated 5- or 6-membered heterocyclyl optionally substituted with lower alkyl or alkoxy, wherein the heteroatom is one oxygen atom.
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- Knoevenagel Reactions with β-Oxo Acids. Regiospecific Enol Equivalents for Syntheses of α,β-Unsaturated Ketones and of Some β-Ketols
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3-Oxobutanoic acid reacts with aliphatic aldehydes in the presence of pyridine to give α,β-unsaturated methyl ketones in good yields.Analogous results were obtained with a series of other β-oxo acids.Synthesis of (E)-7-methyloct-4-en-3-one, a major constituent of the marine sponge Plakortis zygompha, has been carried out using this methodology.Aromatic aldehydes are generally less reactive under these conditions but give β-ketols when the phenyl ring bears an electron-withdrawing substituent.Some observations on the mechanism of the reaction between 3-oxobutanoic acid and benzaldehyde are presented.
- Grayson, David H.,Tuite, Mathew R. J.
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p. 2137 - 2142
(2007/10/02)
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- A Simple Total Synthesis of (+/-)-δ-Cadinene
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This paper reports on a total synthesis of racemic δ-cadinene (2), which had been obtained previously in optically active form by acid catalyzed cyclization of (-)-germacene D.The Robinson annelation using cyclohexenone enamine (12) proceeded stereoselectively to form δ-cadinenone (3), whose oxygen was removed by the thioketal-Raney Ni Method to produce δ-cadinene.
- Nishimura, Hiroyuki,Takabatake, Tetsuhiko,Kaku, Koichiro,Seo, Akira,Mizutani, Junya
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p. 1861 - 1864
(2007/10/02)
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