- Rhodium-mediated 18F-oxyfluorination of diazoketones using a fluorine-18-containing hypervalent iodine reagent
-
Geminal 18F-oxyfluorination of diazoketones was performed in the presence of rhodium mediators. The reactions were performed using a hypervalent iodine-based [18F]fluoro-benziodoxole reagent. By this methodology various α-[18/s
- Cortés González, Miguel A.,Jiang, Xingguo,Nordeman, Patrik,Antoni, Gunnar,Szabó, Kálmán J.
-
-
Read Online
- A Short New Azulene Synthesis
-
A short new azulene synthesis requiring no dehydrogenation step, has been developed (Scheme 1).Intramolecular carbene addition creates the bicyclic ring system of azulene with a high degree of unsaturation and versatile functionality in a single step from a simple benzene derivative.The synthesis is particularly amenable to preparation of specific 13C- and 2H-labeled azulenes.
- Scott, Lawrence T.,Minton, Mark A.,Kirms, Mark A.
-
-
Read Online
- Trimethylsilyldiazomethane in the preparation of diazoketones via mixed anhydride and coupling reagent methods: A new approach to the Arndt-Eistert synthesis
-
Reaction of trimethylsilyldiazomethane with a mixed anhydride derived from a carboxylic acid by the action of ethyl chloroformate, yields the corresponding diazoketone in high yield. Subsequent Wolff rearrangement of the diazoketone leads to the homologated ester. Reaction of trimethylsilyldiazomethane with carboxylic acid-dicyclohexylcarbodiimide mixtures leads to the formation of diazoketone and trimethylsilylmethyl ester in equimolar ratio via an acid anhydride intermediate. The N-hydroxysuccinimide ester of the acid does not react with trimethylsilyldiazomethane or with its more reactive lithiated derivative.
- Cesar, Jo?ko,Sollner Dolenc, Marija
-
-
Read Online
- Stability of diazocarbonyl compounds under the conditions of gas chromatography and chromatography-mass spectrometry analysis
-
The gas chromatographic analysis of alkyldiazoacetates N 2CHCO2R (R = CH3 - C4H9), α-aliphatic diazoketones RCOCHN2 (R = C3H 7, C5H11, and C9H19), and aryl-substituted diazoketones Ph (CH2)nCOCHN2 (n = 0-2) is shown to be possible when their retention temperatures are below the boiling points of compounds of this series at atmospheric pressure without decomposition (about 140°C). At higher temperatures occurs partial or complete decomposition of α-diazoketones in chromatographic columns to form ketenes. Among the impurities in the reaction mixtures at the diazotization of corresponding alkyl glycinates were identified for the first time the nitrate esters of glycolic acid O2NOCH2CO2R, as well as the dimeric products. All diazocarbonyl compounds and the impurities were characterized by mass spectra. For the first time their gas chromatographic retention indices were determined. Pleiades Publishing, Ltd., 2012.
- Kornilova,Ukolov,Kostikov,Zenkevich
-
-
Read Online
- Selective bond cleavage of [5.3.1]propellanes by lead tetraacetate: A facile entry into the carbocyclic frame [A,B ring] of taxol
-
[5.3.1]Propellanes e.g., the tricyclo[5.3.1.01,7]undeca-2,4-dien-10-one 8 and the corresponding methylidene compound 10 were prepared from methyl cinnamate 2 in several steps involving rhodium(II) acetate mediated cyclization of 4 to 6 as a key step. The selective central cyclopropyl bond cleavage in 8 and 10 by lead tetraacetate provides the basis of a new approach to the construction of carbocylic frame of A,B ring of Taxol.
- Kumar, Pradeep,Rao, Ashok T.,Saravanan,Pandey, Bipin
-
-
Read Online
- First synthesis of poly(acylmethylene)s via palladium-mediated polymerization of diazoketones
-
Palladium-mediated polymerization of diazoketones (1a, 2a, 3a, 4a, and 6a) proceeded to give poly(acylmethylene)s (1b, 2b, 3b, 4b, and 6b), in which all of the main chain carbons had acyl groups. The structures of the novel polymers were characterized by
- Ihara, Eiji,Fujioka, Masayasu,Haida, Nobuyuki,Itoh, Tomomichi,Inoue, Kenzo
-
-
Read Online
- 3-Phenylalkyl-2H-chromenes and -chromans as novel rhinovirus infection inhibitors
-
Following our studies on structure-activity relationships of anti-rhinovirus chromene and chroman derivatives, we designed and synthesized new series of 3-phenylalkyl-2H-chromenes and -chromans bearing differently sized, aliphatic linker chains between the two cycles. The cytotoxicity and the antiviral activity of the new compounds on human rhinovirus (HRV) serotype 1B and 14 infection were evaluated in HeLa cell cultures. Most of the tested compounds interfered with HRV1B multiplication in the micromolar or submicromolar concentrations while HRV14 was less susceptible. 3-[3-(4-Chlorophenyl)propyl]chroman (9c) was selected for preliminary mechanism of action studies due to its potent activity against both serotypes (IC50 of 0.48?μM and 1.36?μM towards HRV1B and 14, respectively) coupled with high selectivity (SI?=?206.18 and 73.26, respectively). Results of time of addition/removal studies suggest that 9c, similarly to related derivatives, behaves as a capsid binder interfering with some early events of the HRV1B infectious cycle.
- Conti, Cinzia,Proietti Monaco, Luca,Desideri, Nicoletta
-
p. 2074 - 2083
(2017/03/23)
-
- Safe and reliable synthesis of diazoketones and quinoxalines in a continuous flow reactor
-
A flow method for the synthesis of aliphatic and aromatic diazoketones from acyl chloride precursors has been developed and used to prepare quinoxalines in a multistep sequence without isolation of the potentially explosive diazoketone. The protocol showcases an efficient in-line purification using supported scavengers with time-saving and safety benefits and in particular a reduction in the operator's exposure to carcinogenic phenylenediamines.
- Martin, Laetitia J.,Marzinzik, Andreas L.,Ley, Steven V.,Baxendale, Ian R.
-
supporting information; experimental part
p. 320 - 323
(2011/03/23)
-
- Studies on the chemistry and reactivity of α-substituted ketones in isonitrile-based multicomponent reactions
-
(Chemical Equation Presented) Using the Passerini and Ugi reactions as representative tests, the utility of several α-substituted ketones R-CO-CH2-X (X = sulfonyloxy, acyloxy, azido, halo, hydroxy, and sulfonyl) in isonitrile-based multicompone
- Fan, Lijun,Adams, Ashley M.,Polisar, Jason G.,Ganem, Bruce
-
body text
p. 9720 - 9726
(2009/04/07)
-
- ARYLTHIAZOLIDINEDIONE DERIVATIVES
-
Substituted 5-aryl-2,4-thiazolidinediones are potent agonists of PPAR, and are therefore useful in the treatment, control or prevention of diabetes, hyperglycemia, hyperlipidemia (including hypercholesterolemia and hypertriglyceridemia), atherosclerosis, obesity, vascular restenosis, and other PPAR alpha , delta and/or gamma mediated diseases, disorders and conditions.
- -
-
Page/Page column 59
(2010/11/25)
-
- Arylthiazolidinedione and aryloxazolidinedione derivatives
-
Substituted 5-aryl-2,4-thiazolidinediones or 5-aryl-2,4-oxazolidinediones that also carry a second substituent in the 5-position of the heterocyclic ring are potent agonists of PPAR, and are therefore useful in the treatment, control or prevention of diabetes, hyperglycemia, hyperlipidemia (including hypercholesterolemia and hypertriglyceridemia), atherosclerosis, obesity, vascular restenosis, and other PPAR α, δ and/or γ mediated diseases, disorders and conditions.
- -
-
-
- New results in homoheptalene chemistry
-
The thermal reaction of homoazulene (= bicyclo[5.3.1]undeca-1,3,5,7,9-pentaene; 2) with dimethyl acetylenedicarboxylate (ADM) in 1,2-dichloroethane (ClCH2CH2Cl) results, in contrast to an earlier report [5], in formation of not only
- Rueedi, Georg,Hansen, Hans-Juergen
-
p. 1017 - 1047
(2007/10/03)
-
- Arylthiazolidinedione derivatives
-
Substituted 5-aryl-2,4-thiazolidinediones are potent agonists of PPAR, and are therefore useful in the treatment, control or prevention of diabetes, hyperglycemia, hyperlipidemia (including hypercholesterolemia and hypertriglyceridemia), atherosclerosis, obesity, vascular restenosis, and other PPAR α, δ and/or γ mediated diseases, disorders and conditions.
- -
-
-
- The Intramolecular Buchner Reaction of Aryl Diazoketones. Substituent Effects and Scope in Synthesis
-
Rhodium(II) acetate-catalysed cyclisation of α-diazoketones derived from 3-arylpropionic acid produces bicyclodecatrienones or 2-tetralones depending on the substitution pattern of the aryl ring in the precursor; the former products are transformed into the latter catalytically with trifluoroacetic acid.Precursors with methyl, methoxy, and acetoxy substituents have been examined, efficient cyclisation occurring in all cases.When the precursor contains a meta-methoxy substituent, 2-tetralones are obtained directly.The efficient conversion of 3-phenylpropionicacid into trans-1-methylbicyclodecan-2-one is also described, partial asymmetric synthesis having been realised through the use of rhodium (S)-mandelate as the cyclisation catalyst.Cyclisations of diazoketones derived from 4-phenylbutyric acid and 5-phenylpentanoic acid have also been studied; the former provides a new entry into the bicycloundecane system whereas the latter produces a 2,3-disubstituted cyclopentanone via C-H insertion.Aspects of the cycloheptatriene-norcaradiene equilibrium in fused ring systems are discussed.
- Kennedy, Michael,McKervey, M. Anthony,Maguire, Anita R.,Tuladhar, Sarbajna M.,Twohig, M. Fiona
-
p. 1047 - 1054
(2007/10/02)
-
- Efficient Synthesis of Bicyclodecatrienones and of 2-Tetralones via Rhodium(II) Acetate-catalysed Cyclisation of α-Diazoketones derived from 3-Arylpropionic Acids
-
Rhodium(II) acetate-catalysed cyclisation of α-diazoketones derived from 3-arylpropionic acids produces bicyclodecatrienones or 2-tetralones depending on the substitution pattern of the aryl ring; the former products are transformed into the latter by catalytic amounts of trifluoroacetic acid.
- McKervey, M. Anthony,Tuladhar, Sarbajna M.,Twohig, M. Fiona
-
p. 129 - 130
(2007/10/02)
-
- REGIOSPECIFIC SYNTHESIS OF α-(PHENYLTHIO)CYCLOALKENONES AND OF α-PHENYL-α-(PHENYLTHIO)KETONES VIA αα-ADDITION OF PHENYLSULPHENYL CHLORIDE TO α-DIAZOKETONES
-
Cyclic α-diazoketones react with phenylsulphenyl chloride at room temperature to furnish α-chloro-α-(phenylthio)cycloalkanones which undergo ready dehydrochlorination to α-(phenylthio)cycloalkenones when treated with triethylamine; acyclic, terminal α-diazoketones also furnish α-chloro-α-(phenylthio)adducts which are useful electrophiles in the synthesis of α-phenyl-α-(phenylthio)ketones.
- McKervey, M. Anthony,Ratananukul, Piniti
-
p. 117 - 120
(2007/10/02)
-
- Photoreactions of α-sulfonyloxyketones
-
Earlier work on the photochemistry of α-sulfonyloxyketones uncovered their propensity to form the corresponding α-ketocarbonium ions on photolysis.Typical reactions such as intramolecular cyclizations, carbonium ion rearrangements, and solvent trapping were found.This paper describes an attempt to extend this reaction to a general synthetic technique for polyene cyclizations.During the course of this work two other major reaction pathways were found.The first is an α-keto carbonium ion to acylium ion rearrangement and the second is a photoreduction-elimination process that leads to an α-keto radical rather than the corresponding cation.
- Charlton, James Leslie.,Lai, Hoi Kiong.,Lypka, Gerald Nicholas
-
p. 458 - 462
(2007/10/02)
-