Showing papers on "Methyl vinyl ketone published in 1993"
TL;DR: In this paper, the carbonyl products of isoprene, methacrolein (MTA), methyl vinyl ketone (MVK), hydroxyacetaldehyde, and Hydroxyacetone have been identified and their concentrations measured in experiments involving sunlight irradiations of 1 ppm organic and 200 ppb NO in purified air.
Abstract: The carbonyl products of isoprene, methacrolein (MTA), methyl vinyl ketone (MVK), hydroxyacetaldehyde, and hydroxyacetone have been identified and their concentrations measured in experiments involving sunlight irradiations of 1 ppm organic and 200 ppb NO in purified air. The MTA/MVK yield ratio was 1.4 for isoprene. The hydroxycarbonyljmethylglyoxal yield ratio was 4.3 for MTA and was 1.9 for MVK. The peroxyacyl nitrates PAN [RC(O)OONO 2 , R=CH 3 - ] and MPAN [R=CH 2 C-(CH 3 )-] have been measured. MPAN/PAN concentration ratios were 0.65±0.04 for isoprene and 2.3±0.1 for MTA
191 citations
TL;DR: The mixing ratios of methyl vinyl ketone and methacrolein were measured at a site located in the Kinterbish Wildlife Management Area in western Alabama between June 15 and July 20, 1990.
Abstract: The mixing ratios of methyl vinyl ketone (CH2=CHCOCH3) and methacrolein (CH2=C(CH3)COH) were measured at a site located in the Kinterbish Wildlife Management Area in western Alabama. The measurements were made between June 15 and July 20, 1990. Considering all the data over the whole measurement period, the concentrations of these two carbonyls were approximately equal at this isolated rural site. The average mixing ratios for methyl vinyl ketone and methacrolein were 0.98 parts per billion by volume (ppbv) and 0.66 ppbv, respectively, while the medians were 0.87 ppbv and 0.57 ppbv. The methyl vinyl ketone mixing ratio varied from 3.4 ppbv to the detection limit of the instrument, ≈0.01 ppbv, while the methacrolein mixing ratio varied from 2.6 ppbv to 0.027 ppbv. These carbonyls constituted a significant fraction of the volatile organic compounds observed at the site: their mixing ratios, measured 2 m above the top of the forest canopy, were less than that of the dominant compound isoprene but were considerably greater than the mixing ratios of anthropogenic compounds (e.g., benzene). The mixing ratios of methyl vinyl ketone and methacrolein were found to be highly correlated and exhibited a systematic variation with respect to each other. On average, during the day, methyl vinyl ketone was larger than methacrolein, while methacrolein tended to be slightly larger during the night. The systematic behavior of these compounds with respect to each other and other compounds measured at the site were simulated using a one-dimensional photochemical model. These observations were consistent with the production and loss of isoprene, methyl vinyl ketone, and methacrolein by photochemical oxidation reactions.
184 citations
TL;DR: In this article, the structures and energy properties of Diels-Alder reactions between cyclopentadiene and ethylene, isoprene and methyl vinyl ketone were investigated.
Abstract: Ab initio molecular orbital calculations have been used to investigate the structures and energetics for the reactants and transition states of Diels-Alder reactions between cyclopentadiene and ethylene, isoprene, cyclopentadiene, acrylonitrile, and methyl vinyl ketone (MVK). Geometry optimizations were performed with both RHF/3-21G and RHF/6-31G * calculations, and the energies were computed to the MP3/6-1G * //6-31G * level in each case. Calculations the vibrational frequencies permitted computation of the enthalpies and entropies of activation
180 citations
TL;DR: In this article, various β-carbonyl radicals are generated from cyclopropanol derivatives by the use of manganese(III) 2-pyridinecarboxylate (Mn(pic)3).
Abstract: Various β-carbonyl radicals are generated oxidatively from cyclopropanol derivatives by the use of manganese(III) 2-pyridinecarboxylate (Mn(pic)3). These β-carbonyl radicals react with electron-rich olefins such as conjugated silyl enol ethers, a ketene thioacetal, a ketene dithioacetal, and a vinyl ether intermolecularly to give crossed-addition products in good yield. Furthermore, the combined use of Mn(pic)3 and tributylhydridotin makes it possible to carry out the 1 : 1 addition reaction of these β-carbonyl radicals with electron-deficient olefins such as acrylonitrile, acrylaldehyde, methyl acrylate, methyl vinyl ketone, and N,N-dimethylacrylamide, and the corresponding products are obtained in moderate to good yield.
64 citations
TL;DR: In this paper, a cyclopentanoid was constructed by an initial 1,4-addition followed by a 1,2-silyl migration and a final cyclization step involving the derived boron enolate.
Abstract: Functionalized (E)-crotysilanes 1 undergo Lewis acid promoted conjugate addition reactions with α-substituted enals and methyl vinyl ketone 2 to produce tetrasubstituted cyclopentanes 3 with high levels of diastereoselection. The reaction is believed to proceed by an initial 1,4-addition which is followed by a 1,2-silyl migration and a final cyclization step involving the derived boron enolate resulting in the construction of the cyclopentanoid product
61 citations
TL;DR: In this article, the primary dissociation processes in the photolysis of methyl of methyl vinyl ketone (MVK) at 193.3 nm have been investigated and a quantum yield of close to unity for the formation of both CH 3 and C 2 H 3 radicals has been determined using real-time absorption data in conjunction with gas chromatography analysis of final products.
Abstract: The primary dissociation processes in the photolysis of methyl of methyl vinyl ketone (MVK) at 193.3 nm have been investigated. A quantum yield of close to unity for the formation of both CH 3 and C 2 H 3 radicals has been determined using real-time absorption data in conjunction with gas chromatography analysis of final products. Detailed kinetic modeling of the system indicates a rate constant of (1.5±0.3)×10 -10 cm 3 molecule -1 s -1 for the cross-combination of methyl vinyl radicals
50 citations
TL;DR: In this article, the frontier orbital coefficients of the isomunchnone were determined by semi-empirical AMAC calculations, and the expected dipolar cycloadducts were not isolated, but underwent a 4+2-cycloreversion instead to furnish furanoisocyanates.
36 citations
TL;DR: In this paper, the authors showed that β-Bromopropargyl ethers can be isomerized with potassium tert-butoxide (KO-t-Bu) into the corresponding allenyl derivatives 3a-h, 13, 14, and 9d-h.
Abstract: β-Bromopropargyl ethers 2a-h, 11, and 12 or allyl propargyl ethers 8d-h are easily isomerized with potassium tert-butoxide (KO-t-Bu) into the corresponding allenyl derivatives 3a-h, 13, 14, and 9d-h. These compounds afford α-methylene-γ-butyrolactones 7a-h, 25, and 26 by application of the sequence halogenation/dehydrohalogenation/homolytic carbocyclization. Starting from methyl vinyl ketone 1i, similar transformations lead to botryodiplodin (27) or ethoxybotryodiplodin (28)
36 citations
TL;DR: Clean and efficient Michael addition of silyl enol ethers to methyl vinyl ketone has been achieved through a simple solvent-free reaction on the surfac as mentioned in this paper, which has been shown to be solvent free.
30 citations
TL;DR: In this article, the free stannaimine A reacts with methyllithium, 2,6-diisopropylylaniline, and methyl vinyl ketone to give the corresponding 1,2-addition products (to the SnN bond) 2, 3, and 10.
Abstract: Reactions of a Free Stannaimine and of Base-Stabilized Stannylenes
The free stannaimine A reacts with methyllithium, 2,6-diisopropylaniline, and methyl vinyl ketone to give the corresponding 1,2-addition products (to the SnN bond) 2, 3, and 10. With 2,6-diisopropylphenyl isocyanate and benzaldehyde [2 + 2] cycloadditions to the CO bonds lead to 4 and 5, while with benzonitrile oxide and acroleine [2 + 3] and [2 + 4] cyclo-additions produce 8 and 9. The pyridine adducts bis-[bis(trimethylsilyl)amino]stannylene and -germylene react with aryl azides to give the corresponding derivatives of tri-amino-2-pyridylstannane 11 and -germane 12. Bis[2-pyridyl-bis(trimethylsilyl)methyl]stannylene upon treatment with aryl azides form the 1-aza-8-stannabicyclo[3.2.0]octa-2,4,6-triene systems 13 and 14 via stannaimine intermediates. X-ray structure analyses are presented for 3, 11, and 13.
22 citations
TL;DR: In this article, the absolute configuration of (−)-2-nitro-2-(3-oxobutyl)cyclooctanone and (+)-2 -nitrocycloalkanone derivatives were determined by X-ray diffraction.
Abstract: Michael addition of methyl vinyl ketone 2 to 2-nitrocycloalkanones 1 catalyzed by the Cinchona alkaloid cinchonine 3 affords adducts in high chemical yields in up to 60% enantiomeric excess. The configuration of the products depends on the ring size. Absolute configuration of (−)-2-nitro-2-(3-oxobutyl)cyclooctanone and (+)-2-nitro-2-(3-oxobutyl)cyclododecanone derivatives were determined by X-ray diffraction.
TL;DR: In this paper, the first example of the preparation of C-branched nucleosides using the base catalyzed addition reaction at the α-carbon of a nitro function in the sugar moiety of nucleoside was presented.
TL;DR: In this paper, a Diels-Alder reaction with methyl vinyl ketone on the furan moiety, desulfonylation, intramolecular Diels Alder reaction of the resulting dienes, and retro Diels−alder reaction occurred sequentially to afford the tricyclic fused furans 17a−c; in good yields.
Abstract: Alkylation of 4H,6H-thieno[3,4-c]furan 5,5-dioxide (furan-annulated sulfolene)1 readily gave its 4-alkyl, 4,6-dialkyl, or 4,4-dialkyl derivatives, selectively. Attempts were made to use the appropriate derivatives as 3,4-dimethylenefuran synthons in intramolecular Diels–Alder reactions. Thus when they were heated after treatment with methyl vinyl ketone, a Diels–Alder reaction with methyl vinyl ketone on the furan moiety, desulfonylation, intramolecular Diels–Alder reaction of the resulting dienes, and retro Diels–Alder reaction occurred sequentially to afford the tricyclic fused furans 17a–c; in good yields.
TL;DR: In this article, the selective oxidation of butan-2-one to diacetyl has been studied in the temperature range 200-380°C over a vanadium phosphorus oxide catalyst.
Abstract: The selective oxidation of butan-2-one to diacetyl has been studied in the temperature range 200–380°C over a vanadium phosphorus oxide catalyst. In addition to diacetyl the principal reaction products detected were acetic acid, acetaldehyde, methyl vinyl ketone, propionaldehyde and carbon dioxide. A kinetic analysis indicated that diacetyl formation proceeds through a Mars and van Krevelen type mechanism and that there were two sources of acetaldehyde formation; the first predominating at high oxygen partial pressures involved an enol intermediate and adsorbed molecular oxygen; the second, which predominated at low oxygen partial pressures involved lattice oxygen and a diol intermediate. It is also proposed that acetoin, CH 3 COCHOHCH 3 , is a common intermediate in the formation of diacetyl and methyl vinyl ketone. High selectivities to diacetyl can be achieved by operation in anaerobic conditions.
TL;DR: In this article, the Pd(O2CMe)2-SBui2 system has been studied for the formation of β-carbonyl methyl complexes and alkenones.
TL;DR: In this paper, an asymmetric Michael addition of the corresponding chiral imine, derived from R-(+)-dihydrocarvone, to methyl vinyl ketone was developed.
Abstract: A novel diastereoselective route to octalones 3 and 4 has been developed. The key step involves an asymmetric Michael addition of the corresponding chiral imine, derived from R-(+)-dihydrocarvone, to methyl vinyl ketone.
TL;DR: In this article, the reaction of (butadiene)zirconocene with hexacarbonyltungsten gives the metallacyclic (π-allyl) zirconoxy] carbene complex.
Abstract: The reaction of (butadiene)zirconocene with hexacarbonyltungsten gives the metallacyclic [(π-allyl)zirconoxy]carbene complex 7 This reagent adds to a variety of ketones to yield chiral nine-membered metallacyclic ring systems (8) These systems are thus formed by means of 1,4-selective coupling reactions of 1,3-butadiene with W(CO)6 and an organic carbonyl compound at the zirconocene template The ketones subjected to react with 7 include benzophenone, methyl vinyl ketone, cyclopentanone, and 3-methoxyestra-1,3,5(10)-trien-17-one (12) The coupling products of 7 with cyclopentanone (8c) and 12 (8d-A) were characterized by X-ray crystal structure analyses Of the four possible diastereomeric nine-membered metallacyclic coupling products of 7 with 12 a single isomer [8d-A with (13'S,17'R,2,3,4-pS) configuration] was formed with ≥98% selectivity and isolated in 95% yield Treatment of the complexes 8 in tetrahydrofuran with water and pyridine N-oxide very effectively removed both transition metals with the formation of the corresponding β,γ-unsaturated e-hydroxy carboxylic acids The overall reaction sequence has thus converted the steroid ketone 12 very selectively to 5-[3-methoxy-17β-hydroxyestra-1,3,5(10)-trien-17α-yl]-(E)-pent-3-enoic acid (10d)
TL;DR: In this paper, a chiral imine of 2-methylcyclohexanone having a protected carbonyl function in the 4-position 2 led to monoprotected keto ester 4 or dione 6.
Abstract: Enantioselective Michael reaction of methyl acrylate or methyl vinyl ketone with a chiral imine of 2-methylcyclohexanone having a protected carbonyl function in the 4-position 2 led to monoprotected keto ester 4 or dione 6. The latter was converted into the title compound 10.
TL;DR: The optically active 3,3-dialkyl-4-thianones 3 and 4 were prepared in moderate yields with about 90% enantiomeric purity using an asymmetric process involving a Michael-type alkylation of chiral 3-alkyl-4thianimines with methyl vinyl ketone or methyl acrylate as discussed by the authors.
Abstract: The Optically active 3,3-dialkyl-4-thianones 3 and 4 were prepared in moderate yields with about 90% enantiomeric purity using an asymmetric process involving a Michael-type alkylation of chiral 3-alkyl-4-thianimines with methyl vinyl ketone or methyl acrylate The diketones 3 were then transformed into new heterocycles 5 by base-induced cyclization 3-Methyl- and 3-allyl-3-(2-methoxycarbonylethyl)-4-thianone ((+)-4a and (+)-4b) were converted into the bicyclic lactones (−)-6 and (−)-7, respectively The stereochemistry of the sulfone (+)-8 derived from the lactone (−)-6a was determined by a X-ray crystal structure analysis Desulfurization of the lactone (−)-6b using nickel boride afforded the corresponding lactone (+)-9 A synthesis of optically active 2-alkyl-2-methyl-3-cyclopentenone (S)-(+)-15 via the Ramberg–Backlund reaction from the keto ester (R)-(+)-4a was also accomplished
TL;DR: The pentacovalent oxaphospholene derived from methyl vinyl ketone and trialkyl phosphite has been shown to condense with a variety of electrophiles to produce highly substituted phosphonates as discussed by the authors.
Abstract: The pentacovalent oxaphospholene derived from methyl vinyl ketone and trialkyl phosphite has been shown to condense with a variety of electrophiles to produce highly substituted phosphonates.
TL;DR: Silyl enol ethers bearing a nitrogen atom protected by an electron-withdrawing group give in high yield a Micheal-type addition with hemiacetal vinylog or a mixture of methyl vinyl ketone and an alcohol in the presence of boron trifluoride etherate as a catalyst as mentioned in this paper.
TL;DR: In this paper, various approaches to synthesize the tropoloisoquinoline alkaloids grandirubrine (1) and imerubrine(2) were investigated, and the results showed that proceeding from the known 8-bromo-5,6,7-trimethoxyisoquinoline (27) proved most efficient.
Abstract: In connection with efforts to develop total syntheses of the tropoloisoquinoline alkaloids grandirubrine (1) and imerubrine (2), preparations of tricyclic ketone (8) and the related ethoxycarbonyl system (47) are described. Of the various approaches to (8) which were investigated, that proceeding from the known 8-bromo-5,6,7-trimethoxyisoquinoline (27) proved most efficient. Thus, conversion of (27), over three steps, into the Reissert anion (37), followed by alkylation of the latter with methyl iodide or ethyl bromoacetate, afforded (38) and (46), respectively. Treatment of compound (38) with sodium ethoxide resulted in regeneration of the isoquinoline nucleus and provided the C1-substituted compound (40). Upon reaction with lithium diisopropylamide, isoquinoline (40) underwent Dieckmann-type cyclization to give compound (8). A similar reaction sequence involving diester (46) afforded enamine (47), the X-ray crystal structure of which is reported. Efforts to effect Robinson annulation of (8) or (47) with methyl vinyl ketone (or a synthetic equivalent), and thereby produce the tetracyclic compound (10), have been unsuccessful.
TL;DR: In this article, L-Tryptophan methyl ester reacts with 1,1,3,3-tetramethoxypropane to give methyl carbolinecarboxylate 2 as a 1:2 mixture of the (1R,3S) and (1S, 3S) stereoisomers.
TL;DR: In this paper, the authors investigated the regioselectivity involved in the gas-phase hydride reduction of α,β-unsaturated carbonyl compounds by pentacoordinate silicon hyddride ions.
Abstract: The regioselectivity involved in the gas-phase hydride reduction of α,β-unsaturated carbonyl compounds by pentacoordinate silicon hydride ions is investigated. The kinetics and product distributions of the reactions of acrolein, methyl vinyl ketone and cyclohex-2-enone with monoalkoxysiliconate ions of the general composition RSiH3(OR′)− were examined with the flowing afterglow–triple quadrupole technique. All three substrates react by hydride transfer and by formation of a siliconate adduct in which hydride reduction of the organic reactant has occurred. The structures of these adducts and the hydride transfer products were identified by various tandem mass spectrometric protocols, including analysis of competitive collision-induced dissociation (CID) reactions and comparisons of CID spectra obtained from reference ions with known structures. 1,4-Reduction forming an enolate ion product is found to be the dominant or exclusive process with all three substrates, i.e. acrolein (70 ± 5%), methyl vinyl ketone (72 ± 5%) and cyclohex-2-enone (100%). Comparisons are made between these gas-phase results and the regioselectivity reported for analogous condensed-phase reactions. The observed behavior is discussed in terms of the reaction thermochemistry.
TL;DR: In this article, the structures and energy properties of Diels-Alder reactions between cyclopentadiene and ethylene, isoprene and methyl vinyl ketone were investigated.
Abstract: Ab initio molecular orbital calculations have been used to investigate the structures and energetics for the reactants and transition states of Diels-Alder reactions between cyclopentadiene and ethylene, isoprene, cyclopentadiene, acrylonitrile, and methyl vinyl ketone (MVK). Geometry optimizations were performed with both RHF/3-21G and RHF/6-31G * calculations, and the energies were computed to the MP3/6-1G * //6-31G * level in each case. Calculations the vibrational frequencies permitted computation of the enthalpies and entropies of activation
TL;DR: In this article, a [η 6 -benzylcopper(I)]tricarbonylchromium complex was obtained and its 1,4-addition reaction with methyl vinyl ketone was carried out.
TL;DR: In this article, 2-Amino-5-methyl-4-(2, 2,2,2-trichloroethyl)-3-furonitrile was synthesized from 3,5, 5, 5-tetrachloropentan-2-one, a product of the radical addition of CCl4 to methyl vinyl ketone, according to a scheme known for α-haloketones.
Abstract: 2-Amino-5-methyl-4-(2,2,2-trichloroethyl)-3-furonitrile was synthesized from 3,5,5,5-tetrachloropentan-2-one, a product of the radical addition of CCl4 to methyl vinyl ketone, according to a scheme known for α-haloketones. The product was converted via the corresponding imino-ether into N2-substituted N1 [5-methyl-4-(2,2,2-trichloroethyl)-3-cyano-2-furyl]formamidines. Cyclization of these formamidines gave 2-methyl-3-(2,2,2-trichloroethyl)-5-R-4-imino-4,5-dihydrofuro[2,3-d]pyrimidines, which readily regroup according to Dimroth into 2-methyl-3-(2,2,2-trichloroethyl)-4-R-aminofuro[2,3-d]pyrimidines.
TL;DR: In this paper, a deuterium labelled 1,5-diketone was transformed into a pyridine via a dioxime, from the bicyclic ketal.
Abstract: 6,8-Dioxabicyclo[3.2.1]octanes 1, prepared from methyl vinyl ketone dimer, have been readily converted into 2,6-disubstituted pyridine derivatives 2 in one step by treatment with AlCl3–NH2OH·HCl/AcOH. The transformation mechanism of this reaction has been studied by the preparation of a deuterium labelled 1,5-diketone, which was transformed into a pyridine via a dioxime, from the bicyclic ketal.
Patent•
26 Jan 1993
TL;DR: In this paper, the authors proposed a method to obtain the subject compound useful as an intermediate for medicines, agricultural chemicals, etc., under a mild condition in a short time and in high yield by reacting a vinyl group-containing compound with an aldehyde in the presence of a specific phenolic compound and a nitrogen containing compound.
Abstract: PURPOSE:To obtain the subject compound useful as an intermediate for medicines, agricultural chemicals, etc., under a mild condition in a short time and in high yield by reacting a vinyl group-containing compound with an aldehyde in the presence of a specific phenolic compound and a nitrogen-containing compound. CONSTITUTION:A vinyl group-containing compound (e.g. acrylonitrile, acrolein or methyl vinyl ketone) is allowed to react with an aldehyde (e.g. formaldehyde, acetaldehyde or propionaldehyde) in the presence of a phenolic compound (preferably phenol, 2-methylphenol, 4-methoxyphenol, 2,4-dimethylphenol, etc.) shown by the formula [X is H, 1-4C alkyl, OR (R is H or 1-4C alkyl), SR or NR R (R is H or 1-4C alkyl); (n) 1-5] and a nitrogen-containing compound (e.g. triethylenediamine) preferably at 20-50 deg.C to give the objective compound.
12 Feb 1993
TL;DR: In this paper, a pulsed photolysis-pulsed laser induced fluorescence (PP-PLIF) technique is described and compared with other detection techniques for studying gas-phase radical-molecule reactions that are important in atmospheric chemistry.
Abstract: This paper evaluates pulsed photolysis techniques for studying gas-phase radical-molecule reactions that are important in atmospheric chemistry. Reactions of OH are discussed. The pulsed photolysis-pulsed laser induced fluorescence (PP-PLIF) technique is described and compared with other detection techniques. As an example of application of this technique the kinetics of the OH reaction with Methyl Vinyl Ketone (MVK) and Methacrolein (MACR) over the temperature range 232-378 K are presented. Measurements of the UV absorption cross sections of MVK and MACR over the wavelength range 190-450 nm using a diode array spectrometer are also described. These data are used to calculate the tropospheric lifetimes of MVK and MACR.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.