Showing papers on "Methyl vinyl ketone published in 1997"
TL;DR: In this paper, a model accounting for the pressure effect and rationalizing the observed absolute stereochemistry is discussed, and a model for Baylis-Hillman condensation of aldehydes with methyl vinyl ketone is presented.
122 citations
TL;DR: In this article, 1,3-bis(2-oxazolinyl)benzenes with LDA/TMEDA followed by the addition of PdBr2(1,5-COD) gave 2,6-bisphenylbromopalladium(II) complexes.
114 citations
TL;DR: In this article, the [4 + 2]-cycloaddition of N-(5-nitrofuranyl)morpholine with methyl vinyl ketone affords a mixture of three phenols derived from a Diels−Alder reaction followed by nitro group ejection and subsequent aromatization.
Abstract: 5-Amino-2-furancarboxylic acid methyl ester undergoes a facile Diels−Alder cycloaddition with a variety of dienophiles to afford ring-opened cycloadducts that are readily dehydrated using BF3· OEt2 to give polysubstituted anilines. In each case, the cycloaddition proceeds with high regioselectivity, with the electron-withdrawing group being located ortho to the amino group. The most favorable FMO interaction is between the HOMO of the furanamine and the LUMO of the dienophile. The atomic coefficient at the ester carbon of the furan is larger than that at the amino center, and this nicely accommodates the observed regioselectivity. The [4 + 2]-cycloaddition of N-(5-nitrofuranyl)morpholine with methyl vinyl ketone affords a mixture of three phenols. One of the phenols is derived from a Diels−Alder reaction followed by nitro group ejection and subsequent aromatization. The remaining two phenols are the result of cleavage of the initially formed oxabicyclic intermediate with concomitant migration of the nitro...
109 citations
TL;DR: The five-coordinate complex OsHCl(CO)(PiPr3)2 (1) reacts with KOH in methanol to give the hydroxo derivative OsH(OH)(CO) (2) as mentioned in this paper.
74 citations
TL;DR: In this paper, the addition of several 1, 3-dicarbonyl compounds and thiols as donors with methyl vinyl ketone, acrolein and methyl acrylate as acceptors without any solvent is described.
55 citations
TL;DR: In this paper, the gas phase reaction of NO3 radicals with isoprene was investigated under flow conditions at 298 K in the pressure range 6.86±2.60 cm3 molecule−1 s−1.
Abstract: The gas-phase reaction of NO3 radicals with isoprene was investigated under flow conditions at 298 K in the pressure range 6.8
42 citations
TL;DR: In this article, 2.4-Ethenylidene-2.oxazolidinones 2, 6, and 9 were prepared in reasonable yields by the reaction of 2-butyn-1,4-diol biscarbamates in the presence of catalytic amounts of Pd2(dba)3·CHCl3 (0.005 equiv) and triethylamine ( 0.1 equiv).
35 citations
TL;DR: In this article, an improved synthesis of exo-heterocyclic dienes like N-substituted 4,5-dimethylene 2-oxazolidinones 1, by a one-step method from diacetyl and isocyanates, was described.
Abstract: An improved synthesis of exo-heterocyclic dienes like N-substituted 4,5-dimethylene 2-oxazolidinones 1, by a one-step method from diacetyl and isocyanates, was described. This highly convergent synthetic strategy has been successfully used for the preparation of novel (Z)-5-ethylidene-4-methylene analogs 4 in fair yields. Both dienes 1 and 4 undergo efficient addition of symmetric dienophiles in thermal Diels−Alder reactions, inasmuch as they react stereo- and regioselectively with the unsymmetric olefins methyl vinyl ketone (MVK) and methyl propiolate. This regioselectivity was greatly improved by using Lewis acid catalysts (TiCl4, AlCl3). The nitrogen atom of the 2-oxazolidinone ring seems to control the orientation of the dienophile approach. These results have been rationalized in terms of the frontier molecular orbital theory by ab initio calculations. For dienes 4, addition of MVK gave the endo isomer as the major product. Dimerization of dienes 4 was also highly regio-, chemo-, and stereoselective,...
33 citations
TL;DR: Model studies for the syntheses of phosphonate analogs of sphingomyelin and ceramide 1-phosphate are described and confirmation of stereochemical assignments in 11 (3:1, trans:cis) was accomplished via NOE experiments.
Abstract: Model studies for the syntheses of phosphonate analogs of sphingomyelin and ceramide 1-phosphate are described. The pentacovalent oxaphospholene 3b (derived from methyl vinyl ketone and triethyl phosphite) readily condensed with dialkyl azodicarboxylates (R = Et, t-Bu, CH2CCl3) to form β-hydrazido γ-ketophosphonates 5 and 8 in excellent yields. Cleavage of the N−N bond in 5a (R = Et) or 5b (R = t-Bu) via standard methods was unsuccessful. Upon reduction with NaBH4, 8 produced the oxazolidinone 9 (93%) as a diastereomeric mixture of 3:1. Treatment of 9 with Zn/HOAc/acetone at rt readily cleaved the N−N bond to form 11 (78−83%). Confirmation of stereochemical assignments in 11 (3:1, trans:cis) was accomplished via NOE experiments.
28 citations
TL;DR: In this paper, 1-(t-butyldimethylsilyloxy)-1-aza-1,3-butadienes 1 and 2 are prepared by the reaction of O(t)-butyldehydroxylamine with methyl vinyl ketone and methacrolein, respectively.
26 citations
TL;DR: In this paper, the copper(II) salt of weakly coordinating bis((trifluoromethyl)sulfonyl)amide anion was newly prepared and a remarkable catalytic effect of the copper salt Cu(NTf 2 ) 2 was demonstrated in the Diels-Alder reactions of cyclopentadiene with methyl vinyl ketone in CH 2 C 1 2 in comparison with other metal salts.
TL;DR: In this paper, the authors explored the Stork enamine reactions with mono-fluorinated enamines derived from α-fluoroacetophenones and pyrrolidine.
TL;DR: In this article, the addition reactions of tetramesitylgermasilene with methyl vinyl ketone (MVK), crotonaldehyde, and acrylonitrile were studied.
TL;DR: Fused pyridinoporphyrins (3a and 3b) were obtained from the reaction of nickel (II) β-amino-meso-tetraphenylporphyrin with propenal or methyl vinyl ketone.
TL;DR: In this article, radical copolymerization of 2-methylene-1,3,6-trioxocane with methyl vinyl ketone, enzymatic degradation of the copolymers, before and after photo-lysis, and photolysis of thecopolymers.
Abstract: We report here radical copolymerization of 2-methylene-1,3,6-trioxocane with methyl vinyl ketone, enzymatic degradation of the copolymers, before and after photolysis, and photolysis of the copolymers
TL;DR: The absorption spectrum and cross sections of vinyl radicals were determined in the gas phase in the spectral range 220−550 nm as mentioned in this paper, where the spectrum exhibits a relatively broad and intense absorption centered at about 232 nm, followed by at least two identifiable and weaker absorptions with maxima at about 340 and 420 nm.
Abstract: The absorption spectrum and cross sections of vinylperoxy (C2H3O2, ethenylperoxy) radical have been determined, for the first time in the gas phase, in the spectral range 220−550 nm. The spectrum exhibits a relatively broad and intense absorption centered at about 232 nm, followed by at least two identifiable and weaker absorptions with maxima at about 340 and 420 nm. The absorption tail persists at longer wavelengths into the visible region. To discern competition between the stabilization of the vinylperoxy isomers and reaction, the effect of pressure on the absorption has been examined. Vinylperoxy radicals in these experiments were produced through photochemical production of vinyl radicals followed by reaction of vinyl radicals with molecular oxygen. Vinyl bromide (C2H3Br) photolyzed at 193 nm was used as the precursor of vinyl radicals, and methyl vinyl ketone (CH3COC2H3) photolyzed at 193 nm was used as a precursor of both methyl and vinyl radicals. In the latter system identical concentrations of ...
TL;DR: In this article, the [4 + 2]-cycloaddition of N-(5-nitrofuranyl)morpholine with methyl vinyl ketone affords a mixture of three phenols derived from a Diels−Alder reaction followed by nitro group ejection and subsequent aromatization.
Abstract: 5-Amino-2-furancarboxylic acid methyl ester undergoes a facile Diels−Alder cycloaddition with a variety of dienophiles to afford ring-opened cycloadducts that are readily dehydrated using BF3· OEt2 to give polysubstituted anilines. In each case, the cycloaddition proceeds with high regioselectivity, with the electron-withdrawing group being located ortho to the amino group. The most favorable FMO interaction is between the HOMO of the furanamine and the LUMO of the dienophile. The atomic coefficient at the ester carbon of the furan is larger than that at the amino center, and this nicely accommodates the observed regioselectivity. The [4 + 2]-cycloaddition of N-(5-nitrofuranyl)morpholine with methyl vinyl ketone affords a mixture of three phenols. One of the phenols is derived from a Diels−Alder reaction followed by nitro group ejection and subsequent aromatization. The remaining two phenols are the result of cleavage of the initially formed oxabicyclic intermediate with concomitant migration of the nitro...
TL;DR: In this paper, the isobaric vapor-liquid equilibrium (VLE) data were determined at 100.0 ± 0.2 kPa for three binary mixtures formed by methanol, acetone and methyl vinyl ketone.
TL;DR: In this paper, the experimental VLE data were correlated according to the Margules, Wilson, NRTL and UNIQUAC equations, and a comparison of model performances was made using the criterion of average absolute deviations in boiling point and in vapor phase composition.
Patent•
01 Aug 1997
TL;DR: In this article, a cyclizing reaction is carried out in the presence of the condensing agent in (or without) a solvent to produce a cyclohexenone derivative represented by formula III, which is then reacted with a halogenating agent in a (non-cooperative) setting to form a compound representing by formula IV or the like.
Abstract: PROBLEM TO BE SOLVED: To selectively produce the subject derivative useful as an intermediate for medicines, agrochemicals, liquid crystals, heat-resistant polymers or the like from an inexpensive raw material by reacting a specific cyclohexenone derivative with a halogenating agent in (or without) a solvent and then carrying out an eliminating reaction of the halogen atom in the presence of a base in (or without) a solvent. SOLUTION: A compound represented by formula I (X is H or the like; Y is CO2 or the like) is reacted with methyl vinyl ketone in the presence of a condensing agent in (or without) a solvent to synthesize a compound represented by formula II. A cyclizing reaction is then carried out in the presence of the condensing agent in (or without) a solvent to produce a cyclohexenone derivative represented by formula III, which is then reacted with a halogenating agent in (or without) a solvent to form a compound represented by formula IV or the like. The halogen atom of the resultant compound represented by formula IV or the like is further eliminated in the presence of a base in (or without) a solvent to afford the objective derivative represented by formula V.
TL;DR: In this paper, the addition of several 1, 3-dicarbonyl compounds and thiols as donors with methyl vinyl ketone, acrolein and methyl acrylate as acceptors without any solvent is described.
Abstract: Zeolites, an environmentally attractive solid catalyst, proves to be an efficient catalyst for Michael addition of several 1, 3-dicarbonyl compounds and thiols as donors with methyl vinyl ketone, acrolein and methyl acrylate as acceptors without any solvent are described.
TL;DR: In this article, the inhibitory effect of condensation products of thiosemicarbazide (TSC) with furfruldehyde (FrA), Crotonaldehyde (CrA), or methyl vinyl ketone (MVK) was investigated as corrosion inhibitors for aluminium and zinc in 0.5 M NaOH using gasometry and d.c. polarization technique.
Abstract: The inhibitory effect of the condensation products of thiosemicarbazide (TSC) with furfruldehyde (FrA), Crotonaldehyde (CrA) or methyl vinyl ketone (MVK) was investigated as corrosion inhibitors for aluminium and zinc in 0.5 M NaOH using gasometry and d.c. polarization technique. Correlation of the structural changes with the protection efficiency of CrTSCN MVTSCN and FrTSCN with the parent TSC Was reported. The experimental results indicate that the presence of adsorbed inhibitors on aluminium or zinc surfaces does not affect the mechanism of hydrogen evolution. Furthermore, polarization curves show that the compounds act as mixed-type inhibitors. Variation of the protection efficiency is evident fo the different compounds, with increase of π-electron density of the center of adsorption, by addition of double bonds or by heterocyclic ring, contributing to improvement in protection effieciency. All data were compared and fitted to kinetic-thermody-namic model. The number of active sites on the metal occupied by a molecule of the inhibitor and the binding constant of the inhibitor to the active site were calculated for the investigated compounds. The results are compared with fits obtained from the application of other adsorption isotherms.
TL;DR: The pyrolysates of bicyclo[2.2.1] and its derivatives have been investigated by pyrolysis-mass spectrometry and microwave spectroscopy (Py-MS/MW).
TL;DR: In this paper, a model accounting for the pressure effect and rationalizing the observed absolute stereochemistry is discussed, and a model for Baylis-Hillman condensation of aldehydes with methyl vinyl ketone is presented.
Abstract: Several chiral amino-alcohols induce asymmetry in the Baylis-Hillman condensation of aldehydes with methyl vinyl ketone. Pressure plays an interesting role in this reaction. A model accounting for the pressure effect and rationalising the observed absolute stereochemistry is discussed. Copyright (C) 1996 Elsevier Science Ltd
01 Jan 1997
TL;DR: In this paper, a trans-fused octalin hemiacetal with a β-equatorial methyl group and an axial hydroxyl was derived from the TMS ether of hexadienol.
Abstract: The AlCl3 catalysed ‘ionic’ Diels-Alder (DA) reaction of 6-methyl-2-cyclohexenones with 3,5-hexadien-1-ol in dichloromethane gives a trans-fused octalin hemiacetal with a β-equatorial methyl group and an axial hydroxyl. In contrast, trimethylsilyl triflate (TMSOTf, 5 mol%) at −20 °C in acetonitrile catalyses the DA reaction to give the trans-fused adduct acetal, whose controlled hydrolysis gives the hemiacetal with an α-axial methyl group. The adduct is thereby differentiated from the AlCl3 DA adduct, and may be converted into the latter by treatment with p-toluenesulfonic acid in aqueous THF or by AlCl3 in dichloromethane. In similar fashion, TMSOTf provides full acetal adducts from 2-cyclohexenone, 2-cycloheptenone and methyl vinyl ketone. The optically active enone acetal derived from (1R,2R)-1,2-diphenyl-1,2-ethanediol and 2-cyclohexenone gives a racemic acetal adduct derived from the TMS ether of hexadienol. The TMS ether of a mixture enriched in the 3E-isomer of (2R,5E)-2-methyl-3,5-heptadien-1-ol in acetonitrile containing TMSOTf (10 mol%) at −20 °C with 6-methyl-2-cyclohexenone gives the trans-fused acetal adduct, hydrolysis which provides the corresponding octalin hemiacetal as a single enantiomer. Similarly, the mixture enriched in the 3E-isomer of (2S,5E)-2-methyl-3,5-heptadienol TMS ether is converted by way of the octalin acetal into the octalin hemiacetal, enantiomeric with the foregoing product. The reactions are thereby shown to proceed via endo transition states.
TL;DR: In this paper, the authors explored the Stork enamine reactions with mono-fluorinated enamines derived from α-fluoroacetophenones and pyrrolidine.
Abstract: Stork enamine reactions are explored with mono-fluorinated enamines derived from α-fluoroacetophenones and pyrrolidine. The resulting enamines react under mild conditions with Michael acceptors (acrylonitrile, methyl acrylate, methyl methacrylate, methyl vinyl ketone and cyclohexenone) to generate a variety of substituted α-fluoroketones.
TL;DR: In this article, 1,3-bis(2-oxazolinyl)benzenes with LDA/TMEDA followed by the addition of PdBr2(1,5-COD) gave 2,6-bisphenylbromopalladium(II) complexes.
Abstract: Treatment of 1,3-bis(2-oxazolinyl)benzenes with LDA/TMEDA followed by the addition of PdBr2(1,5-COD) gave 2,6-bis(2-oxazolinyl)phenylbromopalladium(II) complexes. Subsequent bromide abstraction with silver salts provided a series cationic 2,6-bis(2-oxazolinyl)-phenylpalladium(II) complexes that effectively catalyse the addition of α-cyano carboxylates to methyl vinyl ketone.
TL;DR: In this article, 2.4-Ethenylidene-2.oxazolidinones 2, 6, and 9 were prepared in reasonable yields by the reaction of 2-butyn-1,4-diol biscarbamates in the presence of catalytic amounts of Pd2(dba)3·CHCl3 (0.005 equiv) and triethylamine ( 0.1 equiv).
Abstract: 4-Ethenylidene-2-oxazolidinones 2, 6, and 9 are prepared in reasonable yields by the reaction of 2-butyn-1,4-diol biscarbamates in the presence of catalytic amounts of Pd2(dba)3·CHCl3 (0.005 equiv) and triethylamine (0.1 equiv). The allenic three carbons are not aligned straight, but considerably distorted (173.6°); the enamine double bond is reactive toward unsaturated amides (providing 4) and methyl vinyl ketone (providing 10).