Showing papers on "Methyl vinyl ketone published in 1991"
TL;DR: In this article, a variety of trialkylborane-induced reactions were examined for the preparation of α-carbonyl radicals: (1) addition of alkyl radical to methyl vinyl ketone, (2) reduction of α -halo ketone and (3) intramolecular radical addition to α,β-unsaturated carbonyl moiety.
Abstract: A variety of trialkylborane-induced reactions were examined for the preparation of the α-carbonyl radicals: (1) addition of alkyl radical to methyl vinyl ketone, (2) reduction of α-halo ketone, and (3) intramolecular radical addition to α,β-unsaturated carbonyl moiety. Trialkylborane reacted with α-carbonyl radicals to give boron enolates. The resulting boron enolates were efficiently trapped by carbonyl compounds to give β-hydroxy ketones in good yields.
105 citations
Journal Article•
TL;DR: The tetraaza macrocyclic ligand 3,14-dimethyl 2,6,13,17-tetraazatricyclo docosa-2,12-diene(B) has been prepared as its dihydroperchlorate salt by the nontemplate condensation of methyl vinyl ketone with 1,2-diaminocyclohexane and perchloric acid as mentioned in this paper.
Abstract: The tetraaza macrocyclic ligand 3,14-dimethyl-2,6,13,17-tetraazatricyclo docosa-2,12-diene(B), that contains two cyclohexane rings, has been prepared as its dihydroperchlorate salt by the nontemplate condensation of methyl vinyl ketone with 1,2-diaminocyclohexane and perchloric acid. Reduction of B with sodium borohydride produces 3,14-dimethyl-2,6,13,17-tetraazatricyclodocosane(C). Square planar Ni(Ⅱ) and Cu(Ⅱ) complexes of B and C have been prepared by the reaction of the metal ions and the ligands. Synthesis, characterization, and the properties of the ligands and their metal complexes are reported.
87 citations
TL;DR: Dityltin bis(triflate) is a mild Lewis acid which catalyzes the clean Michael addition of enol silyl ethers as discussed by the authors, which allows to employ various labile acceptors such as methyl vinyl ketone and 2-cyclopentenone which do not undergo smooth reaction with conventional Lewis acids.
48 citations
TL;DR: The Michael additions of activated nitriles to methyl acrylate (MA) and methyl vinyl ketone (MVK) proceeds with fair to high yields (46–92%) in the presence of catalytic amount of HRh(CO)(PPh3)3 1 under mild eaction conditions.
47 citations
TL;DR: The Michael reaction of several β-dicarbonyl compounds, such as methyl vinyl ketone, acrolein and methyl acrylate as acceptors, was carried out in this paper without any solvent.
46 citations
TL;DR: In this paper, two Michael-type addition reactions of nitromethane to chalcone, reaction (1a), and of methyl 1-oxo-2-indanecarboxylate to methyl vinyl ketone (reaction (1b)) have been tested for catalytic asymmetric induction when carried out in the presence of Ni(II) or Co(II), and homochiral ligands.
44 citations
TL;DR: In this article, the same reaction with α,β-unsaturated ketones (methyl vinyl ketone or 2-cyclohexanone) yielded the expected products of a 1,4-addition.
Abstract: The lithiation of the chloro ketals 9 with lithium naphthalenide at −78 o C led to the corresponding masked lithium bishomoenolates 4, which are stable species under these conditions and react with different electrophilic reagents to give, after hydrolysis with water, the corresponding bifunctionalized compounds. When alkyl halides were used as electrophiles the reaction failed. In the presence of a catalytic amount of the complex CuBr•Me 2 S, the same reaction with α,β-unsaturated ketones (methyl vinyl ketone or 2-cyclohexanone) yielded the expected products of a 1,4-addition
40 citations
TL;DR: It is demonstrated that alkylating agents are cytotoxic to both proximal tubular and distal tubular cells, and that interaction with cellular GSH is a factor determining nephron cell type specificity of injury.
40 citations
TL;DR: In this paper, the reaction of bromomethylenebis(phosphonates) with electron-deficient alkenes 2a-d as Michael acceptors in the presence of thallium(I) ethoxide leads to a new and facile route to 2-substituted 1,1-cyclopropanediylbis (phosphorus) 3 in satisfactory yield.
Abstract: Reaction of bromomethylenebis(phosphonates) 1 with electron-deficient alkenes 2a-d as Michael acceptors in the presence of thallium(I) ethoxide leads to a new and facile route to 2-substituted 1,1-cyclopropanediylbis(phosphonates) 3 in satisfactory yield. These are converted into the corresponding free acids 7 by treatment with chlorotrimethylsilane in the presence of potassium iodide followed by treatment with water. The products resulted from bromomethylenebis(phosphonates) 1 and other alkenes 2 e, f and methyl vinyl ketone are identified and discussed
15 citations
TL;DR: In this paper, the authors showed that the dimerization of vinyl ketones at 80°C in the presence of the catalytic system [RhCl(C 2 H 4 ) 2 ] 2 MCl 2 leads preferably to either α, β-unsaturated 1,6-diketones RC(O)CHCHCH 2 CH 2 C(O), II when M = Ge or to diene 1, 6-ketones R, III if M = Sn.
13 citations
TL;DR: The pyrrolizidine ring stems from NH4OAc exclusively as shown by reduction of 5-nitropentadecane-2,8-dione as discussed by the authors.
Abstract: Stereoselective Synthesis von Pyrrolizidin Alkaloids from Nitroalkanones
Reduction of 5-nitropentadecane-2,8-dione (11), synthesized by a Michael reaction from nitromethane, methyl vinyl ketone, and dec-1-en-3-one, gave, depending on the conditions, two epimeric 3-heptyl-2,3,5,6,7,7a-hexahydro-5-methyl-1H-pyrrolizines as the main products: Catalytic hydrogenation (Pd/C) afforded the expected 7aα-hydro epimer 1b with cis-orieted H-atoms at C(3), C(5), and C(7a). NaBH3CN/NH4OAc reduction of the nitrodione 11 yielded all four diastereoisomers with the 7aβ-hydro epimer 1a as the predominant component; 1a is a pheromone of the cryptic thief ant Solenopsis sp. The N-atom of the pyrrolizidine ring stems from NH4OAc exclusively as shown by reduction of 11 with NaBH3CN/(15N)H4OAc.
TL;DR: Among the proscillaridin derivatives, compounds 4 and 7 moderately inhibited Na+,K(+)-ATPase activity, and the concentration range of 7 over which its positive inotropic effect on guinea-pig papillary muscle preparations, increased from 5% to 95% of maximum was broader than that of 1.
Abstract: The Diels-Alder reactions of a cardiac glycoside, proscillaridin (1), with some dienophiles were investigated. The reaction of 1 with alkenes such as methyl vinyl ketone and methyl acrylate afforded 3-oxo-2-oxabicyclo[2.2.2]oct-7-enes (2-5) and para-substituted benzene derivatives (6 and 7), while 1 reacted with alkynes (3-butyn-2-one, methyl propiolate) to yield para- or meta-substituted benzene derivatives (6-9). The biological activities of the resulting derivatives were evaluated by the use of isolated guinea-pig papillary muscle preparations and Na+,K(+)-adenosine triphosphatase (ATPase) preparation from dog kidney. Among the proscillaridin derivatives, compounds 4 and 7 moderately inhibited Na+,K(+)-ATPase activity. Furthermore, the concentration range of 7 over which its positive inotropic effect on guinea-pig papillary muscle preparations, increased from 5% to 95% of maximum was broader than that of 1, i.e., concentration dependency was maintained over a greater range of concentration.
TL;DR: In this paper, the chlorination of a series of α,β-unsaturated ketones and esters by Cl2 in CH3OH, with and without acid scavengers such as N-chlorosuccinimide (NCS), pyridine and 2,6-lutidine, is described.
Abstract: The chlorination of a series of α,β-unsaturated ketones and esters by Cl2 in CH3OH, with and without acid scavengers such as N-chlorosuccinimide (NCS), pyridine and 2,6-lutidine, is described. Methyl vinyl ketone and cyclohex-2-enone have also been chlorinated in ethanol. Mixtures of Markovnikov(M) and anti-Markovnikov(AM) methoxy chlorides and dichlorides are formed in most cases; phenyl vinyl ketone gives no M products in the absence of pyridine, M methoxy chloride is not formed with (E-)-4-chlorobut-3-en-2-one under any conditions, pyridine has no effect on the product ratios and methyl 3-chlorobut-2-enoate forms only dichloride. Chlorination of the ketones in the presence of the pyridines results in a significant increase in the M regioisomer (except for methyl isopropenyl ketone and the ketones mentioned), giving M:AM ratios which are similar to the corresponding esters. Ratios for the esters are not affected significantly by pyridine. We ascribe the effect of the pyridine bases to the elimination of acid and the acid-catalysed mechanism, permitting the chlorination to occur via a carbon–carbon π-bond (chloronium ion) mechanism. The rate of chlorination of methyl vinyl ketone is retarded by pyridine but is still considerably faster than methyl acrylate. NCS, in contrast to N-bromosuccinimide (NBS) reported previously, has no effect on the M:AM ratio. The chlorination of methyl vinyl ketone with NCS and HCl gives markedly different results from Cl2.
TL;DR: In this paper, the gas phase reaction of isoprene with the OH radical, in the resence of NOx, was investigated at 298 ± 2 K and atmospheric pressure of air by long path length FT-IR spectroscopy.
Abstract: The gas-phase reaction of isoprene with the OH radical, in the resence of NOx, was investigated at 298 ± 2 K and atmospheric pressure of air by long path length FT-IR spectroscopy. The primary products identified and their formation yields were: methacrolein, 0.21 ± 0.05; methyl vinyl ketone, 0.29 ± 0.07; and HCHO, with the observed yield being consistent with the sum of the methacrolein and methyl vinyl ketone yields. Combined with the previously reported yield of 0.044 ± 0.006 for 3-methylfuran, these products accounted for 55 ± 9% of the isoprene which reacted. Under conditions where the dark reaction of isoprene with NO2is not significant, the balance of the isoprene consumed could possibly be accounted for by the “organic nitrates” and “other carbonyl compounds” formed in estimated overall yields of ca. 12% and ca. 25%, respectively.
Journal Article•
TL;DR: In this article, the photolysis of methyl methacrylate/methyl vinyl ketone copolymers does not occur by an unusual form of Norrish type II scission as previously suggested but probably by a norrish type I process.
Abstract: NMR spectroscopic evidence is presented to show that the photolysis of methyl methacrylate/methyl vinyl ketone copolymers does not occur by an unusual form of Norrish type II scission as previously suggested but probably by a Norrish type I process
Patent•
14 Jun 1991
TL;DR: In this paper, a 4-(6methoxy-2-naphthyl)-3-buten-2)-one of formula (I) is effected by reacting a 2-methoxynaphthalene cpd with methyl vinyl ketone (MVK) in the presence of a Pd catalyst.
Abstract: Prodn of 4-(6-methoxy-2-naphthyl)- 3-buten-2-one of formula (I) is effected by reacting a 2-methoxynaphthalene cpd of formula (II) with methyl vinyl ketone (MVK) in the presence of a Pd catalyst. In (I) and (II) X = H, halogen or COCl.
TL;DR: In this article, the Michael reaction of (+)-2-caranone with methyl vinyl ketone, ethyl vinyl ketone or methyl acrylate was used for synthesis of corresponding diketones4 and 5 and keto ester8.
Abstract: The Michael reaction of (+)-2-caranone (1) with methyl vinyl ketone, ethyl vinyl ketone or methyl acrylate was utilized for synthesis of corresponding diketones4 and5 and keto ester8. These compounds were subjected to cyclization to obtain the sesquiterpenoid systems.
TL;DR: In this paper, a mixture of the ketone in artificial air over vanadium phosphorus oxide catalysts in the temperature range 200-350°C was used to select a set of products, including diacetyl, methyl vinyl ketone, acetaldehyde, acetic acid and carbon dioxide.
Abstract: Selective oxidation of methyl ethyl ketone to diacetyl has been studied by passing a mixture of the ketone in artificial air over vanadium phosphorus oxide catalysts in the temperature range 200–350°C. Products observed included diacetyl, methyl vinyl ketone, acetaldehyde, acetic acid and carbon dioxide. C4 products were favoured at low temperatures and at low or zero oxygen partial pressures. These results are rationalised in terms of two pathways for C2 products, namely oxidation of the double bond in the enol form of methyl ethyl ketone to yield acetic acid and acetaldehyde, and acid catalysed hydration of the keto form to yield acetaldehyde only. The C4 products are envisaged to go through a common intermediate, namely, CH 3 COCHOHCH 3 , formed by interaction between methyl ethyl ketone and lattice oxygen.
TL;DR: In this paper, the stereoselectivity of the reaction between methyl vinyl ketone dimer and zinc borohydride or diisobutylaluminum hydride has been studied in order to illuminate the factors involved in the high levels of asymmetric induction obtained in the bicyclic system.
Abstract: The stereoselectivity of the reaction between methyl vinyl ketone dimer, which contains two possible sites of chelation, and zinc borohydride or diisobutylaluminum hydride has been studied in order to illuminate the factors involved in the high levels of asymmetric induction obtained in the bicyclic system. The conditions for the formation of the exo-5,7-dimethyl-6,8-dioxabicyclo[3.2.1]octane are DIBAH reduction of MVK dimer in ether at reflux followed by acidic cyclizatioan, and for the endo isomer are reduction with at
TL;DR: In this paper, the authors performed copolymerization of methyl vinyl ketone (MVK) with styrene at 50°C in the presence of cobalt(II) nitrate and found that the resulting monomer reactivity ratios decreased with an increasing concentration of the cobalt salt.
Abstract: Copolymerization of methyl vinyl ketone (MVK) with styrene was carried out at 50°C in the presence of cobalt(II) nitrate. The resulting monomer reactivity ratios decreased with an increasing concentration of the cobalt salt. This finding suggests that the metal salt participates in the propagation step of the copolymerization. Absolute copolymerization parameters were determined by assuming a three-component system as free MVK (M1), MVK complexed with cobalt(II) nitrate (M2), and styrene (M3): k11/k12 = 0.184, k11/k13 = 0.235, k22/k21 = 7.18 × 10−2, k22/k23 = 6.79 × 10−4, k33/k31 = 0.380, and k33/k32 = 2.77 × 10−3, and Q2 = 19.65 and e2 = 2.83. The complexed MVK monomer is more reactive to the polymer radical with the terminal styrene unit than the free MVK. Very small values for the monomer reactivity ratios, k22/k23 and k33/k32, show the marked alternating tendency for the copolymerization of the complexed monomer with styrene. In practice, however, alternating copolymer could not be obtained because of the poor solubility of cobalt(II) nitrate.
TL;DR: In this article, anions with acrylonitrile, acrolein, methyl vinyl ketone, and methyl acrylate at room temperature under SIFT conditions are described.
Abstract: Reactions of anions with acrylonitrile, acrolein, methyl vinyl ketone, and methyl acrylate at room temperature under SIFT conditions are described. Stabilized carbanions such as benzyl anion, cyanomethyl anion, cyclohexadienide, acetone enolate, and nitromethyl anion add to activated carbon-carbon double bonds in a process that is competitive with other modes of reaction. With acrylonitrile and methyl acrylate, addition is in a 1,4 or Michael fashion, while with acrolein and methyl vinyl ketone, 1,2 addition completes with 1,4 addition. Hydroxide, methoxide, fluoride, and cyanide do not add to activated olefins by either mode. A mechanism is proposed for hydride transfer from cyclohexadienide to activated olefins
TL;DR: In this article, the same reaction with α,β-unsaturated ketones (methyl vinyl ketone or 2-cyclohexanone) yielded the expected products of a 1,4-addition.
Abstract: The lithiation of the chloro ketals 9 with lithium naphthalenide at −78 o C led to the corresponding masked lithium bishomoenolates 4, which are stable species under these conditions and react with different electrophilic reagents to give, after hydrolysis with water, the corresponding bifunctionalized compounds. When alkyl halides were used as electrophiles the reaction failed. In the presence of a catalytic amount of the complex CuBr•Me 2 S, the same reaction with α,β-unsaturated ketones (methyl vinyl ketone or 2-cyclohexanone) yielded the expected products of a 1,4-addition
Patent•
12 Nov 1991
TL;DR: In this paper, a process for converting the pendant keto groups of ketonic polymers to ester groups is described, which involves reacting the polymer with an organic peroxyacid oxodizing agent in an inert liquid medium at a temperature from -20 DEG C. to 150 DEGC.
Abstract: A process for converting the pendant keto groups of ketonic polymers to ester groups is provided. The process involves reacting the polymer with an organic peroxyacid oxodizing agent in an inert liquid medium at a temperature from -20 DEG C. to 150 DEG C. to convert substantially all or only a portion of the pendant carbonyl functionality to oxycarbonyl moieties. Homopolymers or copolymers of alpha , beta -unsaturated ketones, such as methyl vinyl ketone and ethyl vinyl ketone, are readily modified with the process of this invention.
TL;DR: In this paper, the effect of the modification on the electrochemical response of 2,6-diaminopurin-8-ol, a small, electrochemically fast biological molecule with primary amine groups which absorbs on active graphite, was evaluated.
TL;DR: In this article, photolytic homolysis of cobalt salophen reagents is used to add to activated carbon-to-carbon double bonds, producing useful yields of new alkene products.
Abstract: Alkyl radicals generated by photolytic homolysis of cobalt salophen reagents, e.g.(6) and (15), are shown to add to activated carbon-to-carbon double bonds, i.e. ethyl acrylate, methyl vinyl ketone, acrylonitrile, and styrene, producing preparatively useful yields of new alkene products, viz.(9), (10), (12) and (14)[from (6)], and (16)[from (15)]. The reactions proceed via radical (Michael) additions, followed by ‘dehydrocobaltation’ from the presumed organocobalt intermediates (2)(Scheme 4). By use of this chemistry, in combination with the Schrauzer ‘hydrocobaltation’ reaction of alkenes, a new method for the cross-coupling reactions between two alkenes, leading to new functionalised alkenes, e.g.(24), (25), (26), (27), (28), and (29), is developed [Equation (2)].
TL;DR: In this paper, the chlorination of a series of α,β-unsaturated ketones and esters by Cl2 in CH3OH, with and without acid scavengers such as N-chlorosuccinimide (NCS), pyridine and 2,6-lutidine, is described.
Abstract: The chlorination of a series of α,β-unsaturated ketones and esters by Cl2 in CH3OH, with and without acid scavengers such as N-chlorosuccinimide (NCS), pyridine and 2,6-lutidine, is described. Methyl vinyl ketone and cyclohex-2-enone have also been chlorinated in ethanol. Mixtures of Markovnikov(M) and anti-Markovnikov(AM) methoxy chlorides and dichlorides are formed in most cases; phenyl vinyl ketone gives no M products in the absence of pyridine, M methoxy chloride is not formed with (E-)-4-chlorobut-3-en-2-one under any conditions, pyridine has no effect on the product ratios and methyl 3-chlorobut-2-enoate forms only dichloride. Chlorination of the ketones in the presence of the pyridines results in a significant increase in the M regioisomer (except for methyl isopropenyl ketone and the ketones mentioned), giving M:AM ratios which are similar to the corresponding esters. Ratios for the esters are not affected significantly by pyridine. We ascribe the effect of the pyridine bases to the elimination of acid and the acid-catalysed mechanism, permitting the chlorination to occur via a carbon–carbon π-bond (chloronium ion) mechanism. The rate of chlorination of methyl vinyl ketone is retarded by pyridine but is still considerably faster than methyl acrylate. NCS, in contrast to N-bromosuccinimide (NBS) reported previously, has no effect on the M:AM ratio. The chlorination of methyl vinyl ketone with NCS and HCl gives markedly different results from Cl2.
TL;DR: In this paper, a variety of trialkylborane-induced reactions were examined for the preparation of α-carbonyl radicals: (1) addition of alkyl radical to methyl vinyl ketone, (2) reduction of α -halo ketone and (3) intramolecular radical addition to α,β-unsaturated carbonyl moiety.
Abstract: A variety of trialkylborane-induced reactions were examined for the preparation of the α-carbonyl radicals: (1) addition of alkyl radical to methyl vinyl ketone, (2) reduction of α-halo ketone, and (3) intramolecular radical addition to α,β-unsaturated carbonyl moiety. Trialkylborane reacted with α-carbonyl radicals to give boron enolates. The resulting boron enolates were efficiently trapped by carbonyl compounds to give β-hydroxy ketones in good yields.
01 Jan 1991
TL;DR: In the absence of an acid catalyst, this reaction gives extremely low yields [2, 3] as discussed by the authors, and the best yields of the addition products (XII)(XVI) are obtained by reacting (I)-(IV) with (VI) and (VII) using diethylamine hydrochloride as catalyst.
Abstract: roisoquinoquinolines (I)-(IV) have been reacted with acrylonitrile (V), methacrylate (VI), methyl vinyl ketone (VII), and ethyl bromoacetate (VIII). The reaction of (I)-(III) with (V) affords high yields even in the absence of a catalyst, but the best yields of the addition products (XII)(XVI) are obtained by reacting (I)-(IV) with (VI) and (VII) using diethylamine hydrochloride as catalyst. In the absence of an acid catalyst, this reaction gives extremely low yields [2, 3]. It has been shown that, in the preparation of (XII) and (XIV) addition of amines to the conjugated C=C bond can be successfully carried out using ultrasound (to give yields of 66.7 and 85.0% respectively). However, N-alkylation of (I)-(IV) with (VIII) was carried out in the presence of sodium carbonate.