2-Methyl crotonaldehyde

Hydroformylation of 1,4-diacetoxybutene HRh(CO)(PPh3)3 or Rh complex without PPh,3 4-Acetoxy-2-methyl crotonaldehyde—an intermediate in vitamin A synthesis Stinson (1986)... 

The hydrogenation of 3-methyl crotonaldehyde was investigated over Ru supported on NaY and KY zeolites in both liquid- and gas-phase reactions. Significant effects of the nature of the support on the product selectivity were observed. It was suggested that increased basicity of the zeolite resulted in increased selectivity towards the unsaturated alcohol product. 

The high pressure, liquid-phase hydrogenation of 3-methyl crotonaldehyde was carried out in a well-stirred batch autoclave under 4 MPa Ha (Air Liquide, 99.995% purity) pressure using 0.1 mol of 3-methyl crotonaldehyde (UAL) (Merck) and 0.6 g catalyst. Isopropanol (37.5 cc) was used as a solvent. The catalyst was activated by stirring under 4 MPa Ha pressure at 373K for two hours prior to introduction of the unsaturated aldehyde UAL reactant at the same temperature. The reaction products were monitored by repetitive sampling and gas chromatographic analysis. Since this was a batch reaction, data are reported as selectivity vs. conversion. Time of reaction to reach about 30% conversion was close to 60 minutes for Ru/NaY and 150 minutes for Ru/KY. 

Figure l. Product selectivities as a function of conversion in liquid-phase hydrogenation of 3-methyl crotonaldehyde over A) Ru/NaY and B) Ru/KY. UOL = unsaturated alcohol SOL = saturated alcohol SAL = saturated aldehyde. Pressure = 4 MPa Temperature = 373K. 

The other compound, called Zl, which was much more acid-labile, was hydrolyzed to equimolar amounts of pyruvate and shikimate, and was tentatively assigned the structure of shikimate 3- or 5-enolpyruvate ether. In a more recent study, it was found that the barium salt of Zl does not absorb in the carbonyl region of the infrared absorption spectrum (no ester structure), and that it has a strong band at 8.2iu characteristic of a vinyl ether. It is oxidized very rapidly by periodate, giving rise to an unstable compound with maximum absorption at 235 m i ( = 4000). A similar unstable chromophore, most likely having the structure XVII, was produced by periodate oxidation of shikimate 3-phosphate but not of shikimate 5-phosphate. (3-Methyl-crotonaldehyde shows Xm 235, t = 6700. ) These observations suggest that Zl is shikimate 3-enolpyruvate ether (XVIII). 

The effect on selectivity and activity for the hydrogenation of 3-methyl crotonaldehyde using Pt/SiOj modified with cations from successive groups in the periodic table was studied by Ponec et The most effective promoter was found to be Fe and Sn both of which raised the selectivity to the unsaturated alcohol from 21% to about 80%. Interestingly, this increase in selectivity was also accompanied by a substantial rate enhancement from 2.0 to 12.7 pmol s" (g cat) in the case of Pt Sn prepared with a 4 1 ratio. Similar selectivity and activity enhancement were reported by Vannice and Sen for crotonaldehyde hydrogenation over Pt/TiOj in the vapour phase using a Hg aldehyde ratio of 22.7 Under both low tem-... 

All these reactions occurring over supported metal catalysts utilise the full range of metal crystal faces normally present on microcrystalline metals. A theoretical study by Delbecq and SauteT showed that the adsorption geometries of acrolein, crotonaldehyde and 3-methyl crotonaldehyde differed depending onto which face they were adsorbing. Pt(lll) yielded di-o adsorption, whilst Pt(lOO)... 

Methylal Crotonaldehyde Biacetyl Methyl acrylate Ethyl chloroacetate Butyronitiile Isobutyronitrile Pyrroline... 

The bicyclic nature of the labile adduct (79) from 3-methyl-pyridine was established by Acheson and Taylor who found that hydrogenation, yielding (80), followed by oxidation gave pyridine-3,4,5-tricarboxylic acid. This conclusion is consistent with Diels and Alder s observations that acid hydrolysis of the labile pyridine adduct gave pyridine and some crotonaldehyde, whereas alkaline hy-... 

Diels-Alder reactions Neutral ionic liquids have been found to be excellent solvents for the Diels-Alder reaction. The first example of a Diels-Alder reaction in an ionic liquid was the reaction of methyl acrylate with cyclopentadiene in [EtNH3][N03] [40], in which significant rate enhancement was observed. Howarth et al. investigated the role of chiral imidazolium chloride and trifluoroacetate salts (dissolved in dichloromethane) in the Diels-Alder reactions between cyclopentadiene and either crotonaldehyde or methacroline [41]. It should be noted that this paper describes one of the first examples of a chiral cationic ionic liquid being used in synthesis (Scheme 5.1-17). The enantioselectivity was found to be < 5 % in this reaction for both the endo (10 %) and the exo (90 %) isomers. 

The reaction of crotonaldehyde and methyl vinyl ketone with thiophenol in the presence of anhydrous hydrogen chloride effects conjugate addition of thiophenol as well as acetal formation. The resulting j3-phenylthio thioacetals are converted to 1-phenylthio-and 2-phenylthio-1,3-butadiene, respectively, upon reaction with 2 equivalents of copper(I) trifluoromethanesulfonate (Table I). The copper(I)-induced heterolysis of carbon-sulfur bonds has also been used to effect pinacol-type rearrangements of bis(phenyl-thio)methyl carbinols. Thus the addition of bis(phenyl-thio)methyllithium to ketones and aldehydes followed by copper(I)-induced rearrangement results in a one-carbon ring expansion or chain-insertion transformation which gives a-phenylthio ketones. Monothioketals of 1,4-diketones are cyclized to 2,5-disubstituted furans by the action of copper(I) trifluoromethanesulfonate. ... 

Cyclic hydrazides 411 react with acrolein, crotonaldehyde, and methyl vinyl ketone either by heating in a sealed tube at 150 °C or by refluxing in aqueous ethanol containing a catalytic amount of sodium hydroxide, to provide acceptable yields of the corresponding products 412 (Equation 57). Both possible cyclic tautomers are detectable <2002EJO3447, 2002PCJ598>. 

This compound is prepared by the addition of ethyl vinyl ether to acrolein, under conditions similar to those described for a similar addition of methyl vinyl ether to crotonaldehyde in Org. Syntheses, 34, 29 (1954) see Longley and Emerson, J. Am. Chem. Soc., 72, 3079 (1950). Glutaraldehyde is available currently as a 30% aqueous solution from the Carbide and Carbon Chemicals Company, 30 East 42nd Street, New York. 

Cinnamaldehyde, 3134 f Crotonaldehyde, 1516 f Cyclopropyl methyl ether, 1608 f Diallyl ether, 2431... 

As expected, the reactivity of crotonaldehyde and methyl vinyl ketone (MVK) is dominated by the reaction with the carbonyl moiety, leading... 

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