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2.4- Pentadienoic, acid, 4-methyl

The reaction proceeds well with unhindered secondary amines as both nucleophiles and bases. The yield of allylic amine formed depends upon how easily palladium hydride elimination occurs from the intermediate. In cases such as the phenylation of 2,4-pentadienoic acid, elimination is very facile and no allylic amines are formed with secondary amine nucleophiles, while phenylation of isoprene in the presence of piperidine gives 29% phenylated diene and 69% phenylated allylic amine (equation 30).84 Arylation occurs at the least-substituted and least-hindered terminal diene carbon and the amine attacks the least-hindered terminal ir-allyl carbon. If one of the terminal ir-allyl carbons is substituted with two methyl groups, however, then amine substitution takes place at this carbon. The reasons for this unexpected result are not clear but perhaps the intermediate reacts in a a- rather than a ir-form and the tertiary center is more accessible to the nucleophile. Primary amines have been used in this reaction also, but yields are only low to moderate.85 A cyclic version occurs with o-iodoaniline and isoprene.85... [Pg.850]

Stereochemistry is largely lost in die diene vinylation, at least at 100 C, as evidenced by die reaction of (Z,E)-3-methyl-2,4-pentadienoic acid shown in equation (40). [Pg.856]

Butadienoate esters undergo AICI3 and EtAlCh catalyzed stereospecific [2 + 2] cycloadditions with a wide variety of alkenes to give alkyl cyclobutylideneacetates in good yield. The stereospecificity and ratios of ( )- and (Z)-isomers suggest a [ 2 + v2a] cycloaddition of the ester-Lewis acid complex to the alkene analogous to the cycloaddition of ketenes with alkenes. Similar results are obtained with methyl 2,3-pentadienoate, methyl 4-methyl-2,3-pentadienoate and methyl 2-methyl-2,3-butadi-... [Pg.10]

R)-3-heptyl-2-hydroxy-3,4-pentadienoic acid yield (of the methyl ester) 53% 33% cc... [Pg.494]

Unsaturated acids can also be obtained in this way, by hypohalite oxidation of a,/ -unsaturated methyl ketones 3-methyl-2-butenoic acid has thus been obtained from mesityl oxide,136 and 5-phenyl-2,4-pentadienoic acid in 70% yield from cinnamylideneacetone 137... [Pg.1042]

Pentadienoic acid, 5- 1-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-3-methyl-, [S-(Z, )]- abscisic acid 1156, 3216, 3218, 1206a, 3973,4090 ... [Pg.185]

Abscisic add [abscisin II, ABA histor. name dormin (2Z,4 )-5-((5)-l-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexenyl)-3-methyl-2,4-pentadienoic acid]. [Pg.1]

Ketone [162585-05-9]. 5- l-Hydroxy-2,2-dimethy 1-6-methylene-3-oxocyclohexy[)-3-methyl-2,4-pentadienoic acid, r-Hydroxy-3 -oxo-y-ionylideneacetic acid... [Pg.111]

Hydroxy-2,2-diinethyl-6-methyIenecyclohexyl)-3-methyl-2,4-pentadienoic acid, 9Ci... [Pg.210]

Dihydroxy-2,2-dimethyl-6-methylenecyclohexyl)-3-methyl-2,4-pentadienoic acid Me ester, in D-30155 1,6-Dihydroxy-3,11(13)-eudesmadien-12-oic acid Me ester, in D-30171 3-Hydroxy-6-methoxy-7( 11 )-eremophilen-12,8-olide, in D-30168... [Pg.542]

E3 C]5 Acid [14398-42-6] ( , )-3-Methyl-5-(2,6,6-trimethyl-2-cyclohexen-l-yl)-2,4-pentadienoic acid... [Pg.402]

Durene, 3, 683, 752 38B, 163 39B, 85 40B, 126 43B, 155 CiiH,o02f 5-Phenyl-2,4-pentadienoic acid, 46B, 10 CiiHiiClOft, p-Chlorobenzaldehyde hydrate diacetate, 44B, 107 C11H15CI, Chloropentamethylbenzene, 33B, 70 CiiHiSf 1-Methyl-4-t-butylbenzene, 46B, 115 Ci2Br2F8, 2,2 -Dibromooctafluorobiphenyl, 46B, I15 Ci2CliOf Decachlorobiphenyl, 4IB, 148... [Pg.61]

Another alternative method to produce sebacic acid iavolves a four-step process. First, butadiene [106-99-0] is oxycarbonylated to methyl pentadienoate which is then dimerized, usiag a palladium catalyst, to give a triply unsaturated dimethyl sebacate iatermediate. This unsaturated iatermediate is hydrogenated to dimethyl sebacate which can be hydrolyzed to sebacic acid. Small amounts of branched chain isomers are removed through solvent crystallizations giving sebacic acid purities of greater than 98% (66). [Pg.63]

Structurally rather complicated target molecules can be synthesized with the aid of thi-olate 1,6-addition reactions to acceptor-substituted dienes as well. For example, a richly functionalized proline derivative with a 2,4-pentadienal side chain was converted into the corresponding 6-phenylthio-3-hexen-2-one derivative by 1,6-addition of phenylthiolate, treatment of the adduct with methyl lithium and oxidation (equation 46)127. The product was transformed into acromelic acid A, the toxic principle of clitocybe acromelalga ichimura. Similarly, the 1,6-addition reaction of cesium triphenylmethylthiolate to methyl 2,4-pentadienoate served for the construction of the disulfide bridge of the macrobicyclic antitumor depsipeptide FR-901,228128. [Pg.666]

An attractive alternative to building a world scale adipic acid plant is to construct a specialty smaller volume oxycarbonylation plant which is capable of exclusively producing the more valuable precursors for pelargonic and sebacic acid. Oxycarbonylation process conditions can be controlled to give methyl, 4-pentadienoate which is the product from butadiene mono-carbonylation(39,40). Methyl, 4-pentadienoate can react in a subsequent step with butadiene to give an unsaturated pelargonic acid precursor in high yield(41). Methyl, 4-pentadienoate... [Pg.87]

To understand how to control process conditions to give methyl, 4-pentadienoate, the reaction mechanism must be examined. (See Equation 2.). -palladium hydride elimination from 4 gives rise to trans and cis-methyl penta-, 4-dienoate which is the desired monocarbonylation intermediate for sebacic acid. The desired mono-carbonylation reaction is promoted by low carbon monoxide pressure ( 1000 psig) while high pressure (1800 psig) gives excellent 1,4-dicarbonylation product yield. The mono-carbonylation reaction is also facilitated by using a Lewis Acid as a co-catalyst and iodide as the preferred palladium counter-ion (Table III.). Chloride is the preferred palladium counter-ion for 1,4-dicarbonylation. [Pg.88]

Although several Lewis Acids were evaluated, including titanium(lV) chloride, aluminum(lll) chloride and tin(lV) chloride, ferric(lll) chloride proved to be the most effective co-catalyst. We believe that in the presence of a Lewis Acid, the rate of j3-palladium hydride elimination (H-Pd-X) from the -allyl carbomethoxy palladium complex 4 can be enhanced. A good leaving group such as iodide attached to -allyl carbomethoxy palladium complex 4 would facilitate iodopalladium hydride elimination to selectively form methyl, -pentadienoate (Equation 11.). [Pg.88]

Methyl 2, -pentadienoate self-dimerization as a potential route to sebacic acid precursors was extensively evaluated. Homogeneous metal catalyzed dimerization of compounds containing conjugated double bonds is known to give cyclic, branched, and linear dimers(43-45). At higher temperatures or in the presence of many zero-valent metal catalysts, cyclodimerization (Equation 12.) is the only observable reaction. [Pg.90]


See other pages where 2.4- Pentadienoic, acid, 4-methyl is mentioned: [Pg.265]    [Pg.77]    [Pg.281]    [Pg.165]    [Pg.86]    [Pg.58]    [Pg.265]    [Pg.497]    [Pg.984]    [Pg.351]    [Pg.111]    [Pg.466]    [Pg.536]    [Pg.537]    [Pg.1]    [Pg.274]    [Pg.326]    [Pg.201]    [Pg.87]    [Pg.267]   
See also in sourсe #XX -- [ Pg.984 ]




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2,4-Pentadienoates

2.4- Pentadienoic acid methyl ester

Methyl 2,4-pentadienoate

Methyl 2,4-pentadienoates

Pentadienoic acid

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