Esters of unsaturated acids

Esters of unsaturated acids are of experimental interest because of their ability to be converted into insoluble products. Cellulose crotonate, upon heating in the presence of air, or upon exposure to ultraviolet light, becomes completely insoluble. This action may be accelerated by the addition of small quantities of benzoyl peroxide. Esters of more active unsaturated acids, such as cellulose acetate linoleate, become insoluble upon exposure to air at ordinary temperatures.  

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Cellulose esters of unsaturated acids, such as the acetate methacrylate, acetate maleate (34), and propionate crotonate (35), have been prepared. They are made by treating the hydrolyzed acetate or propionate with the corresponding acyl chloride in a pyridine solvent. Cellulose esters of unsaturated acids are cross-linkable by heat or uv light solvent-resistant films and coatings can be prepared from such esters. 

Methyl esters of unsaturated acids (loss of CH3OH + HzO) Methyl esters of straight-chain hydroxycarboxylic acids except 2-hydroxy acids... 

This section contains syntheses of enol esters and esters of unsaturated acids as well as ester molecules bearing a remote alkenyl unit. 

An important characteristic of mammalian 15-LOX is its capacity to oxidize the esters of unsaturated acid in biological membranes and plasma lipoproteins without their hydrolysis to free acids. Jung et al. [19] found that human leukocyte 15-LOX oxidized phosphatidylcholine at carbon-15 of the AA moiety. Soybean and rabbit reticulocyte 15-LOXs were also active while human leukocyte 5-LOX, rat basophilic leukemia cell 5-LOX, and rabbit platelet 12-LOX were inactive. It was suggested that the oxygenation of phospholipid is a unique property of 15-LOX. However, Murray and Brash [20] showed that rabbit reticulocyte... 

In contrast, reactions of esters of unsaturated acids with the sulfur tetrafluoride/hydrogen fluoride/chlorine reagent result in formal addition of C1F across the C = C bond to formchloro-fluoroalkanoic acid esters. The Markovnikov-type addition occurs in reactions with methacrylic and but-2-enoic esters to give 3-chloro-2-fluoro esters, e.g. 17, while from acrylic esters anti-Markovnikov products, 2-chloro-3-fluoro esters, e.g. 16, are formed.242... 

This section contains syntheses of enol esters and esters of unsaturated acids. 

When methyl esters of unsaturated acids 9 are treated in acetonitrile with iodine, cycliza-tion occurs with high stereoselectivity although the rate of cyclization is slow18a. 

On the other hand, there is a need to use inhibitors of the platinum catalysts temporarily to reduce their catalytic activity in the presence of hydro- and vinyl-polysiloxanes in order to stop the curing process at room temperature, but to allow the platinum catalyst to be activated at elevated temperature. Among the principal types of compounds reported are alkenyl derivatives, esters of unsaturated acids, crown ethers, organic nitrogen compounds, phosphines, linear and cyclic vinyl-siloxanes, and poly(vinyl)siloxanes [2], and recently fumarate [44] and maleinate [33]. New co-activators of the catalysts (precursors) have been revealed in the 1990s to reduce to ppm the levels of platinum required to effect hydrosilylation curing [45, 46]. 

Miryan, N.L, Isaev, S.D., Kovaleva, S.A., Petukh, N.V., Dvornikova, E.V., Kardakova, E.V., and Yurchenko, A.G., Homer-Emmons reaction in the synthesis of esters of unsaturated acids from adamantane series and related carcass compounds, Zh. Org. Khim., 35, 882, 1999 Russ. J. Org. Chem. (Engl. Transl.), 35, 857, 1999. 

Michael additions with 8-phenylmenthyl esters of unsaturated acids Chiral auxiliaries attached elsewhere in asymmetric Michael additions Other Chiral Auxiliaries in Conjugate Addition The Evans oxazolidinones Chiral sulfoxides Asymmetric Birch Reduction Birch reduction of benzene Asymmetric Birch reduction of heterocycles... 

Esters from unsaturated fatty acid chlorides are usually viscous or limpid oils soluble in hydrocarbons and turpentine, and whose primary applications are as varnishes, films, artificial threads, aqueous emulsions, and rubber-like plastics.2067,2068 Heating them in an inert gas produced insoluble products formed by polymerization involving double bonds in the acyl moieites.2069 As mentioned in the section on nitrates, acetates of amylose are less compact than amylopectin acetate.1468 Esters of unsaturated acids have also been proposed as re-moistenable adhesives.1971 1972... 

TABLE V. HYDROFORMYLATION OF UNSATURATED ESTERS (Continued) B. Esters of Unsaturated Acids... 

Some manufacturers (e.g., Supelco, Bellefonte, PA, U.S.A. [12]) produce special micro-hydrogenators, made as small autoclaves, for carrying out hydrogenation in the liquid phase. For the hydrogenation of methyl esters of unsaturated acids a suspension of a platinum catalyst (Pt02) is used. Hydrogenation is carried out in ethanol solution for 15—30 min. 

Addition of vinyl esters occurs still more readily. 2-(Acyloxy)propionitriles are obtained in more than 80% yield. Also, hydrogen cyanide can be added to esters of, / -unsaturated acids,116,117 e.g., ethyl crotonate and alkylidene-malonate) ... 

Whereas monoallyl derivatives sdeld thermoplastic polymers, allyl esters containing two or more unsaturated groups yield thermosetting resins. Thus, monoallyl esters of unsaturated acids, e.g., allyl acrylate, allyl methacrylate, allyl crotonate, and allyl itaconate, and diallyl esters of dibasic acids, e.g., diallyl oxalate, diallyl phthalate, and diallyl itaconate, yield thermoset resins, which generally combine solvent resistance, toughness, hardness, transparency, and heat resistance. The cross-linking tendency of the allyl esters makes them useful in copolymerization wherein they impart these properties to normally linear polymers. 

Phase-transfer hydrocarboxylation of terminal acetylenes 254 (R = Bu, pentyl, Ph or PhCH2CH2) with carbon monoxide, catalysed by nickel(II) cyanide, affords the alkenoic acids 255 Similarly, phenylacetylene reacts with carbon monoxide and alcohols in the presence of palladium(dibenzylideneacetone)2 to give esters of unsaturated acids, e.g. 256192. 

Stereoregular, crystalline polymers are said to form from allyl esters of unsaturated acids in hydrocarbons or ether with such catalysts as butyl lithiiun, phenyl magnesium bromide, or lithium diethylamide [107]. Typically, these polymerizations were carried out between — 70°C and -l-20°C. According to the patent, films and fibers are readily formed from these polymers. The properties of these articles can be greatly modified by cross-linking [120]. 

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