Crotonate resin

Cristsll, c., = Kristall, fete. CzocflDScrocein scarlet. CKrtc -lAi Zj n. croton, resin. -61, n. croton oil. 

Croton oil is an extract of the seed of the plant Croton tiglium and has been commercially prepared as Croton resin since 1932. Its activity on the skin is related to free hydroxyl groups, which cause skin vesiculation even in low doses. 

Croton cascarilloides Raeushel C. tiglium L. a Dou (Croton) (seed) Croton resin, phorbol, crotonic acid, crotin, crotonoside.33-144 This herb is very toxic. Purgative, wound healing properties. 

This contains, besides ordinary fats, about 10% of croton-resin, the active component producing the local and systemic effects of the oil. It is destroyed by boiling with alkalis. Croton oil is the most violent of all cathartics, 1/2 to 1 drop producing burning in the mouth and stomach, often vomiting, and after 1/2 to 3 h, several extensive fluid evacuations, with much colic and tenesmus. It was formerly used in extreme cases of constipation, and in unconscious patients (uremic and... 

Representative procedure. A suspension of (17 ,2iS )-/V-Wang-bound ephedrinyl crotonate resin 14 (0.49mmol, 3.2 equiv) in THF (5 ml) under argon was gently stirred for 15min prior to the addition of cyclohexanecarboxaldehyde (18.4ml,... 

Chief constituents Glycerides of stearic, palmitic, myristic, lauric, and oleic acids and croton resin, a vesicant. 

Croton Oil. Fixed oil expressed from seeds of Croton tiglium L., Euphorbiaceae. Constit. Croton resin—a powerful vesicant glycerides of stearic, palmitic, myristic, lauric. tiglic, etc., acids crotin phorbol (q. v.) esters. Review Meeker, Schmidt. Fortschr. Chem. Org. Naturst. 31, 377 (1974). 

Poly(vinyl alcohol) has the structure 10.67. Poly(vinyl acetate) is the fully esterified derivative of polyfvinyl alcohol), in which the -OH groups are replaced by -OCOCH3 groups. As indicated in Table 10.5, commercial polyvinyl sizes are effectively copolymers of polyfvinyl acetate) and polyfvinyl alcohol) that vary in the degree of saponification of the ester groups. These products may comprise 100% of either polymer, or combinations of the two monomers in any proportions. Crotonic acid (2-butenoic acid), widely used in the preparation of resins, may also be a component. This compound exhibits cis-trans isomerism (Scheme 10.17). The solid trans form is produced readily by catalysed rearrangement of the liquid cis isomer. 

Acrylic acid esterified with cross-linked hydroxymethyl polystyrene or Wang resin reacts smoothly with primary or secondary aliphatic amines at room temperature (Entries 1 and 2, Table 10.6). Only sterically demanding amines or amines of low nucleophilicity (anilines, a-amino acid esters) fail to add to polystyrene-bound acrylate. Support-bound acrylamides are less reactive than acrylic esters, and generally require heating to undergo addition with amines (Entries 4 and 5, Table 10.6). a, 3-Unsaturated esters with substituents in the 3-position (e.g. crotonates, Entry 3, Table 10.6) react significantly more slowly with nucleophiles than do acrylates. The examples in Table 10.6 also show that polystyrene-bound esters are rather stable towards aminolysis, and provide for robust attachment even in the presence of high concentrations of amines. Entry 10 in Table 10.6 is an example of the alkylation of a resin-bound amine with an electron-poor alkene to yield a fluorinated peptide mimetic. 

Crotonic acid forms numerous salts. It is used mainly in the prepn of synthetic resins, surface coating s, plasticizers pharmaceuticals Refs 1) Beil 2, 408,. (187), [390] l255>... 

Oxybutyric Acid (CH3-CH(OH)-CH2-COOH).—From this acid were obtained in the positive electrolyte crotonic aldehyde and a little formic acid, also resinous substances. Considerable quantities of carbonic acid, also a little carbon monoxide and unsaturated hydrocarbons, are formed. The small quantities... 

Procter reported a solid-phase variant of Fukuzawa s asymmetric y-butyr-olactone synthesis (see Chapter 5, Section 5.2) that involves the intermolecular reductive coupling of aldehydes and ketones with a,p-unsaturated esters, immobilised using an ephedrine chiral resin 12.44 For example, treatment of acrylate 13 and crotonate 14 with cyclohexanecarboxaldehyde, employing Sml2 in THF, with tert-butanol as a proton source, gave lactones 15 and 16, respectively, in moderate yield and good to high enantiomeric excess (Scheme 7.11).44 The ephedrine resin 12 can be conveniently recovered and recycled.45... 

Crotonates bearing an atropisomeric 1-naphthamide moiety can be reacted in a Sml2-mediated reductive coupling with a variety of aldehydes to yield enantiomerically enriched 7-butyrolactones. The crotonate derived from 2-hydroxy-8-methoxy-Tnaphthamide reacted with pentanal to afford the highest ee of >99% in a combined yield of 90% with a cisltrans-mt o of 90 10. The chiral crotonate can also be linked to a Rink amide resin with the C-8 oxygen, and in the solid-phase reaction the same level of axial-to-central chirality transfer was obtained (Equation 103) <2006JOC2445>. 

For example, treatment of acrylate and crotonate ephedrine resins 150 and 151, with cyclohexanecarboxaldehyde 149, employing Sml2 in THF with f-butanol as a proton source, gave 152 and 153 respectively, in moderate yield and good to high enantiomeric excess (Scheme 34). The process can be considered an example of an asymmetric catch-release process, where a substrate immobilized using a chiral support captures a reactive intermediate, in this case a ketyl radical anion, from solution [23]. The chiral support controls the asymmetry of the capture step and leads to a diastereomeric, resin-bound intermediate that breaks down to release a non-racemic product. 

Manufacture. Obtained from the secretions of lac insects, which are parastic on the small branches of some kinds of wood, e.g. croton, in the districts of east India and Indo-China. These insects secrete resinous matter due to stimuli from the females, and the branches are eventually covered by the substance this is called Stick Lac . The substance is collected, selected and powdered. Then this is dipped in water and a clear red dye is extracted from it. The residue is called Raw Lac . It is melted,... 

A mixture of GY-280 epoxy resin, ethylene glycol diacrylate, and crotonic acid combined with hydroquinone monomelbyl ether and N, N-dimethylaniline (41). 

Product isolation is very simple as only the solvent has to be removed after separation from the polymer. The polymer can be returned to the active chlorinating agent by reaction with carbonyl chloride. A variation of this procedure does not require polymer-bound phosphorus halide but uses Lewis acid-Lewis base complexes between anion-exchange resins, such as Amberlite IRA 93, and phosphorus pentachloride (equation 4). Again, isolation of the resultant acid chloride is simple and the exhausted polymer can be regenerated for further use by simply washing it with aqueous acidic and basic solutions. Yields range from 51 % for crotonic acid chloride to 86% for decanoic acid chloride. 

Cascarilla. Eleuthera bark sweei-wood bark. Dried bark of Croton eluteria (L.) Sw, Euphorbiaceae. Habit. Bahama Islands, Cuba, Haiti. Constit. About 15% resin 5,39-6.33% far 7.6-8.13% ash theobromine, volatile oil, cascarillin, betaine, tannin. Ref Farb, C.A. 44, 806Qe (1950). 

Beilstein Handbook Reference) BRN 1719943 2-Butenoic acid, (Ej- (E)-2-Butenoic acid trans-2-Butenoic acid (E)-Crotonic acid Crotonic acid, (E)- trans-Crotonic acid EINECS 203-533-9 NSC 8751. Synthesis of resins, polymers, plasticizers, drugs. Prisms or needles mp = 72° bp = 184.7° d = 0.9604 very soluble in H2O (54.6 g/l), EtOH, soluble in Et20, Me2CO, ligroin LD50 (rat orl) n 1.0 g/kg. Alcoa Ind. Chem. Allchem /nd. Chisso Corp. USA Eastman Chem. Co. Sigma-Aldhch Fine Chem. 

OTHER COMMENTS used as a chemical intermediate in the manufacture of butyl alcohol, butyraldehyde, maleic acid, crotyl alcohol, sorbic acid, crotonic acid, and 2-ethylhexyl alcohol minor amounts are used in the preparation of rubber accelerators utilized as a solvent in purification of lubricating oils, and in the manufacture of insecticides, rubber antioxidants and resins. 

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. 

Other, more structurally complex resins, which are highly functional and in use today, are the copolymers of three monomers (vinyl acetate, crotonic acid, and vinyl neodecanoate) and a polymer formed from octylacrylamide, t-butylaminoethyl methacrylate, and two or more monomers consisting of acrylic acid, methacrylic acid, or their simple esters (Table 7-5). This polymer provides a low-molecular-weight version acceptable in low-VOC systems however, it is very expensive when used at 30% higher concentration for optimal holding power. 

Poly(vinyl acetate) and vinyl acetate copolymers with crotonic acid, vinyl laurate, and dibutyl maleate are important solid resins some are available in solution. 

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