Croton alcohol

Sulfur has also been found to be a promoter for the hydrogenation of crotonaldehyde to croton alcohol [96]. When small amounts of thiophene were added, it acted as a promoter, especially when the... 

CHa CHlCH CHO. Colourless lachrymatory liquid with a pungent odour. B.p. 104 "C. Manufactured by the thermal dehydration of aldol. May be oxidized to crotonic acid and reduced to crolonyl alcohol and 1-butanol oxidized by oxygen in the presence of VjOj to maleic anhydride. It is an intermediate in the production of l-butanol from ethanol. 

Methyl crotonate. Purify commercial crotonic acid by distiUing 100 g. from a 100 ml. Claisen flask attached to an air condenser use an air bath (Fig. II, 5, 3). The pure acid passes over at 180-182° and crystallises out on cooling, m.p. 72-73° the recovery is about 90 per cent. Place 75 g. of absolute methyl alcohol, 5 g. (2 -7 ml.) of concentrated sulphuric acid and 50 g. of pure crotonic acid in a 500 ml. round-bottomed flask and heat under reflux for 12 hours. Add water, separate the precipitated ester and dissolve it in ether wash with dilute sodium carbonate solution until effervescence ceases, dry with anhydrous magnesium sulphate, and remove the ether on a water bath. Distil and collect the methyl crotoiiato at 118-120° the yield is 40 g. 

Ethyl crotonate may be prepared readily from technical crotonic acid by action of sulfuric acid and alcohol. The checkers obtained 72% yield both by the ordinary procedure and by the method of azeotropic distillation. 

Muconic acid has been obtained in a variety of ways. The procedures that seem most important from a preparative point of view are by treatment of ethyl o ,5-dibromoadipate with alcoholic potassium hydroxide, by condensation of glyoxal (as the sodium bisulfite addition product) with malonic acid, by heating ethyl l-acetoxy-l,4-dihydromuconate (obtained by condensing ethyl oxalate and ethyl crotonate, acetylating, and reducing),and by oxidation of phenol with peracetic acid. ... 

Allyl cyanide, CHg. CH CH. CN, occurs in some of the oils of the mustard type. It is a liquid of specific gravity 0 8365 boiling at 120° to 123°, and yields, on boiling with alcoholic potash solution, crotonic acid, melting at 72°. 

The synthesis of key intermediate 12, in optically active form, commences with the resolution of racemic trans-2,3-epoxybutyric acid (27), a substance readily obtained by epoxidation of crotonic acid (26) (see Scheme 5). Treatment of racemic 27 with enantio-merically pure (S)-(-)-1 -a-napthylethylamine affords a 1 1 mixture of diastereomeric ammonium salts which can be resolved by recrystallization from absolute ethanol. Acidification of the resolved diastereomeric ammonium salts with methanesulfonic acid and extraction furnishes both epoxy acid enantiomers in eantiomerically pure form. Because the optical rotation and absolute configuration of one of the antipodes was known, the identity of enantiomerically pure epoxy acid, (+)-27, with the absolute configuration required for a synthesis of erythronolide B, could be confirmed. Sequential treatment of (+)-27 with ethyl chloroformate, excess sodium boro-hydride, and 2-methoxypropene with a trace of phosphorous oxychloride affords protected intermediate 28 in an overall yield of 76%. The action of ethyl chloroformate on carboxylic acid (+)-27 affords a mixed carbonic anhydride which is subsequently reduced by sodium borohydride to a primary alcohol. Protection of the primary hydroxyl group in the form of a mixed ketal is achieved easily with 2-methoxypropene and a catalytic amount of phosphorous oxychloride. 

Crotonic acid, esterification with sec-butyl alcohol, 41, 60 Crystal Violet, from condensation of oxalyl chloride with dimethyl-aniline, 41, 2-4... 

Aliphatic compounds Several water-soluble simple organic acids and alcohols are cannon plant and soil constituents. They include methanol, ethanol, n-propanol and butanol (40), and crotonic, oxalic, formic, butyric, lactic, acetic and succinic acids (41, 42), all of which inhibit seed germination or plant growth. Under aerobic conditions, however, aliphalic acids are metabolized in the soil and therefore, should not be considered a major source of allelopathic activity (40). 

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. 

Chiral fl-amino esters. The conjugate addition of primary amines to alkyl crotonates proceeds in satisfactory yield when carried out under high pressure. French chemists have recently examined this reaction using crotonates derived from chiral alcohols. Thus addition of diphenylmethylamine to 8-phenylmenthyl croton-ate proceeds in 85-90% chemical yield and in 60% de. Optical yields are increased... 

Other classes of alcohols are unreactive. Ethyl 3-hydroxybutyrate (a p-hydroxy ester) went to the phosphate stage, but would not undergo azide displacement. In this example about 30% of the crotonate was formed because of p-elimination. 

Ru(II)-TPPTS to the corresponding unsaturated alcohols in biphasic mode. If one compares the reaction times until full conversion, it becomes clear that the reaction rate correlates with the solubility of the substrate in the aqueous phase, as expected. The latter decreases with increasing chain length or branching of the chain at the C3-atom. In contrast to heterogeneously catalysed hydrogenations of o , d-unsaturated aldehydes, the steric hindrance of substituents at the C3-atom only plays a minor role in the coordination mode of the substrate at the metal centre, since selectivity differences from croton-aldehyde to citral are marginal. 

When aqueous NaOH is given as a base, isomerization of the product butenoic acids can be extensive depending on the nature and concentration of base. In dilute aqueous solutions alcohols do not react to form the respective esters, however, the reactions are strongly accelerated due to the increased solubility of the substrates in the catalyst-containing aqueous-alcoholic phase. For example, with 23-33 % (v/v) ethanol in water the [PdCl2(TPPTS)2]-catalyzed hydroxycarbonylation of allyl chloride proceeded with TOF-s of 1850-2400 h and with a vinylacetic/crotonic acid ratio of 21 [16]. Addition of [CuCb] increased the overall conversion rate (by a factor of 2 at [Cu]/[Pd] = 8) but at the same time the side reactions... 

The double bond of certain a,p-unsaturated esters (e.g. crotonates, methacrylates) is so reactive that it tends to add the elements of the alcohol present as solvent the resulting p-alkoxy-substituted guanamines (LXXXV) (79) are therefore readily and cheaply produced, and the use of expensive p-alkoxycarboxylic esters required in the conventional synthesis (706) is avoided. Crotonic esters give the alkoxyguanamine... 

Among the most commonly applied chiral moiety for nitrones (2) is the N-a-methylbenzyl substituent (Scheme 12.6) (18-25). The nitrones 8 with this substituent are available from 1 -phenethylamine, and the substituent has the advantage that it can be removed from the resulting isoxazolidine products 9 by hydrogeno-lysis. This type of 1,3-dipole has been applied in numerous 1,3-dipolar cycloadditions with alkenes such as styrenes (21,23), allyl alcohol (24), vinyl acetate (20), crotonates (22,25), and in a recent report with ketene acetals (26) for the synthesis of natural products. Reviewing these reactions shows that the a-methylbenzyl group... 

A. sec-Butyl crotonate. In a 2-1. round-bottomed flask are placed 258 g. (3 moles) of crotonic add (Note 1), 370 g. (5 moles) of sec-butyl alcohol in which has been dissolved 6-7 ml. of concentrated sulfuric acid, and 300 ml. of benzene. A few boiling chips are added, and the flask is fitted with a suitable water separator (Note 2) in the top of which is placed a reflux condenser. The mixture is heated under reflux for about 12 hours or until no further separation of aqueous phase occurs. About 65 ml. of water is collected. The cooled reaction mixture is diluted with 200 ml. of ether, washed with 10% sodium carbonate solution... 

Methyl n-amyl carbinol. 247, 254 Methyl n-amyl ketone, 482 Methylaniline (mono), pure, from commercial methylaniline, 562, 570 P-Methylanthraquinone, 728, 740 Methyl benzoate, 780, 781 p-Methyl benzyl alcohol, 811,812 Methyl benzyl ketone, 727, 735 Methyl y-bromocrotonate, 926, 927 2-Methyl-2-butene, 239 Methyl n-butyl carbinol, 247,255 Methyl n-butyl ether, 314 Methyl n-butyl ketone, 475, 481 4-Methylcarbostyril, 855 p-Methylcinnamic acid, 719 4-Methylcoumarin, 853, 854 Methyl crotonate, 926, 927 Methylethylacetic acid, 354, 358 Methylethylethynyl carbinol, 468 Methyl ethyl ketone, 335, 336 purification of, 172 Methyl n-hexyl ether, 314 Methyl n-hexyl ketone, 335, 336 Methyl n-hexyl ketoxime, 348 Methyl hydrogen adipate, 938 Methyl hydrogen sebacate, 938,939 4-Methyl-7-hydroxycoumarin, 834 Methyl iodide, 287 Methyl isopropyl carbinol, 247,255 Methyl 4-keto-octanoate, 936... 

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