Olefinic acid

Conjugated Double Bonds. Sorbic acid is brominated faster than other olefinic acids (7). Reaction with hydrogen chloride gives predominately 5-chloro-3-hexenoic acid (8). 

Most ion exchangers in large-scale use are based on synthetic resins—either preformed and then chemically reacted, as for polystyrene, or formed from active monomers (olefinic acids, amines, or phenols). Natural zeolites were the first ion exchangers, and both natural and synthetic zeolites are in use today. 

Neutralization of the sulfonation product from a-olefins is more complex than neutralization of the corresponding products of alkylbenzenes. This is because the S03-a-olefin acid product contains about 50% free sulfonic acid, the rest being C(l,3) and D(l,4) sultones, assuming that with acid aging the 0(1,2) sultones have disappeared. In the case of a-olefins an excess of caustic (1.5-2.0% excess) must be added to neutralize both the sulfonic acid initially present and that formed on subsequent hydrolysis of the C(l,3) and D(l,4) sultones. The sultones (ring-structured esters) cannot be converted to their proper salts by a simple neutralization but need a hydrolysis step. 

In addition, several S/S ligands were also investigated for the asymmetric hydrogenation of olefins. In 1977, James and McMillan reported the synthesis of various disulfoxide ligands, which were applied to the asymmetric ruthenium-catalysed hydrogenation of prochiral olefinic acid derivatives, such as itaconic acid. These ligands, depicted in Scheme 8.16, were active to provide... 

The BDPCH system was again effective for the a-acetamido olefinic acids (up to 79% ee, which could be increased to nearly 100% ee after recrystallization of the A-acetylamino acid products), while the BDPCP system gave 60% ee for hydrogenation of a-ethylstyrene which is one of the highest ee values yet recorded for a substrate containing no polar substituents (—COOH, CONHR) (see also Section IV,B). 

In contrast, the homogeneous DIOP system gave 33% ee with the butene and up to 79% ee with the olefinic acids. 

This stearolic acid has been thoroughly characterized 3 6 by the freezing-point curve, ultraviolet and infrared spectra, ozonization, and hydrogenation. It has been shown to be free both of positional isomers and of olefinic acids such as oleic and elaidic acids. Its properties include m.p. 46-46.5°, iodine number (Wijs titration, 30 minutes) 89.5, d 5 1.4510, d 5 1.4484, neutral equivalent 279.2-279.6 (theory 280.4), hydrogen uptake 95-100% of theory for a triple bond. The last trace of color is difficult to remove by recrystallization from petroleum ether. It can be removed, however, by crystallization from a 20-30% solution in acetone at —5 to —8°, or from an 8-10% solution at —20°, or by distillation (b.p. 189-190°/2mm.). 

The acyl radical equivalents formed by the electroreduction of acyl phosphonium salts have an interesting reactivity and the electroreduction of nonconjugated olefinic acids yields intramolecular coupling products (Scheme 28) [11, 54, 55]. 

This series is divided into normal, secondary, and olefine acids. In the normal acid f a>0 in the second it must be a positive integer. 

Tth. Seeondartf OXtfiw Aoids.—h. secondarj olefine acid of this series is one in which tho atom of carbon united with oxatyl is not combined with hydroxyl, and in which tho atom of carbon united with hydroxyl is also combined with two monad alcohol radicals, as shown in tho following formula —... 

STEREOCONTROLLED IOOOLACTONIZATION OF ACYCLIC OLEFINIC ACIDS THE TRANS AND CIS ISOMERS OF 4,5-DIHVDRO-5-IODOMETHYL-4-PHENYL-2(3H)-FURANONE... 

Cyclization of olefinic acids 5-23 Hydrocarboxylation of unsaturated alcohols... 

P is an optically active tertiary phosphine, likely will resemble the RhCl(PPh3)3 system (23). However, even in this exhaustively studied system, both hydride and/or unsaturate routes are feasible (23, 24) by varying conditions, the choice of route could affect stereoselectivity. Most asymmetric hydrogenations have used prochiral olefinic acid substrates, and these systems have not been thoroughly studied even with nonchiral catalysts. 

This method of preparation can be applied generally to the esters of the phenyl-olefinic acids. Although metallic sodium is used, yet as in the acetoacetic ester synthesis (see Reaction XLVI.) a trace of alcohol must always be present to form sodium ethoxide. This is usually the case. If necessary, sodium ethoxide itself can be employed. The use of some other condensing agents will be clear from the following preparation. 

Also via Acetylenic esters (Section 306) Olefinic acids (Section 322 g-hydroxyesters (Section 327)... 

Further investigations of the robustness of synthon XX have recently been reported by Batchelor et al. [59]. Co-crystallization of phenazine with the /raw.s-olefinic acids, fumaric 32 and mesaconic 33, produces 1 1 supramolecular tapes incorporating only synthon XX (Figs. 12.16a, b). With the dv-olefinic acids, maleic 34 and citraconic 35, however, 2 1 tapes are produced in which the... 

Figure 12.16. Tapes formed between 30 and the olefinic acids (a) 32 and (b) 33 form 1 1 tapes incorporating only synthon XX, whereas (c) 34 and (d) 35 form 2 1 tapes incorporating both synthon XX and synthon I.

Alkaline hydrolysis led to the acid 67 which was debenzylated and reduced with lithium in methylamine to the olefinic acid 68. Introduction of the 15-hydroxy group 69 into the 7-oxaprostanoid was possible as in the PGF, series with Se02. ( )-7-oxa-PGEj 70 and its 15-epimer were then obtained by removal of the ketal group with trifluoroacetic acid and chromatography on silica gel columns. 

The alkylation acid penalty for ethylene is so large it makes close control of the feed deethanizer absolutely mandatory for economical overall operation. The ethane and lighter content of the C3-C4 cut should be maintained nil as measured by continuous chromatography. Even a trace amount of C2 s may represent several barrels of ethylene per day. In addition, if a slug of ethylene is accidentally charged to the alkylation reactor it can also have the effect of suddenly reducing the strength of the acid catalyst to the point that alkylation ceases, olefin absorption rapidly dilutes the acid, and chain polymerization of olefins ("acid runaways") can occur. 

The condensation of aldehydes and ketones with halo esters may lead directly to olefinic acids and esters by dehydration of the intermediate /S-hydroxy compounds (Reformatsky). ° More often, the hydroxy esters are isolated and purified prior to dehydration (method 103). 

As a preparative method the direct decarboxylation of olefinic acids is almost limited to the formation of styrenes and stilbenes from substituted cinnamic acids. Thermal decomposition of cinnamic acid gives styrene (41%). The yield is nearly quantitative if the reaction is carried out in quinoline at 220° in the presence of a copper catalyst. The yields of substituted styrenes where the aryl radical contains halo, methoxyl, aldehyde, cyano, and nitro groups are in the range of 30-76%. cis-Stilbene and cis-p-nitrostilbene are prepared in this way from the corresponding a-phenylcinnamic acids (65%). One aliphatic compound worthy of mention is 2-ethoxypropene, prepared by heating -ethoxycro-tonic acid at 165° (91% yield). The mechanism of acid-catalyzed decarboxylations of this type has been studied. Isomerization of the double bond from the a,/5- to the /5, y-position before decarboxylation very likely occurs in many instances. ... 

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