Crotonic acid Synthesis

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. 

DL-Threonic acid (10) seemed to be a promising source of DL-threose. Therefore, other routes to 10 were elaborated. By a procedure consisting of five steps" 2-propenal (acrolein) — vinylglycoloni-trile — ethyl vinylglycolate — ethyl 4-bromocrotonate — 3-hydroxy-crotonic acid — 10, DL-threonic acid was obtained in an overall yield of 4.1%. Another synthesis of 10 was achieved17 in six steps starting... 

Now the aldehyde which yields crotonic acid on oxidation, i.e., crotonic aldehyde, may be prepared by a synthesis which shows clearly that it must have the constitution of the first of these isomeric aldehydes, A 2-buten-al, CH3—CH = CH—CHO. 

Crotonic and Iso-crotonic Acids.—We have then for the two cro-tonic acids only one possible constitution remaining and their synthesis proves that both of these acids do in fact have the same structural constitution, viz., that of /3-methyl acrylic acid or A2-butenoic acid. 

Crotonic Acid from Crotonic Aldehyde.—We have previously shown (p. 169), that crotonic aldehyde is A2-butenal because of its synthesis by the aMol condensation of acetaldehyde. On simple oxidation crotonic aldehyde yields crotonic acid which must therefore have the constitution of A2-butenoic acid,... 

From Acetaldehyde and Malonic Acid.—Another synthesis proves the constitution of crotonic acid as A2-butenoic acid. A di-basic acid known as malonic acid has the constitution of di-carhoxy methane HOOC—CH2—COOH. When this acid is heated with acetaldehyde (paraldehyde) and glacial acetic acid condensation occurs as in the synthesis of crotonic aldehyde and in the Perkin-Fittig synthesis (p. 172). A dibasic acid is obtained which loses carbon dioxide and yields a mono-basic acid which is crotonic acid. 

A recent synthesis of (+)-sedridine (167) was reported in which a key step was the asymmetric cycloaddition of the nitrone 2,3,4,5-tetrahydropyridine A-oxide with an asymmetric crotonic acid derivative containing a chiral auxilliary [439], Sedridine has recently been isolated from the bark of Punica granatum [440],... 

Direct reaction of 191 with acrylic acid resulted in efficient formation of 192 (eq. 41).66 Subsequent dehydrogenation at elevated temperatures provided the aromatic species 193, which was a key intermediate in the synthesis of 194, a compound that displays strong p-blocking activity. Under similar conditions, reaction of 191 with crotonic acid, cinnamic acid, and ethyl acrylate did not generate the corresponding bicyclic alkaloid skeletons. 

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. 

Poly(N-vinylpyrrolidone), P(NVP), is a nonionic, water-soluble polymer with high thermal and hydrolytic stability (7-9). Copolymers of N-vinylpyr-rolidone (NVP) with various carboxylate and carboxylate-precursor monomers (e.g., acrylic acid, sodium acrylate, crotonic acid, itaconic acid, and maleic anhydride) are also well-known (10). In addition, the homo- and copolymerization kinetics of these monomers are well-established. On the other hand, reports of copolymerizations of NVP with sulfonate monomers are sparse 11, 12). This chapter describes the synthesis, kinetics, and reactivity ratios for the copolymerization of NVP and some of the newer sulfonate monomers. A comparison of some of the solution properties for such copolymers is also included. 

Among the carboxylic acid and anhydride functional monomers that have been employed in the synthesis of these thickener polymers are acrylic acid, methacrylic acid, itaconic acid, citraconic acid, maleic acid, fumaric acid, crotonic acid, maleic anhydride, and citraconic anhydride. The copolymers containing maleic and citraconic anhydride monomers are either hydrolyzed or partially esterified to obtain the required carboxyl functionality. Among these carboxylic monomers, maleic anhydride and particularly methacrylic acid are most frequently favored. Carboxylic homopolymers, where they can be formed, might be considered the simplest examples of ASTs were it not for the fact that they are not copolymers as defined, and some are water soluble in their un-ionized states. Examples of carboxylic homopolymers are the un-ionized free-radical-polymerized atactic forms of polyacrylic acid (i) and polymethacrylic acid (2), which are both readily soluble in water. 

The hydroxy-acid (53), an intermediate in vitamin A synthesis, has been prepared in 51 % yield from )9-ionone and crotonic acid using lithium naphthal-enide. ... 

One of the first industrial muscone syntheses stems from work at BASF. [182] Analogous to the synthesis of exaltone, cyclododecanone is converted, by reaction with but-3-yn-2-ol, into a diol, which is further transformed by a Meyer-Schuster rearrangement and Nazarov cyclisation into a methyl-substituted bicycle. A very short route to the same product was described by Mitsui Petrochemical Industries a few years later this involved the direct conversion of cy-clododecene with crotonic acid in the presence of polyphosphoric acid, and resulted in a remarkable yield of 54 %. [183]... 

Uses Intermediate in mfg. of n-butanol, crotonic acid, sorbic acids mfg. of resin and rubber antioxidants solvent in min. oil purification warning agent in fuel gas for locating breaks and leaks in pipes alcohol denaturant mfg. of butyraldehyde, quinaldine minor amts, in mfg. of maleic acid, crotyl alcohol, butyl chloral hydrate, rubber accelerators in org. synthesis insecticides chemical warfare... 

Dimethyl sulfoxide Sodium glucoheptonate paint swelling agent Pentaerythritol paint synthesis Crotonic acid paint thinner... 

Crotonic acid 2-Ethylhexyl chloride 2-Methylpropanal Pyrocatechol Triisobutylene resin synthesis, coatings m-Divinyl benzene resin, automotive components Polyarylether ketone resin resin, blow moldings Ethylene/methyl acrylate copolymer Polyarylether ketone resin resin, coatings Epoxy-novolac resin, coatings UV-curable... 

In addition, bio-based green solvents can be generated from PHAs after their utilization via pyrolysis. This way, unsaturated compounds such as crotonic acid and 2-pentenoic acid needed for synthesis of lactones are generated. 

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