Hydrolysis acrolein synthesis

The main use of acrolein is to produce acrylic acid and its esters. Acrolein is also an intermediate in the synthesis of pharmaceuticals and herhicides. It may also he used to produce glycerol hy reaction with isopropanol (discussed later in this chapter). 2-Hexanedial, which could he a precursor for adipic acid and hexamethylene-diamine, may he prepared from acrolein Tail to tail dimenization of acrolein using ruthenium catalyst produces trans-2-hexanedial. The trimer, trans-6-hydroxy-5-formyl-2,7-octadienal is coproduced. Acrolein, may also he a precursor for 1,3-propanediol. Hydrolysis of acrolein produces 3-hydroxypropionalde-hyde which could he hydrogenated to 1,3-propanediol. ... 

In a recently published report by MacMillan s group [121] on the enantioselective synthesis of pyrroloindoline and furanoindoline natural products such as (-)-flustramine B 2-219 [122], enantiopure amines 2-215 were used as organocatalysts to promote a domino Michael addition/cyclization sequence (Scheme 2.51). As substrates, the substituted tryptamine 2-214 and a, 3-unsaturated aldehydes were used. Reaction of 2-214 and acrolein in the presence of 2-215 probably leads to the intermediate 2-216, which cyclizes to give the pyrroloindole moiety 2-217 with subsequent hydrolysis of the enamine moiety and reconstitution of the imidazolid-inone catalyst. After reduction of the aldehyde functionality in 2-217 with NaBH4 the flustramine precursor 2-218 was isolated in very good 90 % ee and 78 % yield. 

A number of routes are available for the synthesis of 2,2 -bipyridines where one of the pyridine rings is built up from simpler entities. For example, condensation of 2-(aminomethyl)pyridine (31) with acetaldehyde or acetylene over a silicon-alumina catalyst at 450°C gives 2,2 -bipyridine, ° whereas 2-cyanopyridine reacts with acetylene at 120°C in the presence of a cobalt catalyst to afford 2,2 -bipyridine in 95% yield.2-Acetylpyridine with acrolein and ammonia gives 2,2 -bipyridine in the presence of dehydrating and dehydrogenating catalysts, and related condensations afford substituted 2,2 -bipyridines. ° In a similar vein, condensation of benzaldehyde with 2 mol of 2-acetylpyridine in the presence of ammonia at 250°C affords 2,6-di(2-pyridyl)-4-phenylpyridine, ° and related syntheses of substituted 2,2 6, 2"-terpyridines have been described. Likewise, formaldehyde with two moles of ethyl picolinoylacetate and ammonia, followed by oxidation of the product and hydrolysis and decarboxylation, affords a good... 

Zeolites have also been successfully applied in the reverse reaction, i.e. the hydrolysis of ethers to alcohols. A relevant example is the splitting of bis(3-hydroxypropyl)ether. This compound is a by-product in 1,3-propanediol synthesis, which can be performed by hydration of acrolein and reduction of 3-hydroxypropanal (23). In the hydrolysis of bis(3-hydroxypropyl)ether, a 20 weight % aqueous solution of the ether is passed over a ZSM-5 catalyst at 240°C ... 

Scheme 1 Methods for the synthesis of aldehyde functional polysiloxanes described in the literature [1-5] (1) hydroformylation, (2) and (3) ozonolysis, (4) hydrosilylation of acrolein acetals and acid hydrolysis...

Acrolein and condensable by-products, mainly acrylic acid plus some acetic acid and acetaldehyde, are separated from nitrogen and carbon oxides in a water absorber. However in most industrial plants the product is not isolated for sale, but instead the acrolein-rich effluent is transferred to a second-stage reactor for oxidation to acrylic acid. In fact the volume of acrylic acid production ca. 4.2 Mt/a worldwide) is an order of magnitude larger than that of commercial acrolein. The propylene oxidation has supplanted earlier acrylic acid processes based on other feedstocks, such as the Reppe synthesis from acetylene, the ketene process from acetic acid and formaldehyde, or the hydrolysis of acrylonitrile or of ethylene cyanohydrin (from ethylene oxide). In addition to the (preferred) stepwise process, via acrolein (Equation 30), a... 

Hydrolysis of 2-alkoxy-3,4-dihydro-l,2-pytans with dilute hydrochloric acid furnishes a convenient synthesis of glutaraldehyde (R = H) and other l,5 dicarbonyl compounds. The starting materials are obtained by the 1,4-addition of vinyl ethers to a,/3-unsaturated carbonyl compounds. The wide selection of diene systems includes acrolein, crotonaldehyde, meth-acrolein, cinnamaldehyde, /3-furylacrolein, methyl vinyl ketone, benzal-acetone, and benzalacetophenone. Ethyl vinyl ether is preferred as the dienophile. The yields in the cyclization step are in the range of 25 87% and in the subsequent hydrolysis Step, 55 85%. ... 

This disconnection led to the C3 synthon 48 (and hence to its already familiar synthetic equivalent 44) and C9 amino dialdehyde 47. The Michael addition of malonic ester to acrolein was employed for the synthesis of the key starting material 49. The Claisen ester condensation of the latter followed by decarboxylation and reductive aminolysis led to the preparation of amino-bis-acetal 47a. The respective amino dialdehyde 47, generated in situ by a controlled hydrolysis of the acetal groups of 47a, reacted smoothly with acetonedicarboxylic diester and gave the required adduct 46 in a good yield and nearly complete stereoselectivity. 

A convenient three-component coupling reaction of Meldrum s acid, acrolein, and thioacetic acid was described <1997TL5785> for the synthesis of 2-(l,2-dithiolan-3-yl)acetic acid 315 (Scheme 58). As shown, diacetylthiolated propyl Meldrum s acid 311 was refluxed in methanol affording ester acid dithioacetate 312, which without purification was transformed upon acid-catalyzed methanolysis into diester 313. The subsequent oxidation step led to ester 314 which afforded the final acid 315 by a hydrolysis-decarboxylation sequence. 

Synthesis methods starting with propylene are even more numerous. Most of them pass through allyl alcohol as an intermediate, which can be obtained by the hydrolysis of chlorine or of allyl acetate, by isomerization of propylene oxide, or by the hydrogenation of acrolein ... 

Fluoromalonaldehyde (25), which exists in solution as the enol form Z configuration), has been condensed with heterocyclic JV -alkylinunonium salts to give y-fluoropentamethinecyanine dyes (see Scheme 23). Synthesis of the aldehyde (Scheme 22) involves hydrolysis of 2-fluoro-3-dimethylamino-acrolein, the product of Vilsmeier formylation of sodium fluoroacetate. - ... 

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