Propionaldehyde diethyl acetal 3-Propionaldehydes

The PPA-promoted cyclizations of (phenylthio)acetaldehyde dimethyl acetal and a-(phenylthio)propionaldehyde diethyl acetal yield benzo[6]thiophene together with 3-methoxy-2,3-dihydrobenzo-[6]thiophene, and a mixture of 2- and 3-methylbenzo[6]thiophene, respectively.296 Mechanisms have been proposed to account for these results. 

Secondary and tertiary dialkylcuprates, lithium dialkenyl-, and even diphenyl-cuprates, add in very good yields to the reactive propionaldehyde diethyl acetal. The syn addition products may be trapped with a variety of electrophiles such as alkyl, alkenyl, alkynyl and aryl halides. The method has been used for the synthesis of several natural products. Substituted alkynic acetals also react with lithium dialkylcuprates in ether to furnish stable dialkenylcuprates of type (128) which do not eliminate to the corresponding alkoxy allenes (129) if the temperature is maintained below -20 C.164-179... 

Aryl-l,2,4-triazepin-3-ones (2) were also prepared from the appropriate aryl isocyanate and 3-(methylamino)propionaldehyde diethyl acetal (Scheme 4). The yields in each reaction step were comparable to those for the synthesis of the triazin-3-ones. 

In the course of a study of a synthesis of dZ-pelletierine, Beets and Wibaut (498) discovered a new mode of preparation of 5-coniceine. The catalytic hydrogenation of j8-(2-pyridyl)-propionaldehyde diethyl acetal in glacial acetic acid solution over platinum leads to different products, depending on the concentration used. If the hydrogenation be carried out in concentrated solution, the product is dZ-pelletierine diethyl acetal, but if a dilute solution is used, 5-coniceine is obtained. Solutions of medium concentration afford mixtures of the two products. 

Several efficient oxidation reactions with molecular oxygen were developed using transition-metal complexes coordinated by variuos ligands in combination with apprOTriate reductants. Recently, it was found that cyclic ketones such as 2-methylcyclohexanone and acetals of aldehyde such as propionaldehyde diethyl acetal were effectively employed in aerobic epoxidation of olefins catalyzed by cobalt(II) complexes. In the latter case, ethyl propionate and ethanol were just detected in nearly stoichiometric manner as coproducts (Scheme 12), therefore the reaction system is kept under neutral conditions during the epoxidation. 

Propionaldehyde diethyl acetal heated 12 hrs. at 80° with an equimolar amount of ferf-butyl hydroperoxide 1-ethoxy-1-ferf-butylperoxypropane. Y 90%. 

Preparation of a-pinene oxide (Structure 30). Mukaiyama s catalytic aerobic epoxidation using propionaldehyde diethyl acetal and Co(mac)2 (Scheme 1.8)... 

Remove most of the propionaldehyde diethyl acetal by rotary evaporation (keep the water bath at room temperature to avoid product loss). 

Nelson and Curl (233) reported that benzaldehyde was the major volatile constituent in Montmorency cherry juice. Also, an alcohol, probably geraniol, was found in trace amounts. Recently, Stinson et al. (234) found low-boiling neutral compounds in Montmorency cherry essence. The most abundant compounds were ethanol and methanol, comprising 9.0 and 0.5% of the essence. Other compounds in the essence were acetaldehyde, diethyl ether, propionaldehyde, acetone, isobutyraldehyde, methyl acetate, and ethyl acetate. For the high-boiling components of Montmorency cherry essence, Stinson et al. (235) found that the major compounds were n-propyl alcohol, isobutyl alcohol, isoamyl alcohol, and benzaldehyde. Several other minor components were also identified in the essence. 

Acrolein, diethyl acetal, and propionaldehyde, P-ethoxy-, diethyl acetal)... 

The diethyl acetals of acetaldehyde, propionaldehyde, isobutyraldehyde, and butyraldehyde are converted into at-bromo acetals when treated at 25-40° in sunlight or under irradiation by a 60 W lamp with A-bromosuccinimide added portionwise 651 the reaction being exothermic, cooling is required. This method gives purer products than do those described above, but the yields are no better. 

Aminoacetaldehyde diethyl acetal was obtained in 74% yield by heating a methanolic solution of chloroacetaldehyde diethyl acetal with 18 equivalents of anhydrous ammonia in a pressure vessel at 140° for 10 h.505 2-Amino- and 2-(methylamino)-propionaldehyde diethyl acetal were prepared in 55 %and 40 % yield, respectively, under similar conditions.506 Aromatic amines are best brought to this reaction as A-metal derivatives. 

A powerful oxidizer. Explosive reaction with acetaldehyde, acetic acid + heat, acetic anhydride + heat, benzaldehyde, benzene, benzylthylaniUne, butyraldehyde, 1,3-dimethylhexahydropyrimidone, diethyl ether, ethylacetate, isopropylacetate, methyl dioxane, pelargonic acid, pentyl acetate, phosphoms + heat, propionaldehyde, and other organic materials or solvents. Forms a friction- and heat-sensitive explosive mixture with potassium hexacyanoferrate. Ignites on contact with alcohols, acetic anhydride + tetrahydronaphthalene, acetone, butanol, chromium(II) sulfide, cyclohexanol, dimethyl formamide, ethanol, ethylene glycol, methanol, 2-propanol, pyridine. Violent reaction with acetic anhydride + 3-methylphenol (above 75°C), acetylene, bromine pentafluoride, glycerol, hexamethylphosphoramide, peroxyformic acid, selenium, sodium amide. Incandescent reaction with alkali metals (e.g., sodium, potassium), ammonia, arsenic, butyric acid (above 100°C), chlorine trifluoride, hydrogen sulfide + heat, sodium + heat, and sulfur. Incompatible with N,N-dimethylformamide. 

A diethyl ether cool flame, followed by a second-stage flame can be stabilized in a tube [74] or above a burner [75—77], and Agnew and Agnew [78] have used a quartz probe to remove samples from various positions in these flames. Numerous products were identified including not only carbon monoxide, carbon dioxide, water, various saturated and unsaturated hydrocarbons, acetaldehyde, formaldehyde, methanol, ethanol and acetic acid, but also ethyl formate, ethyl acetate, acetone, propionaldehyde and 2-methyl-l 3-dioxacyclopentane. The main features of the analytical results were... 

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