Pentene Sodium hydroxide

Compound 1, 2,2-diniethyl-4-pentenal, has been prepared by the Claisen rearrangement route described above and by reaction of isobutyraldehyde with allyl chloride in the presence of aqueous sodium hydroxide and a phase-transfer catalyst. Both routes are applicable to the synthesis of a variety of substituted 4-pentenals. 

Perfluoro-2 (1 ethyl 1 methylpropyl)-3-methyl-l-pentene, the major hex-amer of tetrafluoroethylene, reacts with sodium methoxide to yield an ester, whereas a stable crowded ketene is formed by reaction with sodium hydroxide [2d] (equation 23)... 

Methy l-2-penten-4-yn-1 -ol See 3-Methyl-2-penten-4-yn-l-ol Sodium hydroxide... 

Treatment of l,l,l-trichloro-2-penten-4-one with aqueous sodium hydroxide solution gives a good yield of 5-chloro- trans-2- cis-4-pentadienoic acid after standard acid work up. 

Experimental Details.20 1—A solution of 2.2 g. of o-erj/yield from sirupy D-erythrose without the isolation of intermediates) in 50 cc. of absolute ethanol was shaken with hydrogen at room temperature and atmospheric pressure in the presence of 0.2 g. of freshly prepared palladium black. The hydrogenation was interrupted after twenty minutes when 1.05 mole-equivalents of hydrogen had been absorbed and the rate had become slow. The sirup obtained after filtration and concentration was stirred with a mixture of 40 cc. of 1 AT sodium hydroxide solution and 10 cc. of ethanol. After the sirup had dissolved, the solution was added dropwise to a stirred mixture of 5 cc. of sulfuric acid and 7.5 cc. of water at 0°. The reaction mixture was then diluted with ice-water and neutralized by stirring with solid barium carbonate. After filtration, a few drops of glacial acetic acid were added to the filtrate and it was concentrated at reduced pressure to a sirup. The sirup was taken up in a small volume of 75% ethanol and 1.5 cc. of a-benzyl-a-phenylhydrazine added. Slow evaporation of this solution then gave 1.4 g. (59%) of D-erytkro-2-desoxypentose benzylphenylhydrazone. 7 After recrystallization from aqueous ethanol, the pure hydrazone melted at 127-128° and showed [a] — 17.7° in pyridine, c 2. 

Diketones. Coppcr(l) aoetylauetonate is a very effective copper catalyst for the insertion of an a-ketocarbene into C-C double bonds. Thus (3) can be obtained in 55% yield from the reaction of l-dia7 o-2-butanone (I) with isopropenyl acetate (2). When (3) is refluxed with 4% methanolic sodium hydroxide, 2,3-dimethyleydo-pentene-2-one (5) is obtained in 85% yield. 

The data presented in Table 1 also show that pH has an effect on activity in the W/CO2 microemulsion system. When 0.25M sodium hydroxide solution was used instead of pure water, the reaction rates for the hydroformylation of 1-pentene increased even though the temperature was decreased from 87 °C to 66 °C. The pH of the dispersed phase of a W/CO2 microemulsion system has been determined as 5 at a NaOH concentration of 0.25M and as 2.8 without NaOH [20], The increase in the rate might be due to the higher pH value aiding the formation of active species, such as the complete dissociation of the precursor to the monomeric species [19],... 

When propionaldehyde is warmed with sodium hydroxide, one of the products is 2-methyl-2-pentenal. Propose a mechanism for this reaction. 

Cyclic ethers can be prepared by the intramolecular Sj j2 reaction of a halogen-substituted alcohol such as a bromo alcohol. Proton transfer to a base such as sodium hydroxide gives a bromo alkoxide. If the solution is dilute, the alkoxide acts as a nucleophile, and an intramolecular reaction displaces a bromide ion. This process is shown below for 5-bromo-l-penten-l-ol. 

Methyl-l-Pen ten e. This olefin is produced commercially by dimeriza tion of propylene in the presence of potassium-based catalysts at 150—160°C and - 10 MPa. Commercial processes utilize several catalysts, such as sodium-promoted potassium carbonate and sodium- and alurninum-promoted potassium hydroxide (12—14) in a fixed-bed reactor. The reaction produces a mixture of C olefins containing 80—85% of 4-methyl- 1-pentene. 

Methyl-l-penten-3-one-l-ol 1 and glacial acetic acid in benzene was added to pyrrolidine to give 2-methyl-l-pen ten-1-[N-pyrrolidinyl]-3-one 2. Compound 2 when treated with oxalyl chloride and methanol was added, 3,5-dimethyl-2-methoxycarbonyl-4-pyrone 3 was produced. Treatment of compound 3 with sodium borohydride in methanol gives 3,5-dimethyl-2-hydroxymethyl-4-pyrone 4. Compound 4 was converted to 3,5-dimethyl-2-hydroxymethyl-4-pyridone 5 by heating compound 4 with aqueous ammonia in a sealed flask. Compound 5 was converted to 4-chloro-2-chloromethyl-3,5-dimethyl pyridine 6 by treatment with phosphorous oxychloride. Treatment of compound 6 with 5-methoxy-2-mer-captobenzimidazole in tetrahydrofuran gave 2-[2-(4-chloro-3,5-dimethyl pyridinyl)methylthio]-5-methoxy benzimidazole 7. When compound 7 was treated with potassium hydroxide in dimethyl sulfoxide containing methanol, 2-[2-(3,5-dimethyl-4-methoxypyridinyl)methylthio]-5-methoxy... 

A mixture of 200 g. (3.45 moles) of propionaldehyde and 200 g. of ether is cooled to 0° in a flask equipped with a condenser, a dropping funnel, a thermometer, and a stirrer. Ten milliliters of a 15% aqueous solution of potassium hydroxide is added with vigorous stirring. The reaction mixture is cooled so that the temperature does not rise above 10-12°. When the mixture has cooled to about 6-8° another portion of potassium hydroxide solution is introduced in the same manner as before. Base is added in this way until there is no longer an evolution of heat upon addition. This requires 70-80 ml. of base solution and 35-40 minutes. The aqueous layer is separated and washed with ether. The combined ethereal solutions are washed with dilute aqueous acetic acid and with dilute sodium bicarbonate solution and then dried over anhydrous sodium sulfate. The ether is distilled off on a water bath, and the residue is distilled through a 25-cm. Vigreux column. At a pressure of 80-l(K) mm., there is first obtained a mixture of unreacted propionaldehyde and 2-methyl-2-pentenal. The propionaldol is collected at 84-86°/ll mm., and the yield is around 55-60%. 

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