The Addition of Dimethylamine to Benzoquinone

Abstract

Nord, el al.,1 condensed acetaldehyde with magnesium aluminum alkoxide catalysts ánd isolated from the reaction product the monoacetate of l, 3-butanediol. No mention is made in their papers of the ethyl ester of /3-hydroxybutyric acid which we have found to be present in the reaction mixture in approximately equimolecular proportion to the monoacetate of 1,3-butanediol. Similar proportions of the diol and the hydroxy acid have also been found in an oily by-product obtained in the commercial preparation of ethyl acetate from acetaldehyde.2Experimental.-The procedure adopted for separating the constituents of the high-boiling oils was as follows:(1) Acid hydrolysis with excess water and butanol: the mixture was heated in a flask provided with a packed distillation column. The overhead temperature was kept at the boiling point of the butyl acetate-butanol-water ternary azeotrope by adjusting the reflux ratio. The estercontaining top layer of the distillate was drawn off while the water layer was decanted back to the flask. This was continued until the temperature could no longer be kept below 90°by refluxing. The excess butanol was then removed in the same manner at a temperature of 92°.(2) Neutralization and saponification: the saponification equivalent of the aqueous residue was determined, and just sufficient sodium hydroxide was added in 10% solution to neutralize the free acid and saponify the remaining esters. The mixture was boiled for an hour and cooled.(3) Filtration to remove any resinous by-products. (4) Vacuum distillation of filtrate: the excess water Notes Vol. 70 under the above conditions but benzoquinone (and perhaps the intermediate quiñones) can be. If the concentration of cupric ion is significantly diminished such oxidations take place and the yield is less. In the presence of 0.01 mole of cupric acetate the oxygen -absorption was about the same but the bisaminoquinone was then obtained in 72-76% yield.

Kinetics and Byproducts of the Liquid-Phase Oxidation of Phenol to p-Benzoquinone Catalyzed by CuCl2

“…When DMF was used as solvent, the reaction mixture, diluted with water, was extracted by methylene chloride, the organic layer washed by sodium hydroxide to remove phenols, and the solvent evaporated to give a red residue identified as 2,5-bisdimethylamino-p-benzoquinone (always in small amounts). It had a correct elemental analysis, melting point, and an UV spectrum in agreement both with literature data (Braude, 1945) and with a sample prepared by known methods (Baltzly and Lorz, 1948;Martynoff and Tsatsas, 1947). The NMR spectrum showed two singlets at <5 (ppm) 3.30 (methyl protons) and 5.45 (ring protons), with intensity ratio 6:1.…”

An Efficient Synthesis of Functionalized Helicenes

“…Absolute Configuration of 11c and the Addition of Prolinol to it. ( S )-(+)-2-(Hydroxymethyl)pyrrolidine (“prolinol”) 20 combines with 11c as summarized in eq 8, giving in 82% yield a single structural isomer, shown below to be 15 . If 11c is racemic, it gives 15 as a mixture of diastereomers, which can be separated by chromatography.…”

Aerobic Copper-Catalyzed Organic Reactions

“…Amine nucleophiles can also be employed in the oxidation, substitution, and oxidation sequence. In 1948, it was determined the use of copper salts in the double addition of dimethylamine to benzoquinone allows for much higher reaction yields, because the starting quinone was no longer responsible for oxidizing the nucleophilic addition products . Further investigation of this method showed that the reaction was amenable to a number of dialkyl secondary amines (Scheme ) …”