Diethyl succinate: condensation reaction with

The condensation of aldehydes and ketones with succinic esters in the presence of sodium ethoxide is known as the Stobbe condensation. The reaction with sodium ethoxide is comparatively slow and a httlo reduction of the ketonic compound to the carbinol usually occurs a shorter reaction time and a better yield is generally obtained with the more powerful condensing agent potassium ieri.-butoxide or with sodium hydride. Thus benzophenone condenses with diethyl succinate in the presence of potassium [Pg.919]

Succinic esters condense with aldehydes and ketones in the presence of bases, eg, sodium alkoxide or piperidine, to form monoesters of alkybdenesuccinic acids, eg, condensation of diethyl succinate with acetone yields ethyl 2-isopropyhdenesuccinate (eq. 3). This reaction, known as Stobbe condensation, is specific for succinic esters and substituted succinic esters (98,99). 

I. 2,5-Dicarbethoxy-1,4-cyclohexanedione (7) A 500-ml, three-necked, round-bottom flask is fitted with a condenser (drying tube) and arranged for magnetic stirring. A solution of sodium ethoxide is prepared in the flask by the addition of sodium (9.2 g, 0.4 g-atom) in small pieces to 90 ml of absolute ethanol. The mixture is heated at reflux for 3 hours (oil bath) to complete the reaction. Diethyl succinate (34.8 g, 0.2 mole) is added to the hot solution in one portion exothermic ) and the mixture is refluxed for 24 hours. (A pink precipitate forms and persists during the reflux.)... 

Hydroxybenzaldehyde, condensation with hydantoin, 43, 49 5-(/>-Hydroxybenzal)hydantoin, 43, 49 3-Hydroxydnchoninic add, 40, 55 reaction with diethyl succinate to yield 3-hydroxyquinoline, 40, 56... 

A. Z,5-DicaThelhoxy-l,4-cyclohexanedione. A solution of sodium ethoxide is prepared by adding small pieces of sodium (92 g., 4 g. atoms) as rapidly as possible to 900 ml. of commercial absolute ethanol contained in a 3-1., three-necked, round-bottomed flask equipped with two stoppers and a reflux condenser fitted with a drying tube packed with calcium chloride and soda lime. The reaction is completed by heating the mixture under reflux for 3-4 hours (Note 1). To the hot solution is added diethyl succinate (348.4 g., 2 moles) (Note 2) in one portion Caution Exothermic reaction), and the mixture is heated under reflux by maintaining the original bath temperature for 24 hours. A thick pink-colored precipitate is formed almost immediately and remains throughout the reaction. 

Dicarbethoxy-l,4-cyclohexanedione has been prepared by the self-condensation of diethyl succinate by use of sodium or sodixim ethoxide catalyst (with or without a solvent) and by reaction of ethyl 4-bromo-3-ketobutanoate or ethyl 4-chloro-3-ketobutanoate with sodium ethoxide in ethanol. 

CH2,CH2,C02Et. From the latter the three-carbon unit of diethyl succinate may be recognised, and the Stobbe condensation is a suitable illustration of this process. Thus the reaction of aldehydes or ketones with succinic esters in the presence of potassium t-butoxide (or with sodium hydride) gives alkylidene-succinic acid esters (25). The reaction is somewhat slower in the case of the less basic sodium ethoxide. 

Sommelet reaction, 33, 93 Sorbic acid, 5-hydroxy-/3-methyl, J-lactone, 32, 57 Stannic chloride, 33, 91 Stearic acid, 34, 15 Stearone, 33, 84 cis-Stilbene, 33, 88 fraws-Stilbene, 33, 89 Stirrer, for caustic fusion, 30, 104, 105 seal for, 30, 54 Stobbe condensation, 30, 18 Styrene, 33, 72 34, 85 reaction with sulfuric acid, 35, 83 Styrene dibromide, 30, 73 Styrene oxide, 31, 3 0-Styrenesulfonyl chloride, 34, 85 Succinic acid, 34, 44 Succinic acid, < -benzhydrylidene-, a-ETHYL ESTER, 30, 18 CLNNAMYL-, 31, 85 DIPHENYL ESTER, 34, 44 HEPTANOYL-, DIETHYL ESTER, 34, 51 PHENYL-, 30, 83 Succinic anhydride, 34, 40 SUCCINONITRILE, a, -DIPHENYL-, 32, 63 Sulfide, methyl 2-thienyl, 35, 85 Sulfonation of styrene, 34, 85 Sulfonyl chloride, from sodium sulfonate, 34, 85... 

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