Диэтилмалеата

Химические свойства

Diethyl maleate is a colorless clear liquid between the temperatures of -10°C (pour point) and 225°C (boiling point). Insoluble in water, soluble in ethanol and ether. its odor type is fruity and its odor at 100% is described as "fruity bananacitrus". It is prohibited by lFRA and theEU because of sensitization and is notused anymore as fragrance.

Вхождение

Has apparently not been reported to occur in nature.

Использование

Diethyl maleate can be used for the preparation of organophosphorus insecticide malathion. It is unsaturated polyester resins that are used in applications, such as reinforced glass fiber for boats, piping, bathtubs, roof panels, etc., and as protective coatings, finishes, and lacquers.

Определение

ChEBI: Diethyl maleate is a maleate ester resulting from the formal condensation of both carboxy groups of maleic acid with ethanol. A colourless liquid at room temperature (m.p. -10℃) with boiling point 220℃ at 1 atm., it is commonly used as a dienophile for Diels-Alder-type cycloaddition reactions in organic synthesis. It has a role as a glutathione depleting agent. It is a maleate ester and an ethyl ester. It derives from an ethanol.

Подготовка

Diethyl maleate is synthesized by the direct esterification of maleic anhydride and ethanol in the presence of sulfuric acid. Esterification is a commonly used reaction in organic synthesis.

Общее описание

Diethyl maleate is reported to occur in the cabernet sauvignon wine.

Синтез

5g maleic anhydride, 12g dehydrated alcohol, 0.3g acid zeolite, 15ml benzene are added to the reaction vessel, install water trap, reflux condensing tube, and thermometer on the reaction vessel, reflux water-dividing is carried out in heating, reaction reacts 30min again after occurring without the globule, stops heating, after normal temperature cooling 30min, release water layer, reaction solution washes with water, distill after drying, first steam front-end volatiles, the cut regathering 216 ~ 220 DEG C is product Diethyl maleate.

Метаболизм

α/β-Unsaturated compounds, such as diethyl maleate, react enzymically with gluta thione. The reaction has been demonstrated in fractions of rat liver (Boyland & Chasseaud, 1967) and avian liver (Wit & Snel, 1968). The enzyme differs from other known S-alkyl, S-aryl and S- epoxide transferase enzymes responsible for glutathione-conjugate formation (Boyland & Chasseaud, 1967). Diethyl maleate, administered parenterally to rats, reduced the hepatic glutathione content (Boyland & Chasseaud, 1970; Varga, Fischer & Szily, 1974). The latter workers also showed that diethyl maleate pretreatment of rats inhibited the glutathione conjugation of subsequently-adminis tered bromsulphthalein.