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Diethyl malonate is used in organic synthesis for the preparation of alpha-aryl malonates, mono-substituted and di-substituted acetic acid, barbiturates and artificial flavorings. It is also involved in the synthesis of pharmaceuticals like chloroquine, butazolidin and barbital. It acts as intermediate in the synthesis of vitamin B1, vitamin B6, non-steroidal anti-inflammatory agents agrochemicals and perfumes. In Knoevenagel condensation reaction, it reacts with benzaldehyde to get diethyl benzylidenemalonate.
For phase-transfer monoalkylation of the active methylene group see, e.g. (18-crown-6): Synthesis, 37 (1977); and (BTEAC): Org. Prep. Proced. Int., 26, 469 (1994). Solid-liquid phase transfer alkylation has been promoted by microwave irradiation: Synth. Commun., 25,1761 (1995). Dialkylation can also occur in the presence of BTEAC: Synthesis, 54 (1985); Org. Synth. Coll., 7, 411 (1990), to give cyclopropane derivatives. Stereoselective alkylation has been achieved under particularly mild conditions with secondary alkyl mesylates in the presence of Cesium fluoride, 12885 in DMF; complete inversion occurs at the secondary alkyl carbon: J. Org. Chem., 60, 2627 (1995); see also: Synlett, 499 (1998).
Substituents can also be introduced by Michael addition; see e.g.: Org. Synth. Coll., 8, 467 (1993).
Arylation occurs with aryl bromides in the presence of CuI: Gazz. Chim. Ital., 122, 511 (1992).
C-Acylation of malonic esters is normally carried out by reaction of the Mg derivative with an acid chloride. A convenient method using a combination of MgCl2 and triethylamine was introduced by Rathke: J. Org. Chem., 50, 2622 (1985); see also Triethylamine, A12646 for discussion of this system:
A number of procedures have been devised for the direct conversion of malonic esters to acetic esters (decarboalkoxylation), in a single step of which heating in wet DMSO is perhaps the simplest: J. Org. Chem., 43, 138 (1978). See also 1,4-Diazabicyclo[2.2.2]octane, A14003.
Semmes, J. G.; Bevans, S. L.; Mullins, C. H.; Shaughnessy, K. H. Arylation of diethyl malonate and ethyl cyanoacetate catalyzed by palladium/di-tert-butylneopentylphosphine. Tetrahedron Lett. 2015, 56 (23), 3447-3450.
Ramesh, P.; Shalini, B.; Fadnavis, N. W. Knoevenagel condensation of diethylmalonate with aldehydes catalyzed by immobilized bovine serum albumin (BSA). RSC Adv. 2014, 4 (15), 7368-7373.
Dichiarazioni di rischio (UE): H227
Dichiarazioni precauzionali: P260-P201-P280a-P304+P340-P405-P501a
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