Diethyl methylenemalonate

Sometimes a 2 1 adduct is formed between enamines and unsaturated esters instead of the usual 1 1 adduct. This is the case when N,N-dimethyl-isobutenylamine (10) is allowed to react with diethyl methylenemalonate (39) producing compound 41 (37). This product is formed even when an... 

Amino-5-(pyridyl)thiophene-2-carboxylic acids (359) were reacted with diethyl methylenemalonate in DMF at 150°C for 2 hr to give N-[5-(pyridyl)thien-3-yl]aminomethylenemalonates (360) 61-62% yields [82-JAP(K) 116077],... 

Scheme 6.144 Thiochromanes prepared from the 121-catalyzed enantioselective tandem Michael-Knoevenagel reaction between 2-mercaptobenzaldehydes and diethyl methylenemalonates. The product configurations were not determined.

Perhydropyrimidine-2,4,6-trione (barbituric acid) has been incorporated into a polymer framework by modification of poly(diethyl methylenemalonate) (245) with urea (Scheme 119) (72NKKil79). The modified polymers (246) were useful for the adsorption of adenine. 

The a, jfl-unsaturated component for a Michael reaction may be formed in situ by an initial Knoevenagel reaction. An example is provided by the formation of tetraethyl propane-1,1,3,3-tetracarboxylate (14) from formaldehyde and diethyl malonate in the presence of diethylamine. Diethyl methylenemalonate (13) is first formed by the simple Knoevenagel reaction and this is followed by the Michael addition process. 

It can be seen from Tables 11 and 12 that the reactivity of the a-substituted acrylonitriles and acrylates toward the polystyryl radical (l/r2) increases slightly with the bulkiness of the substituent if the electronic factors are kept constant (COOMe < COOEt or COO/Bu), and also increases regularly with the electro-philicity of the olefin in each series. A noticeable exception to the last rule is methyl a-ethylthioacrylate H2C=C(SEt)COOMe, whose l/r2 value of >100 [70] is higher than the values for the very electrophilic methyl a-cyanoacry-late H2C = C(CN)COOMe (l/r2 = 100) [101] and diethyl methylenemalonate H2C = C(COOEt)2 (l/r2 = 33) [96,98]. As mentioned above its equivalent in the... 

DIETHYL METHYLENEMALONATE (Malonic acid, methylene-, diethyl ester)... 

At higher temperatures (about 70°) the diethyl ethoxy-methylmalonate formed tends to eliminate ethanol, forming diethyl methylenemalonate which is hydrogenated to diethyl methylmalonate. 

Diethyl methylenemalonate was first prepared by Perkin 4 from formaldehyde and malonic ester. An alternative procedure involving the reaction of methylene chloride or iodide with... 

Diethyl methylenemalonate is one of the most electrophilic vinyl monomers for which evidence exists of macrozwitterion formation with Lewis bases. Hopff, Lussi, and Allis-son29 carried out the first systematic work. They showed that diethyl methylenemalonate could be polymerized by amines, different types of amine having different initiating powers. 

Recently Johnston and Pepper31 35 investigated the polymerization of various esters of 2-cyanoacrylic acid in tetrahydrofuran. As with diethyl methylenemalonate traces of add had to be added to the monomers if uncontrollable spontaneous polymerization was to be avoided. 

Olefinic esters may be obtained directly by the Knoevenagel reaction. Alkyl hydrogen malonates are used in place of malonic acid. Decarboxylation then gives the ester directly as in the preparation of ethyl 2-heptenoate (78%) and methyl m-nitrocinnamate (87%). Alkyl hydrogen malonates are readily available by partial hydrolysis of dialkyl malonates. The use of malonic ester in the condensation leads to olefinic diesters, namely, alkylidenemalonates such as ethyl heptylidenemalonate (68%). A small amount of organic acid is added to the amine catalyst since the salts rather than the free amines have been shown to be the catalysts in condensations of this type. Various catalysts have been studied in the preparation of diethyl methylenemalonate. Increased yields are obtained in the presence of copper salts. Trimethylacetalde-hyde and malonic ester are condensed by acetic anhydride and zinc chloride. Acetic anhydride is also used for the condensation of furfural and malonic ester to furfurylidenemalonic ester (82%). ... 

The more sterically demanding (7) -2-butenyl)Fp cycloadds to diethyl methylenemalonate to give adduct (8) as a mixture of stereoisomers (equation 5). In this case the poor stereoselectivity may be due to the fact that the starting butenyl complex is a mixture of cis and trans isomers. Formation of the bicyclic ketone (9) ftom the reaction of (Tri -2-methallyl)Fp and 2-ethoxycarbonylcyclopentenone suggests that alkyl substituents can also be tolerated at C-2 of the (allyl)Fp unit (equation 6). The corresponding (t) -2-methoxyallyl)Fp fails to produce any cycloadduct with 2-ethoxycarbonylcyclohexenone or 2-cyclo-... 

Diethyl hercaptoacetal, 35, 51 Diethyl methylenemalonate, 38, 22 Diethyl methylmalonate, 38, 49 Diethyl methylphosphonate, 31, 34 Diethyl o-nitrobenzoylmalonate, 30, 71 Diethyl oxalate, 34, 13 37, 71... 

Introduction of arylsulfonylmethyl substituents into nitroheteroaromatic rings is of great practical value because these sulfones are versatile intermediates in organic synthesis. Nitrobenzyl aryl sulfones and their heterocyclic analogues can easily be transformed into the corresponding ethenyl derivatives by a simple alkylation with simultaneous elimination of arylsulfinate anion [125]. Diethyl methylenemalonate substituent can be introduced in the positimi 4- of 5-nitroimidazole via the VNS reaction of 5-nitroimidazole with the carbanion of chloromethyl phenyl sulfone [112, 124], followed by condensation of the obtained 4-(phenylsulfonyl)methyl derivative with diethyl bromomalonate or diethyl ketomalonate (Scheme 33) [126]. 

Another protecting group which has not yet gained a wide use is the /3,/3-diethylcarbonylethyI group. The thioether (11) is obtained by the addition of the tUoI to diethyl methylenemalonate (12). The protecting... 

Dinitroethane adds to dimethyl methylenemalonate in the presence of triethylamine to provide the dinitro-diester (93)/ Furthermore, nitroform is sufficiently acidic to add directly to diethyl methylenemalonate to give diethyl 2,2,2-trinitroethylmalonate in 87% yield. 

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