Methyl Cyanoacetate Research Articles

A novel synthetic route to highly cross-linked poly(alkylvinylether)s

p-(2-Vinyloxyethoxy)benzylidenemalononitrile (3) and methyl p-(2-vinyloxyethoxy)benzylidenecyanoacetate (4) was prepared by the condensation of p-(2-vinyloxyethoxy)benzaldehyde with malononitrile or methyl cyanoacetate, respectively. Vinyl ether monomers 3 and 4 polymerized quantitatively with radical initiators in γ-butyrolactone solution at 65°C. The trisubstituted terminal double bond participated in the vinyl polymerization and radical polymerization of 3 and 4 led to swelling polymers 5 and 6 that were not soluble in common solvents due to cross-linking. Under the same polymerization conditions ethyl vinyl ether polymerized well with model compounds of p-methoxybenzylidenemalononitrile and methyl p-methoxybenzylidenecyanoacetate, respectively, to give 1:1 alternating copolymers 9 and 10 in high yields. Alternating copolymers 9 and 10 were soluble in common solvents such as acetone and DMSO, and the inherent viscosities of the polymers were in the range of 0.36–0.74 dL/g. Films cast from acetone solution were cloudy and tough and Tg values obtained from DSC thermograms were in the range of 59–60°C.

Structures and fluorescence of secondary products produced from the cope‐knoevenagel reaction of 2‐phenylpropionaldehyde with methyl cyanoacetate

AbstractThe Cope‐Knoevenagel reaction of 2‐phenylpropionaldehyde (7) with methyl cyanoacetate (8) produced methyl (E)‐2‐cyano‐4‐phenylpent‐2‐enoate (9) and the two highly fluorescent secondary products, 2‐amino‐3‐carbomethoxy‐6‐phenyl‐4‐(1‐phenylethyl)pyridine (10) and 3‐cyano‐6‐phenyl‐4‐(1‐phenylethyl)‐2‐pyridone (11). The structure of 10 was determined by X‐ray crystallography while the structure of 11 was confirmed by the conversion of 9 into 11. The mechanism of their formation is discussed. Fluorescence of 10 and 11 and the related compounds are also described.

An Unequivocal Synthesis of 4-Amino-1,5,6,8-tetrahydropyrido[2,3-d]pyrimidine-2,7-diones and 2-Amino-3,5,6,8-tetrahydropyrido[2,3-d]pyrimidine-4,7-diones

An unequivocal set of procedures for the synthesis of 4-amino-1,5,6,8-tetrahydropyrido[2,3-d]pyrimidine-2,7-diones (7) and 2-amino-3,5,6,8-tetrahydropyrido[2,3-d]pyrimidine-4,7-diones (8), in a maximum of four steps from an α,β-unsaturated ester 1, is reported. Thus, the acid hydrolysis of the 2,4-diaminopyrido[2,3-d]pyrimidines 3 yields the 4-amino-2-oxopyrido[2,3-d]pyrimidines 7 while the cyclization of the Michael adducts 9 (formed by reaction of 1 and methyl cyanoacetate) with guanidine affords the corresponding 2-amino-4-oxopyrido[2,3-d]pyrimidines 8. Both isomers were also obtained by hydrolysis of the 4-amino-2-bromo- and 2-amino-4-bromo-5,6-dihydropyrido[2,3-d]pyrimidin-7(8H)-ones 5 and 6, respectively.

Magnesium methoxide complexation in the control of chemical reactions

The insolubility of complex magnsium chelates makes experimentation difficult, so smaller complexes are used as models for NMR and deuteriation studies. Treatment of methyl cyanoacetate with magnesium methoxide however does not give a simple chelate but a novel kinetic Claisen condensation product, methyl 2,4-dicyano-3-hydroxybut-2-enoate, sequestrated as its magnesium-derivative. Replacement of magnesium methoxide by the non-chelating base sodium methoxide gives the known thermodynamic 1,2-addition product, dimethyl 3-amino-2-cyanopent-2-enedioate. A crossed Claisen product, dimethyl 2-cyano-3-hydroxybut-2-enedioate, has been obtained from diethyl oxalate and methyl cyanoacetate in the presence of magnesium methoxide. However, replacement of the oxalate by phenyl cyanomethyl sulfoxide gives a crossed 1,2-addition product, methyl 3-amino-2-cyano-4-phenylsulfinylbut-2-enoate.Reactions between phenyl cyanomethyl sulfoxide or phenylsulfinylacetone and methyl 2-methoxy-methyleneacetoacetate are carried out in the presence of varying amounts of sodium and magnesium methoxides. The products are pyrones, pyridones and aminobenzoates. When sodium methoxide is used in the phenylsulfinylacetone reaction the major product is a pyridine, but with magnesium methoxide it is a hydroxyaminobenzoate. This dichotomy may be explained as a consequence of magnesium complexation by the substrate.

Synthesis and cationic polymerization of ethyl vinyl ethers containing the NLO-phores p-oxybenzylidenemalononitrile and p-oxybenzylidenecyanoacetate in the side chain

p-(2-Vinyloxyethoxy)benzylidenemalononitrile 3 and methyl p-(2-vinyloxyethoxy)benzylidenecyanoacetate 4 was prepared by the condensations of p-(2-vinyloxyethoxy)benzaldehyde 2 with malononitrile and methyl cyanoacetate, respectively. Monomers 3 and 4 were polymerized with cationic initiators to obtain polymers with the NLO-phores p-oxybenzylidenemalononitrile and p-oxycyanocinnamate in the side chain. The resulting polymer 6 was soluble in acetone but the polymer 5 was not soluble in common solvents. The inherent viscosities of polymer 6 were in the range of 0.20-0.30 dL/g in acetone. Solution-cast films were clear and brittle, showing Tg values in the range of 61–70°C.

Electrochemical co-oxidation of C-H acids and methanol as a new route to functionalized cyclopropanes

Electrolysis of dimethyl malonate or methyl cyanoacetate in methanol in the presence of LiCl in an undivided cell leads to formation of 1,1,2,2-cyclopropanetetracarboxylic derivatives.

Acylaminoacetyl derivatives of active methylene compounds. 3. C‐Acylation Reactions via the Hippuric Acid Azlactone

AbstractThe C‐acylation reactions of the active methylene compounds, methyl cyanoacetate and Meldrum's acid, with hippuric acid, using the DCC activation and the mixed anhydride conditions, are shown to proceed through initial formation of 2‐phenyl‐5(4H)‐oxazolone, the hippuric acid azlactone. The conditions of these reactions using the azlactone as the acylating agent were investigated and discussed.

Studies on Heterocyclic Enaminonitriles, XVI. Reactions of 2‐Benzamido‐4,5‐dihydro‐3‐thiophene‐ and ‐3‐furancarbonitriles with Cyanomethylene Compounds

AbstractThe reactions of 2‐benzamido‐4,5‐dihydro‐3‐thiophene‐ and ‐3‐furancarbonitriles (1 and 2) with ethyl or methyl cyanoacetate and malononitrile (2 equiv.) in the presence of sodium hydride (1 equiv.) in dimethyl sulfoxide at 140°C gave ethyl or methyl cyano[3‐cyano‐4,5‐dihydro‐2(3H)‐thienylidene‐ and ‐furanylidene]acetates (3a or 3b and 4a or 4b) and [3‐cyano‐4,5‐dihydro‐2(3H)‐thienylidene‐ and ‐furanylidene]propanedinitriles (3c and 4c). On the other hand, compound 2 reacted with malononitrile (2 equiv.) in the presence of sodium hydride (1 equiv.) in dimethylformamide at room temp. to give [(2‐amino‐4,5‐dihydro‐3‐furanyl)(benzamido)‐methylene]propanedinitrile (5). The same treatment of 2 with ethyl or methyl cyanoacetate followed by reaction with acetic anhydride gave ethyl or methyl 6‐acetoxy‐3‐benzamido‐2,4‐dicyano‐2‐hexenoate (6a or 6b). magnified image

Investigation of Methyl Methacrylate-Styrene Copolymerization Systemin the Presence of Methyl Cyanoacetate

Abstract The copolymerization of the methyl methacrylate-styrene system was studied at 75°C in the absence of any free radical initiator in pure methyl cyanoacetate (MCA) and in a methyl cyanoacetate/benzene mixture. The reactivity ratios were calculated by the YBR and EVM methods. An increasing dielectric constant of the reaction medium influenced the reactivity ratios and enhanced the alternating tendency of monomers in a copolymer. A comprehensive comparative study of the r-parameters achieved for these copolymer systems with the reactivity coefficient values for the same monomer system initiated by free radical initiators and With those obtained for thermal bulk in pure cyclohexanone and in a cyclohexanone/cyclohexane mixture are presented. It was found that the initiating activity of MCA closely resembles those of free radical initiators. The specific interactions of methyl methacrylate monomer and methyl cyanoacetate are explained by the facts that the reactivity ratios obtained for the monomer syst...

Stereoselectivity of Michael Addition to 3-Phenyl-1-(η6-o-tolyltricarbonylchromium)propenone

The stereoselectivity of the Michael addition of several C-nucleophiles to 3-phenyl-1-(η6-o-tolyltricarbonylchromium)propenone has been studied. The ratio of diastereoisomers formed varied from 65 : 35 (malonodinitrile), 72 : 28 (methyl cyanoacetate) and 78 : 22 (nitromethane) and to 90 : 10 (dimethyl malonate). The ratio of diastereoisomers 63 : 37 was found even when addition of dimethyl malonate was carried out at 75 °C in methanol using piperidine as the catalyst. The (S,R) or (R,S) configuration of the main pair of isomers was proved by the X-ray analysis of the dimethyl malonate adduct.

One-Step Synthesis of 2-Amino-3-furancarboxylic Acid Derivatives from 2-Furancarbaldehyde

Reaction of derivatives of 2-furancarbaldehyde or 2-acetylfuran with malononitrile, methyl cyanoacetate or cyanoacetamide in the presence of secondary amines afforded derivatives of 2-amino-3-furancarboxylic acid in 45 - 88% yields.

Product diversion by magnesium chelation in the chemistry of cynaoesters

Whilst treatment of methyl cyanoacetate with sodium methoxide in methanol gives the dimer 1, formed through 1,2-nitrile addition, the employment of magnesium methoxide in methanol as a chelating base, intercepts the Claisen product giving only 2 in excellent yield: a 'crossed example has also been found.

Investigation of Methyl Methacrylate-Styrene Copolymerization System in the Presence of Methyl Cyanoacetate

Investigation of Methyl Methacrylate-Styrene Copolymerization System in the Presence of Methyl Cyanoacetate

1,2,3,4-Tetrahydro-1,6-naphthyridines. Part 2. Formation and Unexpected Reactions of 1,2,3,4-Tetrahydro-7H-pyrano[4,3-b]pyridine-2,7-diones

The nucleophilic substitution of the enol methoxy group of pyridones (1) by methyl cyanoacetate led to (Z)-5-cyano-6-cyanomethoxycarbonylmethylenepiperidones (6), which underwent cyclization in acid medium to 1,2,3,4-tetrahydro-7H-pyrano[4,3-b]pyridine-2,7-diones (7). Surprisingly, the treatment of 7 with ammonia yielded the 5-cyano-6-cyanomethyl substituted pyridones (11) which were not accessible by reaction of 1 with NaCH 2 CN

Studies on pyrrolidones. Synthesis and N‐alkylation of β‐enaminoesters derived from pyroglutamic acid

AbstractThe condensation of iminoether 7, derived from pyroglutamic acid (4), with active methylene reagents such as Meldrum's acid or methyl cyanoacetate, lead to β‐enaminoesters 2. Solid‐liquid phase transfer N‐alkylation of these compounds is described.

Solubilities of carbon dioxide, hydrogen sulfide and sulfur dioxide in physical solvents

AbstractSolubilities expressed by Henry's law constants for carbon dioxide, hydrogen sulfide and sulfur dioxide in four physical solvents (propylene carbonate, N‐formyl morpholine, Selexol, and methyl cyanoacetate) have been measured at several temperatures ranging from 25°C to 70°C, using gas‐liquid chromatography. Thermodynamic properties including enthalpies and entropies of solution have been derived from the solubility data.

Concomitant Formation of Isomeric 1-, 2-, and 3-Substituted Heptafulvenes from 2-Substituted Tropones and Active Methylene Compounds

Abstract Condensations of methyl cyanoacetate and 4-nitrobenzyl cyanide with 2-isopropyl-, 2-methyl-, and 2-phenyltropones in Ac2O gave isomeric 1-, 2-, and 3-substituted heptafulvene derivatives. The mechanism of reaction was explained in terms of a remote nucleophilic attack of the active methylene compounds to acetoxycycloheptatrienylium salt, followed by [1,5] sigmatropic hydrogen shift and elimination of acetic acid.

Partial molar volumes of acidic gases in physical solvents and prediction of solubilities at high pressures

Partial molar volumes at infinite dilution for three acidic gases (carbon dioxide, hydrogen sulfide, and sulfur dioxide) in four physical solvents (propylene carbonate, methyl cyanoacetate, N-formyl morpholine, and Selexol) have been obtained using our new dilatometer. These partial molar volumes, in combination with the Henry's law constants obtained previously, have been used in the Krichevsky–Kasarnovsky equation for predicting the solubilities of acidic gases in physical solvents at high pressures. Keywords: partial molar volume, solubility, physical solvents.

Dimethylgold(III) Aryloxides and Alkoxides Having a Triphenylphosphine Ligand

Abstract Cis-dimethyl(aryloxo or alkoxo)(triphenylphosphine)gold(III), cis-AuMe2(OR)(PPh3) (R = Ph, tol, CH2CF3, CH(CF3)2) were isolated by the reaction of cis-AuMe2[(PPh3) with corresponding potassium aryloxides or alkoxides. Nucleophilic phenoxogold(III) smoothly traps phenol by hydrogen bond and can abstract a proton from methyl cyanoacetate, malononitrile and phenyl acetylene to give corresponding cis-dimethyl(organo)(triphenylphosphine)gold(III) complexes, cis-AuMe2(R′)(PPh3).

Tandem Michael reaction. Synthesis of bridged diketones

Addition of NaOMe, NaOEt, or NaOPr(i) to dispironaphthalenone 1 resulted in the formation of diketones 4a-c and 5a-c. The structure assigned to 4a was confirmed by conversion to the known hemiacetal 3. Similar addition of carbon nucleophiles like diethyl malonate, dimethyl malonate, methyl cyanoacetate, and ethyl cyanoacetate afforded diketones 4d-g. Formation of these compounds has been rationalized.