Levina, R. Ya. et al. published their research in Zhurnal Obshchei Khimii in 1954 | CAS: 10203-58-4

Diethyl isobutylmalonate (cas: 10203-58-4) belongs to esters. Carboxylic acid esters of low molecular weight are colourless, volatile liquids with pleasant odours, slightly soluble in water. Many esters have the potential for conformational isomerism, but they tend to adopt an s-cis (or Z) conformation rather than the s-trans (or E) alternative, due to a combination of hyperconjugation and dipole minimization effects. The preference for the Z conformation is influenced by the nature of the substituents and solvent, if present. Lactones with small rings are restricted to the s-trans (i.e. E) conformation due to their cyclic structure.Product Details of 10203-58-4

Barbituric acids. I. Synthesis of methylenebis(5-alkyl-barbituric acids) was written by Levina, R. Ya.;Godovikov, N. N.. And the article was included in Zhurnal Obshchei Khimii in 1954.Product Details of 10203-58-4 This article mentions the following:

CH2(CO2Et)2 with paraform and 10% alc. KOH gave 60-70% CH2[CH(CO2Et)2]2 (I), b5 174-5°, n20D 1.4425, d20 1.119; mercuration with Hg(OAc)2 gave the di-HgCl derivative, decompose 165-7° (from EtOH-Me2CO). I (34 g.) added to 4.6 g. Na in 150 ml. dry EtOH, then RX added dropwise (the heating being interrupted for the addition), and the mixture heated until the basic reaction had nearly disappeared gave by the usual treatment the following (EtO2C)2CRCH2CR'(CO2Et)2, (R, R’, % yield, b.p./mm., and n20D shown): Me, Me, 30.8, 190-1°/10, 1.4470; H, Me, 11.5, 78-9°/10, 1.4132; H, Et, 30.5, 74-5°/3, 1.4152; Et, Et, -, – (m. 62-3°), -; H, Pr, 32.3, 114-16°/3, 1.4198; Pr, Pr, 40, 206-8°/11 (m. 41-2°), -; Bu, Bu, 37.4, 198-9°/5, 1.4522; H, Bu, 30, 124-8°/18, 1.4226; H, PhCH2, not isolated; PhCH2,PhCH2, 17, 240-5°/4 (m. 44°), -. The reactions yielded minor amounts of the polymers of I, m. 156° [cf. Bottomley and Perkin, J. Chem. Soc. 77, 306(1900)]. Alkylation attempts with iso-PrX, iso-BuX, iso-AmX (where X is halide), and cyclohexyl chloride, failed; only the corresponding RCH(CO2Et)2, polymer of I, and unreacted starting material were isolated. The reaction of the dialkylated esters with urea in the presence of EtONa yielded the following, 5,5′-methylenebis(5,1-alkylbarbituric acids) (alkyl group shown): H, 45%, decompose 300°; Me, 44.8%, m. 252-3°; Et, 61.7%, decompose 364-5°; Pr, 56.2%, decompose 358-9°; Bu, 25.4%, m. 235-8°; PhCH2, 15.3%, m. 210-11°. The ring closures were run 18 hrs. at 120°. In the experiment, the researchers used many compounds, for example, Diethyl isobutylmalonate (cas: 10203-58-4Product Details of 10203-58-4).

Diethyl isobutylmalonate (cas: 10203-58-4) belongs to esters. Carboxylic acid esters of low molecular weight are colourless, volatile liquids with pleasant odours, slightly soluble in water. Many esters have the potential for conformational isomerism, but they tend to adopt an s-cis (or Z) conformation rather than the s-trans (or E) alternative, due to a combination of hyperconjugation and dipole minimization effects. The preference for the Z conformation is influenced by the nature of the substituents and solvent, if present. Lactones with small rings are restricted to the s-trans (i.e. E) conformation due to their cyclic structure.Product Details of 10203-58-4

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics