Synthesis of some acetals of cyclopropane dialdehydes

Conclusions The bis (dimethyl) acetal of fumaric dialdehyde adds dichlorocarbene under the conditions of a two-phase system only if at least a 10-fold excess of chloroform is used.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2803–2805, December, 1978.     

Structure and energetics of cyclopropane carboxaldehyde

We use the energies obtained by a focal point analysis including extrapolation from results with basis sets cc‐pVnZ and aug‐cc‐pVnZ with n up to 4 and correlation corrections through CCSD(T), to estimate thermodynamic functions for the syn and anti isomers of cyclopropane carboxaldehyde (CPCA). These agree with values obtained by well‐established thermochemical schemes CBS‐QB3 and G4. The structures obtained in these studies also conform to the best experimental determination of the rotational constants in the gas phase. The kinetics of gas phase interconversion of the syn‐ and anti‐isomers of CPCA have been studied by a chirped‐pulse dynamic rotational spectroscopy. Computational modeling of the internal rotational potential allows the estimate of the interconversion rates by statistical (RRKM) methods. RRKM rates using a range of barrier heights including a CBS‐Q estimate are more than 10× the rates deduced from the dynamical rotational spectra. This suggests that nonstatistical effects may be limiting the rate. Detailed study of the interconversion potential by a variant of the focal point analysis suggests that previous estimates of the barrier may be too low, and thus, the inferred rice‐ramsperger‐kassel‐marcus (RRKM) rate could be too high. These results cast some doubt on the presence of nonstatistical effects and suggest that molecular dynamics studies should be conducted to characterize the energy flow in detail. © 2013 Wiley Periodicals, Inc.     

Synthesis and some properties of cyclic acetals of malonaldehyde

The Lewis acid-catalyzed addition of cyclic orthoformates to vinyl ethyl ether, which leads to the formation of malonaldehyde acetals, was studied. It is shown that of the linear-cyclic malonaldehyde acetals, 2-(2,2-diethoxyethyl)- and 5,5-dimethyl-2-(2,2-diethoxyethyl)-1,3-dioxanes are stable. The transacetalization of 1,1,3,3-tetraethoxypropane with 1,2- and 1,3-diols, which leads to the formation of cyclic malonaldehyde acetals, was studied. The physicochemical constants of the acetals were determined, and their ¹H and ¹³C NMR spectra are described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 459–463, April, 1983.     

Condensation of acetals of gem-dichlorocyclopropane aldehydes with β-bromovinyl ethyl ether

Conclusions A convenient method was developed for the synthesis of the previously unknown -bromovinylcyclopropane aldehydes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2637–2639, November, 1979.     

Synthesis and properties of cyclopropane derivatives of polybutadienes

Polymer products containing methoxycarbonyl-substituted cyclopropane groups in macromolecules with degrees of functionalization up to 40% have been obtained through the interaction of polybutadiene with methyl diazoacetate in an organic solvent in the presence of an organometallic catalyst. The comparative catalyst activity in the reaction of cyclopropanation of polybutadiene has been estimated. The incorporation of methoxycarbonyl-substituted cyclopropane groups into polydiene units results in substantial changes in the polymer properties: solution viscosity, melt flow, glass-transition temperature, and thermal stability.     

Synthesis of 2,4-dimethyl-cyclohex-3-ene carboxaldehyde derivatives with olfactory properties

Oxidation of the starting aldehyde 1 led to the acid 6 which was esterified in neutral conditions to give the esters 7–11. A Wittig reaction with 1 and various phosphoranes led to compounds 12–15 bearing a functionalized unsaturated side chain. Acidic hydrolysis of 15 gave the aldehyde 16 homologue of 1. Ketone 19 was obtained by Grignard reaction between 1 and the bromoacetal 17 followed by oxidation of the alcohol 18. Intramolecular cyclization of 18 and 19 gave the lactone 22 and the pentenone 20, respectively. Analysis of the olfactory properties of all these compounds revealed that esters 7, 9, ether 15 and aldehyde 16 could be used in the formulation of flowery or fruity compositions.     

Synthesis of gem-dichlorocyclopropane and 1,3-dioxane derivatives from divinylbenzene

Russian Chemical Bulletin - The Prins reaction and cyclopropanation of the light fraction obtained by distillation of the technical grade divinylbenzene and consisting of a mixture of 1,3- and...     

Preparation of isopropylidene acetals from butane-1,2,4-triol and its cyclopropane congeners

Features of isopropylidene acetal synthesis from butane-1,2,4-triol and its cyclopropane congeners were studied. Procedures for the preparation and purification of the respective acetonides have been developed.     

Synthesis and some transformations of bicyclic γ-lactones with a fused cyclopropane ring

Reductive cyclization of 4-hydroxymethyl-5,5-dimethyl(or pentamethylene)-2,5-dihydrofuran-2-ones by the action of sodium tetrahydridoborate gave bicyclic compounds in which the lactone ring is fused to a cyclopropane ring. Hydrolysis of the products with aqueous sodium hydroxide resulted in the formation of the corresponding disodium cyclopropane-1,1-dicarboxylates, which reacted with alkyl halides to produce the diesters. Acid hydrolysis of the fused systems was accompanied by opening of the cyclopropane ring with formation of 4-chloromethyl-5,5-dimethyl-2-oxotetrahydrofuran-3-carboxylic acid.     

Electron-impact-induced fragmentation of some diterpenoid acetals

Study of the low and high-resolution mass spectra of a series of diterpenoid acetals, including both positional isomers and stereoisomers, has permitted the proposal of some characteristic fragmentation pathways leading to analytically distinctive peaks. The mass spectrum was particularly informative in the assignment of structure to an unexpected rearrangement product (V).     

Synthesis and some properties of o-borylphenylphosphine

(o-Dibutylboryl)diphenylphosphine, containing tricoordinated phosphorus and boron atoms, was obtained for the first time in the reaction of (o-bromo-phenyl)diphenylphosphine, butyllithium, and butylchloroborane. Analysis of the spectral indices and their comparison with reported data showed the lack of stabilizing donor-acceptor interactions between phosphorus and boron atoms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2397–2399, October, 1991.