R. R. Muslukhov

First preparative synthesis of alumocyclopentanes involving zirconium complexes

M. Dzhemilev, A. G. Ibragimov, A. P. Zolotarev, R. R. Muslukhov, and G. A. Tolstikov UDC 542.97:547.514+547.256.2 We have recently published several communications on the carbometallation of ~-olefins using diethylmagnesium in the presence of catalytic amounts of Cp2SrCI 2 [i, 2]. Diethylalu ~ minum chloride by the action of TiCI~ or Ti(OBu) 4 [3], and triethylaluminum with two-compon- ent catalysts consisting of Cp2ZrCI 2 + 6Et2Mg or Cp2ZrCI 2 + 6(i-Bu)3Al [3]. In a continuation of a study of these reactions, we have established that, in contrast to the Cp2ZrCI 2 + 6Et=Mg catalyst, the reaction of Et3AI with ~-olefins, such as l-hexene, l-octene, and l-undecene, in the presence of Cp2ZrCl 2 taken in Et3Al:e-olefin:Cp2ZrCl 2 mole ratio equal to (100-120):100:2 at about 20~ over 6-8 h gives the corresponding alumocyclo- pentanes (Ia)-(!c) in 80-95% yields with high selectivity. Datta et al. [4] have proposed that the formation of alumocyclopentanes under the reac- tion conditions proceeds through the formation of zirconocyclopentanes according to scheme: EhAI q- Cp2ZrCl2 /- /\/\/--R -. C~Zr

Hydrochlorinated Derivatives of Syndiotactic 1,2-Polybutadiene

Chlorine-containing polymeric products with a degree of functionalization of up to 70% are synthesized through the hydrochlorination of syndiotactic 1,2-polybutadiene via carbon-carbon double bonds. The introduction of chlorine atoms into polydiene units causes substantial changes in the viscosity of polymer solutions, the flowability of the polymer melt, the glass-transition and flow temperatures, and the thermal stability of polymers. The hydrochlorinated derivatives of syndiotactic 1,2-polybutadiene demonstrate good adhesion with respect to steel and can be used in adhesive compositions.

NMR for Determining the Structure of New Polysulfones

Abstract The reactivity of N-allylated monomers of new structural types—N, N-diallyl-N′-acylhydrazines, 2,2-diallyl-1,1,3,3-tetraethylguanidiniumchloride, and tris(diethylamino)diallylaminophosphonium tetrafluoroborate—and chloride in reactions of free-radical homo- and copolymerization with sulfur dioxide has been studied. The structure of the obtained polysulfones has been identified by 13C NMR. The investigations carried out have shown that these new allyl monomers copolymerize with SO2, both double bonds participating with formation of cis-, trans-stereoisomeric pyrrolidine structures in a cyclolinear polymer chain. The cyclolinear copolymers obtained are soluble due to the intramolecular cyclization of allyl monomers during the formation of the polymer chain and to the absence of intermolecular cross-links.

Kinetics of oxidation of an arabinogalactan from larch (Larix sibirica L.) in an aqueous medium in the presence of hydrogen peroxide

The oxidation of an arabinogalactan in an aqueous medium under the action of hydrogen peroxide and dioxygen is accompanied by accumulation of carbonyl and carboxy groups in the oxidized polysaccharide macromolecules and derived oligomers. The addition of iron sulfate accelerates the radical oxidation of the biopolymer, while the addition of phenol inhibits the oxidation. The influence of the temperature and the initial H2O2 and arabinogalactan concentrations on the kinetics of the initial oxidation stage of the natural polysaccharide was studied.

Synthesis and conversions of metallocycles. 7. A novel approach to the synthesis of 3,4-dialkyl-substituted aluminacyclopentanes in the presence of Cp2ZrCl2

A novel approach was developed for the stereoselective synthesis of trans-3,4-dialkyl-substituted aluminacyclopentanes from α-olefins, metallic magnesium, and EtAlCl2 in the presence of catalytic amounts of Cp2ZrCl2. The hydrolysis and deuterolysis products of the 3,4-dialkyl-substituted aluminacyclopentanes obtained are only in the trans configuration.

Oxidation of Terpenoids with a Cyclohexanone Fragment by Performic Acid

Performic acid is a reactive, inexpensive, and available reagent for Baeyer–Villager oxidation of ketones that is used infrequently in the chemistry of cyclic terpene ketones, e.g., only for the oxidation of isocaranone [1] and allobetulone [2]. The goal of the present work was to expand the scope of this reagent for the oxidation of terpenoids with a cyclohexanone fragment. We found that Baeyer–Villager oxidation of 28-oxoallobetulin-3-one (1), carvomenthone (2), and menthone (3) by performic acid occurred regioand stereospecifically to give lactones 5–7, respectively. Oxidation of isomenthone (4) by H2O2–HCOOH caused racemization of the asymmetric center with the isopropyl substituent (probably due to keto–enol tautomerism under acidic conditions) to give a mixture of diastereomeric lactones 7 and 8 (1:1), in contrast with diastereospecific m-chloroperbenzoic acid [3].

Transformations of peroxide olefin ozonolysis products under the action of hydroxylamine and semicarbazide hydrochlorides in isopropyl alcohol

Hydroxylamine and semicarbazide hydrochlorides were shown to be efficient as reducing agents toward peroxide products of ozonolysis of various olefins with different degrees of substitution. The rate of the transformations aldehyde → aldehyde oxime → nitrile → ester upon treatment of peroxides with hydroxylamine hydrochloride in isopropyl alcohol was lower than in methanol.

Dichlorocyclopropane derivatives of syndiotactic 1,2-polybutadiene

Polymeric products containing hem-dichlorocyclopropane units with a degree of functionalization of up to 97% are synthesized via the reaction of syndiotactic 1,2-polybutadiene with dichlorocarbene obtained by the interaction of chloroform with an aqueous solution of sodium hydroxide in the presence of a phase-transfer catalyst. The incorporation of dichlorocyclopropane groups into units of polydiene substantially changes its molecular mass and polydispersity, the solution viscosity, the polymer melt flowability, and the glass-transition temperature and flow temperature of the polymer.

Chlorinated Polymers Based on Low-Molecular-Mass 1,2-Polybutadiene

It has been shown that chlorinated polymer products based on low-molecular-mass 1,2-polybuta-diene can be produced by incorporation of chlorine and hydrogen chloride via carbon-carbon double bonds of polymer macromolecules. The functionalization of polydiene by halogen atoms results in such significant changes in the physicochemical properties of the polymer as solution viscosity and flowability of the polymer product. 1,2-Polybutadiene modified by chlorination and hydrochlorination shows good adhesion to steel and can be used as a component of adhesive compositions, which are used in the production of PVC adhesive films for insulation of main pipelines.

Synthesis of the Promising Chiral Synthon Isopropyl-4R-Methyl-6-Iodohexanoate from L-(-)-Menthol

A synthesis of the promising optically pure synthon isopropyl-4R-methyl-6-iodohexanoate based on ozonolytic transformation of the product of regiospecific dehydratation of L-(-)-menthol, (R)-p-menth-3-ene, into 2,6R-dimethyl-8-hydroxyoctan-3-one was proposed.