Yu. G. Gololobov

Silicon-containing esters of ?-cyanoacrylic acid: synthesis and properties

A number of cyanoacetates have been synthesized: cyanoacetoxymethyitrimethylsilane (1), cyanoacetoxymethylpentamethyldisiloxane (2), cyanoacetoxyetoxymethylpentamethyldisiloxane (3). They were converted by the Knoevenagel reaction to novel esters of a-cyanoacrylic acid (4–13) containing silicon atoms in the ester groups and having the general formula RCH=C(CN)COOCH2X (where R=H, 4-MeOC6H4, MeCH=CH, 2-furyl; X=SiMe3, SiMe2OSiMe3, CH2OCH2SiMe2OSiMe3). These compounds are capable of copolymerization with esters of cyanoacrylic acid which are the precursors to adhesives for cold curing.

Synthesis of bis(2-cyanoacrylates) from 2-cyanoacryloyl chloride and 2-butene- and 2-butyne-1,4-diols

The interaction of 2-cyanoacryloyl chloride with unsaturated 1,4-diols leads to bis(2-cyanoacrylates) with a double or triple C-C bond.

Kinetics and mechanism of the unusual insertion reactions of aryl isocyanates into the C-C bond of the phosphonium zwitter-ion derived by the reaction of triisopropylphosphine with ethyl 2-cyanoacrylate

The kinetics of the reactions of aryl isocyanates with the zwitterion formed by the addition of triisopropylphosphine to ethyl 2-cyanoacrylate in acetonitrile solution have been determined by a spectrophotometric method. It was established that the reaction is second order overall, first order with respect to each of the reagents. A mechanism is proposed that consists of an attack of the carbanionoid center of the phosphabetaine on the carbonyl carbon atom of the isocyanate group and nucleophilic attack of the isocyanate nitrogen atom on the carbonyl carbon of the ester group, with rupture of the appropriate CC bond, within the framework of a cyclic transition state.

Intramolecular electrophilic rearrangements in saturated acyclic systems. Reactivity of the zwitterion derived from triisopropylphosphine and ethyl 2-cyanoacrylate with respect to different types of electrophiles

The reactions of the zwitterion derived from triisopropylphosphine and ethyl 2-cyanoacrylate with mercuric chloride and aryl isothiocyanates containing Cl atoms in the ortho positions of the benzene ring follow an unusual pathway because this zwitterion represents “latent” triisopropylphosphine due to the reversibility of the reaction of triisopropylphosphine with ethyl 2-cyanoacrylate. The molecular structures of the adducts of triisopropylphosphine with 2,6-dichloro- and 2,4,6-trichlorophenyl isothiocyanates were confirmed by X-ray diffraction study. Protonation of the adduct of triisopropylphosphine with 2,6-dichlorophenyl isothiocyanate occurred at the nitrogen atom, whereas methylation with methyl trifluoromethanesulfonate afforded an S-methylation product. The results of X-ray diffraction study of the resulting compounds are presented.

New Aspects of the Staudinger React

Abstract The unique inductive control of the first step of the Staudinger reaction is used for determination of the inductive characteristics of various radicals. The data are used for elaboration of a new direction in a purposeful synthesis of phosphorus pesticides which are more safe for people and surroundings.

Reactions of distabilized β-dicarbonyl sulfonium and iodonium ylides with isocyanates

The reactions of tosyl isocyanate with diethyl diphenylsulfuranylidenemalonate, 2-dimethylsulfuranylidenedimedone, and 2-dimethylsulfuranylideneindane-1,3-dione afforded 1,3-ditosyl-5,5-diethoxycarbonylimidazolidine-2,4-dione and tosylimination products at the keto groups, respectively. Phenyliodonium ylides derived from diethyl malonate and ethyl acetate react with 3,4-dichlorophenyl isocyanate to form substituted oxazolin-2-ones.

C→N migrations of the ethoxycarbonyl group in reactions of ortho-substituted aryl isocyanates with the 1,3-zwitterion derived from triisopropylphosphine and ethyl 2-cyanoacrylate

The reactions of meta—para-substituted aryl isocyanates with phosphorus-containing 1,3-zwitterions, which proceed with the C→N migration of the CO2Et group to form the corresponding carbamates, were extended to ortho-substituted aryl isocyanates. The influence of the steric and electronic effects of the ortho substituents in the aromatic rings of aryl isocyanates on the ease of this rearrangement is qualitatively considered.

Molecular and crystal structure of 2-cyano-(2E)-pentadien-2,4-oic acid and ethyl-2-cyano-(2E)-pentadien-2,4-oate

X-ray study of 2-cyano-(2E)-pentadien-2,4-oic acid (1) and its ethyl ester (2) showed that the molecules of1 and2 in the crystalline phase form stacks by translating along the shortest crystallographic axis. The nature of the intermolecular interactions favoring the formation of such β-structures was analyzed within the framework of the Bader topological theory. Possible routes of topochemical reactions of compounds1 and2 are considered.

Formation of substituted pyrazolines in the reaction of C, N-diphenylnitrilimine with a zwitterion derived from triisopropylphosphine and ethyl 2-cyanoacrylate

The reaction of C,N-diphenylnitrilimine with a P-zwitterion derived from Pri3P and H2C=C(CN)CO2Et afforded the first representative of 2-pyrazolines containing the phosphonium group and products of the addition of nitrilimine to Pri3P and H2C=C(CN)CO2Et. The reaction of the P-zwitterion with C-4-nitrophenyl-N-phenylnitrilimine gave rise to a condensation product of one Pri3P molecule and two nitrilimine molecules. The three-dimensional structures of the compounds synthesized were established by X-ray diffraction analysis.

On the mechanism of C ⇄ N migration of alkoxycarbonyl groups in reactions of pyridinium ylides with isocyanates

New examples of reversible C ⇄ N migrations of alkoxycarbonyl groups, which occur in the reactions of pyridinium and 3-(diethylcarbamoyl)pyridinium ylides, viz., derivatives of dimethyl and diethyl malonates, with aryl isocyanates were studied. The mechanism of migration of the methoxycarbonyl group from the carbon atom to the nitrogen atom was considered on the basis of quantum-chemical calculations. The product of the primary attack of the isocyanate group by pyridinium ylide was established to be rearranged with low potential barriers to form carbamate without formation of cyclic intermediate compounds.