N. G. Senchenya

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.

C-N migration of allyl- and propargyloxycarbonyl groups

Reactions of triisopropylphosphine with allyl-and propargyl-2-cyanoacrylates give corresponding 1,3-zwitterions. Under the action of phenyl-or 1-naphthylisocyanates the zwitterions exert C-N migration of allyl-or propargyloxycarbonyl groups affording carbamates. Atropisomerism at room temperature was established for the carbamate formed from 1-naphthylisocyanate.

Electrophilic 1,3-C→N− and-N→C− migrations in saturated systems

A new type of intramolecular electrophilic rearrangements involving the shift of COOAlk groups from carbon to an N-anionic center is considered. Carbanionic species with COOAlk groups at anionic centers containing no acidic hydrogen react unusually with alkyl(aryl) iso(thio)cyanates giving carbamates as a result of insertion of RNCX into the C−C bond. The kinetics and mechanism of insertion of aryl isocyanates into the C−C bond of the phosphonium zwitterion obtained from triisopropylphosphine and ethyl 2-cyanoacrylate are discussed. The reaction of α-carbanions derived fromN,N-disubstituted amides with methyl trifluoromethanesulfonate results inO-methylation. Some possibilities of back N→C− migrations are considered.

Synthesis of functionally substituted 2-cyanoacrylates

The conditions for the Knoevenagel synthesis of 2-cyanoacrylates containing double and triple bonds in the alkoxycarbonyl group have been studied. It was found that the esters are formed in 10–70 % yields by the condensation of the respective cyanoacetates with formaldehyde in the 1∶1 ratio in the presence of piperidine, followed by the pyrolysis of the oligomers formedin vacuo at 170–200 °C in the presence ofpara-toluenesulfonic acid. The compounds synthesized readily undergo polymerization at room temperature and can be used as the basis for thermostable rapidly polymerizing adhesives.

Synthesis of 2-cyanoacrylatesvia 2-cyanoacryloyl chloride

Monomers that are difficult to obtain, such as tert-butyl 2-cyanoacrylate, trimethylsilyl-methyl 2-cyanoacrylate, 2,2,3,3-tetrafluoropropyl 2-cyanoacrylate, and the previously unknown adamantyl 2-cyanoacrylate were prepared starting from 2-cyanoacryloyl chloride.

SYNTHESIS OF FUNCTIONALLY SUBSTITUTED CYANOACETATES

Some new cyanoacetates were synthesized and characterized. They are precursors for α-cyanoacrylates used as rapidly polymerized, cold-hardening adhesives.

Intramolecular electrophilic rearrangements in saturated acyclic systems. Reactions of bis-carbanions with isocyanates

The reactions of mono- and bis-isocyanates with bis-carbanions whose COOAlk groups at the anionic centers do not contain acidic hydrogen atoms proceed unusually to form bis-carbamates (including oligomeric carbamates) due to migration of the alkoxycarbonyl groups from the carbon to the nitrogen atom.

Synthesis of adamantane monomers and their properties

ConclusionSyntheses were reported for new adamantane monomers, namely the allyl and propargyl esters of 1-adamantanecarboxylic acid, the diallyl and dipropargyl esters of 1,3-adamantanedicarboxylic acid and di-1-adamantyl maleate. These esters are capable of undergoing thermal copolymerization with α-cyanoacrylate esters.