Andrey Alexandrovich Anishchenko

Single-stage synthesis of 3-hydroxy- and 3-alkoxy-5-arylimidazolidine-2,4-diones by reaction of arylglyoxal hydrates with N -hydroxy- and N -alkoxyureas

Arylglyoxal hydrates interact with N-alkoxyureas and N-hydroxyurea in acetic acid with selective formation of 3-alkoxy-5-arylimidazolidine-2,4-diones and 5-aryl-3-hydroxyimidazolidine-2,4-diones, respectively. The structures of 3-methoxy-5-phenylimidazolidine-2,4-dione, 3-ethoxy-5-phenylimidazolidine-2,4-dione, and 3-butoxy-5-(4-chlorophenyl)imidazolidine-2,4-dione were studied by X-ray structural analysis.

Synthesis and Structure of New N-Alkoxy-N-(1-pyridinium)urea Chlorides

New N-[1-(4-amino)pyridinium]-N-methoxyurea chloride, N-[1-(2-amino)pyridinium]-N-methoxyurea chloride and their analogs were synthesized by N-alkoxy-N-chloroureas reaction with the proper pyridines in acetonitrile or ether solution by improved procedure. XRD study of N-[1-(4-amino)pyridinium]-N-methoxyurea and N-[1-(2-amino)pyridinium]-N-methoxyurea revealed the elongation of N-N + bonds and some shortening of MeO-N bonds, qunonoid deformation of pyridine rings compare to it unsubstituted analog. The substantial pyramidality of central nitrogen atom in O-N-N + moiety and N-C carbamoyl bonds difference were established too. The structure summary of N-alkoxy-N-(1-pyridinium)ureas salts and other derivatives of 1-(N-alkoxyamino)pyridinium salts has been done.

UNUSUAL SPONTANEOUS α→β ISOMERIZATION OF UNSYMMETRICAL BENZOINS. PRODUCTS AND THEIR STRUCTURE

The article describes reactions of a series of arylglyoxals with 2-methylfuran and furfural N,N -dimethylhydrazone. These interactions lead selectively to unsymmetrical benzoins. It was found that some of the benzoins underwent spontaneous thermal α→β benzoin isomerization in situ . The rearrangement took place in the absence of bases, which could be explained by two structural factors: (a) the presence of a halogen atom in the para -position of the aryl moiety, and (b) the presence of the Me 2 NN=CH-substituent in the 5-position of the furan ring. The proposed mechanism of the thermal rearrangement starts with an intramolecular protonation of the carbonyl oxygen by the hydroxyl. This leads to the 1,2-hydride shift onto the carbonyl group, finally yielding β-benzoins. The S -isomer of 2-hydroxy-2-(4’’-chlorophenyl)-1-(5’- N,N -dimethylhydrazonylfuryl-2’)-ethanone-1 was isolated by crystallization, and its structure was confirmed by the X-ray crystallography.