Pyrroles from ketoximes and acetylene. No. 36. 4,4,6,6-Tetramethyl-4,5,6,7-tetrahydro-5-azaindole,its nitroxyl and vinyl derivatives,and spin-labelled copolymer

An oxime containing a nitroxyl functional group site, 2,2,6,6-tetramethyl-1-nitroxyl-4-hydroxyiminopiperidine, has been shown for the first time to engage in productive pyrrole synthesis via reaction with acetylene in KOH-DMSO. The behavior of 2,2,6,6-tetramethyl-4-piperidone oxime and its 1-hydroxy derivative in this reaction has also been investigated. The corresponding 5-azaindole and its 5-nitroxyl and 1-vinyl derivatives have been synthesized in this manner. 1-Hydroxy-4-piperidone oxime reacts at 50–60C under the general reaction conditions undergoing oxidative conversion to 5-azaindole, while at 105C in the presence of excess acetylene reduction of the hydroxy group also takes place. The formation of a pyrrole ring does not involve radical chains, although vinylation of the resulting pyrroles apparently involves one-electron transfer. 1-Vinyl-4,4,6,6-tetramethyl-4,5,6,7-tetrahydro-5-azaindole has been used for the preparation of a spin-labelled polyvinyl alcohol copolymer.For Communication No. 35, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 24, No. 3, pp. 350–355, March, 1988.     

Synthesis of pyrrole-2-carboxylic acids and their N-vinyl derivatives

Haloform cleavage of 2-trifluoroacetyl- and N-vinyl-2-trifluoroacetylpyrroles gives pyrrole-2-carboxylic acids and their N-vinyl derivatives in good yields; most of these compounds do not melt between 120–190C, but rather decompose with CO₂ evolution.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 612–616, May, 1990.     

Addition of benzhydroxamic acid to alkoxyethylenes

A method for the isolation of 1-alkoxyethyl esters of benzhydroxamic acid, based on the addition of this acid to alkoxyethylenes in the presence of the catalyst HBr, was developed. The possible structure of the adducts is discussed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2300–2302, October, 1989.     

Pyrroles from ketoximes and acetylene. 40. Reaction of alkyl hetaryl ketoximes with 1,2-dichloroethane in superbase media

2-(2-Furyl)- and 2-(2-thienyl)pyrroles and their N-vinyl derivatives were synthesized by the reaction of alkyl furyl (thienyl) ketoximes with 1,2-dichloroethane in superbase media. 2-Chloroethyl and vinyl ethers of alkyl hetaryl ketoximes are intermediates in the reaction.See [1] for Communication 39.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 901–906, July, 1989.     

Hydroxy- and aminomethylation of 1-methyl-2-amino-4-imidazolinone

The corresponding imidazolo[3,2-a]-1,3,5-triazines are formed as a result of the aminomethylation of 1-methyl-2-amino-4-imidazolinone (creatinine) and its 5-benzylidene derivative with paraformaldehyde and primary aliphatic amines. Hydroxymethylation is directed to the C₍₅₎, position of the creatinine heteroring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 767–770, June, 1991.The authors thank A. V. Dogadin for recording and discussing the PMR spectra.     

Structure and basicity of ω-substituted ethynyl 2-thienyl ketones

By a comparison of the calculated and experimental dipole moments of ethynyl 2-thienyl ketones, it was shown that the S,O-cis conformation is the most probable one. The basicities of these compounds were estimated by means of IR spectroscopy from the shift of the band of the phenolic OH stretching vibration. The correlation relationships between the dipole moments of the ketones, their basicities, and the association constants of propiolic acids that have identical substituents attached to the triple bond were established. It is noted that the experimental characteristics found do not correlate with the different sorts ofσ substituent constants; this provides evidence for a difference in the mechanism of the interaction of the atomic groups in a number of acetylenic and aromatic molecules.     

The Particle-Size Distribution Method for Studying the Crystallization of Calcium Oxalate in the Presence of Impurities

Crystallography Reports - The crystallization of CaC2O4 · H2О from model solutions of a crystal-forming medium (human urine) has been studied by the dispersion method. It is shown that...     

Kinetic characteristics of the crystallization from model solutions of blood plasma

Crystallography Reports - The kinetic regularities of crystallization (growth order and constants) in a model solution of blood plasma have been investigated. The particular order and...