Vol 55, No 5 (2019)

The reaction of hydroxybenzoyl chlorides with imidazole was studied on an example of the Schotten-Baumann reaction of salicyloyl and acetylsalicyloyl chlorides with imidazole, which, according to soe published data, can take two different ways. It was shown that the Schotten-Baumann reaction with imidazole involves imidazole ring opening (Bamberger cleavage) to form l,2-bis(salicyloylamino)ethylene and l,2-bis(acetylsalicyloylamino)ethylene rather than N-salicyloylimidazole and N-acetylsalicyloylimidazole. N-Hydroxybenzoylimidazoles were synthesized by the reaction of hydroxybenzoyl chlorides (and derivatives) with a double excess of imidazole in an aprotic solvent (chloroform, benzene, or diethyl ether) at room temperature. The highest yields (about 80%) of N-hydroxybenzoylimidazoles were obtained in chloroform. Some of the newly synthesized compounds were tested for psychotropic (open field and passive avoidance response tests) and analgesic activities (vocalization threshold test). The best results were obtained with N-(2-hydroxybenzoyl)imidazole, which showed an evident analgesic activity, and, therewith, the motor score and oriented exploratory activity parameters were higher than in the control group.

The reaction of methyl aroylpyruvates with 2-(4-aminobenzenesulfonamido)thiazole (norsulfazole) in acetic acid-ethanol (1: 1) afforded methyl (2Z)-4-aryl-4-oxo-2-{4-[(1,3-thiazol-2-yl)sulfamoyl]phenyl-amino} but-2-enoates which reacted with ninhydrin in glacial acetic acid to give 4-aroyl-3-{4-[(1,3-thiazol-2-yl)-sulfamoyl]phenylamino} spiro[2,5-dihydrofuran-5,2′-indane]-2,1′,3′-triones.

A new synthesis of N-(5-hydroxynicotinoyl)-L-glutamic acid via a 5-hydroxynicotinic acid imidazolide intermediate has been developed. Its calcium salt (Ampasse) has been synthesized and its structure was studied by X-ray diffraction analysis. The reaction conditions for all stages of the process have been optimized and a method for the purification of the substance has been improved.

The reaction of 6,6-dialkyl-5,6-dihydrobenzo[f]pyrrolo[2,1-a]isoquinoline-8,9-diones with hydrazine is used to prepare enaminoketohydrazides of the 2,2-dialkyl-2,3-dihydrobenzo[f]isoquinoline series, which are polyfunctional reagents. The acylation of the synthesized hydrazides with two equivalents of acylating reagents, such as benzoyl chloride, phenyl isocyanate, phenyl isothiocyanate, and allyl isothiocyanate, involves exclusively the terminal NH₂ group of the hydrazide fragment. The acylation with two equivalents of acetyl chloride leads to the substitution of both hydrogen atoms at the terminal NH₂ group; the structure of the resulting N,N-diacyl derivative is proved by X-ray diffraction analysis.

N-Substituted amino acids with a norbornene fragment were synthesized by the direct fusion of amino acids with endic anhydride at 150°C. The synthesized compounds were used for one-pot synthesis of novel stable allenes with an exocyclic cumulene group derived from l-phenyl-3-(triphenylphosphoranylidene)-pyrrolidine-2,5-dione has been carried out.

Zn(II) octakis(4-fluorophenyl)tetraazoporphyrin and Cu(II) octakis(4-fluorophenyl)tetraazorphorphyrin were synthesized by the cyclization of bis(4-fluorophenyl)maleonitrile with zinc(II) and copper(II) chlorides. The geometry of Zn(II) octa(4-fluorophenyl)tetraazaporphyrin was optimized by the BioCharmm molecular mechanics method in the Hyperchem software package. Mg(II) octakis(4-fluorophenyl)tetraazaporphyrin was obtained by fusing bis(4-fluorophenyl)maleonitrile with metallic magnesium. Ni(II) octakis-(4-fluorophenyl)tetrazaporphyrin and Cu(II) octakis(4-fluorophenyl)tetrazaporphyrin were synthesized by the reaction of the fluoro-substituted magnesium complex with Ni(II) and Cu(II) chlorides in DMF. The synthesized compounds were identified by UV-Vis, ¹H NMR spectroscopy, and mass spectrometry. The UV-Vis spectra of the Zn(II), Cu(II), Mg(II), and Ni(II) complexes were compared with those of Zn(II) octakis(4-methoxyphenyl)porphyrin and Mg(II) octakis(4-methoxyphenyl)porphyrin. The florescence spectra Zn(II) and Mg(II) octaphenyltetraazaporphyrins in chloroform solutions were measured, and the fluorescence quantum yields of the metal porphyrins were determined. Comparative analysis of the fluorescence quantum yields of molecules containing substituents with a large atomic weight was performed.

A new protocol of the synthesis of 3,3′-diaryl-3,3′-diphthalides by dehalogenation of o-keto carboxylic acid pseudochlorides is implemented. The feature of the new protocol is that the reaction is carried out in the presence of a zero-valent nickel complex catalyst generated in situ by mixing zinc powder, nickel(II) chloride, triphenylphosphine, and 2,2′-bipyridine. Along with the target dimerization products of pseudochlorides, minor products were isolated, whose structure allowed to propose possible schemes of side reactions.

N-Substituted pyrroles have been prepared in high isolated yields (702-99%) by the reaction of hexane-2,5-dione with amines or diamines in the presence of Fe(ClO₄)₃/SiO₂ at ambient temperature under solvent-free conditions. The experimental procedure involves simple operations, and the products are readily separated by short column chromatography. The same reaction of hexane-2,5-dione with amines containing electron-acceptor substituents, such as 4-nitroaniline, resulted in fair yields of pyrrole derivatives.

The immobilization of AlCl₃, an extremely hygroscopic Lewis acid, on graphene oxide as a support material with a high surface area was studied. The obtained solid material was characterized by FTIR spectroscopy, TGA/DTA analysis, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy and used as an efficient and bench-top environmentally benign catalyst for the preparation of bis (pyrazolyl)methane derivatives through the condensation of aldehydes and 3-methyl-l-phenylpyrazol-5-one. The catalyst is reusable for at least nine times with a negligible loss in its catalytic activity.

A dicarboxylate-based fluorescent receptor has been synthesized for the recognition of the guanidinium ion and guanidine-containing biomolecules in aqueous medium to address the issue of biomolecular interaction. The acyclic receptor binds to guests in a 1: 2 mode due to the flexibility of its binding motifs. The host-guest binding behavior was studied by means of UV and fluorescence titration. The binding of the host with the guanidinium ion was found to be stronger than with the other guanidine-containing guests.

8-Aroyl-3,4-dihydropyrrolo[2,1-a][1,4]oxazine-1,6,7(1H)-triones were synthesized by the reactions of 3-(2-aryl-2-oxoethylidene)morpholin-2-ones with oxalyl chloride.

4,5-Dibenzoyl-1H-pyrrole-2,3-diones react with 3-aminocyclopent-2-en-1-one to form N-substituted 2-(4-benzoyl-5-oxo-2-phenyl-5H-cyclopenta[b]pyridin-3-yl)-2-oxoacetamides.

Dimethyl 5-amino-2-hydroxy-4,6-dimethylisophthalate and dimethyl 5-amino-2-hydroxy-4,6-dimethylisophthalate were obtained in the free form for the first time. The products were sulfonylated with p-toluenesulfonyl to obtain previously unknown dialkyl 5-(4-toluenesulfonamido)-2-hydroxy-4,6-dimethylisophthalates. The use of p-acetamidobenzenesulfonyl chloride as the sulfonylating agent in this reaction led to the formation of dialkyl 5-(4-acetamidobenzenesulfonamido)-2-hydroxy-4,6-dimethyl isophthalates. The synthesized sulfonamide derivatives are of interest as potentially biologically active compounds. The structure of all the obtained compounds was proved using IR and NMR spectroscopy and mass spectrometry.