2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties.

A series of derivatives of 2-hetaryl-1,3-tropolone (β-tropolone) was prepared by the acid-catalyzed reaction of 2-methylbenzoxazoles, 2-methylbenzothiazoles and 2,3,3-trimethylindoline with 3,4,5,6-tetrachloro-1,2-benzoquinone. The molecular structures of the three representative compounds were determined by X-ray crystallography. In crystal and (as shown by the DFT PBE0/6-311+G** calculations) in solution, 2-hetaryl-4,5,6,7-tetrachloro- and 2-hetaryl-5,6,7-trichloro-1,3-tropolones exist in the NH-tautomeric form with a strong resonance-assisted intramolecular N-H···O hydrogen bond.

[The synthesis of ψ-(2-aryl-1,3-dioxolan-2-yl) alkyl derivatives of purines and their activity towards HIV reverse transcriptase].

Novel non-competitive inhibitors of HIV RT were synthesized by alkylation of 6-substituted purines with different 2-(chloroalkyl)-2-aryl-1,3-dioxolanes and related compounds. The structure-activity relationship within the synthesized compounds was studied.

[The search of novel inhibitors of HIV-1 integrase among 5-(4-halogenophenyl)-5-oxopentyl derivatives of nucleic bases].

By alkylation of uracil, thymine, cytosine, adenine, 6-chloropurine, and 2-amino-6-chloropurine with 5-chloro-1-(4-halogenophenyl)-1-pentanones novel derivatives of nucleic bases were obtained, their physicochemical properties were studied. The influence of synthesized compounds on HIV-1 integrase was investigated.

[The interaction of NS3 protein of hepatitis C virus with polymethylen derivatives of nucleic bases].

NS3 protein of hepatitis C virus plays the key role in the virus functioning. It possesses three enzymatic activities, namely protease activity, associated with N-terminal domain of the protein, and helicase/NTPase activities specific for C-terminal domain. Here, the effect of some polimethylenic derivatives of the nucleic bases on helicase and ATPase enzyme activities has been studied.

Stereospecificity of isotopic exchange of C-α-protons of glycine catalyzed by three PLP-dependent lyases: the unusual case of tyrosine phenol-lyase.

A comparative study of the kinetics and stereospecificity of isotopic exchange of the pro-2R- and pro-2S protons of glycine in (2)H(2)O under the action of tyrosine phenol-lyase (TPL), tryptophan indole-lyase (TIL) and methionine γ-lyase (MGL) was undertaken. The kinetics of exchange was monitored using both (1)H- and (13)C-NMR. In the three compared lyases the stereospecificities of the main reactions with natural substrates dictate orthogonal orientation of the pro-2R proton of glycine with respect to the cofactor pyridoxal 5'-phosphate (PLP) plane.

[Polymethylene derivatives of nucleic bases bearing omega-functional groups. VIII. omega-oxo-omega-phenylalkyl pyrimidines and purines].

Novel polymethylene derivatives of nucleic bases containing a phenylketo function in the omega-position of hydrocarbon chain were synthesized by alkylation of uracil, thymine, cytosine, hypoxantine, adenine, and N(2)-isobutyrylguanine with omega-chloro-1 -phenylalkan-1-ones, their physicochemical properties were studied.

A novel and efficient method to prepare 2-aryltetrahydrofuran-2-ylphosphonic acids.

A novel one-pot method was developed for the synthesis of the title compounds starting from 4-chloro-1-aryl-1-butanones 1, phosphorus trichloride and acetic acid. The end products 2 were obtained in 20-94% yield. The cyclization step under acidic conditions probably occurs as a result of anchimeric assistance of the phosphonic acid group.

[Polymethylene derivatives of nucleic bases with omega-functional groups: VII. Cytotoxicity in the series of N-(2-oxocyclohexyl)-omega-oxoalkyl substituted purines and pyrimidines].

New polymethylene derivatives of nucleic bases with a beta-diketo function in the omega-position were obtained by alkylation of uracil, thymine, cytosine, hypoxanthine, adenine, and N(2)-isobutyryl guanine with 2-omega-chloroal-kanoyl)cyclohexanones. The physical and chemical characteristics of the compounds synthesized and their effect on the K562 and HCT116 tumor cell lines were studied.

[Polymethylene nucleic acid derivatives with omega-functional groups: vi. [8-(2-oxocyclohexyl)-9-oxooctyl]pyrimidines as potential inhibitors of pyrimidine phosphorylases].

New polymethylene derivatives of nucleic bases with beta-diketo function in omega-position were prepared by alkylation of uracil, thymine, and cytosine. Their physicochemical properties and effect on the E. coli uridine phosphorylase were studied.

[Polymethylene derivatives of nucleic bases with omega-functional groups. V. Pyrimidine- and purine-containing gamma-butyrophenones].

New polymethylene derivatives of nucleic bases containing a keto function in the omega-position were synthesized by alkylation of nucleic bases with 2-(3-chloropropyl)-2-phenyl-1,3-dioxolane and the subsequent deblocking of the keto group; their physicochemical properties were studied. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no.

[Polymethylene derivatives of nucleic bases with omega-functional groups: IV. [7-(2-oxocyclohexyl)-7-oxoheptyl]purines].

New polymethylene nucleoside analogues with a beta-dioxo function in the omega-position of their hydrocarbon chain, [7-(2-oxocyclohexyl)-7-oxoheptyl]purines, were synthesized, and their physicochemical properties were studied. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no.

[Polymethylene derivatives of nucleic bases with omega-functional groups. III. N-[7-(2-oxocyclohexyl)-7-oxoheptyl]-substituted pyrimidines].

New polymethylene derivatives of nucleic bases containing a beta-dioxo function at the omega-position were synthesized by alkylation of uracil, thymine, and cytosine with 1-(7-chloroheptanoyl)cyclohexan-2-one, and their physicochemical properties were studied. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no.

Thermal lens studies of the reaction of iron (II) with 1,10-phenanthroline at the nanogram level.

The determination of iron(II) with 1,10-phenanthroline in aqueous solutions was carried out exemplarily by thermal lens spectrometry. The peculiarities of analytical reactions at the nanogram level of reactants can be studied using this method. Under the conditions of the competing reaction of ligand protonation, the overall stability constant for iron(II) chelate with 1,10-phenanthroline was determined at a level of n x 10(-7) mol L(-1), logbeta3 = 21.

[A discrete dynamic model of a neuronal network with space-time organization].

A dynamical model of the neuronal network based on the principles of spatial-temporal organization of information processing was constructed. The additivity law for the formation of input connection factors in this model provides its versatility for a variety of logical functions. The model takes into account real properties of the systemic organization of brain neurones.

[The health status of workers engaged in the manufacture of inorganic manganese salts].

Workers engaged in the production of inorganic manganese salts revealed lesions of the upper respiratory pathways (catarrhal and subatrophic rhinitis, pharyngitis, laryngitis), skin (contact and allergic dermatitis), cardiovascular disorders. They also showed changes of renal function,mineral metabolism,acid stability of erythrocytes. Activation of the B-system of immunity and allergization of the body are also observed.

[Hygienic characteristics of work conditions and health status of workers engaged in cobalt salt production].

It was established that the major hazardous substances in cobalt acetate, chloride, nitrate and sulphate processing shops were the finished product's dusts (disintegration aerosol) in concentrations from 0.05 to 53 mg/m3 depending on the stage of the technological process. An analysis of morbidity with temporary disability and the rate of the workers' appliance for medical advice showed, among the major groups of industrial workers, particular prevalence of the upper respiratory tract diseases (rhinitis, pharyngitis, laryngitis) and the signs of irritation of the mucous in the eyes.

[The mechanisms of the antioxidant action of shielded phenols in biological membranes. The effects of 4-methyl-2,6-di-tert-butylphenol (ionol) and its derivatives].

According to Bulgarian-Soviet program "Biostab" we studied characteristics of different phenol compounds (ionol derivatives). The aim of the present study is to determine antiradical and antioxidant activity of a number of ionol derivatives in pure chemical systems and in different membrane fractions of a natural origin.

[Changes in the indicators of intracardiac hemodynamics in patients with post-infarction cardiosclerosis under the action of verapamil].

Echocardiography was used to examine the intracardiac hemodynamics, contractile and diastolic functions of the heart in 64 patients with postinfarction cardiosclerosis in the presence of eukinetic circulation and the effects of verapamil depending on the index of a cardiometric product (CMP). A relationship was found between the action of the drug and the sizes of the heart and severity of left ventricular hypertrophy. In patients with normal cardiometric parameters, the antianginal effect of the drug was achieved by peripheral arterial vasodilation and a significant rhythm slowness of heart performance.

[The role of non-traditional methods of analgesia in the postoperative period].

192 patients, aged 33 to 67 years, predominantly after abdominal and small pelvic surgery have been examined. Non-conventional techniques of analgesia were used in most of patients: central electroanalgesia, transcutaneous peripheral and paravertebral electroanalgesia, corporal and auricular acupuncture. To ensure postoperative pain relief various types of electrical stimulation were applied using home-made devices, The efficacy of non-conventional anesthesia techniques in the postoperative period has been confirmed.

[Heart size and the status of the cardiohemodynamics in hypertension patients].

The author studied the state of intracardiac hemodynamics, contractile and diastolic function of the heart in patients with hypertensive disease (stage II) depending on the index of the double cardiometric product reflecting the heart sizes. It was established that disorders of the cardio- and hemodynamics in patients with hypertensive disease depend not only on the stage of the disease but also on the degree of hypertrophy of the left cardiac ventricle and sizes of the heart. Groups of patients are distinguished with a different level of exertion of the adaptation-compensation mechanisms at rest and level of functional myocardial insufficiency.

[Functional state of kinesthetic and acoustic analyzers in children with enuresis after complex reflexotherapy].

A study was made of the time-course of changes in function of kinesthetic and acoustic sensitivity in children (n-62) aged 9 to 14 years suffering from enuresis undergoing acupuncture based on cauterization of acupuncture points with 25% silver nitrate. The patients with enuresis manifested normalization of the sensitivity of the analyzers under study. The clinical results of enuresis treatment depend on the degree of correction of the alterations in function of the analyzers.

[Characteristics of the electric activity of the projection areas of the large hemispheres in children with enuresis].

As many as 62 children aged 9 to 14 years with enuresis underwent electroencephalographic examinations. Assay of alpha-activity and study of its correlation dependence made it possible to reveal a decrease in excitability of the projection zones of the cortex of the large hemispheres and weakening of functional conjugation between them. After performing a complex of treatment measures including actions on the acupuncture points, intake of nootropic agents, vitamins a tendency was noted towards normalization of the status of the sensory and integrative brain structures.

[Sensory sphere function in children with enuresis].

The kinesthetic and acoustic analyzers were investigated in 62 enuretic and 50 healthy children. In patients, the sensitivity thresholds of the analyzers were substantially increased. The fall in function of the sensory sphere is a major pathogenetic factor of the disease.