A new group of unsymmetrical ALM-802 analogs, N1-benzyl-N2-2-[(2,3,4-trimethoxybenzyl)amino]-ethylethane-1,2-diamines of general formula 1, in which one of the aromatic groups was changed, was studied. The anti-ischemic and antiarrhythmic activities of the new compounds were studied. Their ADME characteristics were analyzed. The 2,3,4-trimethoxyphenyl group used as one of the aromatic pharmacophores was shown to play a key role in the activity of compounds of this type. The presence of a second aromatic group was also important since its removal led to the disappearance of cardiotropic activity. However, its structure had significantly less impact on the activity of the corresponding compounds because a rather wide variation of substituents in this group did not change the activity in most arrhythmia and ischemia models.

A new group of unsymmetrical ALM-802 analogs, N-1-benzyl-N-2-{2-[(2,3,4-trimethoxybenzyl)amino]-ethyl}ethane-1,2-diamines of general formula 1, in which one of the aromatic groups was changed, was studied. The anti-ischemic and antiarrhythmic activities of the new compounds were studied. Their ADME characteristics were analyzed. The 2,3,4-trimethoxyphenyl group used as one of the aromatic pharmacophores was shown to play a key role in the activity of compounds of this type. The presence of a second aromatic group was also important since its removal led to the disappearance of cardiotropic activity. However, its structure had significantly less impact on the activity of the corresponding compounds because a rather wide variation of substituents in this group did not change the activity in most arrhythmia and ischemia models.

New compounds of bis(2,3,4-trimethoxyphenyl)azaalkanes differing in the structure of the central atom were obtained. The anti-ischemic and antiarrhythmic activities of the new compounds were studied. Their absorption, distribution, metabolism, and excretion (ADME) characteristics were analyzed. Replacement of the central N atom by other atoms (O, C, S) had practically no effect on their antiarrhythmic and anti-ischemic properties but improved their calculated oral bioavailability. The promising compound ALM-863 {2,2′-oxybis[ N -(2,3,4-trimethoxybenzyl)ethane-1-amine] dihydrochloride} at a dose of 3 mg/kg (i.v.) completely repeated the spectrum of cardiotropic properties of the ALM-802 prototype, was less toxic and surpassed it in terms of calculated pharmacokinetic parameters, and was selected.

We report here the synthesis of novel compounds of the bis-(2,3,4-trimethoxybenzyl)propanediamines group and studies of their anti-ischemic and antiarrhythmic activity. Introduction of a hydroxyl group into the central part of the propane linker was found to produce virtually no change in the spectrum of cardiotropic properties of the unsubstituted compound ALM-851, while introduction of two methyl groups led to the complete disappearance of both antiarrhythmic and antiischemic activities. Compound ALM-850 (1,3-bis((2,3,4-trimethoxy-benzyl)amino)propan-2-oldihydrochloride) at a dose of 3 mg/kg significantly blocked the development of rhythm disturbances and death in animals in the aconitine and calcium chloride arrhythmia models, and also decreased ST segment depression in the isoproterenol ischemia model.

Organic salts of N 1 -(2,3,4-trimethoxybenzyl)- N 2 -{2-[(2,3,4-trimethoxybenzyl)amino]ethyl}-1,2-ethanediamine ( I ) (succinate ALM-802S and citrate ALM-802C) were obtained. These organic salts were found to retain completely the anti-arrhythmic and anti-ischemic properties of I trihydrochloride (ALM-802) in equimolar doses (2.15 – 2.75 mg/kg, i.v. administration). The new compounds belonged to toxicity class VI (low-toxicity substances). The LD 50 values of the organic salts of I recalculated as the base corresponded to that of I trihydrochloride. The pH values of the organic salts of I were significantly higher than that of I trihydrochloride (5.5 – 5.8 vs. 3.5), which eliminated the local irritating action and undesirable organoleptic properties.

A new group of aminoalkyl dibenzofuranone oxime derivatives was designed and synthesized. Several compounds were found to exhibit anticonvulsant activity in the maximum electroshock test. The most active compound was 3,4,6,7,8,9-hexahydrodibenzo[b, d]furan-1(2H)-one O-[2-(diethylamino)ethyl]oxime oxalate (GIZh-347), which at a dose of 60 mg/kg (mice, i.p.) was as effective as valproic acid at a dose of 200 mg/kg.

A new series of bis-(2,3,4-trimethoxybenzyl)alkanediamines were obtained. Their anti-ischemic and antiarrhythmic activities were studied. Replacement of the central N atom of the triazaalkane linker in the previously studied compound ALM-802 by a carbon atom and shortening of the linker length led to preservation of the cardiotropic activity spectrum of the corresponding compounds. The most active compounds among the new series were ALM-844 [N1,N5-bis(2,3,4-trimethoxybenzyl)pentane-1,5-diamine dihydrochloride] and ALM-851 [N1,N3-bis(2,3,4-trimethoxybenzyl)propane-1,4-diamine dihydrochloride].

Previous studies at the V. V. Zakusov Science Research Institute of Pharmacology created a dimeric dipeptide mimetic of the most exposed fourth loop of nerve growth factor (NGF), bis-(N-monosuccinyl-L-glutamyl-Llysine) hexamethylenediamide (GK-2), which activates specific TrkA receptors and has neuroprotective activity in vitro (at 10 5 to 10 9 M) and in vivo (0.1 – 10 mg/kg, i.p., or p.o.). The present report describes the construction and synthesis of a mimetic of the first loop of NGF based on the β-turn (-Lys 32 -Gly 33 -Lys 34 -Glu 35 -), bis-(N-aminocaproyl-glycyl-L-lysine) hexamethylenediamide (GK-6). The structure of GK-6 preserves the central dipeptide fragment of the β-turn -Gly 33 -Lys 34 -, the Lys 32 residue being substituted by its bioisostere – a 6-aminocaproic acid residue - and the dimeric structure of NGF being reproduced by dimerization at the C-terminal using a bivalent hexamethylenediamine spacer. Structure-activity relationships of GK-6 were studied by sequential substitution of the side groups of the peptide by hydrogen to produce bis-(N-acetyl-glycyl-Llysine) hexamethylenediamide (GTS-611) and bis-(N-aminocaproyl-glycyl-glycine) hexamethylenediamine (GTS-613). Mimetic GL-6 and its analogs GTS-613, which contains the N-aminocaproyl radical, had neuroprotective effects at concentrations of 10 6 and 10 5 M in conditions of oxidative stress in HT-22 neuron cultures. Dipeptide GTS-611, in which the aminocaproyl fragment was replaced by an acetyl residue, had no neuroprotective activity in these conditions, pointing to the importance of Lys 32 in NGF for this property. In contrast to the loop 4 mimetic GK-2, the loop 1 mimetics GK-6 and GTS-611 showed differentiation-inducing activity on PC12 cells.

A dimeric dipeptide mimetic of nerve growth factor (NGF), bis-(N-monosuccinyl-L-glutamyl-L-lysine) hexamethylenediamide (GK-2), was previously developed at V. V. Zakusov State Institute of Pharmacology, activated specific TrkA receptors, and exhibited neuroprotective activity in vitro (10–5 – 10–9 M) and in vivo (0.1 – 10 mg/kg i.p. and p.o.). GK-2 was designed based on the beta-turn (-Asp94-Glu95-Lys96-Gln97-) of the NGF 4th loop and preserved the central dipeptide fragment (-Glu95-Lys96-). The Asp94 residue was replaced by its monosuccinyl bioisostere. The dimeric structure of NGF was reproduced using a bivalent hexamethylenediamine spacer. The structure—activity (neuroprotective) relationship for GK-2 was studied in the present work using a glycine scan, i.e., successive replacement of the peptide side groups by H. The bis-(N-acetyl-L-glutamyl-L-lysine) (GK-2Ac), bis-(N-monosuccinylglycyl-L-lysine) (GK-2-Gly1), and bis-(N-monosuccinyl-L-glutamylglycine) hexamethylenediamides (GK-2-Gly2) were less active with neuroprotective activity in vitro under oxidative stress for HT22 cells at concentrations 10 – 100 times greater than GK-2. The conclusion was drawn that each side radical of GK-2 was important for manifestation of the full neuroprotective activity of dimeric dipeptide GK-2, a mimetic of the NGF 4th loop. However, removal of any of the side radicals would probably not change the active structure of the beta-turn so that the two remaining side radicals should retain the ability to bind to their TrkA subsites. This could explain the retention of neuroprotective activity in the GK-2 glycine analogs.

Previously, researchers at Zakusov State Institute of Pharmacology used an original strategy for designing pharmacologically active dipeptides based on non-peptide drug structures to prepare the dipeptide ligands of 18-kDa translocator protein (TSPO) N -carbobenzoxy-L-tryptophanyl-L-isoleucine amide (GD-23) and N -phenylpropionyl-L-tryptophanyl-L-leucine amide (GD-102) that showed anxiolytic activity in standard behavioral tests. The present work reports GD-102 analogs with the reverse amino-acid sequence, i.e., N -phenylpropionyl- L -leucyl- L -tryptophan methylamide (GD-140), N -phenylpropionyl- L -leucyl- L -tryptophan (GD-139), N -phenylacetyl- L -leucyl- L -tryptophan amide (GD-141), N -phenylpropionyl- L -leucyl- L -tryptophan methyl ester (GD-138), and N -phenylpropionyl- L -leucyl- L -tryptophan amide (GD-136). Open-field (OF) tests of mice after i.p. administration showed that the newly synthesized dipeptides were less active than GD-102 (0.01 – 0.1 mg/kg). Dipeptide GD-140 showed anxiolytic activity at doses of 0.1, 0.5, and 1 mg/kg; GD-139, 0.5 and 5.0; GD-141, 1 and 5. Dipeptide GD-138 at a dose of 0.1 mg/kg reduced locomotor activity of animals in the OF test. GD-136 was inactive in the dose range 0.1 – 5 mg/kg. Molecular docking studies demonstrated that the studied compounds could be placed at the TSPO binding site of ligand PK 11195 (PDB ID: 2MGY). Also, π-stacking of the phenyl groups of dipeptides GD-136, GD-139, GD-140, and GD-141 with Trp107 of the receptor was revealed. For dipeptides GD-140 and GD-102, π-stacking with Trp95 was also detected. GD-138 did not exhibit π-stacking with either Trp107 or Trp95. It was concluded that the key interaction affecting the manifestation of anxiolytic activity was π-stacking of the dipeptide ligand with Trp95 of the receptor. The Trp-Leu sequence was preferred over the Leu-Trp sequence for the TSPO dipeptide ligands.

The optimal synthetic scheme for the potential nootropic drug GZK-111 ( N -phenylacetylglycyl- L -proline ethyl ester) was developed. Three synthetic schemes were tested, each of which included the following steps: 1) esterification of L-proline; 2) preparation of N -phenylacetylglycine; 3) formation of the peptide bond. Esterification of proline per Brenner and preparation of N -phenylacetylglycine via acylation of glycine with phenylacetyl chloride under Schotten—Baumann conditions were used in all synthetic schemes. Three methods for forming the peptide bond between N -phenylacetylglycine and the proline ester were tried (mixed anhydride under Anderson conditions, activated benzotriazole ester, and activated succinimide ester methods) and showed that the mixed anhydride method was optimal, giving a total yield of 42%.

New dibenzofuranone-oxime derivatives were designed based on active structures of oxime esters. Compounds of the proposed group were synthesized using 3,4,6,7,8,9-hexahydrodibenzo[ b,d ]furan-1(2 H )-one oxime and aromatic acid chlorides. The anticonvulsant activity of the new compounds was studied. The structure— activity relationship was analyzed. Compound 1a [3,4,6,7,8,9-hexahydrodibenzo[ b,d ]furan-1(2 H )-one O -(3,4-dichlorobenzoyl)oxime] was the most active compound after i.p. injection to mice in the maximal electroshock test over a wide dose range of 20 – 100 mg/kg. Compound 1a at doses of 10 and 30 mg/kg exhibited antihypoxic activity in a hypoxia test with hypercapnia in a hermetic chamber and anti-ischemic activity at a dose of 10 mg/kg in a rat ischemic stroke model.

A group of new 1-(methoxybenzyl)-4-{2-[(methoxybenzyl)amino]ethyl}piperazines (1) were synthesized. The relationship of the structure of the triazaalkane linker and the cardiotropic activity in a series of these compounds was compared with that of previously studied linear and cyclic methoxyphenyltriazaalkanes. The most active compound in the group was 1e (1-(3,4,5-trimethoxybenzyl)-4-{2-[(3,4,5-trimethoxybenzyl)amino] ethyl}piperazine trihydrochloride) with statistically significant antiarrhythmic activity in aconitine and CaCl2 arrhythmia models.

2-Isobutyl-4,6-dimethyl-5-hydroxypyrimidine (SNK-411) and its salt (SNK-578) were synthesized. Antitumor and antimetastatic activity of the new derivative 5-hydroxypyrimidine SNK-578 were studied in tests on male C57BL/6 mice using the B16 melanoma model. The standard grafted dose was 5 × 106 tumor cells mouse. SNK-578 was injected i.p. at doses of 10 and 25 mg/kg for two weeks from day 2 to day 15 of B16 melanoma development. Doxorubicin was injected to mice at a dose of 4 mg/kg on day 2 of tumor development to act as a positive control and to reveal an additive effect from combined single use of doxorubicin and injection of a course of SNK-578. The combination of i.p. injection of a course of SNK-578 at a dose of 10 mg/kg and a single i.p. injection of doxorubicin at a dose of 4 mg/kg revealed statistically significant tumor growth inhibition that was expressed as a decrease of tumor volume by 2.4, 1.9, and 1.5 times on day 11, 15, and 21 of the test as compared with the active control group that did not receive SNK-578. SNK-578 possessed pronounced antimetastatic activity at doses of 10 and 25 mg/kg for monotherapy and coadministration with doxorubicin at a dose of 4 mg/kg. The metastasis inhibition index (MII) after SNK-578 injection at a dose of 10 mg/kg was 75.8%; at 25 mg/kg, 92.3%. The most pronounced antimetastatic effect was observed after combined i.p. injection of SNK-578 at a dose of 10 mg/kg for 14 d and a single injection of doxorubicin at a dose of 4 mg/kg. Metastases were not observed in six of nine mice on day 21 of B16 melanoma development; the other three had 1, 2, and 3 very small metastases so that the MII was 98.9%.

Chlorine6 has been known to be attractive as photosensitizer (PS) for PDT for long. Its usefulness as a photosensitizing part of photoimmunotoxines for targeted PDT, as a synton for further chemical modification and as a promising PS has been widely recognized. There is a patented procedure at our disposal now allowing for preparation of a stable, well soluble and filtrating form of chlorine6- 'Photodithazine'. The elaborated production technology includes 4 steps. 'Photodithazine's 1-octanol/Phosphate buffer, pH 7.4 partition coefficient has been found to be 1.4, indicating that it must be able to localize in the plasma membrane. This may be a partial explanation of its higher photodynamic efficacy in vitro, comparing to 'Photosense' and its closeness to 'Photogem'.