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A convenient one-pot approach was proposed for the synthesis of new derivatives of 8,9,10,12tetrahydrobenzo[a]acridin-11(7H)-one and 10,12-dihydrobenzo[f]pyrimido[4,5-b]quinoline-9,11(7H,8H)-dione containing residues of nicotinic and isonicotinic acids covalently attached via ester groups in different positions of the aromatic core. Quaternary ammonium salts of the synthesized acridine derivatives as well as a metal complex with palladium PdLCl2 were obtained. These compounds contain a number of pharmacophore groups so going to be promising potential drugs with antimicrobial, antiviral, and antitumor activity.

The reaction of isonicotinic acid hydrazide with ethyl-, allyl-, and cinnamoyl isothiocyanates has afforded the corresponding alkylthiosemicarbazides and the products of their intramolecular heterocyclization, 1,2,4-triazoles.

A possibility of the direct monoesterification of β-cyclodextrin with benzoic, p-aminobenzoic, 2-(4-isobutylphenyl)propionic, nicotinic, and isonicotinic acids was shown. Regioselectivity of substitution on the primary hydroxyl groups was confirmed by the means of 1H and 13C NMR spectroscopy.

Complexes of cobalt(II), nickel(II), and zinc(II) valerates and benzoates with isonicotinic acid hydrazide (isonicotinic hydrazide) have been synthesized. The prepared compounds have been characterized by means of elemental analysis, thermogravimetry, and IR and diffuse reflectance spectroscopy.

Stable nanoscaled mono- and dimeric inclusion complexes of β-cyclodextrin with hosts based on symmetric diols of various length containing fragments of benzoic, nicotinic, or isonicotinic acid were synthesized.

Using pyridine, quinoline, and related compounds as examples, it has been shown that their interaction with triphenylphosphine occurs via different pathways. Reaction of triphenylphosphine with N-vinylisonicotinic acid chloride leads to the mixture of 1,2-bis(triphenylphosphoniumchlorido)ethane and 4-carboxy-2-(triphenylphosphoniumchloridoethyl)pyridine. In the case of α-(N-2-carboxyquinolinylbromido)-β-bromopropionic acid, the reaction with triphenylphosphine proceeds via phosphine attack on the oxygen atom with elimination of quinaldinic acid, and subsequent nucleophilic substitution with the formation of 3-(triphenylphosphoniumbromido) propionic acid bromide.

Hybrid compounds derived from natural diterpenoid isosteviol and antitubercular drug isoniazid (isonicotinic acid hydrazide) and its isomers (nicotinic and 2-picolinic acid hydrazides) were synthesized, and their structure in crystal and in solution was studied. The newly synthesized compounds were found to inhibit Micobacterium tuberculosis (H37RV strain) in vitro, the minimal inhibitory concentration being 10–20 μg/ml.

On the basis of N-aminofulgimide two new photochromic compounds of the fulgimide class were synthesized. The performed spectral-kinetic studies have shown that the obtained fulgimide derivatives suffer thermally irreversible transformation similar to those observed for the starting N-aminofulgimide except for the absorption bands of the corresponding cyclic forms to undergo red shift. One of the obtained compounds is capable to form complexes with rare-earth metal ions.

Solvation and complexation of Cu(II) and Ni(II) with benzoic (L′), p-methoxybenzoic (L″), and isonicotinic (L) acid hydrazides in aqueous-ethanol solutions (ethanol mole fraction 0.07–0.68) were studied by pH-metry, spectrophotometry, and nuclear magnetic relaxation. The formation constants of the species M(L′)2+, M(L′) 2 2+ , M(L″)2+, M(L″) 2 2+ , M(LH)3+, M(L)2+, M(L)(LH)3+, and M(L) 2 2+ , where M = Cu2+ and Ni2+, were determined. With isonicotinic acid hydrazide, a change in the coordination mode was observed in an isomer of Cu(L) 2 2+ , with one of the ligands coordinating in the bidentate fashion, and the other, in the monodentate fashion via the pyridine nitrogen atom. The suggested structures were confirmed by analysis of the parameters of the ESR and electronic absorption spectra of the complexes. The rate constants of ligand exchange and formation of the complexes Cu(L′)2+, Cu(L′) 2 2+ , Cu(L″)2+, and Cu(L″) 2 2+ in aqueous solutions were determined from nuclear magnetic relaxation measurements; the reactions occur by the associative mechanism. A cyclic process of reduction of Cu(II) to colloidal copper in the presence of L″ and atmospheric oxygen is described.

Solvation and complexation of Ni(II) with benzoic (L1), p-methoxybenzoic (L3), and isonicotinic (L) acids hydrazides in water and aqueous acetonitrile were studied. The coordination of acetonitrile with Ni(II) was qualitatively estimated, and the formation constant were determined for the complexes Ni(L1)2+, Ni(L1)22+, Ni(L3)2+, Ni(L3)22+, Ni(HL)3+, NiL2+, NiL(HL)3+, and NiL22+. The effects of dilution, ligand basicity, and ligand solvation on the stability of Ni(II) compounds with hydrazides of benzoic acid and its derivatives were demonstrated. The stability of the Ni(II) complexes with isonicotinic acid hydrazide is governed by dehydration of the metal ion, decrease in the donor power of the coordinating hydrazide fragment on protonation of the pyridine substituent L, formation of the intracomplex hydrogen bond between the protonated and deprotonated pyridine nitrogen atoms in NiL(HL)3+, and stacking interaction between the heterocycles in NiL22+.