Volume 61, Nº 10 (2025)

A method for the synthesis of 1,1,1-(6-methyl-1-aryl-1,2,3,4-tetrahydropyridine-3,3,5-triyl)triethanolines was developed by the reaction of 3-[(propan-2-ylsulfanyl)methyl]pentane-2,4-dione with anilines in the presence of catalytic amounts of acetic acid. The reactivity of substituted anilines in the studied reaction, depending on the nature and position of the substituent, decreases in the series: 2,4-Me₂-C₆H₃NH₂ > C₆H₃NH₂ = 4-Me-C₆H₄NH₂ = 2-Me-C₆H₄NH₂ > 3-Me-C₆H₄NH₂ = 2-MeO-C₆H₄NH₂ > 4-MeC(O)-C₆H₄NH₂ = 4-Br-C₆H₄NH₂.

The behavior of a representative number of previously unknown 2-(alkylsulfanyl)pyridines obtained from isothiocyanates, acetylene or allene carbonions and alkylating agents through the synthesis and aromatization of 6- (alkylsulfanyl)-2,3-dihydropyridines under electron ionization (70 eV) has been studied for the first time. All the studied compounds form stable molecular ions (M⁺,I_rel21 - 100%), the common direction of primary decay for most compounds is the formation of the [M - H]⁺ ion. Moreover, for 3-ary(heteroaryl)-substituted pyridines, except for 6-(vinyloxymethyl)-2-(methylsulfanyl)-3-phenylpyridine and 6-methyl-2-(methylsulfanyl)pyridine, this pathway is the main one. Other significant directions of primary fragmentation of M⁺ of the studied compounds are associated with the degradation of the alkylsulfanyl group, resulting in ions [M - M]⁺,[M - SH]⁺,[M - SCH]⁺,[M - SCH]⁺,[M - SM]⁺, or [M - Et]⁺ depending on the nature and position of substituents in the pyridine ring. The introduction of a substituent (R, OR, SR) into the pyridine molecule, in which R = Alk > Me, causes the appearance of a competing direction of decomposition of M⁺, associated with the release of an alkene molecule. Fragmentation of molecular ions of 2-(alkylsulfanyl)pyridines containing the OR substituent is determined by the localization of the charge either on the oxygen atom or on the sulfur atom. With an increase in the length of the alkyl substituent (R = Bu, MeCHOEt), along with a simple rupture of bonds, the occurrence of the McLafferty rearrangement is noted. Fragment ions formed during the fragmentation of molecular ions of 3-aryl(heteryl)-containing pyridines are stabilized through rearrangement into polycyclic aromatic structures, which are then practically not destroyed.

By reducing the ethylesters of spirocyclopentane- and spirotetrahydropyranesubstituted 6,7-dimethoxy-dihydroisoquinoline-1-carboxylic acids, the corresponding 1-hydroxymethyl tetrahydroisoquinolines were synthesized, which were converted into oxazoloisoquinolines by reaction with formalin. The interaction of the latter with hydrobromic and concentrated hydrochloric acids led to the products of recrystallization of oxazoloisoquinolines into tetrahydropyranoisoquinolines. The corresponding dioxinoisoquinolines were synthesized by the reaction of spiro-substituted 6,7-dihydroxyisoquinoline-1-methanol with dibromoethane.

2,4,8,10-Tetraoxaspiro[5.5]undecane-3,9-diylbis(methylene)-bis(3- or 4-aminobenzoates) were obtained by interaction of potassium salts of m- and p-aminobenzoic acids with 3,9-dibromomethyl-2,4,8,10-tetraoxaspiro[5.5]undecane in a molar ratio of 1:2. It was found that they react with a double amount of maleic anhydride to form the corresponding bismaleamides, the intramolecular cyclization of which in the presence of p-toluenesulfonic acid yielded previously undescribed 2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diylbis(methylene)bis(3 or 4-(2,5-dioxo-2,5-dihydro-1_H-pyrrol-1-yl)benzoates).

By reacting tribenzo [b,e,g][1,4] dioxocin-7,8-dicarbonitrile or 4,11-dimethyl-2,13-di-p-tolyltribenzo [b,e,g] [1,4] dioxocin-7,8-dicarbonitrile with sodium methylate in methanol followed by treatment with hydrochloric acid, 11H-dibenzo[5,6:7,8][1,4] dioxocin[2,3-f]isoindole-11,13(12H)-dione and 1,8-dimethyl-3,6-di-p-tolyl-11H-dibenzo[5,6:7,8][1,4] dioxocin[2,3-f]isoindole-11,13(12H)-dione were obtained, respectively. Their condensation with quinaldine followed by treatment with BF₃Et₂O in the presence of triethylamine leads to the formation of 12-difluoroboryl-13-(quinolin-2-methylene)-12,13-dihydro-11H-dibenzo[5,6:7,8] [1,4] dioxocin[2,3-f]isoindol-11-one and 12-difluoroboryl-1,8-dimethyl-13-(quinolin-2-methylene)-3,6-di-p-tolyl-12,13-dihydro-11H-dibenzo[5,6:7,8][1,4] dioxocin[2,3- f]isoindol-11-one, respectively. The structure of the synthesized compounds is confirmed by elemental analysis, massspectrometry, vibrational and NMR spectroscopy. The complexes demonstrate high luminescence quantum yields (up to 0.65) with insignificant Stokes shifts (up to 15 nm). Based on DFT and TD- DFT calculations, bands in the electronic absorption spectra were assigned to specific electronic transitions.

Previously unknown cyano-substituted derivatives of pyrrol-2-one containing a 1,5-diaryl fragment in their structure have been synthesized. Their preparation is based on the initial reaction of enamines with oxalyl chloride, leading to intermediate pyrrol-2,3-diones, which then react with malononitrile to form the final products.

Based on 2-amino-7,7-dimethyl-4-(3-nitrophenyl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile and formalin when heated in ethanol was obtained 7-(ethoxymethyl)-4',4'-dimethyl-2-(3-nitrophenyl)-2',6',8-trioxo-5,7-diazaspiro[bicyclo[3.3.1]nonane-3,1'-cyclohexane]-1-carbonitrile, the structure of which has been studied using spectral methods and X-ray diffraction analysis.

A two-step transition from individual diastereomeric 2,2-dichloro-2-[(1_R,5_S)- and 2,2-dichloro-2-[(1_S,5_R)-5-hydroxycyclopent-2-en-1-yl]-N-[(1_R)-1-phenylethyl]acetamides to the enantiomers of Grieco lactone is described with a total yield of 77%.