Том 54, № 5 (2018)

Sterical hindrances in N-(arylsulfonyl)-1,4-benzo(naphtho)quinone mono- and -diimines and in half-quinoid structures originating therefrom and having bulky equatorially located substituents in both α-positions are manifested in two competing ways: either by a deviation of the fragment C=N–S from the plane of the ring (therewith the torsion angle C=C–C=N may attain 36 deg, the distance of the sulfur atom from the plane 1.69 Å), or by the increased bond angle C=N–S to 132–133 deg. In all investigated cases the activated sterically strained bond C=N appeared at the value of the angle C=N–S >130 deg.

Derivatives of 2,3,6,7-tetrahydro-5H-[1,3]thiazolo[3,2-a]pyridine and 5,6-dihydropyridin-2(1H)-one were unexpectedly obtained at treating methyl 2-[(6-methyl-3-ethoxy-5,6-dihydropyridin-2-yl)sulfanyl]-acetate with a dilute solution of hydrochloric acid. Their formation resulted from the hydration of 5,6-dihydropyridine at the C=N bond accompanied with the elimination of a methyl 2-sulfanylacetate molecule and the addition of the methyl 2-sulfanylacetate to the second 5,6-dihydropyridine molecule at the C³=C⁴ bond followed by the elimination of a methanol molecule and the closure of a thiazole ring.

Catalytic aminomethylation of pyrrole and indole with N,N,N′,N′-tetramethylmethanediamine in the presence of 5 mol % of ZrOCl₂·8H₂O proceeds selectively at the positions 2, 5 of pyrrole and 1, 3 of indole. Carbazole under the same conditions affords 3-formyl-9-aminomethyl derivative. The reaction in the presence of 5 mol % of K₂CO₃ occurs as monoaminomethylation: for pyrrole at the position 2, for indole at the position 3, and for carbazole at the nitrogen atom of the substrate. Water-soluble 1,1′-(1H-pyrrole-2,5-diyl)bis(N,N-dimethylmethanamine) exhibits a fungistatic activity with respect to phytopathogenic fungi Rhizoctonia solani.

By reaction of Ritter cyclization of cyanoacetylureas with dimethylbenzylcarbinoles the corresponding enaminoureides were obtained, derivatives of 3,3-dimethyl-1,2,3,4-tetrahydroisoquinoline. The polyfunctional character of obtained compounds is confirmed by the structure of products of reaction with some electrophiles: phenyl isocyanate reacts at the γ-C atom of enamine and CONH₂ group of urea, under the action of oxalyl chloride annelation of a pyrrole cycle occurs with the formation of a derivative of 2,3-dioxopyrrolo[2,1-a]isoquinoline. Reaction with ninhydrin occurs similary with enaminoamides having hydrogen atoms at the amide nitrogen: a pyrrole ring is fused with the formation of a system of indeno[1,2-b]pyrrole.

One of hydroxy groups of ethylene glycol was protected by hemiketal, obtained by treating Michael adduct of levoglucosenone and cyclohexanone with reagents system Me₃SiCl‒NaI, while the other one was oxidized by Collins method. Stereocontrol in reactions of 1,2-addition to the obtained aldehyde was investigated (in reactions of Grignard, Henry, and Reformatsky).

An approach is developed to the synthesis of 2-methyl-7-phenyl-5,8-dihydro-4H-pyrazolo[5,1-d]-[1,2,5]triazepin-4-one, based on the recyclization of 2-methyl-6-phenyl-4H-pyrazolo[5,1-c][1,4]oxazin-4-one with hydrazine.

By reaction of 5,5-dimethyl-2-(3-aryl-4-nitrobutanoyl)cyclohexane-1,3-diones with hydroxylamine and hydrazine hydrate 6,7-dihydrobenzo[d]isoxazol-4(5H)-ones and 6,7-dihydro-1H-indazol-4(5H)-ones were prepared containing a nitromethyl substituent in the side chain. Basing on the nitromethyl group of the latter nitrile oxide intermediates were generated that were brought into reaction of 1,3-dipolar addition with phenylacetylene, styrene, and vinyl ethyl ether with the formation of the corresponding isoxazole and isoxazoline derivatives.

3-Acylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones regioselectively react with thiobenzamide forming substituted spiro[thiazolo-5,2′-pyrroles], whose structure was confirmed by X-ray diffraction analysis.

Boiling in toluene of 5-(arylmethylidene)pyrimidine-2,4,6(1H,3H,5H)-triones with L-proline and aldehyde led to the formation of previously unknown substituted 1′-arylhexahydro-1H-spiro[pyrimidine-5,2′-pyrrolysine]-2,4,6(1H,3Н,5Н)-triones.

Reaction of 3,4-dithienylmaleic anhydrides with aminoacetaldehyde dimethylacetal results in the formation of 3,4-dithienyl-substituted 1-(2,2-dimethoxyethyl)-1H-pyrrole-2,5-diones. The hydrolysis of the latter in acid medium results in the preparation of 2-[3,4-bis(thienyl)-2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl]-acetaldehydes. The obtained functionalized derivatives of maleimide demonstrate photochromic properties in solution.

Preparation method was developed for N-(2,2-dichlorovinyl)-N-alkylarenesulfonamides based on dehydrochlorination of the corresponding N-(2,2,2-trichloroethyl)-N-alkylarenesulfonamides.

Successive treatment of 3-acylcyclopropane-1,1,2,2-tetracarbonitriles with sodium hydrogen carbonate and alkylmercaptan in water environment results in the formation of 2-(5-amino-2-aryl-2-alkyl-sulfanyl-4-cyano-2,3-dihydrofuran-3-ylidene)propanedinitriles.

New effective method of direct functionalization of С_sp3–H bond in methyl substituent of quinaldine under the action of 5-arylfuran-2,3-diones was developed.

(Z)-1-Aryl-3-(2-aryl-2-oxoethylidene)piperazin-2-ones react with oxalyl chloride at cooling with the formation of (Z)-2-aryl-8-[hydroxy(aryl)methylidene]-8а-chlorotetrahydropyrrolо[1,2-a]pyrazine-1,6,7(2H)-triones. At heating HCl is eliminated from them to produce 8-aroyl-3,4-dihydropyrrolо[1,2-а]pyrazine- 1,6,7(2H)-triones.

Convenient one-pot method was developed for the preparation of 5-alkyl-3-(2-pyridyl)-, 5-alkyl-3-(4-pyridyl)- or 5-alkyl-3-(quinolin-2-yl)-1,2,4-triazines in up to 92% yield by condensation of hydrazones of isonitrosopropiophenone, isonitrosobutyrophenone, and isonitrosovalerophenone with aldehydes of (benzo) pyridine series with subsequent aromatization in boiling acetic acid.