卷 54, 编号 3 (2018)

The effect of the structure of alcohols on their reaction with ethyl 2-diazo-3-oxobutanoate catalyzed by copper(II) trifluoromethanesulfonate has been studied. The corresponding ethyl 2-alkoxy-3-oxobutanoates were obtained in quantitative yield from primary alcohols. Introduction of a 1,3-dioxolane or 1,3-dioxane fragment into the alcohol molecule changes the reaction direction toward the formation of polyoxa macrocycles that are products of formal insertion of the diazo ester into the carbon–oxygen bond.

Aminomethylation of bicyclo[2.2.1]heptane-2,3-diol, as well as of its O-allyl- and 5-vinyl derivatives, afforded a series of N-substituted 2-hydroxy(or allyloxy)-3-(aminomethoxy)bicyclo[2.2.1]heptanes which showed high bactericidal and fungicidal activity in lubricating oils.

The oxidation of mono- and diiodo- and -bromo-substituted polymethylbenzenes (mesitylene and durene) in the system PbO₂–CF₃COOH–CH₂Cl₂ at room temperature (2–70 h) leads mainly to the formation of iodo- and bromobenzyl alcohols as result of oxidation of methyl group. The reaction involves intermediate formation of haloarene radical cations. ESR study of these radical cations made it possible to determine the structure of their singly occupied molecular orbitals a₂ or b₁ and interpret their reactivity.

5-(Hydroxymethyl)furfural is readily oxidized to furan-2,5-dicarbaldehyde with sodium nitrite in phosphoric acid at room temperature (25°C). The best selectivity for furan-2,5-dicarbaldehyde is achieved using 2.5 equiv of sodium nitrite with respect to the substrate. In this case, nearly quantitative yield of furan- 2,5-dicarbaldehyde is attained in 1 h, the substrate conversion being complete. Due to high selectivity in combination with low cost and toxicity of phosphoric acid, the system NaNO₂–H₃PO₄ is more convenient than NaNO₂–CF₃COOH for the preparative synthesis of furan-2,5-dicarbaldehyde.

Pyridoxine derivatives, 3-hydroxy-2-methylpyridine-4- and -5-carbohydrazides, were synthesized according to optimized known procedures, and a method for the synthesis of 5-(hydroxymethyl)-2,2,8-trimethyl-4H-[1,3]dioxino[4,5-c]pyridine-6-carbohydrazide was developed. The hydroxymethyl groups in positions 5 and 6 of 2,2,8-trimethyl-4H-[1,3]dioxino[4,5-c]pyridine showed different reactivities, and only the 6-hydroxymethyl group was selectively oxidized to aldehyde under mild conditions. The lactone ring in 5,6-dihydrofuro[3,4-b]pyridin-7(5H)-one was found to be stable to nucleophiles. The synthesized hydrazides showed no antimycobacterial activity.

2-(Allylamino)pyrido[3,2-d]pyrimidin-4(3H)-one was converted to linearly fused dihydroimidazo- [1,2-a]pyrido[3,2-d]pyrimidine on heating in polyphosphoric acid, whereas its reactions with molecular iodine and chlorosulfanylarenes afforded mainly angularly fused analogs. 2-(Cinnamylamino)pyrido[3,2-d]pyrimidin- 4(3H)-one reacted with polyphosphoric acid and chlorosulfanylarenes to give linear pyrido[3,2-d]pyrimido-[1,2-a]pyrimidinones, and its iodocyclization led to the formation of angularly fused derivative.

The reduction of acetylcymantrene with sodium tetrahydridoborate gave cymantrenylethanol which was acylated with 4,5-dichloroisothiazole- and 5-(4-methylphenyl)isoxazole-3-carbonyl chlorides to obtain esters containing a 1,2-thia(oxa)zole fragment. The condensation of acetylcymantrene with 5-arylisoxazole-3- carbaldehydes, (5-arylisoxazol-3-yl)methoxybenzaldehydes (Ar = Ph, 4-Tol), and 4,5-dichloroisothiazole-3- carbaldehyde afforded the corresponding (E)-3-(azol-3-yl)-1-cymantrenylprop-2-en-1-ones. The resulting α,β- unsaturated ketones reacted with semicarbazide hydrochloride and thiosemicarbazide to produce substituted 4,5-dihydro-1H-pyrazole-1-carboxamides and -1-carbothioamides, and their reaction with hydroxylamine hydrochloride led to the formation of 4,5-dihydroisoxazoles containing cymantrene and 1,2-azole fragments. Heterocyclization of azolylcymantrenylpropenones with guanidine gave 2-aminopyrimidine derivatives, and dihydropyrimidine-2-thiones were obtained by their reaction with thiourea.

Reactions of 2-(propargylsulfanyl)-5-methyl-1,3,4-thiadiazole, N-[5-(propargylsulfanyl)-1,3,4-thiadiazol- 2-yl]benzamide, 2-(propargylsulfanyl)-1,3-benzothiazole, and 2-(propargylsulfanyl)-4,5-dihydro-1,3- thiazole with iodine involved annulation of the unsaturated substituent with formation of fused thiazole ring. 2(5)-(Propargylsulfanyl)-1,3,4-thiadiazole derivatives reacted with bromine to give mixtures of heterocyclization products and bromine adducts to the triple bond. The bromination of 2-(propargylsulfanyl)-4,5-dihydro- 1,3-thiazole afforded only the bromine addition product to the triple bond.

The azidation of 2,2-bis(2-cyanoethyl)-20-hydroxydammar-24-en-3-one afforded new tetrazole derivatives of natural dipterocarpol, 2-(2-cyanoethyl)-2-[2-(1H-tetrazol-5-yl)ethyl]-20-hydroxydammar-24-en- 3-ones, 2,2-bis[2-(1H-tetrazol-5-yl)ethyl]-20-hydroxydammar-24-en-3-one, and 2,2-bis[2-(1H-tetrazol-5-yl)- ethyl]-3-oxo-25,26,27-trinordammaran-(20S),24-olide. The structure of the final and intermediate products was determined by NMR spectroscopy and X-ray analysis.

An efficient synthesis of a widely used fragrance, 2-[(2E)-hex-2-en-1-yl]cyclopentan-1-one, has been developed on the basis of iron-catalyzed cross-coupling of 2-[(2E)-3-chloroprop-2-en-1-yl]cyclopentan-1- one with propylmagnesium bromide.

2-Pyrazolylpyrrolidines were synthesized by acid-catalyzed reaction of N-(4,4-diethoxybutyl)ureas with 1-aryl-3-methyl- and 2,3-dimethyl-1-phenyldihydropyrazol-5-ones.

Diaminofurazan reacted with 8-benzoyl-2-phenyl-3,4-dihydropyrrolo[1,2-a]pyrazine-1,6,7(2H)- trione to give addition product of the amino group to the double bond of the pyrrole ring, which underwent cyclization to 2,8-diphenyl-3,4-dihydro[1,2,5]oxadiazolo[3,4-b]pyrazino[1′,2′: 1,2]pyrrolo[2,3-e][1,4]diazepine-1,6,7(2H,9H,13H)-trione by the action of N,N′-dicyclohexylcarbodiimide.