Polyfunctional imidazoles: I. Synthesis of 1-substituted 4-chloro-1<Emphasis Type="Italic">H</Emphasis>-imidazole-5-carbaldehydes by Vilsmeier-Haack reaction

2-[Alkyl(aryl)amino]acetamides in reaction with Vilsmeier-Haack reagent afforded 1-alkyl(aryl)-4-chloro-1H-imidazole-5-carbaldehydes.     

Polyfunctional imidazoles: II. Synthesis and reactions with nucleophilic reagents of 1-substituted 2,4-dichloro-1<Emphasis Type="Italic">H</Emphasis>-imidazole-5-carbaldehydes

1-Alkyl(aryl)imidazolidine-2,4-diones reacted with Vilsmeier-Haack reagent affording 1-alkyl(aryl)-2,4-dichloro-1H-imidazole-5-carbaldehydes whose reactions with sodium azide, sodium alkoholates, with phenols, thiols, and secondary cycloalkylamines led to the substitution of chlorine in the position 2 of the imidazole ring. The reaction with primary amines resulted in the condensation products at the aldehyde group.     

Synthesis of 2-aryl-6-nitro-4-(<Emphasis Type="Italic">vic</Emphasis>-triazol-1-yl)-1<Emphasis Type="Italic">H</Emphasis>-indoles from <Emphasis Type="Italic">E</Emphasis>-2,4,6-trinitrostilbenes

A method is developed for the preparation of 4-(vic-triazol-1-yl)indoles that involves replacement of the ortho-NO₂ group in E-2,4,6-trinitrostilbenes by an azido group, condensation of E-2-azido-4,6-dinitrostilbenes with acetylacetone, replacement of the second ortho-NO₂ group in the resulting stilbenes by N₃, and subsequent thermolysis of the azide into the target indole. The reactions of E-2-azido-4,6-dinitrostilbenes with cyclohexane-1,3-dione gave E-2-amino-4,6-dinitrostilbenes, which can be used for selective transformation of the ortho-NO₂ group into an amino group in E-2,4,6-trinitrostilbenes. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1293–1296, May, 2005.     

Polyfunctional imidazoles: V. Synthesis of 1-aryl-4-chloro- 5-di(tri)fluoromethyl-1<Emphasis Type="Italic">H</Emphasis>-imidazoles

1-Aryl-4-chloro-1H-imidazole-5-carbaldehydes and 1-aryl-4-chloro-1H-imidazole-5-carboxylic acids reacted with sulfur(IV) fluoride to give, respectively, 1-aryl-4-chloro-5-difluoromethyl- and 1-aryl-4-chloro-5-trifluoromethyl-1H-imidazoles.     

Polyfunctional imidazoles: III. Synthesis of 1-aryl-2,4-dihalo-1<Emphasis Type="Italic">H</Emphasis>-imidazole-5-carboxylic acids and their derivatives

1-Aryl-4-chloro(2,4-dichloro)-1H-imidazole-5-carbaldehydes reacted with N-bromosuccinimide affording bromides of 1-aryl-2-bromo(2,4-dichloro)-1H-imidazole-5-carboxylic acids which were converted into the corresponding acids, esters, and amides.     

Ultrasound-accelerated one-pot synthesis of <Emphasis Type="Italic">N</Emphasis>-acetyl-2-aryl-1,2-dihydro-4<Emphasis Type="Italic">H</Emphasis>-3,1-benzoxazin-4-ones

The one-pot synthesis of N-acetyl-2-aryl-1,2-dihydro-4H-3,1-benzoxazin-4-one derivatives from the condensation reaction of anthranilic acids with heteroaromatic aldehydes in the presence of excess amount of acetic anhydride has been explored. The reactions proceed smoothly under ultrasound irradiation and without catalyst at 35 − 40 °C to afford the title products in high yields.     

Synthesis of isobornylphenol-containing 3-aryl-1,2,4-triazin-5(4<Emphasis Type="Italic">H</Emphasis>)-ones

A method for modification of 3-aryl-1,2,4-triazin-5(4H)-ones with isobornylphenols was proposed. The influence of various acylating agents on the reaction pathway was studied.     

Synthesis of 4<Emphasis Type="Italic">H</Emphasis>-imidazole-5-carbaldoxime 3-oxides and 4<Emphasis Type="Italic">H</Emphasis>-imidazole-5-carbonitrile 3-oxides

The condensation of 3-hydroxyamino-3-methylbutan-2-one or 3-ethyl-3-hydroxyamino-pentan-2-one with aldehydes and ammonia afforded a series of new 1-hydroxy-4-methyl-2,5-dihydroimidazoles, whose oxidation gave rise to the corresponding 5-methyl-4H-imidazole 3-oxides. The latter, like 1-hydroxy-4-methyl-2,5-dihydroimidazoles, react with PrⁱONO in the presence of bases to form 4H-imidazole-5-carbaldoxime 3-oxides, which are transformed into 4H-imidazole-5-carbonitrile 3-oxides in the reaction with TsCl in the presence of Et₃N. The by-products produced in different steps of the synthesis were isolated and characterized. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1487–1503, July, 2008.     

Synthesis and Stereochemistry of 1<Emphasis Type="Italic">H</Emphasis>,5<Emphasis Type="Italic">H</Emphasis>-Naphtho[1,8-<Emphasis Type="Italic">ef</Emphasis>][1,3]dithiocine 2-Oxides

3-Substituted 1H,5H-naphtho[1,8-ef][1,3]dithiocines (R = H, Me, Ph, t-Bu) were oxidized with m-chloroperoxybenzoic acid to the corresponding 2-oxides having trans configuration (R ≠ H). According to the ¹H and ¹³C NMR data (including NOESY experiments), the disubstituted compounds at room temperature exist in a boat conformation with equatorial orientation of the substituent on C³ and oxygen atom on S². The compound with no substituent on C³ gives rise to a mixture of boat conformers with axial and equatorial sulfoxide oxygen atoms at a ratio of 83:17.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 7, 2005, pp. 1109–1112.Original Russian Text Copyright © 2005 by Kikilo, Khairutdinov, Shtyrlin, Klochkov, Klimovitskii.     

Synthesis of 5-and 7-fluoroquinazolin-4(1<Emphasis Type="Italic">H</Emphasis>)-ones

5-Fluoroquinazoline-2,4-diones and their 2-thio analogs were obtained from 6-fluoroanthranilic acid. Two convenient routes to 5-fluoroquinazolin-4-ones involved cyclocondensation of 6-fluoroanthranilamide with acid chlorides (anhydrides) or with aromatic (heterocyclic) aldehydes. A method for the synthesis of 7-fluoroquinazolin-4-one from 2,4-difluorobenzoic acid was proposed. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1758–1764, September, 2007.