Selenium heterocycles. XXXI. Reaction of ethyl propiolate with 5-phenyl-2-thioxo-1,3-thiaselenole and 4-phenyl-2-thioxo-1,3-dithiole

Reaction of ethyl propiolate with 4-phenyl-2-thioxo-1,3-dithiole afforded 4-carbethoxy-2-thioxo-1,3-dithiole in high yield. Reaction of ethyl propiolate with 5-phenyl-2-thioxo-1,3-thiaselenole gave 4-carbethoxy-2-thioxo-1,3-thiaselenone (IX), 4-carbethoxy-2-selenoxo-1,3-dithiole (X) and 5-carbethoxy-2-thioxo-1,3-thiaselenole (XI). A possible mechanism for the formation of these compounds is given.     

Reaction of iodonium ylides of 1,3-dicarbonyl compounds with HF reagents

Reaction of dibenzoylmethane with (diacetoxyiodo)benzene in the presence of KOH in MeCN quantitatively gave the corresponding iodonium ylide, which was treated with a HF reagent to afford the corresponding 2-fluorinated dibenzoylmethane in 14-50% yields. The similar reaction of the iodonium ylides obtained from 1-phenylbutan-1,3-dione, ethyl benzoylacetate, and ethyl p-nitrobenzoylacetate with TEA·3HF gave the corresponding fluorinated products in 17-34% yields. It is suggested that the fluorinated products were formed through the C-protonation of the ylide, followed by displacement with fluoride ion. The same reaction of the iodonium ylide of dibenzoylmethane with concentrated HCl gave the corresponding chlorinated product in 45% yield.     

Synthesis of novel 2-phenyl-5-substituted dihydropyrimidines using 2-phenyl-1,3-diaza-1,3-butadienes and electron-deficient olefins

A novel synthetic method for 2,5-disubstituted dihydropyrimidines was developed. The cyclization of 1,3-diaza-4-dimethylamino-1,3-butadienes having a N-protecting group (N-Boc, N-Cbz, N-n-C₄H₉, N-Bn or N-Ph) with electron-deficient olefins, such as α,β-unsaturated carbonyl compounds, phenyl vinyl sulfone, and acrylonitrile was studied in detail. The cyclization smoothly proceeded to afford 4-dimethylamino-1,4,5,6-tetrahydropyrimidines or 1,6-dihydropyrimidines in good yields. The isolated 4-dimethylamino-1,4,5,6-tetrahydropyrimidines were converted to 2,5-disubstituted-1,6-dihydropyrimidines through the β-elimination of the dimethylamino group. 2,5-Disubstituted-1,4(6)-dihydropyrimidines were obtained after removal of the N-Boc or N-Cbz group. Independent tautomers of the resulting dihydropyrimidines were observed.     

Synthesis and Crystal Structure of 2-Morpholinylthioformyl-2-phenyl-4-morpholinyl-5-phenyl-1,3-dithiole

1　ＩＮＴＲＯＤＵＣＴＩＯＮα Ｔｈｉｏｃａｒｂｏｎｙｌｔｈｉｏｆｏｒｍａｍｉｄｅｓｗｅｒｅｓｙｎｔｈｅｓｉｚｅｄｉｎ 1 980 [1～ 2 ],ｈｏｗｅｖｅｒ,ｔｈｅｒｅｗａｓｎｏｒｅｐｏｒｔｏｎｔｈｅｉｒｐｒｏｐｅｒｔｉｅｓａｎｄｒｅａｃｔｉｏｎａｃｔｉｖｉｔｉｅｓ[3].Ｗｅｒｅｐｏｒｔｅｄｔｈｅｒｅａｃｔｉｏｎｏｆα ｔｈｉｏｃａｒｂｏｎｙｌｔｈｉｏｆｏｒｍａｍｉｄｅｓｐｒｅｖｉｏｕｓｌｙ[4 ].Ｈｅｒｅ ,ｗｅｒｅｐｏｒｔｔｈｅｓｙｎｔｈｅｓｉｓｏｆ 2 ｍｏｒｐｈｏｌｉｎｙｌｔｈｉｏｆｏｒｍｙｌ 2 ｐｈｅｎｙ…     

Heterocycles from ylides. Part VIII Reactivity of 2-arylmethylenebenzofuran-3-ones with stabilized sulphur ylides

2-Arylmethylenebenzofuran-3-ones react with carbonyl stabilized sulphur ylides yielding spiro-[cyclopropane-1,2′-benzofuran-3′-ones], whose structure and stereochemistry were assigned on the basis of spectroscopic data and chemical behaviour.     

1,3-Dipolar cycloaddition of phthalazinium ylides to 5-arylidene-2-spirocyclohexane-1,3-dioxane-4,6-diones

Tetrahydrospiropyrrolo[2,1-a]phthalazines were synthesized by the reaction of 5-arylidene-2-spirocyclohexane-1,3-dioxane-4,6-diones with phthalazinium ylides. One of the reaction products, viz., 3-ethoxycarbonyl-2-(4-methoxyphenyl)-2′,2′-pentamethylene-1,2,3,10b-tetrahydrospiro[pyrrolo[2,1-a]phthalazine-1,5′-[1,3]dioxane]-4′,6′-dione, was studied by X-ray diffraction. The spectroscopic characteristics of the reaction products are discussed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2362–2365, October, 2005.     

Reaction of 5-phenyl- and 4,5-diphenyloxazoline-2-thiones with arenediazonium salts

The corresponding 2-arylthio-5-phenyloxazoles, 2-arylthio-4-arylazo-5-phenyl-oxazoles, and 2-arylthio-4,5-diphenyloxazoles are formed by the action of arenediazonium salts on 5-phenyl- and 4,5-diphenyloxazoline-2-thiones.     

Reaction of 2-isobutyl-5-methyl-4-phenyl-1,3,2-dioxaborinane with acetonitrile

Reaction of 2-isobutyl-5-methyl-4-phenyl-1,3,2-dioxaborinane (a mixture ofcis- andtrans-isomers in a 81 : 19 ratio) with acetonitrile yielded 2,5-dimethyl-4-phenyl-5,6-dihydro1, 3-oxazine as a mixture ofcis- andtrans-forms in a 50 : 50 ratio. The possible mechanism of this transformation is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1297–1298, May, 1996.     

5-Acyl-4-amino-2-phenyl-1,3-oxazin-6-ones

Intramolecular cyclization of acyl(ethoxycarbonyl)keteneN-benzoylaminals in boiling Ph₂O gives 5-acyl-4-amino-2-phenyl-1,3-oxazin-6-ones.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1322–1323, July, 1995.This study was financially supported by the Russian Foundation for Basic Research (Grant No. 94-03-08964).     

New transformations of 5-Hydrazino-2-phenyl-1,3-oxazole-4-carbonitrile

Treatment of 5-hydrazino-2-phenyl-1,3-oxazole-4-carbonitrile with acetylacetone lead to the formation of a substituted pyrazole residue on C⁵, which enhanced the electrophilicity of the cyano group in position 4 so that it became capable of reacting with hydrogen sulfide, sodium azide, and hydroxylamine. As a result, the corresponding azole fragments were introduced into position 4 of the 5-(1H-pyrazol-1-yl)-1,3-oxazole system.     

Reaction of halides with tricarbonylcyclohexadienyliron cation: Preparation of tricarbonyl(5exo-Fluorocyclohexa-1,3-diene)iron

Tricarbonyl(5-exo-fluorocyclohexa-1,3-diene)iron has been prepared by reaction of tricarbonyl(cyclohexadienyl)iron cation with KF in the presence of 18-crown-6. Reactions of chloride and bromide salts of potassium also give unstable 5-substituted compounds while the iodo salt reacts to form a mixture of the ring and metal substituted products.     

Reaction of i-acetyl-2-phenyl-5-hydroxypyrazolidines with alcohols on the surface of adsorbents

A novel method for synthesis of 5-alkoxypyrazolidines on the surface of an adsorbent allows us to obtain derivatives of allyl, tertiary, and chiral alcohols.M. V. Lomonosov Moscow State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp 1489–1493, November, 1995.