A new synthetic route to 2-substituted naphtho[2,3-b]furan-4,9-dione2-Substituted Naphtho[2,3-b]furan-4,9-dione

4,9-Dimethoxynaphtho[2,3-b]furan 9 was obtained in 91% yield via the reductive methylation of naphtho[2,3-b]furan-4,9-dione 2 . After treatment of 9 with butyllithium, the mixture was allowed to react with N,N-dimethylacetamide, followed by oxidization with cerium(IV) diammonium nitrate to give 2-acetylnaphtho[2,3-b]furan-4,9-dione 1 . 2-Formylnaphtho[2,3-b]furan-4,9-dione 13 and 2-trimethylsilyl-naphtho[2,3-b]furan-4,9-dione 14 were also obtained from 9 by a similar method. The halodesilylations of 14 easily gave 2-iodonaphtho[2,3-b]furan-4,9-dione 16 , 2-bromonaphtho[2,3-b]furan-4,9-dione 17 , and 2-chloronaphtho[2,3-b]furan-4,9-dione 18 in 82%, and 93% and 83% yield, respectively. Furthermore, the nitrodesilylation of 14 gave 2-nitronaphtho[2,3-b]furan-4,9-dione 3 in 77% yield.     

Reaction of 5-phenyl-2,3-dihydrofuran-2,3-dione with 6,7-dimethoxy-3,4-dihydroisoquinoline. Crystal structure of 1-benzoyl-8,9-dimethoxy-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-dione

The reaction of 5-phenyl-2,3-dihydrofuran-2,3-dione with 6,7-dimethoxy-3,4-dihydroisoquinoline gave 1-benzoyl-2-hydroxy-8,9-dimethoxy-3,5,6,10b-tetrahydropyrrolo[2,1-a]isoquinolin-3-one and its oxidation product,viz., 1-benzoyl-8,9-dimethoxy-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-2,3-dione. The last-mentioned compound was studied by X-ray structural analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1845–1848, October, 1997.     

Synthesis of 1H-pyrrolo[2,3-b]phenoxathiin-2,3-dione

The title compound was obtained using the Sandmeyer reaction starting from 2-aminophenoxathiine. A new synthesis of N-methylpyrrolo[2,3-b]phenoxathiin-2,3-dione was also presented. Chemical and spectral data supporting the structure of the newly synthesized compounds were given. The isatin analogue, 1-methylpyrrolo-[2,3-b]phenoxathiin-2,3-dione-10, 10-dioxide, could not be obtained.Faculty of Chemistry, Organic Chemistry Department, University of Bucharest, 90–92 Panduri Road, Romania. Faculty of Pharmacy, Organic Chemistry Department, University of Medicine and Pharmacy Carol Davila, Bucharest, Romania. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 396–399, March, 1998.     

A facile synthesis of 2-acetylnaphtho[2,3-b]furan-4,9-dione

Reaction of the parent naphtho[2,3-b]furan-4,9-dione 2 with various electrophilic reagents was difficult, and only nitration of 2 gave small amounts of 2-nitronaphtho[2,3-b]furan-4,9-dione 4 . Then 2-acetylnaphtho[2,3-b]furan-4,9-dione 1 was not obtained by the acetylation of 2 . On the other hand, compound 1 that is isolated from Tabebuia Cassinoides and has cytotoxic activity, was obtained from 3-lithiofuran in five steps.     

Nucleophilic substitutions of 2-chloronaphtho[2,3-b]furan-4,9-dione with amines

2-Chloronaphtho[2,3-b]furan-4,9-dione 4 was allowed to react with pyrrolidine to produce 2-(1-pyrrolidinyl)naphtho[2,3-b]furan-4,9-dione 8 in 64% yield. In a similar manner, the reaction of 4 with cyclic amines (piperidine, morpholine, 4-substituted piperazines, etc.) gave the desired compounds. 2-Dimethylaminonaphtho[2,3-b]furan-4,9-dione 20 and 2-propylaminonaphtho[2,3-b]furan-4,9-dione 23 were obtained from the reactions of 4 with amines in 67% and 48% yields, respectively. Furthermore, the reactions of 4 with acyclic amines (diethylamine, dipropylamine, isopropylamine, butylamine, etc.) gave the desired compound. Compound 4 was treated with sodium azide to give 2-azidonaphtho[2,3-b]furan-4,9-dione 28 in 42% yield. All these nucleophilic substitutions were carried out at room temperature. It was found that 4 showed high reactivity for amines. Unexpectedly, 2-morpholinonaphtho[2,3-b]furan-4,9-dione 13 was obtained from the reaction of 4 with 1-morpholino-1-cyclohexene.     

Decarbonylation Path of 5-Phenyl-2,3-dihydrofuran-2,3-dione: Ab Initio Calculations

The gradient path of decarbonylation of 5-phenyl-2,3-dihydrofuran-2,3-dione in the gas phase was calculated ab initio [RHF/6-31G(d)]. It includes formation of a planar transition state which is less polar than the initial compound.     

One-pot efficient green synthesis of 1,4-dihydro-quinoxaline-2,3-dione derivatives

An efficient synthesis of the potential pharmacophore 1,4-dihydro-quinoxaline-2,3-dione (1) has been achieved in a one-pot reaction at room temperature from substitutedo-phenylene diamine and oxalic acid under solvent-free conditions by a simple grinding method with unsurpassed atom economy. Thermal and powder X-ray diffraction analysis was carried out for some hydrated crystals.     

Heterocyclic analogs of 5,12-naphthacenequinone 7*. Synthesis of naphtho-[2,3-f]isatin-5,10-dione derivatives

On chlorination of 4,11-dimethoxynaphtho[2,3-f]indole-5,10-dione with sulfuryl chloride in chloroform, its mono-, di-, and trichloro derivatives are formed depending on the conditions. Hydrolysis of the di- and trichloro derivatives gives a new polycondensed derivative of isatin, 4,11-dimethoxynaphtho-[2,3-f]isatin-5,10-dione. Its demethylation occurs effectively on extended heating with HBr in acetic acid and leads to 4,11-dihydroxynaphtho[2,3-f]isatin-5,10-dione (4,11-di-hydroxynaphtho[2,3-f]indole-2,3,5,10-tetraone). *For Communication 6 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1532–1536, October, 2008.     

Thermal and photochemical reaction of isoxazolone with indole-2,3-dione derivatives

The reaction of indole-2,3-dione derivatives with five membered heterocycle, viz isoxazolone under ther mal as well as photochemical conditions is described. While under refluxing ethanol these conditions afforded 2,3-dihydro-3-(5′-oxo-3′-phenylisoxazolidyl)indol-2-one 3 and a spiro product 2′,3′-dihydro-3,7-diphenylspiro[diisoxazolo[4,5-e:4,5-b]pyran-8,3′-indol]-2′-one 4 , the uv light induced irradiation mainly produced 4,5-dioxo-3-phenylisoxazolo[5,4-b][1]benzazepine 5 and 3-phenylisoxazolo[5,4-b]quinoline-4-carboxylic acid 6 . The products have been characterised on the basis of spectral data and elemental analyses.     

Condensed imidazo-1,2,4-azines. 15. Reaction of 1,2-diaminobenzimidazole with 5-phenyl-2,3-dihydrofuran-2,3-dione

The reaction of 1,2-diaminobenzimidazole with 5-phenyl-2,3-dihydrofuran-2,3-dione in acetic acid gave a mixture of 2-benzoylmethyl-1,2,4-triazino [2,3-a]-benzimidazol-4H-3-one and 3-benzoylmethyl-1,2,4-triazino[2,3-a]benzimidazol-1H-2-one, the intramolecular cyclization of which gave isomeric 2-phenylfuro-[5,4-e]- and 2-phenylfuro[4,5-e]-1,2,4-triazino[2,3-a]benzimidazoles. Only the corresponding furo[4,5-e]-1,2,4-triazino[2,3-a]benzimidazole was isolated when the reaction was carried out in sulfuric acid.See [1] for Communication 14.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 533–535, April, 1987.     

Synthesis of 5,8-dihydroxynaphtho[2,3-c][1,2,5]thiadiazole-6,9-dione and 6,9-dihydroxybenzo[g]quinoxaline-5,10-dione

The synthesis of 5,8-dihydroxynaphtho[2,3-c][1,2,5]thiadiazole-4,9-dione 3 , 6,9-dihydroxybenzo[g]quinoxaline-5,10-dione 4 , and their lesser oxygenated analogs via Friedel-Crafts and Diels-Alder synthesis is reported.     

Naphthoindazoles. Synthesis of 4,11-Dimethoxynaphtho[2,3-f]indazole-5,10-dione

The previously unknown 4,11-dimethoxynaphtho[2,3-f]indazole-5,10-dione has been obtained by the thermal cyclization of N-nitroso derivative of 2-acetamido-3-methyl-1,4-dimethoxyanthraquinone.     

Synthesis of pyrazine-2,3-dicarbonitriles via the one-pot three-component reaction of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione,diaminomaleonitrile, and functionalized alcohols in acetonitrile

An efficient one-pot three-component reaction of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione, diaminomaleonitrile, and alcohols with hetero-atom substituents or several hydroxyl groups in acetonitrile solvent under reflux led to the formation of 5-(2-substituted ethoxy or propoxy-2-phenyl-1-N-phenylthiocarbamoylethenyl)-6-oxo-1,6-dihydropyrazine-2,3-dicarbonitrile derivatives in good yields.     

Naphthoindoles. 9. Synthesis of N-derivatives of 4,11-Dimethoxynaphtho-[2,3-f]indole-5,10-dione

N-Acetylation and several N-alkylation reactions have been carried out for the previously synthesized 4,11-dimethoxynaphtho[2,3-f]indole-5,10-dione.     

CIDNP study of the photochemistry of 1-acetylindole-2,3-dione

CIDNP is a convenient means to study reactionsvia radical pairs, which provides a way to distinguishthe reactions via radical pairs from the reactions in-volving exciplexes and short-chain biradicals[1]. Het-erocyclic compounds with different electron wit…     

The synthesis of 5,8-difluoronaphtho[2,3-c]thiophene-4,9-dione and its facile conversion to 2-[2-(dimethylamino)ethyl]- 5-[2-(dimethylamino)ethylamino]-8-fluoro-naphtho[2,3-c] pyrrole-4,9-dione

The synthesis of 5,8-difluoronaphtho[2,3-c]thiophene-4,9-dione ( 2a ) has been accomplished. Treatment of 2a with 2,2-dimethylaminoethylamine leads to 2-[2-(dimethylamino)ethyl]-5-[2-(dimethylamino)ethylamino]-8-fluoronaphtho[2,3-c]pyrrole-4,9-dione ( 6 ).     

Influence of substituents on carbonyl carbon chemical shifts in 4-substituted bornane-2,3-diones and the preparation of bornane-2,3-dione

¹³C Chemical shifts of the 4-substituted boniane-2,3-dione(1–6) have been assigned. The shielding of the CO carbons brought about by electron withdrawing substituents is attributed to a field effect of the substituent which serves to increase the CO bond order. For the substituent bearing carbons C(4), enhanced shielding is noted and these carbons exhibit small substituent chemical shifts. A preparative method leading to borane-2,3-dione is described and briefly discussed.     

二氢吲哚-2,3-二酮衍生物抑菌活性研究进展

二氢吲哚-2,3-二酮是一种结构简单且应用广泛的药物小分子,其衍生物的合成、结构和药理活性等备受关注。已有报道表明二氢吲哚-2,3-二酮具有抗菌、抗衰老、降血脂、抗癫痫、抗病毒等多种生物活性。本文主要围绕抑菌生物活性,对国内外关于二氢吲哚-2,3-二酮类化合物的构效关系进行分析总结,为后期该类新型抗菌化合物的设计合成提供参考。     

Acetylenic chemistry: Part 15 [1]. Reactions of 1,2,3,4-Tetrahydro-2,4-dioxopyrido[2,3-d]pyrimidine with 3-bromoprop-1-yne

Reaction of 1,2,3,4-tetrahydro-2,4-dioxopyrido[2,3-d]pyrimidine with 3-bromoprop-1-yne gave 1-prop-2′-ynylpyrido[2,3-d]pyrimidine-2,4-dione ( 4a ), 3-prop-2′-ynylpyrido[2,3-d]pyrimidine-2,4-dione ( 4b ), and 1,3-diprop-2′-ynylpyrido[2,3-d]pyrimidine-2,4-dione ( 4c ). Subsequent boiling of 1,3-diprop-2′-ynylpyrido-[2,3-d]pyrimidine-2,4-dione ( 4c ) in formic acid afforded 1-methylimidazo[1,2-a]pyridyl-N-prop-2′-ynylamide ( 5 ) and 1-acetonyl-3-prop-2′-ynylpyrido[2,3-d]pyrimidine-2,4-dione ( 6 ).     

Room temperature cyclization of arylpropiolic acid anhydride: Synthesis of naphtho[2,3-c]furan-1,3-dione derivatives

Cyclic anhydrides such as naphtho[2,3-c]furan-1,3-dione derivatives were synthesized from the reaction of arylpropiolic acids and 2-chloro-4,6-dimethoxy-1,3,5-triazine in the presence of N-methylmorpholine at room temperature. This mild condition provided the naphtho[2,3-c]furan-1,3-dione derivatives in good yields. Spectroscopic analysis suggested that the formation of arylpropiolate is the rate-determining step.