2－芳胺基－2－硒唑啉－4－酮的简便合成

芳基硒脲与溴乙酸乙酯在乙醇溶液中作用，可合成得到含硒杂环化合物2-芳胺 基-2-硒唑啉-4-酮，反应产率为71%。     

Regioselective synthesis of functionalized naphtho[b]thiophenes through a ‘lactone methodology’

Benzo[b]thiophene and its benzannulated derivatives are important classes of compounds due to their unique chemical properties and biosteric relationship with indole. In this letter, we report a convenient route for the synthesis of substituted naphtho[b]thiophenes through a ring transformation reaction of suitably functionalized 2H-pyran-2-ones with 6,7-dihydro-5H-benzothiophene-4-one, in good yields.     

An ionic liquid mediated one-pot synthesis of substituted thiazolidinones and benzimidazoles

An expeditious one-pot synthesis of 2,3-diaryl/2-aryl-3-heteroaryl-1,3-thiazolidin-4-ones and 1-aryl-1H,3H-thiazolo[3,4-a]benzimidazoles have been accomplished by condensing hetero/aromatic amine, 2-mercaptoacetic acid, aromatic aldehyde and 1,2-phenylenediamine, 2-mercaptoacetic acid and aromatic aldehyde, respectively, in ionic liquids, viz, 1-butyl-3-methyl-imidazolium tetrafluoroborate and 1-methoxyethyl-3-methylimidazolium trifluoroacetate.     

A convenient synthesis of dihydro- and tetrahydro-1,3-thiazine derivatives from β-aryl-β-amino acids

A facile synthesis of 2-alkyl-4-aryl-5,6-dihydro-4H-1,3-thiazines and cis-2-alkyl-4-aryl-3,4,5,6-tetrahydro-2H-1,3-thiazines with potential therapeutic interest was achieved starting from readily accessible β-aryl-β-amino acids.     

An efficient synthesis of ortho-N-Boc-arylmethyl ketone derivatives

A new and efficient method for the preparation of ortho-N-Boc-arylmethyl ketone derivatives is reported. The reaction involves the intermediacy of a 4-methylene-3,1-benzoaxin-2-one moiety which smoothly converts to the target compounds under acidic conditions. The ortho-N-Boc-arylmethyl ketone derivatives can be formed in a one-pot reaction or alternatively the 4-methylene-3,1-benzoaxin-2-ones can be isolated and subsequently transformed into the desired products.     

A rapid and convenient synthesis of novel 1-imino-2,3-dihydro-1H-pyrazino[2,1,-b]quinazolin-5-ones

Exploring original approaches for the synthesis of therapeutic agents having a quinazoline part, we discovered that novel 3,4-dihydro-2H-pyrazino[2,1,-b]quinazolines (3) may be rapidly and easily obtained via the chemistry of 4,5-dichloro-1,2,3-dithiazolium chloride (1). Our synthetic approach of this reaction is described with the aim of obtaining a well-controlled access to this very rarely described pyrazino[2,1,-b]quinazoline skeleton.     

A methodology for the synthesis of highly functionalized 2- and 4-aminoquinoline derivatives

A methodology for the synthesis of 2- and 4-aminoquinoline derivatives, which takes advantage of selective activation of 2- or 4-substituent of 2-methylsulfanyl-3-acyl-1H-quinolin-4-one 1, has been developed. Since a procedure for formation of 3-aminoquinolinones from the 4-quinolinone 1 was described previously, the new methodology comprises a general methodology for the selective syntheses of three isomeric 2-, 3- and 4-aminoquinoline derivatives starting with the common 4-quinolinone 1.     

A convenient synthesis of polyfunctionally substituted 2-(arolyl-(arylsulfonyl)-methylene)-2,3-dihydrothiazoles and -thiazolidin-4-ones and their fused derivatives

Summary The reaction of phenyl isothiocyanate with arylsulfonylacetophenones1a–d in alkaline medium afforded the non-isolable intermediates2a–d. Upon reaction with some bromo compounds, the latter underwentin situ heterocyclization to afford the corresponding polyfunctionally substituted 2-(aroyl-(arylsulfonyl)-methylene)-2,3-dihydrothiazoles and-thiazolidin-4-ones. The structures of the newly synthesized compounds were assigned and confirmed on the basis of their elemental analyses, spectroscopic data, and alternative syntheses whenever possible.

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Eine einfache Synthese von polyfunktionell substituierten 2-(Aroyl-(arylsulfonyl)-methylen)-2,3-dihydrothiazolen und -thiazolidin-4-onen und ihrer kondensierten Derivate

Zusammenfassung Die Reaktion von Phenylisothiocyanat mit den Arylsulfonylacetophenonen1a–d in alkalischem Medium führt zu den nicht isolierbaren Zwischenprodukten2a–d. Diese cyclisieren mit einigen Bromverbindungenin situ zu den entsprechenden polyfunktionell substituierten 2-(Aroyl-(arylsulfonyl)-methylen)-2,3-dihydrothiazolen und -thiazolidin-4-onen. Die Strukturen der neuen Verbindungen wurden aufgrund ihrer Elementaranalysen und ihrer spektroskopischen Daten aufgeklärt und, wenn möglich, durch alternative Synthesen bestätigt.

     

二氧化硫脲:一锅合成吡喃并[4,3-b] 吡喃类化合物的高效可重复使用有机催化剂（英文）简

A series of pyrano[4,3-b]pyran derivatives have been synthesized in excellent yields by the reaction of aromatic aldehydes with malononitrile or cyanoacetate and 4-hydroxy-6-methylpyran-2-one in water at 80℃, with the transformation being catalyzed by an aqueous solution of thiourea dioxide (TUD). Upon completion of the reaction, the product was isolated by filtration or extraction and the remaining aqueous TUD solution could be reused several times without any discernible impact on its catalytic activity. This procedure offers several advantages over existing procedures, including high yields, operational simplicity, the use of a non-toxic catalyst and solvent, short reaction time and minimum pollution of the environment, making it a useful and attractive process for the preparation of pyrano[4,3-b]pyran derivatives.     

l-Proline catalyzed efficient and convenient synthesis of substituted 2H-chromenes by three-component reaction

A convenient and efficient method is described for the synthesis of alkoxy substituted 2H-chromens by l-proline catalyzed reaction of salicylaldehydes with diketone in alcohol. The method is applicable for various substituted salicylaldehydes and aliphatic as well as benzylic alcohols.     

Reaction of 2-methoxy-1,3,2-dioxaphosphorino[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-4(4<Emphasis Type="Italic">H</Emphasis>)-one with hexafluoroacetone

The reaction of the di-O-trimethylsilyl derivative of 2-hydroxynicotinic acid with methyl phosphodichloridite afforded 2-methoxy-1,3,2-dioxaphosphorino[4,5-b]pyridin-4(4H )-one. The NMR spectrkscopic data suggest that the reaction of the latter with hexafluoroacetone produces unstable 2-methoxy-2,5-dioxo-4,4-bis(trifluoromethyl)-4,5-dihydro-1,3,2-dioxaphosphepino[4,5-b]pyridine, which is readily transformed into 9-methyl-2,5-dioxo-4,4- bis(trifluoromethyl)-4,5-dihydro-1,3,2-dioxaphosphepino[4,5-b]pyrid-9-inium-2-oate. The structure of the hydrolysis product of the latter, viz., 1-methyl-3-(2-hydroxy-3,3,3-trifluoro-2- trifluoromethylpropanoyl)pyridin-2-one, was established by X-ray diffraction analysis.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1640–1646, August, 2004.     

Tandem versus single C-C bond forming reaction under palladium-copper catalysis: regioselective synthesis of α-pyrones fused with thiophene

We herein report a highly convenient protocol for rapid construction of α-pyrone fused with thiophene. This includes one-pot and regioselective synthesis of 4,5-disubstituted and 5-substituted thieno[2,3-c]pyran-7-ones, 6,7-disubstituted and 6-substituted thieno[3,2-c]pyran-4-ones. The synthesis of thieno[2,3-c]pyran-7-ones involves palladium mediated cross coupling of 3-iodothiophene-2-carboxylic acid with terminal alkynes in a simple synthetic operation. The coupling-cyclization reaction was initially studied in the presence of Pd(PPh₃)₂Cl₂ and CuI in a variety of solvents. 5-Substituted 4-alkynylthieno[2,3-c]pyran-7-ones were isolated in good yields when the reaction was performed in DMF. Similarly, 6-substituted 7-alkynylthieno[3,2-c]pyran-4-ones were synthesized via palladium-catalyzed cross coupling of 2-bromothiophene-3-carboxylic acid with terminal alkynes. A tandem C-C bond forming reaction in the presence of palladium catalyst rationalizes the formation of coupled product in this apparently three-component reaction. The cyclization step of this coupling-cyclization-coupling process occurs in a regioselective fashion to furnish products containing six-membered ring only. This sequential C-C bond forming reaction however, can be restricted to the formation of single C-C bond by using 10% Pd/C-Et₃N-CuI-PPh₃ as catalyst system in the cross coupling reaction. 5-Substituted thieno[2,3-c]pyran-7-ones were obtained in good yields when the coupling reaction was performed under this condition. Some of the compounds synthesized were tested in vitro for their anticancer activities.     

New convenient synthesis of 2,3-diaminothieno[2,3-d]pyrimidin-4(3H)-one derivates from substituted alkyl 2-(1H-tetrazol-1-yl)thiophene-3-carboxylates

4,5-Disubstituted and 4-substituted alkyl 2-amino-thiophene-3-carboxylates react with triethyl orthoformate and sodium azide in acetic acid to yield new 2-(1H-tetrazol-1-yl)-4-R¹-5-R²-thiophene derivates. It was established that the reaction of these tetrazoles with hydrazine generates the insufficiently studied 2,3-diaminothieno[2,3-d]pyrimidin-4(3H)-one system. It is significant that the reaction mentioned above is the unique tetrazole ring cleavage under the action of hydrazine.     

A novel one-pot synthesis of hydroximoyl chlorides and 2-isoxazolines using N-tert-butyl-N-chlorocyanamide

Treatment of aldoximes with N-tert-butyl-N-chlorocyanamide gave hydroximoyl chlorides in quantitative yields in less than a minute, which on dehydrohalogenation in the presence of triethylamine gave the corresponding nitrile oxides. The nitrile oxides underwent 1,3-dipolar addition to dipolarophiles and gave 2-isoxazolines in excellent yields under mild conditions.     

A radical mediated first total synthesis from ‘diacetone glucose’ and determination of the absolute stereochemistry of xylobovide

The first total synthesis by an intramolecular radical cyclisation protocol on a carbohydrate derived 5-hexynyl system, and determination of the absolute stereochemistry of xylobovide are reported.     

A Ce(III)-catalyzed expeditious multicomponent stereoselective synthesis of 3-mercapto-2(1H)-pyridinones

A novel Ce(III)-catalyzed, convenient, expeditious, and diastereoselective synthesis of 3-mercapto-2(1H)-pyridinones via one-pot, [3+2+1] three-component coupling reactions of chalcones, 2-methyl-2-phenyl-1,3-oxathiolan-5-one, and amines is reported. The synthesis involves sequential Michael addition, condensation, and ring transformation. Ambient temperature, operational simplicity, use of an environmentally clean catalyst, high yields, and diastereoselectivity are the key features of the present synthetic protocol.     

A new and convenient synthesis of 13,16-diazaestrone analogs

Imidazolidine-2,4-dione was chemoselectively N-alkylated at the imidic NH with several 2-(3,4-dihydro-1-naphthalenyl)ethyl-4-methylphenylsulphonates to give the corresponding imides for the first time which on selective reduction at one of the carbonyl groups followed by cyclization in PPA gave the corresponding title compounds.     

A novel synthesis and herbicidal activity of fluorine-containing pyrazolo[3,4-d]pyrimidin-4-one derivatives

The 6-(4-alkoxycarbonylalkoxy)phenoxy-3-alkylthio-5-(fluoro-substituted)phenyl-1-phenylpyrazolo[3,4-d]pyrimidin-4-ones 6 have been successfully synthesized via a tandem aza-Wittig and annulation reactions of the corresponding iminophosphorances 4, aromatic isocyanate, and substituted phenols 2 in 59-69% isolated yields using actonitrile as solvent. These novel compounds 6 could be oxidized to sulfones 7 by hydrogen peroxide in satisfactory yields (57-93%). Their structures were clearly verified by spectroscopic data (IR, ¹H NMR, ¹³C NMR, MS, Elemental analysis or X-ray diffraction crystallography). The results of preliminary bioassay indicated that these compounds possess herbicidal activity against the root of rape and barnyard grass.     

A selective and convenient ruthenium mediated method for the synthesis of mixed acetals and orthoesters

Addition of alcohols and phenols to O-allyl compounds (allyl ethers and acrolein acetals), catalyzed by [RuCl₂(PPh₃)₃], was examined. Intramolecular addition of an OH group, leading to the formation of cyclic acetals and orthoesters, was also investigated. As a result, a new, selective and convenient method for the synthesis of symmetrical and unsymmetrical (mixed) acetals and orthoesters was developed.