氰基取代的含杂环烯酮缩胺的合成及其波谱和结构特性

由氰基乙酸酯或丙二腈先制得氰基取代的烯酮缩硫醇, 然后与二胺反应合成了氰基取代的含杂环烯酮缩胺, 测定了它们的UV、IR、^1H及^1^3C NMR等波谱, 并测定了其中两个化合物的晶体结构, 对所得的波谱和结构特性进行了讨论。     

Synthesis of Ethyl 2-Cyano-3-Methylthio-3'-Arylaminoacrylate From Low Nucleophilic Amine

The synthesis of ketene N,S-acetals has attracted a considerable attention as building blocks in organic synthesis, especially in the preparation of heterocycles^[1]. The addition reaction of ketene S,S-acetals with highly nucleophilic amines, such as alkylamines, can easily afford the corresponding ketene N,S-acetals, under gentle condition, which could be converted into conjugated ketene aminals by reaction with a second equivalent of the same or a different amine^[2,3]. However, this addition reaction with low nucleophilic amines, such as arylamine or heterocyclic amine, can hardly give the corresponding ketene N,S-acetals under gentle conditions. If under powerful condition,such as refluxing, the addition reaction affords a mixture of the N,S-acetals and conjugated ketene aminals^[4]. Recent studies showed that this addition reaction with low nucleophilic amines affords the corresponding ketene N,S-acetals in the presence of a catalyst^[5].     

The regiospecific N‐sulfonylation and N‐phosphorylation of benzoyl‐substituted heterocyclic ketene aminals

The regiospecific N‐sulfonylation and N‐phosphorylation of benzoyl‐substituted heterocyclic ketene aminals have been investigated. In the presence of sodium hydride, benzoyl‐substituted heterocyclic ketene aminals 1 or 2 reacted with p‐toluenesulfonyl chloride 3 to give (E)‐1‐(p‐toluenesulfonyl)‐2‐(aroylmethylene)imidazolidine 4 or (E)‐1‐(p‐toluenesulfonyl)‐2‐(aroylmethylene)hexahydropyrimidine 5, respectively. Under the same condition, 1 reacted with diethyl chlorothiophosphate 6 to give diethyl [2‐(aroylmethylene)imidazolidin‐1‐yl]thiophosphate 7. However, 2 failed to react with 6 to give N‐phosphorylated products. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 297–301, 1999     

Cascade reaction synthesis of multisubstituted bicyclic pyridone derivatives

An efficient synthesis of novel bicyclic pyridone derivatives via cascade reaction of heterocyclic ketene aminals (HKAs) and 4-arylmethylene-2-phenyloxazol-5(4H)-ones in the presence of acetic acid has been established. Significantly, the protocol affords a straightforward approach to the construction of multisubstituted bicyclic pyridones in which one C–O bond was cleaved and new C–C and C–N bonds were formed in one pot under mild conditions.     

Synthetic exploitation of halogenated alkenes containing an electron-withdrawing group: synthesis of α-chlorohydrazones and ketene aminals by regiospecific reactions of in situ generated imide chlorides

A concise approach for the construction of ketene aminals and α-chlorohydrazones has been developed. It involves reactions of the regiodefined gem-dihalo nitrovinyl compound of in situ generated imide chlorides in different media with primary arylamines being dependent on the aryl groups. A range of ketene aminals and α-chlorohydrazones are obtained in good to high yields. In addition, α-aminohydrazones are prepared by using α-chlorohydrazones as the precursors.     

Regiospecific Synthesis of N-Sulfanilyl Heterocyclic Ketene Aminals

Heterocyclic ketene aminals 1 or 2 reacted with N-acetylsulfanilyl chloride 3 in the presence of sodium hydride to afford N-sulfanilyl heterocyclic ketene aminals 4 or 5 regiospecifically.     

Recent developments in the heterocyclic ketene aminal-based synthesis of heterocycles

Research on Chemical Intermediates - Small poly-functionalized heterocycles are frequently found in pharmacophores and play important roles in drug discovery. Heterocyclic ketene aminals (HKAs) are...     

THE REACTION OF BENZOYL SUBSTITUTED HETEROCYCLIC KETENE AMINALS WITH ARYL AZIDES.A FACILE APPROACH TO SYNTHSIZE 1, 5-DIARYL-4-(2-IMIDAZOLINYL)-1, 2, 3-TRIAZOLES

Heterocyclic ketene aminals 1 react with aryl azides 2 to give thetitled compounds 3, and in some cases also with the formation offused heterocycles 4.     

Chelate synthesis of pyrazolyl(ethoxycarbonyl)ketene aminals,the precursors of functionalized pyrazolo[1,5-c]pyrimidines

A scheme for the preparation of novel synthetic reagents. pyrazolyl(ethoxycarbonyl)ketene aminals, from acetyl(ethoxycarbonyl)ketene (N-benzoyl)aminalvia its difluoroboron chelate is suggested. The possibility of cyclization of the ketene aminals obtained into functionally substituted pyrazolo[1,5-c]pyrimidines is shown.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2211–2214, December, 1994.This work was carried out with the support of the International Science Foundation (ISF, Grant No. M5Q 000), and a part of the work was supported by the Russian Foundation for Basic Research (Project No. 94-03-08964).     

烯酮缩胺与芳基异硫氰酸酯的反应: 合成异噻唑化合物 的一个途径

具有不同取代基的五状和非环状的烯酮缩胺与芳基异硫氰酸酯在两酮中回流,可高产率地获得α-碳加成产物,该产物在溴存在下可氧化关环生成异噻唑类化合物。     

Stereodefined Acyclic Polysubstituted Silyl Ketene Aminals: Asymmetric Formation of Aldol Products with Quaternary Carbon Stereocenters

The regio‐ and stereoselective formation of stereodefined polysubstituted silyl ketene aminals is easily achieved through selective combined carbometalation–oxidation–silylation reactions. These substrates are ideal candidates for Mukaiyama aldol reactions with aliphatic aldehydes as they give the aldol products with a quaternary carbon stereocenter α to the carbonyl groups in outstanding diastereoselectivities.     

THE SECONDARY REACTION IN THE CONDENSATION OF 1-METHYL-2-METHYLTHIO-IMIDAZOLINE WITH ACTIVE METHYLENE COMPOUNDS

Mono-substituted heterocyclic ketene aminals are formed by the reactionof 1-methyl-2-methylthio-imidazoline with active methylene compoundscontaininq an acetyl or benzoyl group by the elimination of both amethylthio and an acyl group.This is resulted by the secondary reactioof the produced methanethiol to attack the more active carbonyl group.     

Synthesis of Spiro Heterocyclic Ketene Aminals

A method is provided for the synthesis of the previously unknown spiro heterocyclic ketene aminals, 3,9-bis(substituted-methylene)-2,4,8,10-tetraazaspiro[5.5]undecane 3 in moderate to excellent yields by cyclocondensation reaction of ketene dithioacetals 1 with tetrakis(aminomethyl)methane 2.     

A novel and facile synthesis of 2-oxo-1,2-dihydropyridine-fused 1,3-diazaheterocycles via heterocyclic ketene aminals and Konevenagel adducts formed by phthalic anhydride and ethyl cyanacetate

An efficient synthetic pathway to 2-oxo-1,2-dihydropyridine-fused 1,3-diaza heterocycles from heterocyclic ketene aminals,phathalic anhydride and ethyl cyanacetate was established.This protocol involved aza-ene reaction/imine-enamine tautomerization/enamine-ester exchange/ring-opening reaction sequence.     

Solid-phase Synthesis of a Novel Kind of Hydroxylated Heterocyclic Ketene Aminals

An efficient solid-phase synthesis method for novel heterocyclic ketene aminals containing a hydroxyl group has been developed. The loading of the substrate on the resin through the hydroxyl group and the protection of the amine by the Schiff base were the key steps in the synthesis.     

THE RADICAL NUCLEOPHILIC SUBSTITUTION REACTION OF HETEROCYCLIC KETENE AMINALS WITH 2,4-DINITROHALOBENZENES

The anion of heterocyclic ketene aminals reacted with 2,4-dini-tro-halobenzenes to give an arylated product through the radical nucleo-philic substitution confirmed by ESR spectroscopy,ESR-spin trapping techni-que,and depression of the reaction rate by the addition of inhibitor.     

Synthesis of novel tetracyclo-isocoumarins via AcOH-catalyzed cascade reaction of heterocyclic ketene aminals with 2,2-dihydroxy-2H-indene-1,3-dione

A facile synthesis of tetracyclo-isocoumarins based on the AcOH-catalyzed cyclocondensation and rearrangement reaction between heterocyclic ketene aminals and 2,2-dihydroxy-2H-indene-1,3-dione is described. This method provides direct access to tetacyclo-isocoumarins, a class of compounds with potential broad spectrum biological activities.     

Diaminomethylidene derivatives of β-oxo sulfones as potential reagents in heterocyclic synthesis and chelating ligands

Active methylene β-oxo sulfones add to the C≡N bond of benzoylcyanamide in the presence of catalytic amounts of Ni(acac)₂. Debenzoylation of the reaction products under the action of MeONa in MeOH gives N,N′-unsubstituted diaminomethylidene derivatives of β-oxo sulfones (acyl(R-sulfonyl)ketene aminals), which can be used as reagents for heterocyclic synthesis and as chelating ligands. The syntheses of 2-amino-3-arylsulfonylpyridin-4(1H)-ones and 5-sulfonylcytosine derivatives are presented as examples.     

Silver(I)-mediated coupling reaction of heterocyclic ketene aminals (HKAs) with bis(phenylsulfonyl)sulfides to synthesis of benzenesulfonothioyl-HKAs

An efficient and convenient method was developed for the preparation of 2-benzenesulfonothiol-HKAs via a silver(I)-mediated direct sulfenylation of heterocyclic ketene aminals (HKAs). The method involves a variety of functionalized substrates, leading to α-arylthioyl HKAs in a mild, easy operation, and mild reaction conditions.     

O—Maltosylation of Heterocyclic Ketene Aminals

The stereoselective synthesis of O-maltosides by reacting benzoyl-substituted heterocyclic ketene aminals 1 or 2 with acetylated maltosyl bromide 3 was investigated.Compounds 1 or 2 reacted with 3 in the presence of mercuric cyanide to give O-maltosides 4 or 5 with E-configuration.While 1 reacted with 3 in the presence of calcium hydride to give O-maltosides 6 with Zconfiguration.