Synthesis of functionalized α-amino-phosphine oxides and -phosphonates by addition of amines and aminoesters to 4-phosphinyl- and 4-phosphonyl-1,2-diaza-1,3-butadienes

1,2-Diaza-1,3-butadienes derived from phosphine oxides and phosphonates and with optically active substituents on N-1 and C-3 are obtained by 1,4-elimination from chlorohydrazonoalkyl-phosphine oxides and -phosphonates in the presence of bases. Michael addition (1,4-addition) of ammonia, aliphatic and aromatic amines and aminoesters to these azo-alkenes gives functionalized α-amino-phosphine oxides and -phosphonates.     

Addition of amine derivatives to phosphorylated 1,2-diaza-1,3-butadienes. Synthesis of α-aminophosphonates

Achiral and chiral 1,2-diaza-1,3-butadienes derived from phosphine oxides and phosphonates are obtained from hydrazonoalkyl-phosphine oxides and -phosphonates. Michael addition (1,4-addition) of ammonia, aminoesters and aminoalcohols to these azo-alkenes gives functionalized α-amino-phosphine oxides and -phosphonates.     

Pyrolysis of 3-hydroxy-2-arylhydrazonoalkanoic acid derivatives

1,2-Diaza-1,3-butadienes have been obtained from readily available 3-hydroxy-2-arylhydrazonopropanoates under various reaction conditions including pyrolysis, dehydration under Mitsunobu conditions or with acetic anhydride or acetic acid. According to their method of synthesis these 1,2-diaza-1,3-butadienes underwent subsequent reactions to give interesting products, and in the presence of proper dienophiles gave the corresponding cycloaddition products. Also, a new approach to pyrazole-3-carboxylic acid derivatives was discovered during an attempt to dehydrate 3-hydroxy-2-arylhydrazonobutanoic esters.     

1,3-Dipolar Cycloaddition of 5-Substituted-1-Methyl-3-Oxidopyridiniums

5-Methoxy- and 5-dimethylamino-1-methyl-3-oxidopyridiniums were shown to give the 1,3-dipolar cycloadducts widely with methyl acrylate, acrylonitrile, N-phenylmaleimide, styrene, phenylacetylene, cyclopentadiene, cyclopentene, diethyl azodicarboxylate and singlet oxygen.     

氟烷基叠氮化合物和缺电子烯烃反应的研究

本论文研究了氟烷基叠氮化合物和缺电子烯烃的1,3-偶极反应, 合成了一系列含氟烷基三唑啉和氟烷基吡唑啉类化合物, 并提出了一个通过开环和以重氮化合物为中间体的反应机理.     

Stereoselective cycloaddition of 1-glucosyl-1,3-butadienes with tert-butyl 2H-azirine-3-carboxylate, glyoxylates and imines

Glucosyl dienes 1 have been reacted with the achiral 2H-azirine 4 and with glyoxylates, forming fused structures of type 5 and disaccharide-like compounds 7 with good to excellent selectivity. Glucosyl dienes 1 participated as dienophiles in reactions with Schiff bases derived from anilines forming isoquinolines 10 and 11. The diastereoselectivity of this reaction is poor.     

Reactions of heterocyclic paramagnetic aldonitrone, 2,2,5,5-tetramethyl-3-imidazoline-1-oxyl 3-oxide, with alkynes

The reactions of heterocyclic paramagnetic aldonitrone,viz., 2,2,5,5-tetramethyl-3-imidazoline-1-oxyl 3-oxide, with mono- and disubstituted alkynes afford unstable isoxazoline derivatives. The reactions with monosubstituted alkynes yield predominantly 5-substituted regioisomers. The resulting isoxazoline derivatives are readily (and often spontaneously) converted into enaminoketones,viz, imidazolidine-1-oxyl derivatives. In the presence of tolan, the title paramagnetic aldonitrone gives a dimer in which one imidazoline ring undergoes profound transformation. The structure of the resulting dimer was established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 112–117, January, 2000.     

Reactions of heterocyclic paramagnetic aldonitrone, 2,2,5,5-tetramethyl-3-imidazoline-1-oxyl 3-oxide, with alkynes

The reactions of heterocyclic paramagnetic aldonitrone,viz., 2,2,5,5-tetramethyl-3-imidazoline-1-oxyl 3-oxide, with mono- and disubstituted alkynes afford unstable isoxazoline derivatives. The reactions with monosubstituted alkynes yield predominantly 5-substituted regioisomers. The resulting isoxazoline derivatives are readily (and often spontaneously) converted into enaminoketones,viz, imidazolidine-1-oxyl derivatives. In the presence of tolan, the title paramagnetic aldonitrone gives a dimer in which one imidazoline ring undergoes profound transformation. The structure of the resulting dimer was established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 112–117, January, 2000.     

微波辐射下5-取代-2-硫代海因衍生物的合成

微波辐射下, 由硫氰酸铵与α-氨基酸通过两步反应合成了11种5-取代-2-硫代海因衍生物, 并用¹H NMR, IR和元素分析确证了中间产物和终产物的结构. 对比常规加热方法, 微波辐射具有反应时间短(4 min), 每步反应产率高(85%～93%)的优点. 同时对合成化合物2h的反应历程进行了讨论.     

Synthesis of complex dispirocyclopentanebisoxindoles via cycloaddition reactions of 4-dimethylamino-1-alkoxycarbonylmethylpyridinium bromides with 2-oxoindolin-3-ylidene derivatives

The cycloaddition reactions of 4-dimethylamino-1-alkoxycarbonylmethylpyridinium bromides with various 2-oxoindolin-3-ylidene derivatives in ethanol in the presence of triethylamine afforded the unprecedented dispirocyclopentanebisoxindole derivatives in good yields and in high diastereoselectivity. Under similar reaction conditions, the reactions of 1-alkoxycarbonylmethylpyridinium bromides with 3-phenacylideneoxindoles only resulted in 4-oxo-3-(2-oxoindolin-3-ylidene)-4-arylbutanoates. The stereochemistry of the complex spirooxindoles was established by ¹H NMR data and single crystal structures.     

新型2,4-二取代四氢吡咯-3-羧酸衍生物的合成

N-三甲硅甲基苯甲醛亚胺为非稳定型亚甲胺基叶立德前体,在磷酸催化下与取代噁唑烷酮烯烃经1,3-偶极环加成反应合成了10个具有cis-trans立体结构的新型2,3,4-三取代四氢吡咯-3-羧酸衍生物（3a~3j）,收率65%~75%,其结构经¹H NMR, ¹³C NMR和HR-MS表征。3b的立体结构经X-单晶衍射确证。     

Phosphine‐Catalyzed [3+2] Cycloaddition Reactions of Azomethine Imines with Electron‐Deficient Alkenes: A Facile Access to Dinitrogen‐Fused Heterocycles

An efficient method for the phosphine‐catalyzed [3+2] cycloaddition reaction of azomethine imines with diphenylsulfonyl alkenes to give dinitrogen‐fused bi‐ or tricyclic heterocyclic compounds in high yields has been described. Moreover, two phenylsulfonyl groups installed on the heterocyclic products could be conveniently removed or transformed to other functional groups, making the reaction more useful.     

The 1,3-Dipolar Cycloadditions of 3-Arylsydnone-4-Carbonitrile Oxides with Alkenes

3-Arylsydnone-4-carbonitrile oxides may undergo 1,3-dipolar cycloadditions with alkenes to produce the corresponding 3-aryl-4-(5-substituted-isoxazolin-3-yl)sydnones. The direct reaction of 3-arylsydone-4-carbohydroximic acid chlorides with alkenes may also give the same products, and with higher yield.     

1,3-Dipolar Cycloaddition of Nitrones with 5-Methylenehydantoins: Synthesis and Transformation of New Spirohydantoin Derivatives

1,3-Dipolar cycloaddition of various acyclic nitrones with 5-methylenehydantoin derivatives afforded new chiral spiroadducts in good yields. All the spirohydantoins were obtained through a regio- and stereospecific pathway, and the spirocarbon atom was linked to the isoxazolidine oxygen atom. A representative example of the reduction of the spirohydantoin 8 with Zn/AcOH led to the substituted 1,3-aminoalcohol hydantoin 20.     

Carbon-phosphorus bond formation and transformation in the reaction of 1,2-diaza-1,3-butadienes with alkyl phenylphosphonites

The reaction of 1,2-diaza-1,3-butadienes with dialkyl phenylphosphonites under solvent-free conditions proceeds via zwitterionic intermediate and gives, by precipitation, the stable ylidic α-phosphanylidene-hydrazones that, in turn, can be transformed into the corresponding 3-phenyl-2H-1,2,3λ⁵-diazaphospholes. The latter compounds are converted by hydrolytic cleavage in methanol-water (95:5) into E-hydrazonophosphonates that are useful for the preparation of the corresponding β-ketophosphonates and 4-[alkoxy(phenyl)phosphoryl]-1,2-diaza-1,3-butadienes. These peculiar 1,2-diaza-1,3-butadienes, bearing an alkoxy(phenyl)phosphoryl group on the carbon atom in position 4 are also able to add different nucleophiles, such as methanol or thiourea, giving 2-[alkoxy(phenyl)phosphoryl]-2-methoxyhydrazones and 5-phosphinate-substituted thiazol-4-ones, respectively.     

Synthesis and Reactions of New Fused Heterocycles Derived from 5-Substituted-4-Amino-3-Mercapto-(4H)-1,2,4-Triazole with Biological Interest

The reaction of thiocarbohydrazide with carboxylic acids at the melting temperature allows an improved preparation of 5-substituted-4-amino-3-mercapto 1,2,4-triazoles 1 _{a ? g} . Compound 1 _a reacted with 2-bromopropionic acid to give acid derivative 2 . The latter was reacted with a mixture of acetic anhydride and triethylamine to afford the mesoionic compound 3 . Heating of compound 3 in ethanol gave the ester derivative 4 , which on alkaline hydrolysis in methanol gave ketone derivative 5 . Substituted 1,2,4-triazolo [3,4-b]-6H-1,3,4-thiadiazine 6 _h,i and 7 were synthesized by reaction of 1 _a with acetylacetone, ethyl acetoacetate and chloroacetamide. Heterocyclic systems 8 and 9 were prepared through the reaction of 1 _a with 2,3-dichloro-1,4-naphthoquinone and 2,3-dichloroquinoxaline. In addition, thenoyl isothiocyanate, thenoyl chloride, 2-thiophenecarbaldehyde, and p-chlorophenyl isocyanate reacted with compound 1 _a to afford 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole ring system 10 , 11 , and urea derivative 12 . 1,2,4-Triazolo[3,4-b]-5H-pyrazole derivatives 14 _j,k were prepared through the reaction of compound 1 _a with 3-chloro-2,4-pentandione and ethyl-2-chloroacetoacetate. Compound 14 _j was treated with hydrazine to afford products 15 , 16 , and 17 depending on the type of hydrazine derivative and reaction conditions. Compound 19 was synthesized by refluxing of compound 14 _j with hydroxylamine hydrochloride to afford the corresponding oxime derivative 18 followed by treatment with thenoyl chloride.     

Reactions with Hydrazonoyl Halides 341: Synthesis of Some New 2,3-Dihydro-1,3,4-thiadiazoles

Hydrazonoyl halides 4a–h have been caused to react with each of alkyl carbodithioates (3, 13–17)a,b in the presence of triethylamine to give 2,3-dihydro-1,3,4-thiadiazoles in good yields. Structures of the new compounds were elucidated on the basis of elemental analyses, spectral data, and alternative methods of synthesis whenever possible.     

Synthesis and Some Reactions of Coumarin‐3‐yl Crotononitrile Derivatives

Several new coumarinyl crotononitriles, 2a‐i, coumarinyl cinnamocoumarines 3a,b, 4‐amino‐3‐(substituted)‐3,4‐dihydrocoumarin 4a‐c and 9a‐c, nicotinic acid derivatives 10a,b and 4‐ethoxy‐3‐substituted‐3,4‐dihydrocoumarins 11, were synthesized from 3‐acetyl and/or 3‐benzoyl coumarin. The behavior of coumarin‐3‐yl crotononitriles 2a,b toward some electrophilic and nucleophilic reagents have been described with the aim of preparing some new heterocyclic compounds.     

Gold‐Catalyzed Cascade Reactions for Synthesis of Carbo‐ and Heterocycles: Selectivity and Diversity

This account describes our recent efforts devoted to gold chemistry since 2009. Based on furyl–Au 1,3‐dipole analogues and related gold carbene intermediates, a rich variety of gold‐catalyzed cascade reactions have been developed, which provide facile access to a diverse range of novel carbo‐ and heterocycles. In these reactions, the selectivity can be well controlled by the catalyst (ligand and metal), substrate or reagent. In addition, we have also developed the corresponding enantioselective variants, which are guided by bis(phosphinegold) complexes derived from axially chiral scaffolds and asymmetric gold/chiral Brønsted acid relay catalysis.