Reactions of N- and C-Alkenylanilines: V. Synthesis of Iodo-Substituted Heterocycles from o-Cycloalkenylanilines and Their Transformations

Iodination of N-isopropyl- and N-benzyl-2-(2-cyclohexenyl)anilines gave the corresponding 1-iodo-hexahydrocarbazoles which underwent quantitative isomerization into 3-iodo-2,4-propano-1,2,3,4-tetrahydro-quinolines. Nucleophilic substitution in 1-iodohexahydrocarbazoles and 3-iodo-2,4-propano-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indole was studied. N-Allylation of the latter via reaction with allyl bromide is accompanied by replacement of the iodine atom by bromine.     

Reactions of N- and C-Alkenylanilines: II. Halocyclization of 2-(2-Cycloalkenyl)anilines

The reaction of 2-(2-cyclopentenyl)anilines with I₂ in the presence of NaHCO₃ results in formation of 3-iodocyclopenta[b]indoles in high yields. Under similar conditions 2-(2-cyclohexenyl)anilines give rise to cyclization products whose structure depends on the solvent and substituents in the aromatic ring and on the nitrogen atom.     

Reactions of N- and C-Alkenylanilines: III. Synthesis and Cyclization of Substituted 2-(1-Methyl-2-butenyl)anilines

Reactions of substituted 2-(1-methyl-2-butenyl)anilines with iodine result in cyclization and formation of 3-iodo-1,2,3,4-tetrahydroquinolines; N-methylsulfonyl-2-(1-methyl-2-butenyl)anilines give rise exclusively to the corresponding 2-(1-iodoethyl)-3-methyl-2,3-dihydroindoles.     

Reactions of N- and C-Alkenylanilines: IV. Synthesis of Heterocycles by Oxidation of N-Acyl-o-(1-alkenyl)anilines with Hydrogen Peroxide

Heterocyclic compounds of the 4H-3,1-benzoxazine and cyclopenta[b]indole series were syn- thesized by oxydation of N-acyl derivatives of 2-(1-alkenyl)anilines with hydrogen peroxide. The structure of the oxidation products is determined by the reaction conditions, substituent in the ortho-position of the aromatic ring, protecting group, and alkenyl radical structure.     

Synthesis of N-[chloro(diorganyl)silyl]anilines

A series of N-[chloro(diorganyl)silyl]anilines RR′Si(NR″Ph)Cl (R, R′ = Me, Ph, CH₂=CH, ClCH₂, Cl(CH₂)₃; R″ = H, Me) was prepared via the reaction of diorganyldichlorosilanes with aniline or N-ethylaniline in the presence of triethylamine.     

Base-Catalyzed Synthesis of N-(2-Arylethyl)anilines and Base-Promoted Domino Synthesis of 2,3-Dihydroindoles

The base is the key to the new one-pot reaction , which leads to pharmacologically interesting 2,3-dihydroindoles. The use of potassium tert-butylalcoholate enables the selective addition of primary anilines to substituted styrenes and a new domino reaction, consisting of a hydroamination and an aryne cyclization (see scheme).     

Synthesis of substituted quinolines by electrophilic cyclization of N-(2-alkynyl)anilines

Quinolines substituted in the 3-position by an iodo or phenylseleno group are readily prepared in good to excellent yields by the reaction of propargylic anilines with appropriate electrophiles under mild reaction conditions. [reaction: see text]     

New Tetranuclear Ruthenium(I) Carbonyl Trifluoroacetate Complex: Gas-Phase Transformations and Coordination Reactions

A new mixed ligand ruthenium(I) complex of the composition [Ru₂(O₂CCF₃)₂(CO)₅] (1) has been prepared by refluxing Ru₃(CO)₁₂ with trifluoroacetic acid in a dichloromethane/benzene mixture. Crystals of 1 were obtained by gas phase sublimation of the crude product at 110°C. The X-ray diffraction study has revealed a tetranuclear `8dimer of dimers' 9 structure [Ru₂(O₂CCF₃)₂(CO)₅]₂ in 1. Complex 1 can be re-sublimed without decomposition at temperatures up to 130°C, while at higher temperatures fragmentation accompanied by a ligand re-distribution reaction has been observed. As a result, two new ruthenium(I) complexes have been isolated from the gas phase transformation of 1 at 160°C: [Ru₂(O₂CCF₃)₂(CO)₆] (2) and [Ru₂(O₂CCF₃)₂(CO)₄] (3). Complex 2 has a dinuclear cis-trifluoroacetato-bridged core, while 3 exhibits a polymeric structure built on axial Ru···O interactions of the dimetal units, [Ru₂(O₂CCF₃)₂(CO)₄]. The above reaction suggests the possible gas phase dissociation of the tetranuclear molecule 1 to the dimetal fragments, [Ru₂(O₂CCF₃)₂(CO)₅] that have one open axial coordination site. The latter was proved by codeposition of 1 with an aromatic hydrocarbon, [2. 2]paracyclophane, that afforded a new sandwich compound, [Ru₂(O₂CCF₃)₂(CO)₅·(₂-C₁₆H₁₆)·Ru₂(O₂CCF₃)₂(CO)₅] (4), in which the ligand is entrapped between two dimetal complexes. In contrast, when 3 is codeposited with [2. 2]paracyclophane, a new 1D polymeric product, [Ru₂(O₂CCF₃)₂(CO)₄·(₂-C₁₆H₁₆)] (5) has been isolated. Complexes 1–5 have been fully characterized by IR and NMR spectroscopy, as well as by X-ray diffraction.     

Organosilicon compounds : LI. Further studies of the base-catalysed solvolysis of N-(triorganosilyl)anilines

Relative rates of solvolysis of some N-triorganosilylanilines in mixtures of ethanol and aqueous potassium hydroxide have been determined, with results as follows. (i) For XC₆H₄NHSiEt₃ compounds in MeOH (5 vol) + aq. alkali (2 vol) at 50°: (X =) H, 1.0;p-Me, 0.80;p-OMe, 0.83;m-Me, 0.90; o-Me, 0.87; p-SMe, 1.90; p-F, 1.7; p-Cl, 2.8; o-Cl, 14; m-Cl, 4.2; m-NO₂, 18; p-CN, ca. 43; p-NO₂, ca. 120. (ii) For PhNHSi(C₆H₄Y)₃ compounds in MeOH (10 vol) + aq. alkali (1 vol) at 50°: (Y =) H, 1.0; p-OMe, 0.12; p-Cl, ca. 32; m-Cl, ca. 84. (iii) For PhNHSiR₃ compounds in MeOH (5 vol) + aq. alkali (2 vol) : (R₃ =) Et₃, 1.0; Et₂Me, 18 (at 30°); Me₂-i-Pr, 8 (at 30°);Me₂-t-Bu, 0.012 (at 50°);i-Pr₃, 0.006 (at 50°). In series (i) the relative rates correlate with σ, or where appropriate σ^?-constants, with a ? value of 1.6. It is suggested that in the transition state of the rate-determining step the OSi bond is fully formed, or almost so, the SiN bond approximately 20—50% broken, and the bond between the nitrogen atom and a proton from the solvent ca. 10—30% formed.     

Regioselective and enantiospecific rhodium-catalyzed allylic amination with N-(arylsulfonyl)anilines

[reaction: see text]. The regioselective and enantiospecific rhodium-catalyzed allylic amination of secondary allylic carbonates 1 with N-(arylsulfonyl)anilines provides a convenient process for the construction of arylamines 2. This method, in conjunction with ring-closing metathesis and radical cyclization reactions, allows the direct construction of biologically relevant pharmacophores as exemplified by the construction of dihydroquinoline and dihydrobenzo[b]indoline derivatives.     

Triphenyltin Esters of N-(2-Carboxybenzylidene)anilines: Synthesis,Spectroscopic Characterization,X-ray Structure Analysis and Fungicidal Activity

Four triphenyltin carboxylates formulated as o- Ph₃SnOCOC₆H₄CH=N–Ar (Ar=C₆H₅; p -CH₃C₆H₄; o -CH₃C₆H₄; o -HOC₆H₄) were prepared and spectroscopically characterized. The crystal structure of o -Ph₃SnOCOC₆ H₄CH=NC₆H₅ indicates that the tin atom, in each of the two molecules comprising the asymmetric unit, exists in a distorted tetrahedral geometry owing to an intramolecular acyl O. . .Sn contact. These new triphenyltin carboxylates display marked toxicity against the fungus Ceratocystis ulmi .     

N-(2,4-二硝基苯基)-N -取代苯腙衍生物对阴离子识别研究

合成了4种N-(2,4-二硝基苯基)-N -取代苯腙类阴离子结合受体(1～4, 取代基 R＝H, o-OCH₃, o-Cl, o-OH), 应用紫外吸收光谱方法研究了其与阴离子的相互作用, 以及考察N -苯环取代基对受体分子之阴离子亲合力和选择性的影响. 实验显示: 乙腈中F^－、CH₃CO 等阴离子使受体分子吸收光谱红移, 溶液由黄色转变为红色, 其中受体分子2对 F^－表现出高选择性的灵敏响应. 实验表明受体-阴离子间形成了氢键型超分子配合物, Job作图法给出了受体分子与阴离子的1∶1结合计量比, ¹H NMR滴定为受体分子与阴离子间的氢键作用本质提供了直接证据.     

N-(polyfluoroaryl)-hydroxylamines. Synthesis and properties

Fluorine-containing N-arylhydroxylamines have been obtained by the action of hydroxylamine or its N- and O-derivatives on polyfluorinated benzenes and pentafluoropyridine. The influence of fluorine atoms on the reactivity of hydroxylamino group has been investigated. The reaction of N-polyfluoroarylhydroxylamines with aldehydes has been shown not to occur, whereas their reaction with nitrosobenzenes leads to azoxybenzenes and with Lewis acids leads to corresponding nitrosobenzenes, azoxybenzenes and anilines. The action of acids on 2,3,5,6-tetrafluorophenylhydroxylamine leads to the acid-catalyzed rearrangement of the latter into 4-amino-2,3,5,6-tetrafluorophenol. C,N-Diarylnitrones have been obtained by the oxidation with MnO₂ of fluorine-containing arylhydroxylamines possessing the CH-fragment in an α-position.     

Reactions of N- and C-alkenylanilines: X. Synthesis of 2-vinyldihydroindoles from 4-methyl-2-(pent-3-en-2-yl)aniline

2-(1-Iodoethyl)-3,5-dimethyl-1-(4-methylphenylsulfonyl)-2,3-dihydro-1H-indole reacted with pyridine, piperidine, N-alkylpiperidines, and dimethylformamide to give dehydrohalogenation and halogen substitution products whose ratio depended on the reagent structure. Heating of 2-(1-iodoethyl)-3,5-dimethyl-1-methylsulfonyl-2,3-dihydro-1H-indole with piperidine resulted in the formation of only dehydroiodination products.     

Synthesis of N-(Hydroxy)amide- and N-(Hydroxy)thioamide-containing peptides

Methods developed with N-(benzoyloxy)amines and hydroxamic acids were used in the synthesis of N-(hydroxy)amide-containing pseudopeptides. Acylation of N-(benzoyloxy)phenethylamine with the acid chloride of N(alpha)-Fmoc-L-leucine provided a N(alpha)-Fmoc-N-(benzoyloxy)-L-leucinamide in 90% yield. Deprotection of the benzoyl group (using 10 vol % NH(4)OH/MeOH) provided the N(alpha)-Fmoc-N-(hydroxy)-L-leucinamide in 87% yield. In general, the appended Fmoc group allowed for further elaboration of the N-hydroxy-N-(alkyl)amides using classic peptide-coupling methods. A practical synthetic strategy was developed, and racemization issues were addressed using diastereomeric Val-Leu derivatives. In addition, N-(hydroxy)thioamides were generated from the corresponding N-(benzoyloxy)thioamides. N-(Benzoyloxy)thioamides were obtained in moderate yields (53-76%) from the reaction of the corresponding N-(benzoyloxy)amides with Lawesson's reagent (i.e., 2, 4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disu lfide). In summary, this new technology allows for the introduction of either N-hydroxyamide or N-(hydroxy)thioamide linkages into pseudopeptide chains without racemization.     

三氯化铈促进的反应及其在有机合成中的应用

综述了近年来三氯化铈促进的多种有机反应及其在有机合成中的应用, 其中重点讨论了三氯化铈促进下的碳—碳原子键、碳—杂原子键的形成反应以及多种保护基团的选择性脱保护反应等.     

(Iodomethyl)fluorosilanes: Synthesis and Reactions

The methods of synthesis of bifunctional (iodomethyl)fluorosilanes of general formula ICH₂SiMe_nF_3–n (n = 0, 2) have been elaborated; the structure was proved by ¹H, ¹³C, ²⁹Si NMR spectroscopy. The reaction of (iodomethyl)dimethylfluorosilane with O-trimethylsilyl derivative of N,N'-dimethylhydrazide of trifluoroacetic acid gives rise to the formation of 2,2,4,4-tetramethyl-6-(trifluoromethyl)-3,4-dihydro-2Н-1,4,5,2-oxadiasilin-4-ium iodide with tetracoordinate silicone atom.