Synthesis of 2,3-bis(perfluoroalkyl)quinoxalines and 2,3-bis(perfluoroalkyl)-1,4-benzoxazines from oxides of internal perfluoroolefins

The reactions of oxides of internal trans-, cis-perfluoroolefins with o-phenylenediamine and 2-aminophenol in dioxane gave 2,3-bis(perfluoroalkyl)quinoxalines and 2,3-bis(perfluoroalkyl)-2H-1,4-benzoxazin-2-ols respectively in yields of 23-67%. When N,N-dimethylacetamide was used as a solvent an anionic isomerization of the oxides into ketones, which further yielded 2-(perfluoroalkyl)benzimidazoles in the case of o-phenylenediamine and 2-hydroxy-N-perfluoroalkanoylanilines in the case of 2-aminophenol, became the main path of these reactions. Unusual cyclization resulting in 2-pentafluoroethyl-2-pentafluoropropanoylbenzoxazolidine occurs on interaction between dodecafluoro-3,4-epoxyhexane and 2-aminophenol in N,N-dimethylacetamide.     

Reaction of 2,3-epoxyoctafluorobutane with 2-aminobenzenethiol

The reaction of 2,3-epoxyoctafluorobutane with 2-aminobenzenethiol in N,N-dimethylacetamide gave 3-(2-aminophenylsulfanyl)-1,1,1,3,4,4,4-heptafluorobutane-2,2-diol. In the reaction of the same compounds in dioxane, 2,3-bis(trifluoromethyl)-3,4-dihydro-2H-1,4-benzothiazin-2-ol was formed as a result of primary attack by the amino group in 2-aminobenzenethiol on the epoxy ring. The same product was obtained by treatment with 2-aminobenzenethiol of 2,3-bis(trifluoromethyl)-2H-1,4-benzoxazin-2-ol which was synthesized from 2,3-epoxyoctafluorobutane and 2-aminophenol.     

Features of the reactions of β-aryl(heteryl)-α-nitroacrylates with N,N-, N,O-, and N,S-binucleophiles

The reactions of ??-aryl(heteryl)-??-nitroacrylates with N,N-, N,O-, and N,S-binucleophiles proceed regiospecifically through the initial formation of the Ad_N products, among which only the product from o-aminothiophenol was isolated. The conditions of converting the S-adducts into 2-aryl(heteryl)benzothiazole were found. The N-adducts formed in the reaction with hydrazine, o-phenylenediamine, and o-aminophenol undergo immediately the spontaneous transformation into the linear (azine, azomethine) or heterocyclic (benzimidazole) structures.     

Benzimidazole polymers from aldehydes and tetraamines

A new method for the preparation of benzimidazole polymers is described. The solution polymerization of aromatic tetraamines with isophthalaldehyde bis bisulfite adduct in N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (MP), and dimethyl sulfoxide (DMSO) produced polybenzimidazoles with viscosities (ηinh) in the range of 0.3–0.5 measured in formic acid solution. Also a model compound study with benzaldehyde, benzaldehyde diethyl acetal, and benzaldehyde bisulfite adduct with o-phenylenediamine was carried out. The results showed that the reaction of benzaldehyde bisulfite adduct with o-phenylenediamine in DMAc as the solvent gave quantitative yields of 2-phenylbenzimidazole. Excellent yields of 2-phenylbenzthiazole, 2-phenylbenzoxazole, and 2-pyridylbenzimidazole were also obtained with the benzaldehyde bisulfite adduct and picoline-2-carboxaldehyde bisulfite adduct with o-aminothiophenol, o-aminophenol, and o-phenylenediamine. The reaction conditions for the preparation of the polymers and the model compounds are very mild and the reaction times range from 15 min to 1 hr for the model compounds and 3–5 hr for the polymers. Longer reaction times did not increase the viscosities of the polymers to any extent.     

Reactions of internal perfluoroolefin oxides with urea

Internal perfluoroolefin oxides reacted with urea to give, depending on the solvent nature, two types of new fluorine-substituted nitrogen-containing heterocycles. 1,5-Bis(perfluoroalkyl)tetraazabicyclo[3.3.0]octane-3,7-diones were formed in dimethyl sulfoxide, N,N-dimethylacetamide, and acetonitrile, while the reaction in dioxane resulted in the formation of unexpected products, 2-amino-5-fluoro-4,5-bis(perfluoroalkyl)-4,5-dihydrooxazol-4-ols, existing mainly as trans isomers. trans Orientation of perfluoroalkyl substituents in these compounds was determined by analysis of ¹⁹F-¹⁹F spin-spin coupling constants in the ¹⁹F NMR spectra. The molecular structure of trans-2-amino-5-fluoro-4,5-bis(trifluoromethyl)-4,5-dihydrooxazol-4-ol was studied by X-ray analysis.     

Synthesis,characterization, anticancer activity,thermal and electrochemical studies of some novel uranyl Schiff base complexes

Some tetradentate N₂O₂ Schiff base ligands, such as N,N′-bis(naphtalidene)-1,2-phenylenediamine, N,N′-bis(naphtalidene)-4-methyl-1,2-phenylenediamine, N,N′-bis(naphtalidene)-4-chloro-1,2-phenylenediamine, N,N′-bis(naphtalidene)-4-nitro-1,2-phenylenediamine, N,N′-bis(naphtalidene)-4-carboxyl-1,2-phenylenediamine, and their uranyl complexes were synthesized and characterized by ¹H NMR, IR, UV–Vis spectroscopy, TG (thermogravimetry), and elemental analysis (C.H.N.). Thermogravimetric analysis shows that uranyl complexes have very different thermal stabilities. This method is used also to establish that only one solvent molecule is coordinated to the central uranium ion and this solvent molecule does not coordinate strongly and is removed easier than the tetradentate ligand and also trans oxides. The electrochemical properties of the uranyl complexes were investigated by cyclic voltammetry. Electrochemistry of these complexes showed a quasireversible redox reaction without any successive reactions. Also, the kinetic parameters of thermal decomposition were calculated using Coats–Redfern equation. According to Coats–Redfern plots the kinetics of thermal decomposition of the studied complexes is first-order in all stages. Anticancer activity of the uranyl Schiff base complexes against cancer cell lines (Jurkat) was studied and determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide) assay.     

The interaction of fluorinated 2-arylhydrazono-1,3-dicarbonyl compounds with o-phenylenediamine

2-Arylhydrazono-3-fluoroaklyl-3-oxo esters react with o-phenylenediamine under neutral conditions to form mainly o-aminoanilides, from which can be obtained 1,5-benzodiazepin-2-ones. Ethyl-2-(benzimidazol-2-yl)-2-(4-methylphenyl)hydrazonoethanoate was isolated also from the reaction of di(tri)fluoromethyl-containing 2-arylhydrazono-3-oxo esters. The reactions of o-phenylenediamine with 1,2,3-triketone 2-arylhydrazones containing alkyl substituents result in the formation of 1-(benzimidazol-2-yl)-1,2-dioxoalkane arylhydrazones, whereas phenylsubstituted analogues afford 2-phenylbenzimidazole. Nickel(II) chelates of N,N′-phenylene-bis(2-arylazo-1,3-aminovinylketones) were obtained from 1,2,3-triketone 2-arylhydrazones and o-phenylenediamine using a template method.     

1,5-Benzoheteroazepines through eco-friendly general condensation reactions

Condensation reactions of o-phenylenediamine and 2 equiv of acetone produce biaryl-substituted 1,5-benzodiazepines. The synthetic protocol shows general applicability since similar reaction of o-phenylenediamines, o-aminophenol, and o-aminothiophenol with ketones or chalcones leads to formation of functionalized 1,5-benzoheteroazepines in good to excellent yields. The synthetic protocol fulfills many green-chemical requirements using simple MW-assistance to promote the activation of ketones and the eco-compatible Er(III) triflate as activator of chalcones.     

Utility of [4-(3-methoxyphenyl)pyrimidin-2-yl]cyanamide in synthesis of some heterocyclic compounds

N-[4-(3-Methoxyphenyl)pyrimidin-2-yl]cyanamide ( 1 ) was reacted with morpholine and respective binuclephilic reagents namely: ethylenediamine, o-phenylenediamine, o-aminothiophenol, or o-aminophenol to give the corresponding carboximidamide 2 , imidazolidine 3 , and benzazoles 4–6 . While its reaction with hydrazides in DMF at 90°C, gave the corresponding 1,2,4-triazols 7–11 . Also, treatment of cyanamide 1 with heterocycles having both nucleophilic and electrophilic groups (─NH₂/─COOEt) in iso-propanol in presence of catalytic amount of Conc. HCl, gave the corresponding thieno[2,3-d]pyrimidinone 12 and unexpected thieno[3,2-d]pyrimidine 13 instead of bis-thieno[3,2-d]pyrimidine 14 , respectively. While, its reaction with ethyl 5-amino-1,3-thiazole-4-carboxylate yielded the unexpected N-(pyrimidin-2-yl)urea 15 rather than the corresponding thiazolo[5,4-d]pyrimidine 16 . Unexpected N-(pyrimidin-2-yl)thiourea 17 was obtained, when cyanamide 1 reacted with potassium thiolates in iso-propanol with catalytic amount of Conc. HCl.     

5-(N-2-羟乙基)羟乙酰氨基-N,N'-双(2,3-二羟丙基)-2,4,6-三碘-1,3-苯二甲酰胺的合成

5-氨基-N,N'-双(2,3-二羟丙基)-2,4,6-三碘-1,3-苯二甲酰胺(2)在N,N-二甲基乙酰胺中可直接与乙酰氧基乙酰氯反应, 产物再经碱性水解得5-羟乙酰氨基-N,N'-双(2,3-二羟丙基)-2,4,6-三碘-1,3-苯二甲酰胺(3), 后者再与氯乙醇反应生成5-(N-2-羟乙基)羟乙酰胺基-N,N'-双(2,3-二羟丙基)-2,4,6-三碘-1,3-苯二甲酰胺(1), 经乙二醇甲醚/正丁醇重结晶, 纯度高于99% (HPLC), 反应总收率由39.3% (文献值)提高到55.1%.     

Reactions of perfluoro(2,3-epoxy-2-methylpentane) with o-phenylenediamine and ethylenediamine

Perfluoro(2,3-epoxy-2-methylpentane) reacted with o-phenylenediamine and ethylenediamine via cleavage of the C-C bond to produce 2,2,3,3,3-pentafluoro-N-[2-(2,2,2-trifluoro-1-trifluoromethylethylamino)-phenyl]propanamide and 2,2,3,3,3-pentafluoro-N-[2-(2,2,2-trifluoro-1-trifluoromethylethylamino)ethyl]-propanamide, respectively. Presumably, these compounds are formed as a result of rearrangement of intermediate ketone generated by intramolecular haloform-type reaction. According to the NMR and X-ray diffraction data, 2,2,3,3,3-pentafluoro-N-[2-(2,2,2-trifluoro-1-trifluoromethylethylamino)phenyl]propanamide in crystal exists as Z conformer with respect to the amide C-N bond.     

Facile synthetic protocols for perfluoroalkyl-substituted diazapentaphenes

Novel syntheses of 13,14-bis(perfluoroalkyl)-substituted 5,8-diazapentaphene derivatives were realized by such a facile two-step protocol as consecutive benzyne insertion into C(O)–NH bonds of p-phenylene-bis(perfluoroalkanamides), followed by Friedel–Crafts type cyclization reaction, yielding the corresponding title compounds especially for the case of Rf=CF₃ or C₂F₅. Additionally, an alternative approach based on condensation of cyclohexane-1,4-dione with (o-aminophenyl) perfluoroalkyl ketones, followed by dehydrogenation enabled us to effectively access to the same final products in better yields.     

CuO nano-particles supported on silica,a new catalyst for facile synthesis of benzimidazoles,benzothiazoles and benzoxazoles

A facile synthetic route for benzimidazoles, benzothiazoles and benzoxazoles comprising the reaction of corresponding o-phenylenediamine, o-aminothiophenol and o-aminophenol with various aldehydes using silica supported nano-copper (II) oxide as a catalyst has been described. The catalyst exhibited a clean reaction profile with excellent yields in a short reaction time. The catalyst can be recycled effectively after use.     

Synthesis of 4-Aryl-1,5-benzodiazepine-2-carboxamides

4,N-Diaryl-1,5-benzodiazepine-2-carboxamides were synthesized by acid-catalyzed reaction of (Z)-4,N-diaryl-2-hydroxy-4-oxo-2-butenamides with o-phenylenediamine or N,N'-bis(triphenylphosphoranediyl)-o-phenylenediamine. The reaction mechanism is discussed.     

An efficient and reusable heterogeneous catalyst Animal Bone Meal for facile synthesis of benzimidazoles, benzoxazoles, and benzothiazoles

A library of benzimidazoles, benzoxazoles, and benzothiazoles was efficiently synthesized by condensation of o-phenylenediamine, o-aminophenol, and o-aminothiophenol respectively with aromatic aldehydes in the presence of catalytic amounts of Animal Bone Meal (ABM) and Lewis acids doped ABMs. Reactions were conducted under reflux conditions in air. The remarkable features of this new protocol are high conversion, short reaction times, and cleaner reaction profiles, straightforward procedure, and reduction in catalyst toxicity.     

5-Aryl-2-furaldehydes in the Synthesis of 2-Substituted 1,3-Benzazoles

2-[2-(5-Aryl-2-furyl)ethenyl]-1,3-benzazoles were synthesized by reaction of 5-aryl-2-furaldehydes with 2-methylbenzoxazole, 2-methylbenzothiazole, 2-methylbenzimidazole, and 2-cyanomethylbenzimidazole. The corresponding benzazoles were also obtained by reaction of N-(5-arylfurfurylidene)anilines with 2-methylbenzoxazoles and of 3-(5-aryl-2-furyl)-2-cyanopropenoyl chlorides with o-phenylenediamine. The acylation of o-aminophenol with 3-(5-aryl-2-furyl)-2-cyanopropenoyl chlorides occurs at the amino group without subsequent oxazole ring closure.     

Naphtho[1′,2′:5,6]pyrano[2,3–6][1,5]benzodiazepine Derivatives

The reaction of 3-(dimethylamino)-1-oxo-1H-naphtho[2,1-b]pyran-2-carbaldehyde (Ia) with o-phenylenediamines or N-monosubstituted o-phenylenediamines in refluxing glacial acetic acid afforded the corresponding naphtho[1′,2′:5,6]pyrano[2,3-b][1,5]benzodiazepin-15-(8H)ones V in very good yields. A similar result was achieved when the reaction was carried out in refluxing pyridine, using N-monosubstituted o-phenylenediamine hydrochlorides. The isolation of a significant intermediate as well as the synthesis through a different univocal pathway confirmed the structure of the compounds V. Moreover the reaction of Ia with N-monosubstituted o-phenylenediamines in refluxing pyridine generally afforded only low yields of compounds V, sometimes together with naphtho[1′,2′:5,6]pyrano[2,3-b][1,5]benzodiazepin-15-(13H)ones VII, isomers of V.     

Efficient propylphosphonic anhydride (®T3P) mediated synthesis of benzothiazoles,benzoxazoles and benzimidazoles

Propylphosphonic anhydride (®T3P) promotes cyclization of o-aminobenzenethiol, o-aminophenol, and o-phenylenediamine with carboxylic acids under microwave irradiation. The one-pot procedure is efficient and allows short reaction times, easy workup, and good yields. Thus, we describe here a method for quick preparation of benzothiazoles, benzoxazoles and benzimidazoles.     

Reactions of 1,2-bis(trifluoroacetyl)benzene with nucleophiles leading to heterocyclic compounds

The reaction of 1,2-bis(trifluoroacetyl)benzene (II) with ammonia, hydrazine, hydroxylamine and L-alanine has been investigated and the resulting heterocyclic compounds fully characterized on the basis of spectral data. The reaction of II with $\text{o}$-aminophenol and $\text{o}$-phenylenediamine led to the formation of tetracyclic compounds XI and XII respectively. The structure of compound XII has been further supported by single crystal X-ray crystallography. Our studies reveal the potential of the diketone II as a valuable synthon for the synthesis of a variety of heterocyclic systems with trifluoromethyl substituents.     

Reaction ofN,N-bis(chloromethyl)amides withN,N′-diacylated alkene(arylene)diamines

Reactions ofN,N-bis(chloromethyl)amides withN,N′-diacyl derivatives of ethylenediamine (oro-phenylenediamine) result in formation of the corresponding 1,3,5-triacylated perhydro-1,3,5-triazepines (or their benzoanalogs) or 1,3-diacylated imidazolidines (or their benzoanalogs). Reactions ofN,N-bis(chloromethyl)amides withN,N′-ditosylated trimethylenediamine occur in a similar way. The direction of the reactions depends on the type of the acyl substituents and the strength of the bases. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2270–2273, November, 1998.