Simple ammonium ionic liquid catalyses the 1,5-benzodiazepine derivatives under mild conditions

Abstract

An incredibly elementary procedure for the effective synthesis of 1,5-benzodiazepine derivatives using triethyl ammonium acetate (TEAA) [Et₃NH][CH₃COO] ionic liquid has been developed. TEAA was found to be practical, inexpensive, reusable and has a simple work-up procedure, which is absent in other catalyst. The role of TEAA as the reaction medium as well as the catalyst has shown the benefits of the use of TEAA in organic synthesis. The effect of [Et₃NH][CH₃COO] on the synthesis of 1,5-benzodiazepine derivatives has been studied and results are provided herein.     

An efficient synthesis of 1,5-benzodiazepine derivatives catalyzed by a solid superacid sulfated zirconia

2,3-Dihydro-1H-1,5-benzodiazepines are synthesized by the condensation of o-phenylendiamine and various ketones in the presence of a versatile solid superacid catalyst ‘sulfated zirconia’ under solvent free conditions.     

Room temperature ionic liquids promoted three-component coupling reactions: a facile synthesis of cis-isoquinolonic acids

Room temperature ionic liquids are found to catalyze efficiently the three component-coupling reactions of aldehydes, amines and homophthalic anhydride under mild and convenient conditions to afford the corresponding cis-isoquinolonic acids in excellent yields with high cis-selectivity.     

Efficient TCT-catalyzed synthesis of 1,5-benzodiazepine derivatives under mild conditions

2,4,6-Trichloro-1,3,5-triazine (TCT) efficiently catalyzed the condensation reactions between 1,2-diamines and various enolizable ketones to afford 1,5-benzodiazepines in good to excellent yields. Simple and mild reaction conditions, the use of a cheap catalyst and easy workup and isolation are notable features of this method.     

碱性离子液体催化合成取代萘并吡喃衍生物

离子液体具有强极性、不挥发、化学稳定性好等特点,其极性和亲水/亲脂性可通过改变烷基碳链的长短和阴、阳离子的种类来进行调节,对其结构进行化学修饰,可以得到具有特定功能的离子液体[1-3],因此被誉为绿色溶剂和可设计的溶剂[2]。许多萘并吡喃衍生物都具有重要的生物活性和药     

Preyssler catalyst-promoted rapid,clean, and efficient condensation reactions for 3H-1,5-benzodiazepine synthesis in solvent-free conditions

A simple, convenient, and environmentally benign synthesis of 1,5-benzodiazepines is developed by condensing different o-phenylenediamines and 1,3-aryl-1,3-propanodiones. The reaction is catalyzed by a Preyssler (NaH₁₄P₅W₃₀O₁₁₀, HPA) heteropolyacid as a safe, clean, and recyclable catalyst. The method is operationally simple and provides access to a variety of 1,5-benzodiazepines in good to excellent yields.     

A combinatorial access to 1,5-benzodiazepine derivatives and their evaluation for aldose reductase inhibition

Aryldiazepinothiophenones 4 were prepared from the reaction of o-phenylenediamines with acetone in the presence of 2-mercaptocarboxylic acids along with thiazolobenzodiazepines 6, thiazolobenzimidazoles 7 and 1,5-benzodiazepines 5, which were obtained as by-products. The benzodiazepinothiophenones 4a-d and the benzodiazepines 5a-d were also isolated from the reaction of o-phenylenediamines 1a-c with phorone. Structural assignments of the new compounds as well as complete assignment of ¹H and ¹³C NMR signals were based on the analysis of their ¹H and ¹³C NMR (1D and 2D), IR, MS and elemental analysis data. Compounds 4 were evaluated for aldose reductase inhibition and also as antioxidants.     

NBS as an efficient catalyst for the synthesis of 1,5-benzodiazepine derivatives under mild conditions

Various biologically important 1,5-benzodiazepine derivatives were efficiently synthesized in excellent yields using catalytic amounts of NBS (10 mol %). This inexpensive, nontoxic, and readily available catalyst efficiently catalyzes the condensation of several aromatic as well as aliphatic ketones with substituted o-phenylenediamines.     

Efficient and green synthesis of 4H-pyrans and 4H-pyrano[2,3-c] pyrazoles catalyzed by task-specific ionic liquid [bmim]OH under solvent-free conditions

Abstract

A facile and convenient procedure for the synthesis of 4H-pyrans from aldehydes, malononitrile, and ethyl acetoacetate/acetylacetone and also synthesis of 4H-pyrano[2,3-c]pyrazoles from three-component condensation of aldehydes, malononitrile, and pyrazolone or four-component condensation of aldehydes, malononitrile, ethyl acetoacetate, and hydrazine monohydrate using [bmim]OH as task-specific ionic liquid has been described. The protocol proves to be efficient and environmentally benign in terms of high yields, low reaction times, ease of recovery, and reusability of reaction medium.

     

Room temperature imidazolium ionic liquid: a solvent for extraction of carbamates prior to liquid chromatographic analysis

A simple and rapid method for preconcentration of carbamate insecticides, including methomyl, propoxur, carbofuran, carbaryl, isoprocarb, methiocarb and promecarb, has been developed. It was based on a liquid-liquid microextraction using a [C₄MIM][PF₆] room temperature ionic liquid as an extraction solvent prior to analysis by high performance liquid chromatography with UV detection. Experimental parameters affecting the extraction performance, such as the volumes of sample, extractant and dissolving solvent, and extraction time, were studied. Under the selected conditions, the enrichment factors in the range between 10 and 25 could be achieved with the limit of detection in the range of 2-40 μg L⁻¹, and with the relative standard deviations of lower than 0.6 and 10.2% for retention time and peak area, respectively. The proposed method offers advantages in reduction of the exposure danger to toxic solvents used in the conventional liquid-liquid extraction, simplicity of the extraction processes, rapidity, and sensitivity enhancement. The method was demonstrated to apply to the analysis of fruit and natural surface water samples.     

Room temperature ionic liquid as a novel medium for liquid/liquid extraction of metal ions

Room temperature ionic liquids (RTILs) have been used as novel solvents to replace traditional volatile organic solvents in organic synthesis, solvent extraction, and electrochemistry. The hydrophobic character and water immiscibility of certain ionic liquids allow their use in solvent extraction of hydrophobic compounds. In this work, a typical room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C₄mim][PF₆], was used as an alternative solvent to study liquid/liquid extraction of heavy metal ions. Dithizone was employed as a metal chelator to form neutral metal-dithizone complexes with heavy metal ions to extract metal ions from aqueous solution into [C₄mim][PF₆]. This extraction is possible due to the high distribution ratios of the metal complexes between [C₄mim][PF₆] and aqueous phase. Since the distribution ratios of metal dithiozonates between [C₄mim][PF₆] and aqueous phase are strongly pH dependent, the extraction efficiencies of metal complexes can be manipulated by tailoring the pH value of the extraction system. Hence, the extraction, separation, and preconcentraction of heavy metal ions with the biphasic system of [C₄mim][PF₆] and aqueous phase can be achieved by controlling the pH value of the extraction system. Preliminary results indicate that the use of [C₄mim][PF₆] as an alternate solvent to replace traditional organic solvents in liquid/liquid extraction of heavy metal ions is very promising.     

Homogeneous ionic liquid microextraction of the active constituents from fruits of Schisandra chinensis and Schisandra sphenanthera

Homogeneous ionic liquid microextraction (HILME) was developed for the extraction of schizandrin, schisantherin A and deoxyschizandrin from Schisandra chinensis and Schisandra sphenanthera. 1-Butyl-3-methylimidazolium tetrafluoroborate ([C₄MIM][BF₄]) aqueous solution was used as extraction solvent, and ammonium hexafluorophosphate ([NH₄][PF₆]) was used as ion-pairing agent. 1-Butyl-3-methylimidazolium hexafluorophosphate ([C₄MIM][PF₆]), which is barely soluble in water, was formed in situ, and was used as sample solution. High-performance liquid chromatography (HPLC) was employed for separation and determination of the analytes. The calibration curve showed good linear relationship (r > 0.9998). The recoveries were between 69.71% and 88.33% with RSDs lower than 4.86%. External standard method was adopted in the proposed method, and internal standard method was applied for the evaluation of the proposed method. The two methods were compared and the results indicated that the proposed method was acceptable and simple. The HILME is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and Soxhlet extraction. There was no obvious difference in the extraction yields of active constitutions obtained by the three extraction methods.     

无溶剂条件下离子液体催化香豆素衍生物的绿色合成(英文)

Brnsted acidic ionic liquids, namely 2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium dihydrogen phosphate, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulfate, and triphenyl(propyl-3-sulfonyl)phosphonium toluenesulfonate, catalyzed efficient Pechmann condensation of phloroglucinol with β-keto ethyl/ methyl esters. 5,7-Dihydroxy-4-methylcoumarin and 5,7-dihydroxy-4-phenylcoumarin were prepared in good to excellent yields under mild, ambient, and solvent-free conditions. Pyrano[2,3-h] coumarins were then prepared by one-pot three-component reactions of 5,7-dihydroxy-4-subsituted coumarin, malononitrile, and aldehydes in the presence of catalytic amounts of Br nsted basic ionic liquids, namely 2-hydroxyethylammonium formate, 3-hydroxypropanaminium acetate, 1-butyl-3-methylimidazolium hydroxide, pyrrolidinium formate, and pyrrolidinium acetate, under thermal solvent-free conditions. The catalysts are environmentally benign and can be easily prepared, stored, and recovered without significant loss of activity.     

Protic guanidinium ionic liquid as a green and highly efficient catalyst for the synthesis of functionalized spirochromenes under solvent-free conditions

A simple and efficient method for the synthesis of functionalized spirochromenes is explained using protic guanidinium ionic liquid as a catalyst under solvent-free conditions at room temperature. This procedure is simple, clean, and excellent yields are obtained in short reaction times.     

室温离子液体在分离科学研究中的新进展

室温离子液体作为一种重要的绿色溶剂,由于在金属离子、小分子有机物的萃取分离,气体吸附分离以及作为液相和气相色谱固定相等许多分离过程中体现出高分离效率和高选择性的特点,正在成为分离科学研究的前沿领域.着重总结了从2003—2006年的室温离子液体在分离科学领域中的新进展,并对其应用领域和发展前景做了展望.提出进一步加强离子液体的功能化和固定化技术及其在分离科学中的应用基础研究,探索离子液体有效的回收和再循环利用的新方法,是离子液体今后在分离科学研究中的一系列重要内容.     

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.     

An efficient protocol for the synthesis of quinoxaline derivatives at room temperature using molecular iodine as the catalyst

The use of molecular iodine as the catalyst for a one-pot synthesis of quinoxaline derivatives at room temperature is reported.     

Regioselective synthesis of novel substituted pyrazolo[1,5-a]pyrimidines under solvent-free conditions

A series of 6-(2-hydroxybenzoyl)-5-methyl-7-phenylpyrazolo[1,5-a]pyrimidines 5 have been synthesized directly by the solvent-free reaction between 5-amino-1H-pyrazoles 1 and 3-benzoyl-2-methyl-4H-chromen-4-one 4. This solvent-free reaction proceeds in a regiospecific fashion by intramolecular opening of the γ-pyrone ring in a Michael-type reaction, that followed by cyclization via nucleophilic attack of endocyclic pyrazole nitrogen toward benzoyl group gives the pyrazolo[1,5-a]pyrimidines 5. The use of this method affords high yields in short reaction times.     

Thermodynamic investigation of room temperature ionic liquid

The molar heat capacities of the room temperature ionic liquid 1-butylpyridinium tetrafluoroborate (BPBF₄) were measured by an adiabatic calorimeter in temperature range from 80 to 390 K. The dependence of the molar heat capacity on temperature is given as a function of the reduced temperature X by polynomial equations, C _p,m [J K⁻¹ mol⁻¹]=181.43+51.297X −4.7816X ²−1.9734X ³+8.1048X ⁴+11.108X ⁵ [X=(T−135)/55] for the solid phase (80–190 K), C _p,m [J K⁻¹ mol⁻¹]= 349.96+25.106X+9.1320X ²+19.368X ³+2.23X ⁴−8.8201X ⁵ [X=(T−225)/27] for the glass state (198–252 K), and C _p,m[J K⁻¹ mol⁻¹]= 402.40+21.982X−3.0304X ²+3.6514X ³+3.4585X ⁴ [X=(T−338)/52] for the liquid phase (286–390 K), respectively. According to the polynomial equations and thermodynamic relationship, the values of thermodynamic function of the BPBF₄ relative to 298.15 K were calculated in temperature range from 80 to 390 K with an interval of 5 K. The glass transition of BPBF₄ was observed at 194.09 K, the enthalpy and entropy of the glass transition were determined to be ΔH _g=2.157 kJ mol⁻¹ and ΔS _g=11.12 J K⁻¹ mol⁻¹, respectively. The result showed that the melting point of the BPBF₄ is 279.79 K, the enthalpy and entropy of phase transition were calculated to be ΔH _m = 8.453 kJ mol⁻¹ and ΔS _m=30.21 J K⁻¹ mol⁻¹. Using oxygen-bomb combustion calorimeter, the molar enthalpy of combustion of BPBF₄ was determined to be Δ_c H _m⁰ = −5451±3 kJ mol⁻¹. The standard molar enthalpy of formation of BPBF₄ was evaluated to be Δ_f H _m⁰ = −1356.3±0.8 kJ mol⁻¹ at T=298.150±0.001 K.     

离子液体[bmim]PTSA的微波合成

近年来,随着绿色化学的兴起,离子液体作为一种新型的绿色溶剂已成为国内外科研工作者的研究热点之一.离子液体是由有机阳离子和无机阴离子组成的盐,可以根据需要控制阴阳离子的组成和结构,设计合成出不同特性的离子液体[1].