Synthesis of Imidazo[2,1‐a]isoquinolines from α‐Tosyloxyketones and 1‐Aminoisoquinoline in Ionic Liquid Solvent

The room temperature ionic liquid n‐butylpyridinium tetrafluoroborate (BPyBF₄) is used as a ‘green’ recyclable alternative to classical molecular solvents for the cyclocondensation of α‐tosyloxyketones with 1‐aminoisoquinoline to prepare imidazo[2,1‐a]isoquinolines in good yields.     

Capillary Electrophoretic Separation of Tricyclic Antidepressants Using 1‐Alkyl‐3‐Methylimidazolium‐Based Ionic Liquids as Background Electrolyte

A capillary electrophoretic (CE) method coupled with the use of 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (1E‐3MI‐TFB) ionic liquid as background electrolyte (BGE) has been developed for the simultaneous separation of nine tricyclic antidepressants, viz. amitriptyline (Ami), clomipramine (Clo), desipramine (Des), fluphenazine (Flu), imipramine (Imi), nortriptyline (Nor), promazine (Pro), thioridazine (Thi) and trimipramine (Tri). Resolution of TCAs with similar molecular structures and pK_a values was accomplished by minute manipulation of the electrophoretic velocities of TCAs via reversed electroosmotic flow (EOF) generated by adsorption of 1E‐3MI cations onto the capillary wall. The optimal separation was obtained with a 50 mM 1E‐3MI‐TFB as the sole BGE at pH 3. Symmetric peaks with efficiencies up to 2.4 × 10⁵ plates/m were achieved. RSD values on migration times and peak areas were in the ranges of 0.63–0.95% and 3.41–6.34% (n = 4), respectively. The role of different alkyl groups on the imidazolium cations was also investigated.     

An Efficient Synthesis of 14‐Aryl or Alkyl‐14H‐Dibenzo[a. j]Xanthenes Using Reusable HBF4‐SiO2 Catalyst Under Thermal and Solvent‐Free Conditions

A simple and convenient procedure for the synthesis of 14‐aryl or alkyl‐14H‐dibenzo[a. j]xanthene derivatives is described through a one‐pot condensation of β‐naphthol with various aryl or alkyl aldehydes in the presence of HBF₄‐SiO₂ as the catalyst under thermal and solvent‐free conditions.     

Solvent‐Free Synthesis of Heterocyclic Thioureas Using Microwave Technology

A new and rapid solvent‐free synthesis of heterocyclic thioureas in a microwave oven has been reported for the first time. Nine heterocyclic thioureas that possess biological activity have been synthesized. The reaction time is short (2–4.5 min) and gives excellent yields (82.9–95.5%).     

New Substituted 1‐Aryl‐4,4,6‐Trimethyl‐3,4‐Dihydropyrimidine‐2‐(1H)Thiones; A Metal‐Free and Solvent‐Free Synthesis,Characterization, and Lymphoid Tyrosine Phosphatase Inhibition Studies

A series of fourteen 3,4‐dihydropyrimidine‐2‐thiones ( 3a–n ) were synthesized by a green protocol, and their structures were characterized by spectroanalytical data. The compounds were obtained in high yields by efficient annulation of mesityl oxide (4‐methylpent‐3‐en‐2‐one) with anilines in the presence of potassium thiocyanate. The reaction is essentially metal‐catalyst‐ and solvent‐free, as mesityl oxide itself is the solvent as well as the reactant. The compounds were tested for their ability to inhibit the lymphoid tyrosine phosphatase PTPN22, and 5 of the 14 compounds exhibited IC₅₀ values in the mid‐micromolar range, with the most potent hit being the compound 3d , having a methoxy substituent at the 2‐position of the phenyl ring with an IC₅₀ = 18 ± 1 μM, and second most potent compound ( 3c ) with an IC₅₀ value of 45 ± 3 μM, having methyl substituents at both 2‐ and 4‐position of the phenyl ring.     

Substituted Pyrazolo[3,4‐d]pyrimidines: Microwave‐Assisted,Solvent‐Free Synthesis and Biological Evaluation

A simple and efficient method has been developed for the synthesis of various pyrazolo[3,4‐d]pyrimidines by using microwave irradiation under solvent‐free conditions. The advantages of applying microwave irradiation compared with the classical method were demonstrated. The structures of all the compounds were confirmed by the usual techniques and, in two cases, by X‐ray analysis. The compounds did not display appreciable ability to inhibit xanthine oxidase activity. Screening for antifungal activity showed that some derivatives were active against four fungi, with more significant results for Botrytis.     

Iodine‐Catalyzed Friedlander Quinoline Synthesis under Solvent‐Free Conditions

Polyfunctional quinolines were synthesized using Friedlander method catalyzed by molecular iodine in high yields at 60 °C under solvent‐free conditions.     

A Facile Synthesis of 2,2,4‐Trisubstituted‐1,2‐Dihydroquinolines Catalyzed by Zinc Triflate under Solvent‐Free Conditions

An efficient process has been developed for the synthesis of 2,2,4‐trisubstituted‐1,2‐dihydroquinolines in good yields through a simple one‐pot condensation between anilines and ketones in the presence of zinc triflate as a catalyst at room temperature under solvent‐free conditions.     

Synthesis of 2‐Phenylthiazoles from α‐Tosyloxyketones and Thiobenzamide in [Bmim][PF6] Ionic Liquid at Ambient Temperature

The room temperature ionic liquid, 1‐n‐butyl‐3‐methylimidazolium hexafluorophosphate [bmim][PF₆] is used as a ‘green’ recyclable alternative to classical molecular solvents for the cyclocondensation of α‐tosyloxyketones with thiobenzamide to prepare 2‐phenylthiazoles in good yields.     

Electrochemical Study of Indium in a Water‐Stable 1‐Ethyl‐3‐Methylimidazolium Chloride/Tetrafluoroborate Room Temperature Ionic Liquid

The electrochemistry of indium species was investigated at glassy carbon, tungsten and nickel electrodes in a basic 1‐ethyl‐3‐methylimidazolium chloride/tetrafluoroborate ionic liquid. Amperometric titration experiments suggest that In(III) chloride is complexed as [InCl₅]^2? in this ionic liquid. The electrochemical reduction of [InCl₅]^2? to indium metal is preceded by overpotential driven nucleations. The effective anodic dissolution of indium to indium(III) requires, however, the presence of sufficient chloride ions at the electrode surface. The electrodeposition of indium at glassy carbon and tungsten electrodes proceeds via three‐dimensional instantaneous nucleation with diffusion‐controlled growth of the nuclei. At the nickel electrode, the deposition proceeds via three‐dimensional progressive nucleation with diffusion‐controlled growth of the nuclei. Raising the deposition temperature decreases the average radius of the individual nuclei, r. Scanning electron microscopic and x‐ray diffraction data indicated that bulk crystalline indium electrodeposits could be prepared on nickel substrates within a temperature range between 30 and 120 °C.     

Hypervalent Iodine(III) Sulfonate Mediated Synthesis of α‐Thiocynanatoketones in a Task‐Specific Ionic Liquid [bmim]SCN

The task‐specific ionic liquid (TSIL) and 1‐n‐butyl‐3‐methylimidazolium thiocynanate, ([bmim]SCN) were used as the medium as well as the reactant for the synthesis of α‐thiocynanatoketones by the reaction with α‐sulfonyloxy aryl ketones. Significant rate enhancements and improved yields have been observed.     

One‐pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones Catalysed by Cupric Acetate under Solvent‐free Conditions

A solvent‐free synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones from aromatic aldehydes, β‐keto ester/acetyl acetone and urea catalysed by cupric acetate under thermal condition is reported as a simple and an efficient protocol. Compared with classical Biginelli reaction reported in 1893, this new method provides much improved modification in terms of yield and reaction time. The usage of milder catalyst, environmental friendly procedures and excellent yields within a very short time (5–15 min) are the advantages of the method in which the involvement of solvent‐free condition adds an edge to the method. Thus, the efficiency of the protocol enabled the rapid synthesis of 3,4‐dihydropyrimidin‐2(1H)‐one derivatives in a short duration.     

One‐pot Green Procedure for Synthesis of Tetrahydrobenzo[a]xanthene‐11‐one Catalyzed by Brønsted Ionic Liquids under Solvent‐free Conditions

An efficient one‐pot condensation of β‐naphthol, aldehydes and cyclic 1,3‐dicarbonyl compound has been achieved with ionic liquids as catalyst, thus a variety of 8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one derivatives were prepared in good yields. The present approach offers several advantages such as shorter reaction times, good yields and mild reaction conditions.     

Magnetic Nanoparticle Supported Ionic Liquid Assisted Green Synthesis of Pyrazolopyranopyrimidines and 1,6‐diamino‐2‐oxo‐1,2,3,4‐tetrahydropyridine‐3,5‐ dicarbonitriles

A simple and eco‐friendly green protocol was used for synthesis of pyrazolopyranopyrimidines via four‐component reaction of hydrazine hydrate, ethyl acetoacetate, barbituric acid or dimethyl barbituric acid, and aromatic aldehydes under thermal and solvent‐free conditions in the presence of magnetic nanoparticle supported silica bonded n‐propyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane chloride (MNPs@DABCO⁺Cl^?) as an efficient, recyclable heterogeneous catalyst. MNPs@DABCO⁺Cl^? also catalyzed the synthesis of 1,6‐diamino‐2‐oxo‐1,2,3,4‐tetrahydropyridine‐3,5‐dicarbonitrile derivatives by four‐component reaction of hydrazine hydrate, malononitrile, ethyl cyanoacetate and ketones under thermal and solvent‐free conditions at 80 °C. These methods are practical and offer many advantages, such as high yields, short reaction times, and simple work‐up.     

Synthesis of 2H‐Indazolo[2,1‐b]Phthalazine‐1,6,11(13H)‐Trione Derivatives Using Wet Cyanuric Chloride under Solvent‐Free Condition

A simple and facile synthesis of 2H‐indazolo[2,1‐b]phthalazine‐1,6,11(13H)‐trione derivatives has been accomplished by a three‐component condensation reaction of dimedone, aromatic aldehydes and phthalhydrazide under solvent‐free conditions in the presence of wet cyanuric chloride as a catalyst.     

Vanadium‐Catalyzed Solvent‐Free Synthesis of Quaternary α‐Trifluoromethyl Nitriles by Electrophilic Trifluoromethylation

The direct electrophilic trifluoromethylation of silyl ketene imines (SKIs) with hypervalent iodine reagents leads to the formation of quaternary α‐trifluoromethyl nitriles in good yields. This new reaction has been carried out with a variety of substituted SKIs under solvent‐free conditions using a vanadium(IV) catalyst (5 mol %). The corresponding products may be transformed into useful organofluorine building blocks.     

Green Biginelli‐type Reaction: Solvent‐free Synthesis of 5‐unsubstituted 3,4‐dihydropyrimdin‐2(1H)‐ones

The Biginelli‐type compounds, 5‐unsubstituted 3,4‐dihydropyrimdin‐2(1H)‐ones were synthesized by a one‐pot three‐component condensation of aromatic aldehydes, aromatic ketones and urea in the presence of SnCl₄ · 5H₂O under solvent‐free conditions. The advantages of this method are short reaction time (4–10 min), excellent yields (74–97%), inexpensive catalyst and solvent‐free conditions. A plausible mechanism was proposed.     

过无溶剂、无催化的aza-Michael加成反应合成b氨基酸衍生物

本文报道一种安全,环境有好,经济实用的合成b氨基酸衍生物的新方法。利用α,β不饱和化合物和脂肪族胺,通过无溶剂、无催化的aza-Michael加成反应,高产率的合成b氨基酸衍生物。