One‐step synthesis of 2,4,5‐trisubstituted pyrimidines

A simple and straightforward methodology towards the synthesis of 2,4,5‐trisubstituted pyrimidines has been developed by one‐step reaction of isoflavones with thiourea or guanidine. Ten 2‐mercapto‐4,5‐diphenylpyrimidines and eight 2‐amino‐4,5‐diphenylpyrimidines were reported. All of them were characterized by FT‐IR, NMR, and elemental analysis. A variety of substrates can participate in the process with good yields and high purities, making this methodology suitable for library synthesis in drug discovery. J. Heterocyclic Chem., (2011).     

A microwave‐assisted solid‐state synthesis and characterization of diheterocyclic thioureas

In this study, a number of new diheterocyclic thioureas have been synthesized under microwave irradiation coupled with solvent‐free condition, which proves to be simple and efficient. The structures of the prepared compounds are characterized by elemental analysis, IR, ¹H NMR, and ¹³C NMR spectra. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:148–151, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20193     

One‐step in situ growth of magnesium ferrite nanorods on graphene and their microwave‐absorbing properties

The magnesium ferrite nanorods/graphene (MgFe₂O₄ NR/G) composites were prepared by a facile one‐step surfactant‐assisted solvothermal method. The structure and morphology of as‐prepared composite materials were characterized by electron microscopy, energy dispersive spectrometry, Raman spectrometry, X‐ray diffraction, FT‐IR and X‐ray photoelectron spectroscopy. The homogeneous MgFe₂O₄ nanorods with a typical diameter of about 100 nm were well distributed on graphene. The electromagnetic parameters were measured using a vector network analyzer. A minimum reflection loss (RL) of ?40.3 dB was observed at 14.9 GHz with a thickness of 3 mm, and the effective absorption frequency (RL  <   ? 10 dB) ranged from 12.0 to 18.0 GHz, indicating the remarkable microwave absorption performance of the MgFe₂O₄ NR/G composites. The absorbing property of as‐obtained composites was better than that of the pure MgFe₂O₄ nanorods. The synergistic effect of MgFe₂O₄ and graphene was responsible for the enhanced absorbing performance.     

A facile three‐components,one‐pot synthesis of pyrimido[4,5‐d]pyrimidine‐2,5‐dione derivatives under microwave‐assisted conditions

Pyrimido[4,5‐d]pyrimidine‐2,5‐dione derivatives have been synthesized in high yields in a novel, onepot, and efficient process by condensation of 6‐amino‐3‐methyl‐2‐(methylthio)pyrimidin‐4(3H)‐one, aldehydes and urea under microwave‐assisted conditions.     

One‐step synthesis of Ag@PS nanospheres via flash nanoprecipitation

In the work reported, we utilized a facile flash nanoprecipitation process to generate Ag nanoparticles@nanospheres polymer composites. Ag nanoparticles can be loaded onto the polymeric polystyrene (PS) nanosphere surface using a simple and inexpensive method through in situ growth; the amount of loaded Ag nanoparticles and the size of holes on the PS surface prepared by flash nanoprecipitation can be fine‐tuned by changing the pH of the water medium and the PS nanoparticles should have a greater specific area. The as‐synthesized Ag@PS composite nanoparticles obtained via the one‐step and continuous preparation route show high catalytic activity in the reduction reaction of 4‐nitrophenol. Importantly, the nanoparticles show no loss of catalytic performance over five cycles.     

Microwave‐assisted one‐pot synthesis of functionalized pyrimidines using ionic liquid

An efficient one‐pot multicomponent synthesis of 2,4‐diamino‐5‐pyrimidinecarbonitrile derivatives has been achieved in excellent yields by the condensation of aromatic aldehydes, malononitrile, and guanidine using ionic liquid under controlled microwave irradiation (100 W) at 60°C. This green approach offers a number of advantages in terms of methodology, high‐product yield, short reaction time, mild reaction conditions, and easy workup. J. Heterocyclic Chem., (2011).     

Preparation and investigation of LC packing made by microwave‐assisted solid‐phase synthesis

The preparation of the so‐called bonded phase liquid chromatographic packings is usually carried out by heating the silica, the silane, a catalyst, or a scavenger in an appropriate solvent (often toluene.) Due to the longtime of boiling, the procedure is time and energy consuming, and solvent intensive. The goal of this work is to present a simple, environment‐friendly preparation method with reduced solvent consumption to synthetize RP liquid chromatographic stationary phases. The effects of reaction conditions (amount of reagents, composition of the reagent, microwave energy, reaction time, reproducibility of the synthesis) are discussed. Pore structure, surface coverage, the change of the pore structure and surface coverage upon reaction are demonstrated, the efficiency of the column (van Deemter plot for different solutes) is presented. A variety of applications (aromatic hydrocarbons, halobenzenes, bioactive peptides, resveratrol from red wine) demonstrates the separation power of the new phase.     

A convenient Fischer indole synthesis of 2,3′-biindoles

Both symmetrical and unsymmetrical 2,3′-biindoles are efficiently synthesized in good to excellent yields by Fischer indole synthesis. The scope of the method was evaluated by examining substituent effects with para-substituted hydrazines and 3-acylindoles.     

One‐step synthesis of aminopyrimidines from 5‐Oxo‐4H‐benzopyrans

Novel 4‐amino‐6‐aryl‐2‐phenylpyrimidine‐5‐carbonitriles have been prepared in one step procedure from the readily available 4‐aryl‐2‐amino‐3‐cyano‐5,6,7,8‐tetrahydro‐7,7‐dimethyl‐5‐oxo‐4H‐benzopyrans. The mass spectroscopy study under EI conditions shows molecular peaks with high intensity corresponding to the loss of benzonitrile from the C2 position of the pyrimidine ring. Semiempirical (AMI and PM3) and ab initio HF/6–31G* calculations reveal a favored distorted geometry where the three rings are not in the same plane.     

A two step route to indoles from haloarenes--a versatile variation on the Fischer indole synthesis

In a new variation on the Fischer indole synthesis, readily available haloarenes are converted into a wide range of indoles in just two steps by halogen-magnesium exchange, quenching with di-tert-butyl azodicarboxylate, followed by reaction with ketones under acidic conditions.     

Fischer indole synthesis in low melting mixtures

Functionalized indoles are synthezised under mild conditions in a tartaric acid-dimethylurea melt. The melt serves as the solvent and as the catalyst. Under these reaction conditions, sensitive functional groups such as N-Boc, N-Cbz, or azides are stable, and indolenines are obtained regioselectively in excellent yields. The practical use of the method is demonstrated in the synthesis of the hormone melatonin.     

Tetrahydrofuranylmethylamines: An efficient and simple one‐step synthesis and biological activities

Various tetrahydrofuran‐2‐ylmethylamines have been prepared in good yields by an efficient one‐step synthesis utilizing the reaction of tetrahydrofurfurylchloride with different secondary cyclic amines without any catalyst. The compounds were tested for their in vitro affinity for the (α4)₂(β2)₃ and α7* nicotinic acetylcholine receptor (nAChR) subtypes. Pyrrolidine, piperidine and azepane containing analogs ( 1a, 1b, 1c ) showed K_i values in the lower micromolar range for these neuronal nAChR subtypes in rat brain.     

One‐step strategy for the synthesis of a derivatized cyclodextrin‐based monolithic column

Derivatized β‐cyclodextrin (β‐CD) functionalized monolithic columns were prepared by a “one‐step” strategy using click chemistry. First, the intended derivatized β‐CD monomers were synthesized by a click reaction between propargyl methacrylate and mono‐6‐azido‐β‐CD and then sulfonation or methylation was carried out. Finally, monolithic columns were prepared through a one‐step in situ copolymerization of the derivatized β‐CD monomer and ethylene glycol dimethacrylate. The sulfated β‐CD‐based monolith was successfully applied to the hydrophilic interaction liquid chromatography separation of nucleosides and small peptides, while the methylated β‐CD‐functionalized monolith was useful for the separation of nonpolar compounds and drug enantiomers in capillary reversed‐phase liquid chromatography. The structures of the monomers were characterized by Fourier transform infrared spectroscopy and mass spectrometry. The physicochemical properties and column performance of monoliths were evaluated by scanning electron microscopy and micro high performance liquid chromatography. This strategy has considerable prospects for the preparation of other derivatized CD‐functionalized methacrylate monoliths.     

An efficient and expeditious microwave‐assisted synthesis of quinoxaline derivatives via nucleophilic heteroaromatic substitution

A series of 2‐substituted quinoxaline derivatives including five novel compounds have been successfully synthesized from 2‐chloroquinoxaline using microwave methodology. The yields of the quinoxalines synthesized through this method, were an improvement over the thermal methods usually employed.