Microwave Assisted Synthesis of a Small Library of SubstitutedN,N′-Bis((8-hydroxy-7-quinolinyl)methyl)-1,10-diaza-18-crown-6 Ethers

Abstract

N,N'-bis-((8-hydroxy-7-quinolinyl)methyl)-1,10-diaza-18-crown-6 ether 1a and its analogue 1c are known as fluorescent sensors of magnesium in living cells. With the aim to investigate the effects of the substitution pattern on the photophysical properties of ligands 1 and their metal complexes, we developed an efficient microwaves enhanced one-pot Mannich reaction to double-armed diaza-crown ligands 1 carrying a variety of substituents. This new protocol is characterized by shorter reaction times, enhanced yields, and improved product purities with respect to the use of conventional conductive heating.

Multimodal Use of New Coumarin‐Based Fluorescent Chemosensors: Towards Highly Selective Optical Sensors for Hg2+ Probing

“…Figure 4 a clearly shows the high selective optical response of ligand L1 for Hg 2 + ions; the fluorescence emission enhancement due to the presence of this ion, in fact, is much higher compared with that observed for the other metal ions considered, and this is the case also for ligands L2 and In order to investigate the reversibility of the complexation process we also performed spectrophotometric and www.chemeurj.org spectrofluorimetric back-titration experiments with another very efficient ligand for mercury ions consisting of a crown ether with two quinoline moieties at the periphery, in particular N,N'-bis-[(8-hydroxy-5-nitro-7-quinolinyl)methyl]-1,10diaza [18]crown-6 ether (R1). [48] The addition of increasing amounts of this species to a solution of ligand L1 and Hg 2 + ions in 1:1 molar ratio causes a gradual decrease in the emission band at l = 406 nm to reach the typical spectra of the uncomplexed ligand L1 in the presence of an almost equimolar amount of the competitor ligand. The binding of R1 with the mercury ions is also evidenced by the changes in the absorption spectra that present an increasing band at l = 435 nm, characteristic of the complexed R1, and no band at l = 460 nm where the free R1 absorbs.…”

Design, Synthesis and Structure-Activity Relationship Studies of Novel Survivin Inhibitors with Potent Anti-Proliferative Properties

“…Ethers 3b-3e and ethers 3h-3l were synthesized using step b in which substituted benzyl alcohols were allowed to react with salt 2 in the presence of sodium hydride in anhydrous THF. Ethers 3a , 3f and 3g were synthesized through step c and step d. In step c, substituted benzyl alcohols reacted directly with salt 2 with heating to form different salts which were converted to free base by adjusting pH with NH 4 OH solution in step c.[21] The synthesized ethers were than submitted to Mannich reaction conditions with paraformaldehyde and pyrrolidine in ethanol to form the final compounds 4a to 4l . [22] Compounds 6a-6g with the C ring moiety in UC-112 replaced by different function groups were prepared as Fig 3 shown.…”

Alum [KAl(SO4)2•12H2O] catalyzed microwave assisted synthesis of 5-arylidine-2-(methylthio)-thiazolone derivatives in water

“…Use of water as a reaction medium results in increase the rate and selectivity of many organic reactions [15][16][17][18][19]. In addition to using of green solvent with or without combination of microwave irradiation reactions were performed and found reduced reaction time compared to conventional method [20][21][22][23][24][25][26][27][28].…”