Microwave assisted synthesis of a small library of substituted N,N'-bis((8-hydroxy-7-quinolinyl)methyl)-1,10-diaza-18-crown-6 ethers.

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.