Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>@ADMPT/H<sub>6</sub>P<sub>2</sub>W<sub>18</sub>O<sub>62</sub>: a novel Wells–Dawson heteropolyacid-based magnetic inorganic–organic nanohybrid material as potent Lewis acid catalyst for the efficient synthesis of 1,4-dihydopyridines
Green chemistry letters and reviews