Preyssler heteropolyacid [NaP5W30O110]14−, as a new, green and recyclable catalyst for the synthesis of [1,2,4]triazino[4,3-b][1,2,4,5]tetrazines

Catalytic performance of Preyssler, H14[NaP5W30O110], and Keggin, H3[PW12O40], heteropolyacids as pure and supported on silica, H14[NaP5W30O110]/SiO2, H3[PW12O40]/SiO2, have been studied in cyclocondensation of 4-amino-3-hydrazino-6-methyl-1,2,4-triazin-5(2H)-one (4-AHMT) with orthoesters. The catalytic activity of various forms of these catalysts in different solvents was compared with other classical catalysts, such as H2SO4 and HY-zeolite. In all cases the best yields were obtained, using H14[NaP5W30O110].

Graphical abstractPreyssler solid catalyst [NaP5W30O110]14− have been proved to be efficient homogeneous and heterogeneous catalyst for the cyclocondensation reaction of 4-AHMT with orthoesters. The results have been compared with sulfuric acid, HY-zeolite and H3[PW12O40]. Solid acid: H14[NaP5W30O110], H3[PW12O40], H14[NaP5W30O110]/SiO2, H3[PW12O40]/SiO2.Figure optionsDownload full-size imageDownload as PowerPoint slide