1,3-(4,4'-dipyridinium disulfonic acid)propane dimethanesulfonate as an effective double-functional catalyst in preparing N,N′-Methylene bisamides, Tetrahydrochromeno-chromenes, and Pyrido-dipyrimidines. - Saleh, Ebraheem Abdu Musad; Abdullah, Bashar Mudhaffar; Mohammed, Hala Kh.; Kassem, Asmaa F.; Sapaev, I. B.; Ghildiyal, Pallavi; Hamoody, Abdul-hameed. M.; Alawadi, Ahmed; Altimari, Usama S.; Nejad, Maryam Sadat Ghorayshi (Research on Chemical Intermediates, 2024)