facile and simple synthesis of pyrimido[4,5-d]pyrimidinones and pyrano[2,3-d]pyrimidinones catalyzed by nano-sized ns-c4(dabco-so3h)2·4cl

In this work, 4,4′-(butane-1,4-diyl)bis(1-sulfo-1,4-diazabicyclo[2.2.2]octane-1,4-diium)tetrachloride (ns-c4(dabco-so3h)2·4cl), a newly reported nano-sized brönsted acid catalyst is used for the effective synthesis of pyrimido[4,5-d]pyrimidinones and pyrano[2,3-d]pyrimidinones derivatives. the products were formed under mild and environmentally friendly conditions in excellent yields over very short reaction times. using green solvent and simple methodologies, no side reactions and use of inexpensive catalyst with lower loading are other advantages of this work.