An efficient one-pot synthesis of octahydroquinazolinone derivatives using catalytic amount of H2SO4 in water

In this investigation, a practical green chemistry procedure for synthesis of octahydroquinazolinone according to the Biginelli reaction using 5,5-dimethyl-1,3-cyclohexanedione, urea or thiourea, and appropriate aromatic aldehydes in the presence of two drops of concentrated H₂SO₄ as a catalyst is described in water. This methodology is of interest due to the use of water as a solvent without use of any organic solvent and toxic metals as catalyst, thus minimizing the cost, the operational hazards, and environmental pollution. Also this modified route provides much higher yields and simple work-up procedure of products.