In this study, a green and practical approach towards Hantzsch dihydropyridine synthesis of acridine-1,8-diones is introduced. Via the mentioned protocol, the one-pot condensation reaction of structurally diverse aromatic aldehydes, dimedone and NH4OAc was promoted by microwave radiation at solvent and catalyst-free conditions. Consequently, acridinedione products were produced in 81‒97% yields within 3‒8 min. The current protocol represents the prominent advantages in terms of the using a simple synthetic procedure, short reaction times, mild reaction conditions, high yield of the products as well as omission of hazardous and cost-effective organic solvents/reagents.

The title compound 3-(4-hydroxy-3-methoxyphenyl)-7,7-dimethyl-7,8-dihydrocinnolin-5(6H)-one (3) was prepared via one-pot three component reaction of 2-(4-hydroxy-3-methoxyphenyl)-2-oxoacetaldehyde with dimedone in the presence of hydrazine hydrate and studied by the single crystal X-ray diffraction method. Its structure was also con?rmed by IR, 1H and 13C NMR spectroscopy. Compound 3 was crystallized in the monoclinic system, space group P21/c, a = 7.921(2) ?, b = 11.566(4) ?, c = 16.986(6) ?, B = 107.338(5)°, V = 1485.5(8) ?3, Z = 4, R1 = 0.0559 and wR2 = 0.1253. The crystal structure of 3 also shows a weak interaction between O3 and N2 atoms.