ObjectiveTo explore an easily-controllable, environmentally-friendly method for synthesizing monastrol and its derivatives. MethodsMonastrol and its derivatives were synthesized using (substituted) benzaldehyde, ethyl acetoacetate and thiourea (or urea) as the material through a Biginelli reaction catalyzed by green room temperature ionic liquid 1-butyl-3-methylimidazolium-L-camphorsulfonate under microwave irradiation without solvent. ResultsThe green room temperature ionic liquid 1-butyl-3-methylimidazolium-L-camphorsulfonate catalyzed Biginelli reaction in obtaining the title compound under microwave irradiation without solvent. The process was easy to operate, time saving and environmentally-friendly. ConclusionMicrowave-accelerated solvent-free Biginelli reaction using green room temperature ionic liquid 1-butyl-3-methylimidazolium-L-camphorsulfonate as catalyst is a convenient and environmentally-friendly method for synthesizing monastrol and its derivatives.