Green chemistry: A facile synthesis of polyfunctionally substituted thieno[3,4-c]pyridinones and thieno[3,4-d]pyridazinones under neat reaction conditions

A facile, solvent free, ecofriendly approach for the synthesis of pyridine-2,6-diones 4a–d, pyridazinone derivatives 8a–c and thienoazines 6 and 9 is herein described employing neat reaction conditions under both microwave and ultrasound irradiations. This solventless methodology is environmentally benign as it completely eliminates the use of solvent from the reaction procedure.