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. (c) 2009 Elsevier B.V. All rights reserved.