91364-89-5Relevant academic research and scientific papers
REGIOCONTROLLED CYCLISATION TO THE ISOMERIC DIPYRIDAZINOTHIAZINES-----COMPETENCE AND PERFORMANCE OF BENZYLAMINO AND THIOETHER FUNCTIONS ON THE 3(2H)-PYRIDAZINONES AS REGIOCONTROLLING ELEMENTS
Kaji, Kenji,Nagashima, Hiromu,Oda, Hirohisa
, p. 675 - 679 (2007/10/02)
The 5,5'-thioethers (5a-c) perform a regiocontrolled cyclisation affording either the 10H-dipyridazinothiazine-1,9-diones (1'a-c) (by Ullmann mode) or the 10-benzyl derivatives of 1,6-dione isomers (2a-c) (via Smiles rearrangement), only depending on the acidity of media employed.The 4,5'-thioethers (6a-c) exhibit also the regiospecific control to give exclusively the 10H-dipyridazinothiazine-1,6-diones (2'a-c) in acidic conditions or the 10-benzyl-4,6-dione isomers (3a-c) in basic conditions, respectively.Some principal features of the regiocontrolled cyclisation are discussed.
