Novel ring transformations of condensed [1,2,4]triazolo[4,3-b]pyridazine-6(5H)-one-3(2H)-thiones effected by dialkyl-acetylenedicarboxylates
作者:Mónika Simó、Antal Csámpai、Veronika Harmat、Orsolya Barabás、Gábor Magyarfalvy
DOI:10.1016/s0040-4020(01)00672-x
日期:2001.8
On heating with dialkyl-acetylenedicarboxylates in DMF condensed [1,2,4]-triazolo[4,3-b] pyridazine-6(5H)-one-3(2H)-thiones undergo unprecedented ring transformations yielding novel tetracyclic 1,3-diazepines and thiazolotriazole derivatives depending on the applied reaction temperature. The observed substrate selectivity was interpreted on the basis of the results of comparative theoretical calculations carried out at semiempirical level (AMI). (C) 2001 Elsevier Science Ltd. All rights reserved.