in Wiley Online Library (wileyonlinelibrary.com). Synthesis of the title compounds was achieved using the anils 2a-e and 5a-c derived from the 4-aminopyrazole 1 as starting materials. These compounds were allowed to react with mercaptoacetic acid in boiling dry benzene to afford the corresponding thiazolidinones and spiro-thiazolidinones 3a-e and 6a-c, respectively. Pictet-Spengler reaction of the 4-aminopyrazole hydrochloride 7 with aromatic aldehydes and cyclic ketones resulted in the formation of new pyrazolo[4,3-e]pyrrolo[1,2-a]pyrazines 8a-e and 9a,b, respectively. Other derivatives of pyrazolo pyrrolopyrazines 10 and 11 were obtained via the reaction of the amino derivative 1 with 1,1 0 -carbonyldiimidazol and CS 2 , respectively
