PUB - Publikationen an der Universität Bielefeld

4,4-Dimethyl-1,2-bis(4-methylphenyl)-3,5-pyrazolidinedione (4), 1,2-bis(4-methylphenyl)perhydro-3,6-pyridazinedione (5), and 1,2-bis(4-methylphenyl)perhydro-3,7-diazepinedione (6) have been prepared by condensation of p-hydrazotoluene with the appropriate dicarbonyl dichlorides and then converted into the corresponding bis(bromomethyl) derivatives 7-9 by photobromination. 7-9 have been tested as starting compounds for the synthesis of 2-thia-10,11-diaza[3.2]paracyclophan-10-ene (2) and 2,5-dithia-13,14-diaza[6.2]paracyclophan-13-ene (3). In no case 2 has been obtained, independent of the ring size and conformation of 7-9. However, 3 was readily formed from all precursors; the dimethylmalonyl moiety proved to be convenient as a protecting group because of its ease of preparation, its stability, and its facile cleavage by alkali.