114038-65-2Relevant academic research and scientific papers
Access to Pyrazolidin-3,5-diones through Anodic N–N Bond Formation
Gieshoff, Tile,Schollmeyer, Dieter,Waldvogel, Siegfried R.
, p. 9437 - 9440 (2016)
Pyrazolidin-3,5-diones are important motifs in heterocyclic chemistry and are of high interest for pharmaceutical applications. In classic organic synthesis, the hydrazinic moiety is installed through condensation using the corresponding hydrazine building blocks. However, most N,N′-diaryl hydrazines are toxic and require upstream preparation owing to their low commercial availability. We present an alternative and sustainable synthetic approach to pyrazolidin-3,5-diones that employs readily accessible dianilides as precursors, which are anodically converted to furnish the N?N bond. The electroconversion is conducted in a simple undivided cell under constant-current conditions.
Protecting Groups for the Synthesis of Diaza-cyclophanes by the Rigid-Group Principle
Funke, Ulrike,Gruetzmacher, Hans-Friedrich
, p. 1503 - 1508 (2007/10/02)
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-diazaparacyclophan-10-ene (2) and 2,5-dithia-13,14-diazaparacyclophan-13-en (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. - Keywords: Diazacyclophan-enes / Rigid-group principle
DITHIA-DIAZAPARACYCLOPHANE-ENES
Funke, Ulrike,Gruetzmacher, Hans-Friedrich
, p. 3787 - 3796 (2007/10/02)
The dithia-diazaparacyclophane-enes 3a-3h (n=6-14) were synthesized starting from p-hydrazatoluene by using the rigid group prinziple and the high dilution technique. 3a-3c exist only in the cis-azo configuration, while 3d and 3e are obtained as mixtures of the cis- and trans-isomers. 3f-3h are formed as pure trans-azoarene derivatives.A thermal cis/trans-isomerisation is observed only for 3e, but 3d-3f can be transformed into pure cis-azoarene derivatives by photoisomerization.The 1H-NMR and UV/VIS spectra of 3a-3h are discussed.Both types of spectra show characteristic differences for the cis- and trans-isomers.
