Ring interconversion between a 7-membered ring (2,3-dihydro-1,4-benzodiazepine) and a 14-membered ring (2,3,9,10-dibenzo-1,5,8,12-tetra-azacyclotetradeca-4,11-diene)

✍ Scribed by Jan Bergman; Anna Brynolf

• Publisher: Elsevier Science
• Year: 1989
• Tongue: French
• Weight: 209 KB
• Volume: 30
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)99174-3

✦ Synopsis

Structure elucidation of the macrocyclic ligaud 6 and interconversion to the benzodiazepine 4 is reported. Also, a versatile synthesis of the macrocyclic ligands 6 and 13 is described.

In connection with structure determinations of some benzo-1,6diazepine derivatives obtained1 by reaction of the anion (3)2 with a-haloacyl halides, we became interested in the benzo-1,4diazepinedione 13, as well as certain derivatives of 1. The benzo-1,6diazepine 4 seemed then to be an interesting candidate for structure correlations as Uskokovic4 had already described the reductive (LiAlH4 in THF) conversion (1 + 4). More forcing reduction5 with LiAlH4 yielded 5.

The reduction of 4 has now been repeated and the reaction mixture has carefully been separated and the products studied in detail. 4 P Evidence, such as the low solubility and high mp, was obtained indicating that the imine (C9HloN) with the previously assigned structure 4 has in fact the macrocyclic structure 6. These assumptions were corroborated by conversion (Na13H3CN in HOAc) of 6 into 7.6 Furthermore