ChemInform Abstract: STUDIES ON DIAZEPINES. XVII. SYNTHESIS OF MONOCYCLIC 1,3‐DIAZEPINES. (2). SUBSTITUENT EFFECTS ON THE THERMAL RING‐CONVERSION OF 1,2‐DIAZEPINES INTO 1,3‐DIAZEPINES

Abstract

Die auf dem im Formelschema angegebenen Weg hergestellten Pyridinium‐ N‐imide (VI) gehen bei der Bestrahlung in ein Gemisch der 1,2‐Diazepine (VII) und (VIII) und der Bicyclo‐diazaheptadiene (IX) und (X) über.

Dearomatization of Pyridines: Photochemical Skeletal Enlargement for the Synthesis of 1,2-Diazepines

“…[29][30] Several research groups slightly extended the scope of accessible 1,2-diazepines. [31][32][33][34] However, the tedious synthesis and isolation of the starting materials remained a significant drawback. Despite the indisputable interest of 1-aminopyridinium salts in organic synthesis, 35 this reaction remained a scientific curiosity and was never applied to any synthesis.…”

“…We then questioned the functional group tolerance of our strategy. Indeed, nitrile (33), methoxy (34), ketones (35, 36 and 43), esters (37 and 41), amides (42, 46 and 47) or halogens (38 to 40 and 46) were all tolerated and smoothly reacted to afford the corresponding 1,2-diazepines in modest to very good yields. Worth mentioning, these examples highlight the undeniable interest of this methodology as it permits to access previously out-of-reach molecules.…”