A new heterocycle: furo[3,2-c]isoselenazole

Construction of 5-Amino-1,2-Selenazole Scaffolds through N-Selenocyanation/Cyclization of Enaminones Using KSeCN

A metal-free and mild approach for constructing 5-amino-1,2-selenazole skeletons by NBS/KSeCN-mediated N-selenocyanation and nucleophilic cyclization of β-enaminones has been developed. Various isoselenazole compounds and the isoselenazolyl derivatives of anti-inflammatory medicines, including isosepac, oxaprozin, and ibuprofen, have been obtained with good yields. This efficient, "one-pot", and atomic economy strategy may represent an alternative route for the construction of a 1,2-selenazole framework via the "+SeCN" pathway and provide new access to heterocycles containing a Se-N bond.

Silver-Mediated [2 + 2 + 1] Cyclization of ortho-Propioloylbenzonitriles with Elemental Selenium: Synthesis of 4H-indeno[1,2-c][1,2]selenazol-4-ones

An efficient silver-mediated [2 + 2 + 1] cyclization protocol of ortho-propioloylbenzonitriles with elemental selenium for the synthesis of 4H-indeno[1,2-c][1,2]selenazol-4-ones has been developed. One C-Se bond, one N-Se bond, and one C-C bond were rapidly constructed in one step. The reaction might proceed via the formation of a highly reactive selenoketene intermediate, followed by intramolecular cyclization.