NaOAc-Promoted [3+1+2] Annulation of -Pivaloyl Oximes, Aldehydes, and 2-Methylbenzothiazole Salts: Synthesis of 1-Azaphenothiazines.

This paper presents an efficient strategy for constructing 1-azaphenothiazines through the NaOAc-promoted [3+1+2] annulation of -pivaloyl oximes, aldehydes, and 2-methylbenzothiazole salts. The reaction is conducted in ethanol and employs oxygen as the oxidant under catalyst-free conditions. The process is amenable to various -pivaloyl oximes, 2-methylbenzothiazole salts, and aldehydes, affording the target products in satisfactory yields.

AgNOx as Nitrogen Source for [1+1+3] Cycloaddition of Isocyanides with Isocyanates: Selective Synthesis of 1,2,4-Triazoles.

A novel [1+1+3] annulation of AgNOx, isocyanides, and isocyanates for the selective synthesis of 1,2,4-triazoles is presented herein. In this transformation, AgNOx and isocyanates are used as nitrogen sources instead of the traditional hydrazine or diazonium reagents. This process also involves N-O/C-H/C═N bond cleavage and the construction of new N-N/C-N bonds with a good substrate scope and functional group tolerance.