Silver-Catalyzed Skeletal Editing of Benzothiazol-2(3H)-ones and 2-Halogen-Substituted Benzothiazoles as a Rapid Single-Step Approach to Benzo[1,2,3]thiadiazoles

Abstract

A facile silver(I)-catalyzed reaction of benzothiazol-2(3H)-ones with NaNO 2 , or using AgNO 2 directly, enables a single-step transformation to the corresponding benzo[1,2,3]thiadiazoles in moderate to excellent yields, with wide functional group compatibility. It can also be performed in a one-pot manner from readily available 2-halobenzothiazoles. This intriguing transformation involving an atom replacement in the S,Nheteroarene ring thus provides rapid access to isobenzothiadiazoles (while avoiding the usage of unstable precursors) and also expands the toolbox of modern skeletal editing reactions.

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

“…Nitrate and nitrite, which are abundant, inexpensive, and easily handled, are widely used as nitro sources and N–O sources . In contrast, they are rarely used as nitrogen sources under nonacidic conditions. − Our group previously developed a copper-catalyzed [1+1+3] annulation of AgNO 3 , isocyanates, and oximes to access N-2-aryl-1,2,3-triazoles derivatives . Based on this, we report the [1+1+3] ring-forming reaction of isocyanates with methyl isocyanoacetate using AgNO 2 / AgNO 3 as the nitrogen source.…”

“…In this mechanism, nitrate ions are initially reduced to nitrite ions in acetone . The nitrite ions are then captured by 1a to give intermediate A , which is hydrolyzed to produce diazo intermediate B . The released CO 2 gas could be detected by saturated Ca­(OH) 2 solution (see the Supporting Information).…”