Iminium carbonic acid derivative salts. IX. Synthesis of N,S‐containing heterobicycles from N‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts part 1. Preparation of N‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts and their reaction with CH‐acidic compounds

• Published in: Journal of Heterocyclic Chemistry
• Main Authors: Hanefeld, Wolfgang, Naeeni, Mahmoud, Schlitzer, Martin
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1996
• Subjects: Ketene; Carbonic acid
• Online Access: http://dx.doi.org/10.1002/jhet.5570330639; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjhet.5570330639; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jhet.5570330639

Abstract N ‐Boc‐protected 1,3‐thiazine‐2‐thiones and thiazolidin‐2‐thiones were transformed into the corresponding 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts by methyl iodide or trimethyloxonium tetrafluoroborate. This activated species were reacted with CH‐acidic compounds forming ketene‐ N,S ‐acetals. The protection group was removed with trifluoracetic acid to yield the N ‐unsubstituted ketene‐ N,S ‐acetals.