Iminium carbonic acid derivative salts. XI. Synthesis of N,S‐containing heterobicycles from N‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazoüum salts. Part 3. Reaction of N‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts with 3‐amino‐2‐cyano‐3‐arylacrylonitriles

• 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: Carbonic acid
• Online Access: http://dx.doi.org/10.1002/jhet.5570330657; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjhet.5570330657; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jhet.5570330657

Abstract N ‐Boc‐protected 2‐memylthio‐1,3‐thiazinium 1 and 2‐methylthiothiazolium iodides 2, 3 obtained from the corresponding 3,4,5,6‐tetrahydro‐2 H ‐1,3‐thiazine‐2‐thiones and thiazolidine‐2‐thiones by the action of methyl iodide were reacted with 3‐armno‐2‐cyano‐3‐arylacrylonitriles forming the cyclic isothioureas 5–7 . The protection group was removed with trifluoroacetic acid whereupon the desired cyclisation to 3,4‐dihydro‐2 H ,6 H ‐pyrimido[2,1‐ b ][1,3]thiazines 8a‐c, 8a′‐c′ and thiazolo[3,2‐ b ]pyrimidines 9a,b, 9a′,b′, 10a,b took place.