Novel synthesis of 1,4-thiazin-2-one O-(tert-butyl) oximes and benzo[b][1,4]thiazin-2-one O-(tert-butyl) oximes in the presence of K2CO3/SiO2

• Published in: Tetrahedron letters 2019-05, Vol.60 (22), p.1493-1497
• Main Authors: Aoyama, Tadashi, Tashiro, Kenshiro, Hayakawa, Mamiko, Shimada, Shigeru, Ouchi, Akihiko
• Format: Article
• Language: English
• Subjects: 1,4-Thiazin-2-one oximes; Benzo[b][1,4]thiazin-2-one oximes; Heterogeneous reaction; One-pot reaction
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2019.04.053

[Display omitted] •Novel method for the synthesis of 1,4-thiazin-2-one O-(tert-butyl) oxime.•Novel method for the synthesis of benzo[b][1,4]thiazin-2-one O-(tert-butyl) oxime.•Applications of N-tert-butoxy acylimidoylbromide.•All synthesized products have Z-stereochemistry. A simple and efficient method was developed for the synthesis of 1,4-thiazin-2-one O-(tert-butyl) oximes and benzo[b][1,4]thiazin-2-one O-(tert-butyl) oximes from N-tert-butoxy acyl imidoyl bromides and 2-aminothiols in the presence of K2CO3/SiO2. Twenty five novel compounds were readily synthesized in excellent yields using this procedure. The products possessed Z-stereochemistry with regard to the CN double bond. The reaction proceeded with initial substitution of bromine in the N-tert-butoxy acyl imidoyl bromides by mercapto groups in the presence of K2CO3/SiO2, and subsequent intramolecular Schiff base formation.