Acid-Catalyzed Hydrolysis and Intramolecular Cyclization of N -Cyano Sulfoximines for the Synthesis of Thiadiazine 1-Oxides.

Herein, we describe a novel approach for the practical synthesis of thiadiazine 1-oxides 10 . The first example of an intramolecular cyclization with 2- N -cyano-sulfonimidoyl amides 9 to form the desired thiadiazine 1-oxides 10 was developed. One-pot acid-induced hydrolysis of the cyano group and the intramolecular cyclocondensation protocol readily provided various heterocyclic frameworks in good to moderate yields. Notably, the crystal structures of N -urea sulfoximine 11 and thiadiazine 1-oxide 10i have been determined using X-ray crystallography.