1,2,6-Oxadiazines and 1,2,6-Thiadiazines

Cyclopentathiadiazines, new heterocyclic materials from cyclic enaminonitriles

“…Polycyclic 1,2,6-thiadiazine 2,2-oxides have been studied intensely because of their practical use and economic advantage. 1 Bentazone, a benzothiadiazine 2,2-dioxide, is a well-known herbicide 2 and pyrazino[2,3-c][1,2,6]thiadiazine 2,2-dioxides 3 or benzothieno[3,2-a]thiadiazine 2,2-dioxides 4 have shown pharmaceutical properties. In contrast, very few unoxidized polycyclic 1,2,6-thiadiazines are known, 1 probably because of the lack of convenient synthetic approaches.…”

“…1 Bentazone, a benzothiadiazine 2,2-dioxide, is a well-known herbicide 2 and pyrazino[2,3-c][1,2,6]thiadiazine 2,2-dioxides 3 or benzothieno[3,2-a]thiadiazine 2,2-dioxides 4 have shown pharmaceutical properties. In contrast, very few unoxidized polycyclic 1,2,6-thiadiazines are known, 1 probably because of the lack of convenient synthetic approaches. All reported polycyclic 1,2,6thiadiazines were prepared from preformed 3,5-dichloro-4H-1,2,6thiadiazin-4-one or its 4-dicyanomethylene derivative, 5 with the exception of naphtho-and naphthobis [1,2,6]thiadiazines.…”

“…In contrast, very few unoxidized polycyclic 1,2,6-thiadiazines are known, 1 probably because of the lack of convenient synthetic approaches. All reported polycyclic 1,2,6thiadiazines were prepared from preformed 3,5-dichloro-4H-1,2,6thiadiazin-4-one or its 4-dicyanomethylene derivative, 5 with the exception of naphtho-and naphthobis [1,2,6]thiadiazines. 6 We have developed several new methods for the preparation of cyclopenta [1,2,3]dithiazoles, cyclopenta [1,2]dithioles and cyclopenta [1,2]thiazines by the reactions of simple saturated ketoximes with disulfur dichloride.…”

“…All reported polycyclic 1,2,6thiadiazines were prepared from preformed 3,5-dichloro-4H-1,2,6thiadiazin-4-one or its 4-dicyanomethylene derivative, 5 with the exception of naphtho-and naphthobis [1,2,6]thiadiazines. 6 We have developed several new methods for the preparation of cyclopenta [1,2,3]dithiazoles, cyclopenta [1,2]dithioles and cyclopenta [1,2]thiazines by the reactions of simple saturated ketoximes with disulfur dichloride. 7 We thought that a related procedure could be suitable for the one-pot preparation of 1,2,6-thiadiazines.…”

“…15 The CV of 7 showed a reversible reduction at 20.73 V. Irreversible oxidation or reduction waves were seen in the CV of 8. In summary, we have described the one-pot synthesis of new cyclopenta [1,2,6]…”