3,4-Disubstituted and fused 1,2,5-thiadiazole n-oxides

Abstract

Synthesis80 of Ethyl 3-(2-Indanyl)carbazate (33).-Addition of 0.5 ml of glacial acetic to a solution of 5.0 g (38 mmol) of 2-indanone81 and 4.3 g (41 mmol) of ethyl carbazate (purum Fluka) in 75 ml of ethanol (95%) at 50°g ave the precipitation of 6.0 g (28 mmol) of 2-indanone-N-carbethoxyhydrazone (34) in 5 min:

Recent Developments in the Synthesis and Applications of 1,2,5-Thia- and Selenadiazoles. A Review

“…35,60,61 The reaction of α-dioximes 47 with sulfur monochloride was usually complex and led to a mixture of various heterocycles including 1,2,5-thiadiazoles 48, their N-oxides 49 and in some cases 1,2,5-oxadiazoles 50 (Scheme 23); yields were generally low. 35,62 It was reported that the condensation of dithiooxamide with sulfur dichloride led to 1,2,5-thiadiazole-3,4-dithiol 51 (Scheme 24). 63 …”

“…Their reactions with sulfur monochloride (S 2 Cl 2 ) or sulfur dichloride (SCl 2 ) led to thiadiazole oxides 155 in low yield and in mixtures with corresponding 1,2,5-thiadiazoles 156 (Scheme 74). 62,178 Heterofused thiadiazole-N-oxides were prepared from o-aminonitroso derivatives 157. [179][180][181] Their treatment with sulfur monochloride in dimethylformamide at 60 • C gave pyrimidine and pyridine condensed thiadiazole-2-oxides 158 in moderate yields (Scheme 75).…”

NMR study of tautomerism of benzofuroxan and its sulphur and selenium analogues

“…4,5 The data for compounds 2-5 are as follows. 13 C spectra, internal TMS was used as the chemical shift standard, whereas for the nitrogen measurements external nitromethane in a capillary was applied for this purpose.…”

Reaction of 1,2,5-thiadiazolo[3,4-d]pyrimidine-5,7-dione 2-oxide with water

“…From the structural assessment in 1970 [1] up now 1,2,5-thiadiazole N-oxides have remained a poorly explored class of compounds. Two synthetic approaches to these compounds are known.…”

“…Two synthetic approaches to these compounds are known. The first involves the reaction of sulfur monochloride with 1,2dioximes, leading to a mixture of thiadiazoles and their N-oxides [1,2]. The second involves the reaction of 6-amino-5-nitrosouracils with sulfur monochloride in DMF, providing 1,2,5-thiadiazolo [3,4-d]pyrimidine 2-oxides in good yields [3,4].…”