Zur Oxidation von 1,2‐Thiazolen: Ein einfacher Zugang zu 1,2‐Thiazol‐3(2H)‐on‐1,1‐dioxiden

Abstract

Oxidation of 1,2‐Thiazoles; A Convenient Approach to 1,2‐Thiazol‐3(2H)‐one 1,1‐Dioxides The 1,2‐thiazoles obtained from 3‐chloroalk‐2‐enals and ammonium thiocyanate (7 → 9, Scheme 1) are easily transformed to 1,2‐thiazol‐3(2H)‐one 1,1‐dioxidcs 10 on treatment with H2O2 in AcOH at 80°. Hydrogenation of 10 in AcOH yields the corresponding saturated 1,2‐thiazolidin‐3‐one 1,1‐dioxides 16 (Scheme 3). Cycloalka[c]‐1,2‐thiazoles 18 are prepared from 2‐[(thiocyanato)methyliden]cycloalkan‐1‐ones and ammonia (Scheme 4). Surprisingly, oxidation of 18a with H2O2 in AcOH yields the tricyclic oxaziridine 19.

N,N′-Linked 1,2-benzisothiazol-3(2H)-one 1,1-dioxides: synthesis, biological activity, and derived radicals

“…Compared to the related N-heterocyclyl-substituted 4,5-dimethylisothiazol-3(2H)-one 1,1-dioxides and 4,5,6,7-tetrahydro-1,2-benzisothiazol-3(2H)-one 1,1-dioxides, 10 in the case of the sultams 7d and 7e,f the C-3a and C-7a signals had a noticeable upfield shift (124-125 and 136 ppm versus 134-135 and 145-147 ppm for C-4 and C-5 of the analogous 4,5-dimethylisothiazol-3(2H)-one 1,1-dioxides). Similar shift differences were also found for the parent compounds, i.e., saccharin 17 and 4,5-dimethylisothiazol-3(2H)-one 1,1-dioxide 18 (128 and 139 ppm versus 133 and 144 ppm). The IR spectra of the benzisothiazol-3(2H)-one 1,1-dioxides include typical absorption bands of the carbonyl group at 1728-1773 cm À1 and the bands of symmetric and antisymmetric vibrations of the SO 2 group at 1178-1193 and 1330-1358 cm À1 .…”

Synthesis of Monocyclic Hydroperoxy- and Hydroxy-Substituted Sulfin- and Sulfonamides by Oxidation of 4,5-Dimethylisothiazolium Salts

“…13 C-NMR ((D 6 )acetone): 9.24 (Me À C(5')); 11.78 (Me À C(4')); 14.02 (OCH 2 Me); 60.45 (OCH 2 Me); 89.3 (C(3)); 115.6 (C(2,6)); 123.9 (C(4)); 131.1 (C(3,5)); 136.8 (C(5')); 140.7 (C(4')); 146.4 (C(1)); 165 4. Aryl-Substituted 2,3-Dihydro-3-hydroperoxy-4,5-dimethylisothiazole 1,1-Dioxides (15). General Procedure.…”

Synthesis of N,N’-Linked Isothiazolium Salts via Intramolecular Cyclocondensation of Hydrazonium Salts

“…For instance, they are used for transformation of N-nucleophiles (e. g. ammonia) into isothiazoles [1] and of substituted anilines into isothiazolium salts [2].…”