2-Phenyl 1,2-benzisothiazole 1,1-dioxides

Chloro-2-ethyl-l,2-benzisothiazolium chloride 109b reacted with Ar-mono- and IV,IV-dialkylanilines 356 to give 3-phenyl 1,2-benzisothiazolium salts 357, which were converted by thermal treatment to isothiazole 358 and with hydrochloric acid to salts 359 in 70-80% yield (79CB3286, Scheme 119). The isothiazole 358 can be oxidized to 2-phenyl 1,2-benzisothiazole 1,1-dioxides. 

Oxidation of 3-piperazin-l-yl-l,2-benzisothiazole (54) (w = 0) with nitric acid or MCPBA at low temperatures gives the 1-oxide (54) (n = 1), while MCPBA at room temperature, oxone and sodium periodate afford the 1,1-dioxide (54) (n = 2) <91JMC3316>. The oxidation of 2-[(S)-l-phenyl-ethyl]isothiazolin-3-one (55) with MCPBA yields a mixture of the diastereomer 1-oxides (56) and... 

The Movassaghi group has investigated the stereoselective C2 to C3 migration of a 2-phenyl substituent on diastereomerically pure hydroxyindolenines 13 [18]. The requisite hydroxyindolenines were prepared via oxidation of 2-phenyl L-tryptophan with Davis oxaziridine (3-n-butyl-l,2-benzisothiazole-l,1-dioxide oxide). The oxidation step proceeded with modest diastereoselectivity, providing a 2 1 mixture of the (3R) and (35)-hydroxyindolenines 13 that were separated. As illustrated for... 

A soln. of startg. N,N-diphenylarenesulfonamide in THF at —78° treated under N2 with 1.1 eqs. 1.6 M BuLi in hexane, stirred for 1 h, neat benzonitrile added via syringe, after 1 h the mixture allowed to warm to room temp., stirred overnight, and hydrolyzed with satd. aq. NH4CI - 3-phenyl-1,2-benzisothiazole 1,1-dioxide. Y 75%. F.e.s. D. Hellwinkel, R. Karle, Synthesis 1989, 394-5. 

Synthesis.—A series of 4-substituted 6-carboxy-3-phenyl-1,2-benzisothiazole 1,1-dioxides (58) has been produced in almost quantitative yields by the thermolysis of 3-substituted 4-benzoyl-5-sulphamoylbenzoic acids (57). The diuretic... 

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