2,1-Benzisothiazole derivatives

Benzisothiazole derivatives having biological activity in the medical and agrochemical fields have been reviewed (81MI41702). 

There are two series of benzisothiazoles, derived from benz[c]iso-thiazole (2) and benz[d]isothiazole (3), and both, if the benzene ring were suitable weakened, could doubtless be oxidized to isothiazole-dicarboxylic acids. In their first synthesis Adams and Slack... 

Treatment of the sulpholene (19) with hydroxylamine in refluxing ethanol has led to the formation of isothiazol-3-sulpholenes (21) which presumably progressed via the oxime intermediate (20). Subsequent heating of (21) in toluene at 185°C in a sealed tube led to the generation of the diene (22) which could be trapped with 1 -phenylmaleimide and with DMAD, thus providing a new route to 1,2-benzisothiazole derivatives <96TL4189>. 

Benzisothiazole derivatives, 18 (1981) 117 Benzodiazepines, 20 (1983) 157 Beta-adrenergic blockers, 22 (1985) 121 British Pharmacopoeia Commission, 6 (1969) 1... 

C NMR experiments are now routine for the characterization of chemical compounds and there is a vast amount of literature reporting C NMR data. NMR combined with H NMR spectroscopy has been employed to estimate tautomerism (see Section 4.05.4.5) and electronegativity of oxygen and nitrogen atoms in substituted benzisothiazole derivatives (see Section 4.05.3.2.1). 

General features of tautomerism in isothiazole and benzisothiazole derivatives are discussed in CHEC(1984) and CHEC-11(1996) <1984CHEC(6)131, 1996CHEC-II(3)319> and have been reviewed <2000AHC(77)51, 2000AHC(76)157>. 

Scheme 59 Synthesis of hydrazones of hydrazido benzisothiazole derivatives...

Below two examples of benzisothiazole derivatives characterised by antiinflammatory activity functionalised at C-3 with a heterocychc ring, which... 

There is a large literature concerning the preparation and the evaluation of the 3-(piperazinyl)-l,2-benzisothiazole derivatives 258 (Tables 2,3) substituted at nitrogen atom with different oxygen functionalized chains [84-88] as antipsychotic agents. Three main synthetic strategies were adopted for their preparation (Scheme 65). The first one used as key reagent the... 

Table2 Antipsychotic 3-(piperazinyl)-l,2-benzisothiazole derivatives 258 (part I) Entry n Y RZ 258, R Refs.

The biological activity of 1,2-benzisothiazole derivatives was reviewed in 1981 by De.3 Since then, further claims have been made regarding the auxinlike activity of 3-acetic acid derivatives,52 the analgesic activity of 3-benzyl derivatives,53,54 the antithrombogenic activity of 5-chloro-2-alkyl compounds,54,55 the fungicidal activity of 3-thio derivatives,56,57 the antiinflammatory activity of 2-halophenyl derivatives,58 and the diuretic effects59 of l,2-benzisothiazole-6-oxyacetic acid derivatives. 

The photoisomerization of N-alkoxyisosulphobenzimides (91) to the corresponding 1,2-benzisothiazole derivatives (92) (N-alkoxysaccharins) has been briefly reported."... 

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