Benzisothiazolinone

Basicities 565-567 Basis orbitals 2-5 Benzisothiazolinone dioxides 163 Benzofurans 638 Benzoic acids, pKa values of 586 Benzoxathiazine 2-oxides 71 Benzyne intermediates 306 Beta scales 559... 

Incompatibility with fluid formulations is one disadvantage of this chemistry, another is its potential to induce skin sensitisation. Benzisothiazolinone, (see Figure 6) is a chemically more stable isothiazolinone. This material can be incorporated into most metalworking fluid concentrates, over coming the stability problems seen with other isothiazolinones. However, this higher stability is reflected in higher in-use levels required to control micro-organisms. Typical in-use levels are between. ... 

A reaction of rather less general application, but one which produces valuable intermediates, is the treatment of dithiosalicylamide and its A-substituted derivatives with phosphorus pentachloride. Thus, A.A-diethyldithiosalicylamide (20) yields 3-chloro-2-ethyl-l,2-benz-isothiazolium chloride (21).14-16 This salt (21) is a versatile compound for example, heating it with diethylamine gives 3-diethylamino-l,2-benzisothiazole (22)16, treatment with base yields 2-ethyl-l,2-benzisothiazolinone (23), and reaction with ammonia, followed by hydrochloric acid, affords 3-ethylamino-l,2-benzisothiazole (24).14 This final reaction involves an interesting rearrangement which will be discussed in more detail in Sections II, C, 2 and II, C, 3. 

The 1,2-benzisothiazolinones, which can be considered as either oxidized or reduced derivatives of 1,2-benzisothiazole, will be discussed in Section II, E. 

Oxidation of l,2-benzisothiazoline-3-thiones with mercuric acetate affords the corresponding benzisothiazolinones.32... 

Klyuev and Snegireva41 42 have prepared imino derivatives of 1,2-benzisothiazolines, including 1-imino-1,2-benzisothiazolinone (49) and l,3-diimino-l,2-benzisothiazoline (50). These compounds are formed by treating dithiosalicylic acid (47) with excess chlorine and reacting the product (48) with ammonia or urea. The same workers have also prepared a number of derivatives of these imino compounds.43, 44... 

Benzisothiazolinones (53) are readily prepared by treatment of dithiosalicylic acid (47) with chlorine, followed by an amine.46-55 Variations from this basic reaction include the reaction of dithio-... 

Mustafa and co-workers investigated the reaction of 2V-sulfonyl-1,2-benzisothiazolinones with Grignard reagents66 and organolithium compounds.87 In either case the heterocyclic ring is broken and a tertiary alcohol is formed [Eq. (8)]. 

As mentioned earlier, 1,2-benzisothiazolinones have received considerable attention recently. Katz andSchroeder73 were apparently the first to note the antifungal and antibacterial properties of these... 

SYNS ANHYDRO-o-SULFAMINEBENZOIC ACID 3-BENZISOTHIAZOLINONE-l,l-DIOXIDE o-BENZOIC SULPHIMIDE o-BENZOSULFIMIDE BENZO-SULPHIMIDE BENZO-2-SULPHIMIDE o-BENZOYL SULFIMIDE o-BENZOYL SULPHIMIDE 1,2-DIHYDRO-2-KETOBENZISOSULFONAZOLE 1,2-DIHYDRO-2-KETOBENZISOSULPHONAZOLE 2,3-DIHYDRO-3-OXOBENZISOSULFONAZOLE 2,3-DIHYDRO-3-OXOBENZISOSULPHONAZOLE GARANTOSE GLUCID GLUSIDE HERMESETAS... 

The pyrido[2,l- )]quinazolinone 286 could be produced in about 20% yield by simply boiling a solution of benzisothiazolinone (296) in aqueous pyridine for 6 hr. Pyrido[2,l- ]quinazolinone (286) formation can be interpreted by a mechanism in which nucleophilic attack of the pyridine nitrogen atom occurs on the carbonyl group of benzisothiazolinone (296). 

Photodecomposition of 1,2-benzisothiazole (17) affords the ring-opened disulfide 7.40 If the 3-position is blocked by substitution, then more interesting products may result. Photocycloaddition reactions of 3-phenyl-1,2-benzisothiazole (23) with alkenes afford excellent yields of 2,3-dihydro-1,4-benzothiazepins such as 24.41 With electron-rich alkynes, thiazabicyclohep-tadienes (25) are produced, but no reaction occurs with 2-butyne, 1-phenylpropyne, or dimethyl acetylenedicarboxylate.42 An analogous S—N bond fission occurs with 2-aryl-1,2-benzisothiazolinones.43... 

There are a few examples of 1,2-thiazine synthesis of this type which are of importance. The most noteworthy is the preparation of 4-hydroxy-2/f-l,2-benzothiazine 1,1-dioxides (199) from the benzisothiazolinone (200) <81AHC(28)73>. This general procedure can be extended to the preparation of 2-alkyl-4-hydroxybenzothiazines. The treatment of A-methylsaccharin (201) and an alkyl chloro-acetate with NaH in DMSO or DMF affords a 76% yield of the 1,2-benzothiazine (202) (Scheme 39) <83JOC3601, 86CCC 1113,86FES819>. 

Antimicrobials like OBPA, trichlorohydroxy diphenyl ether (Triclosan), as well as n-octyl-isothiazolinone, 4,5-di-chloro-isothiazolinone, mercaptopyridine-n-oxide (pyrithione), and butyl-benzisothiazolinone are frequently used to reduce odours. 

---