2,l-Benzisothiazoline-3-thiones

The reagent does not replace nitrogen atoms, and N-alkyl or N-aryl anthranilic acids yield 2,l-benzisothiazoline-3-thiones (94) on heating with phosphorus pentasulfide in xylene. Curiously, when alkyl iV-arylanthranilates are treated in the same way, only a very small proportion—less than 10%— of 94 is obtained. The major product (80%) is the cyclic phosphorus-containing compound (95), the identification of which gives some clue about the structures of possible intermediates.122... 

Reaction between an iV-alkyl or JV-aryl substituted anthranilic acid (94) and phosphorus pentasulfide, in refluxing xylene, alfords a mixture of a 2,l-benzisothiazoline-3-thione (95) and a 4-3,3 -bis-2,1-benzisothiazoline (96).123,124 Oxidation of the thione (95) with... 

Isothiazoles are reported to yield the lactam (101) on reaction with diphenyl ketene <85BSB149>. Ethyne dicarboxylate esters add to 2,1-benzisothiazole to generate quinoline esters (102), and benzyne reacts to yield aeridine <83H(20)489, 88JCS(Pl)2l4l>. 2-Methyl-2,l-benzisothiazolin-3-thione with acetylene esters forms 2-iminobenzoquinone methides (103), which dimerize to give diazocines (104) or further react with the ethyne ester to yield diadducts (105). The initial adduct formed with phenylethyne and 2-methyl-2,l-benzisothiazolin-3-thione rearranges to produce l,2-dithiole[3,26]... 

Treatment of isatoic anhydride (87) with sodium hydrosulfide solution yields127 the unstable thioanthranilic acid 88, which can be oxidized by hydrogen peroxide to 2,l-benzisothiazolin-3(l//)-one (89).127-131,132 2,1-Benzisothiazolin-3(l//)-thiones can be produced by the action of sodium sulfide on 2-aminobenzotrifluoride the probable intermediate is the anion of dithioanthranilic acid.133... 

A further example of the same type of rearrangement is afforded by the l 2-benzisothiazoline-3-thiones. If the benzisothiazolium salt (40) is treated with thioacetic acid, the product is the 3-arylimino-3/f-1,2-benzodithiole (41), provided R is an aryl group when R is alkyl, the product is the benzisothiazoline-3-thione (42).32 Structures of types 41 and 42 are, however, in equilibrium with each other at 150°, presumably via a dipolar intermediate [Eq. (3)].32 A diradical... 

With the exception of the compounds mentioned in Section II, C, 3, all l,2-benzisothiazoline-3-thiones (46) have been prepared by the reaction between a benzodithiole-3-thione ( trithione ) (45) and a... 

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

Tables II-XI list 1,2-benzisothiazoles, Tables XII-XV 2,1-benzisothiazoles. There are a number of minor groups in these series which, because they appear in only a small number of references, are comparatively easy for the reader to locate, and so they are not tabulated here. These are 2-arylsulfonyl-64 and 2-arylideneamino-1,2-benzisothiazoles58 [(101) and (102), respectively], certain 2,1-benzisothiazole quaternary azo dyes (103),117 2,1-benzisothiazolin-3-ones (97)123 and -3-thiones (95),123,124 3,3 -bis-2,l-benzisothiazol-ylidenes (96),123 and 4,5,6,7-tetrahydro derivatives of types 93,122 99,12s. 27 and 100.125-127...

Chloro- benzisothiazoles (153) or benzisothiazolium (154) salts react with thiolacetic acid to give 1,2-dithioles, and benzo-l,2-dithiole-3-thiones are formed from benzisothiazoline-3-thiones with hydrogen sulfide. An isothiazoline-3-thione (155) reacted with phenylethyne to form what may... 

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