3- Phenyl isothiazolium salts

Methyl-3-phenyl-isothiazolium salts 27a,b were attacked at the N-atom with the /V,A-binucleophile 2-aminoethanthiol to obtain thioethylaminothiones 290a,b in 48-57% yield (72JCS(P1)2305, Scheme 96). 

Accordingly, iV-phenyl-substituted isothiazolium salts bearing a benzo crown ether substituent were employed in this synthetic protocol and led to the synthesis of various crown ether-substituted 6aA4-thia-l,6-diazapentalenes 201... 

The synthesis of novel substituted 6aA4-thia-l,6-diazapentalenes 33 was achieved by a base-induced dimerization of two isothiazolium salts <2001PS(170)29>. It was shown that A -phenyl-substituted isothiazolium salts having active 5-methyl or 5-methylene groups can easily be obtained by reaction of (l-thiocyanatovinylaldehydes and substituted anilines <1995CZ175>. 

Accordance to other named isothiazolium salts 57 (R = H), offered the inspection of the X-ray data of 3,4-dimethyl-2-phenylisothiazolium perchlorate 68a, received after an isomerization of 4,5-dimethyl-2-phenylisothiazolium perchlorate in ethanol, the typical salt structure with S-N bond of 1.682 A and 2-phenyl ring is 86.9° out of plane of the isothiazole ring (98JPR361). 

Especially, 2-phenyl-4,5,6,7-tetrahydro-l,2-benz- (121) and 5-methyl-2,4-diphenyl-isothiazolium salts 62 (R = H, 4-MeO, 2-C1, 2,6-Cl2) were studied with the HPLC-MS(MS) method to monitor the oxidation of isothiazolium salts with H202/acetic acid (96%) (03CG147). The strongly acidic reaction mixture was separated on a RP-18 column without any sample pretreatment and included intermediates, which were identified by API-MS(MS)-techniques. The aim of this work was to establish the reaction mechanism using several N-functionalized salts. 

---