1.3.4- Thiadiazole 2-chloro-, Dimroth rearrangement

Further examples of 5-mercapto-triazoles 59 and bis-triazolo[l,3,6]thiadia-zepines 60 have been reported by these authors [60]. Compounds 59 and 60, resulting from one or two Dimroth rearrangements, respectively, were obtained in one step by ccaidensation of 1,2-phenylenediamine with 5-chloro-l,2,3-thiadiazoles 56. The product distribution is highly dependent upon the reaction time and the presence of EtsN (Scheme 19). Without base, only 59 was obtained, whereas in the... 

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