5-Chloro-l, 2, 3-thiadiazol

The chlorine in 5-chloro-l,2,3-thiadiazole is displaced by methoxide ion <1974JHC343>. 

Chloro-l,2,3-thiadiazole-4-carboxamides 38 react with the sodium salt of diethyl malonate to give the corresponding malonic acid derivatives 39. The yield in these reactions falls as the electron-releasing properties of the 4-substituents in the aromatic ring increase (Equation 8) <1997JCM396>. 

Type cycloadduct 24 (Scheme 1) was obtained as the major product on cycloaddition of n-chloranil with l-ethoxycarbonyl-l/7-azepine <1982H(19)1197>. Treatment of 4-ethoxycarbonyl-5-chloro-l,2,3-thiadiazole with ethylenediamine under basic conditions occurs with heterocyclic ring opening/recyclization to form bis(triazole)-fused thiadiazepine 77 (R = COOEt) (Scheme 14). The benzo-fused analog was prepared by the similar reaction with o-phenylenediamine <1999CC2273>. 

Carbonyl(pentasulfur pentanitrido)molybdenum, 0532 5-Chloro-l,2,3-thiadiazole, 0651... 

Kinetic studies have shown sodium methoxide will displace the chlorine substituent from 5-chloro-l,2,3-thiadiazole (equation 16) (74JHC343). The products were not characterized in the paper. 

Chloro-l,2,3-thiadiazole, 0655 Hexaamminechromium(lll) perchlorate, 4129 Hexaamminecobalt(lll) perchlorate, 4126 MerciuA (ll) oxalate, 0982 Pentaammmeaquacobalt(lll) chlorate, 4124 Tetraperchloratosilicon, 4169 Titanimn tetraperchlorate, 4170 Trinitromethane, 0385... 

Substituted 5-chloro-l,2,3-thiadiazoles react with simple hetero nucleophiles by displacement of the chlorine, but reaction with aryl- and alkyllithiums gives alkynyl-thioethers via attack at sulfur and then ring cleavage with loss of nitrogen. A similar ring cleavage occurs, but by a different mechanism, when the... 

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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