Thiazolo-- and --triazoles

Thiazolo-[2,3-c]- and -[3,2-ft]-[l,2,4]triazoles [C2N3-C3NS].—4-AIlyl-5-phenyl- 

Hellrung, and A. Kneubiihler-Hof, Helv. Chim. Acta, 1974, 57, 1178. 

Cyclization of the triazoles (47) in 48% hydrobromic acid yields the corresponding thiazolo[3,2-6][l,2,4]triazole, isolable as the perchlorate salts. In polyphosphoric acid, the triazole (48) gives the thiazolo[3,2- ][l,2,4]triazole (49 Ri = R2 = ph), and not the isomer, as previously reported.  

Thiazolo-[2,3-c]-, -[3,2-bJ-, and -[3,4-hj-[ 1,2,4] triazoles The hydrazo-derivative (221) was cyclized with NaOEt to the dihydro-thiazolotriazole (222 R = CONHPh). Compound (222 R = H) was also obtained by opening and re-cyclizing (223) with NaOH. Refluxing [224  

5-ones were also described.Thiazolotriazole-5-thiones (226 R = Ph, R = Ph or Me) and (226 R = Me, R = Ph or Me) have been obtained by heating equimolecular quantities of 5-substituted 3-amino-4-oxothiazolidine-2-thiones with PhC(=NR )Cl.  

Thiazolo[4,5-d]-oxazole, -thiazole, and -selenazole [C NX-CiNS], The cycloaddition of ethyl 3-p-anisyl-5-bromo-4-oxothiazolidin-2-ylidenecyano-acetate with KOCN gives the 2,3,4,5-tetrahydrothiazolo[4,5-d] oxazol-2-one derivative (227 X = 0). The sulphur and selenium analogues can be obtained, starting from KSCN and KSeCN, respectively. 

Pyrrolo[2,l-h] thiazoles [C -C NSJ. The pyrrolothiazoles (231 R = H or Et02C) were synthesized from the cycloaddition reaction of imidazothiazole with PhCOC=CCOPh followed by elimination of a nitrile group from the cyclo-adduct. 

Structures comprising One Five-Membered and One Six-Membered Ring 

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