Nucleophilic substitution in 5-halo-1,2,3-thiadiazoles is a convenient method for the synthesis of various heterocycles [1,2]. We have previously shown that such reactions may be accompanied by rearrangement of the thiadiazole ring and reactions at C(4) of the ring [3,4]. In a continuation of our studies, we have developed a simple preparative method for the synthesis of a previously unreported heterocyclic system, namely, [1,2,3]thiadiazolo[5,4-e][1,4]oxazepine by the reaction of the ethyl ester of 5-chloro-1,2,3-thiadiazole-5-carboxylic acid (1) [5] with diethanolamine. This reaction involves nucleophilic substitution of the chlorine atom followed by intramolecular transesterification to give heterocycle 2. In contrast to the reaction indicated above, the reaction of thiadiazole 1 with monoethanolamine leads to the Dimroth rearrangement product [6], 5-mercapto-1,2,3-triazole 3, which reacts with starting 5-chloro-1,2,3-triazole 1 under the reaction conditions to give sulfide 4.
Synthesis of 5,6-Dihydro[1,2,3]thiadiazolo[5,4-e][1,4]oxazepin-8(4)-one. -A simple method for the synthesis of the previously unreported heterocyclic system (III) is developed. -(KROPOTINA, P. E.; GLUKHAREVA, T. V.; ISAKOVA, I. S.; ALEKSEEVA, E. A.; MORZHERIN*, Y. Y.; Chem. Heterocycl. Compd. (N. Y.) 44 (2008) 2, 233-234; Urals State Tech. Univ., Ekaterinburg 620002, Russia; Eng.) -C. Cyrus
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.