Synthesis of Unusually Substituted Ureas Starting from Bis(1,3,4‐thiadiazolo)‐1,3,5‐triazinium Halides via Oxo‐imidothioate Zwitterions

Abstract

Bis(1,3,4‐thiadiazolo)‐1,3,5‐triazinium halides 1 can be converted into various products such as guanidines or bis(azolyl)alkanes. However, they also react with hydroxide ions in aqueous solution to form novel heterocyclic‐substituted ureas 2a–i. The yields were increased from moderate to good or excellent in the presence of excess guanidine 3. The assumption that hydrogen‐bonded intermediate encounter complexes EC are formed gives a reasonable explanation for the observed reaction path. The molecular structures of some of the crystalline products 2 were determined by X‐ray analysis. Furthermore, with copper(II) a dinuclear complex 8 is formed with the two metal ions in a distorted octahedral environment; a water molecule acts as a bridging ligand between the CuII ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

1,3,4-Thiadiazole: Synthesis, Reactions, and Applications in Medicinal, Agricultural, and Materials Chemistry

“…At the forms of thione or imine, deprotonation of ring N–H makes the ring N atom vulnerable to alkylation or acylation or transforming to 1,3,4-thiadiazolium salts. Reactions are conducted with electrophiles such as halides (alkyl halides, benzyl halides, , allylic halides, hydroxyalkyl halides, and heterocyclic halides), trimethylsilylmethyl trifluoromethanesulfonate, formaldehyde, etc …”