Synthesis and Structural Aspects of (2,5)-1,3,4-Thiadiazolo and (3,5)-1,3,4-Thiadiazolino Thia Crown Ethers

Article abstract of DOI:10.1021/jo00391a045

A general route to (2,5)-1,3,4-thiadiazolo thia crown ethers 3, by the high-dilution reaction of 2,5-dimercapto-1,3,4-thiadiazole dipotassium salt 8 with oligoethylene glycol dihalides 9 in ethanol, is described.The reaction of 8 with bis<2-(2-bromoethoxy)ethyl> ether (9c) produced also small amounts of the 15-membered (3,5)-1,3,4-thiadiazolino thione macrocycle 10, which possesses a ring nitrogen pointing into the complexing cavity.The structures of the macrocycles were firmly established by 1H and 13C NMR spectroscopy.Macrocycle 10 was further characterized by a single-crystal X-ray diffraction study.