Synthesis and characterization of fused imidazole heterocyclic selenoesters and their application for chemical detoxification of HgCl2Electronic supplementary information (ESI) available: CIF file, characterization, structure information of compounds 6a-i, 8-10 and HgSe. CCDC 1564403 (9). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7nj03908e

A new series of selenoester derivatives of imidazo[1,2- a ]pyridine and imidazo[1,2- a ]pyrimidine was synthesized under mild conditions using a simple methodology by the reaction of in situ generated sodium selenocarboxylates with 2-(chloromethyl)imidazo[1,2- a ]pyridine/pyrimidine ( 3a-b ) in water and ethanol. Excellent yields of phenyl/4-tolyl selenoesters of imidazo[1,2- a ]pyridine/pyrimidine ( 6a-b and 6e-f ) were obtained in water, whereas 4-methoxyphenyl/4-chlorophenyl/2-thienyl selenoesters of imidazo[1,2- a ]pyridine/pyrimidine ( 6c-d and 6g-i ) could only be synthesized in ethanol. Further, a series of reactions was carried out with 6e as a model compound in order to study the reaction behavior of selenoesters with mercury( ii ) chloride (HgCl 2 ). The deprotection of compound 6e by HgCl 2 was carried out in the presence of K 2 CO 3 under different conditions to obtain bis(imidazo[1,2- a ]pyrimidin-2-ylmethyl)selenide ( 8 ) and bis(imidazo[1,2- a ]pyrimidin-2-ylmethyl) diselenide ( 9 ) along with a small amount of less soluble bis((imidazo[1,2- a ]pyrimidin-2-ylmethyl)selanyl)mercury ( 10 ). The mercury-selenium complex 10 has a short shelf life and decomposes to give HgSe, which was characterized using EDX analysis. The structure of compound 9 was established with X-ray crystallography. The formation of HgSe indicates that the selenoester derivatives may prove useful in the treatment of HgCl 2 induced toxicity. Selenoester derivatives of imidazo[1,2- a ]pyridine/imidazo[1,2- a ]pyrimidine has been synthesized by the reaction of sodium selenocarboxylates with 2-(chloromethyl)imidazo[1,2- a ]pyridine/pyrimidine.