The choice of medium suitable for the reaction of thiol groups with halogen derivatives in the synthesis of some purine and pyrimidine compounds. I. Synthesis of azathioprine.

Investigations were carried out using 6-mercaptopurine and 1-methyl-4-nitro-5-chloroimidazole as model compounds. The reaction kinetics were investigated by the UV spectroscopy at various time intervals. The investigations resulted in elaboration of an efficient synthesis of azathioprine which can be applied on an industrial scale in a yield of 80%.