As a part of our program for synthesis and evaluation of the C-nucleosides as a new type of DNA unit, 1 we have been interested in the C-azanucleosides in which the endocyclic ribosyl ring oxygen is replaced with a nitrogen atom. To our knowledge, many modified nojirimycins, which function as effective glycosidase inhibitors, have been reported, 2 and only three C-azanucleosides3 have been synthesized as nojirimycin analogs. However, ...