September. 96, 1963 l-(ZMesyloxyethyl)-3-nitroguanidine (XIV) rapidly cyclized in pyridine at 40'to the imidazoline (XV), a precursor to the ethylenediamine system formed by a neighboring group reaction. In contrast, the sugar pyranoside, methyl 4, 6-0-benzylidene-3- deoxy-2-0-mesyl-3-(3-nitroguanidino)-c~,~-altropyranoside (XXII), failed to cyclize even in boiling pyridine. Anionic cyclization of XXII with a strong base led to the ...