Cyclization reactions of N1-(glycopyranosylamino) guanidines

Acetylation of N1-(aldopyranosylamino)guanidines 2–4 with d-gluco, d-galacto, and l-arabino configuration gives rise to N1-per(O-acetylglycopyranosylamino)-N1,N2,N3-triacetylguanidines 5–7 in good yields, as already stated by Feather and coworkers [Carbohydr. Res., 267 (1995) 17–25] for the gluco compound. The acylaminoguanidines prepared have been cyclized under mild conditions (boiling in ethanol or treatment with cold 0.1 M sodium methylate solution) to afford 3-amino-N1-glycopyranosyl-5-methyl-1H-1,2,4-triazoles. The structure of these pyranosyl nucleosides 9, 10, 12–14 is discussed using 1H and 13C NMR spectroscopy and mass spectrometry.