Crystal structures of sulfonamide protected bicyclic guanidines: (<i>S</i>)-8-{[(<i>tert</i>-butyldimethylsilyl)oxy]methyl}-1-[(2,2,4,6,7-pentamethyl-2,3-dihydrobenzofuran-5-yl)sulfonyl]-1,3,4,6,7,8-hexahydro-2<i>H</i>-pyrimido[1,2-<i>a</i>]pyrimidin-1-ium trifluoromethanesulfonate and (<i>S</i>)-8-(iodomethyl)-1-tosyl-1,3,4,6,7,8-hexahydro-2<i>H</i>-pyrimido[1,2-<i>a</i>]pyrimidin-1-ium iodide
Acta crystallographica. Section E, Crystallographic communications