Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Two new reagents for the preparation of monoprotected guanidines from primary, secondary and aryl amines are reported. These protected guanidines can be liberated under acidic conditions and are amenable to a variety of synthetic manipulations. ... Two new reagents for the ...