A new reagent for solid and solution phase synthesis of protected guanidines from amines

A new reagent -4-nitro-1-H-pyrazole-1-[N, N'-bis(tert-butoxycarbonyl)]carboxamidine - has been developed to effect the rapid and efficient synthesis of bis(carbamate)-protected guanidines from primary and secondary amines. The reagent is a more electrophilic, and consequently more reactive, derivative of the literature reagent 1-H-pyrazole-1-[N, N'-bis(tert-butoxycarbonyl)]carboxamidine The increased reactivity of the new reagent affords it increased yields in solution and the need for fewer equivalents when guanylating resin-bound amines. (C) 1998 Elsevier Science Ltd. All rights reserved.