Abstract The synthesis of the useful reagent for the preparation of guanidines, 3, 5-dimethyl- N-nitro-1-pyrazole-1-carboxamidine (DMNPC), has been optimised. A detailed protocol for using this reagent for the preparation in pure form of a range of guanidines via nitroguanidines is described. A comparison has been made regarding efficiency between DMNPC and the guanidinylating reagents N, N′-bis-Boc-1-pyrazole-1-carboxamidine (2) ...