Diisopropylethylamine → Methyl 4-(guanidinomethyl)benzoate

Participants

Reaction Steps

The mixture of 4-Aminomethyl-benzoic acid methyl ester HCl (15.7 g, 77.8 mmol) in DMF (85.6 mL) and DIPEA (29.5 mL, 171.2 mmol) was stirred at rt for 10 min. Pyrazole-1-carboxamidine HCl (12.55 g, 85.6 mmol) was added to the reaction mixture and then stirred at rt for 4 h to give clear solution. The reaction mixture was evaporated to dryness under vacuum. Saturated NaHCO3 solution (35 mL) was added to give nice suspension. The suspension was filtered and the filter cake was washed with cold water. The mother liquid was evaporated to dryness and then filtered. The two solids were combined and re-suspended over distilled H2O (50 ml). The filter cake was then washed with minimum quantities of cold H2O and ether to give 12.32 g white crystalline solid intermediate 1 (77% yield, M+1: 208 on MS).

Provenance & Evidence