1-methyl-3-((methylamino)methyl)-1H-pyrazole-5-carbonitrilehydrochloride

1-Methyl-3-((methylamino)methyl)-1H-pyrazole-5-carbonitrile hydrochloride can be used as organic synthesis intermediates and pharmaceutical intermediates, mainly used in laboratory research and development processes and chemical production processes.

To compound 19 (7.0 kg, 26.1 mol) in DCM (30 L) at O℃ was added triethylamine (5.85 kg, 57.8 mol). The mixture was further cooled to -6°C then trifluoroacetic anhydride (5.85 kg, 27.8 mol) added over 90 minutes [temp kept 0 to 5°C], TLC assay showed the reaction was incomplete. Additional triethylamine (4.1 kg, 40.5 mol) and trifluoroacetic acid (4.1 kg, 19.5 mol) 10 were added over 2 hours until TLC showed complete reaction. The reaction mixture was quenched in to water (40 L) [temp to 23°C], The layers were separated and the aqueous re- extracted with DCM (8 L). The organic layers were sequentially washed with brine (7 L), filtered through a pad of silica (3 kg) and eluted with DCM (10 L). The filtrate was evaporated and chromatographed (9 kg silica, eluent 10-30% EtOAc in hexane). Product fractions were 15 evaporated and azeotroped with IPA to afford compound 20 (6.86 kg, ~94 wt%, 25.8 mol, 99%) as an orange oil. To compound 20 (6.86 kg, ~94 wt%, 25.8 mol) in IPA (35 L) at 17°C was added 37% hydrochloric acid (6.4 L, 77.4 mol). The mixture was heated to 35°C overnight then concentrated 20 to a moist solid and residual water azeotroped with additional IPA (8 L). The resulting moist solid was triturated with MTBE (12 L) at 45°C for 30 minutes then cooled to 20°C and filtered, washing with MTBE (5 L). The solids were dried under vacuum at 45°C to afford compound 21 (4.52 kg, 24.2 mol, 94%) as a white solid. 1H-NMR was consistent with desired product; mp 203-205°C; HPLC 99.3%.