Ethylenediamine → 5-(4,5-Dihydro-1H-imidazol-2-yl)-1,3-dimethyl-4-nitro-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

1,3-Dimethyl-4-nitro-5-pyrazolecarboxamide (28 g, 0.15 mol) is added to a solution of 38 g (0.2 mol) of triethyloxonium fluoroborate in 250 ml of methylenedichloride. The mixture is stirred at 20° C. for six hours and evaporated in vacuo. The residue is dissolved in 200 ml of absolute ethanol and 18 g (0.3 mol) of ethylenediamine is added. The yellow solution is stirred overnight at 20° C. and the solvent is evaporated in vacuo. The residue is stirred in 300 ml of 2N hydrochloric acid and filtered from 11.5 g (41%) of recovered starting amide. The filtrate is made basic with sodium carbonate and extracted with methylenedichloride. Evaporation of the methylenedichloride gives 9 g of 2-(1,3-dimethyl-4-nitro-5-pyrazolyl)imidazoline, mp 143°-145° C. from ethyl acetate-pet ether.

Provenance & Evidence