Hydrogen Bromide → 2-(Phenylacetyl)-2-hydrazinoimidazole

Participants

Reaction Steps

Phenylacetic acid (PAA), 0.037 moles (5g) was heated under reflux with an excess of SOCl2 for 60 minutes at a temperature of 75-80° C. After the reaction was completed, the excess SOCl2 was eliminated by vacuum evaporation, using a water pump (40-50° C.). This process was repeated two to three times, each time adding benzene to aid in elimination of SOCl2 and yielding phenylacetyl chloride (PAC). Then, 0.018 mole of 2-hydrazino-2-imidazoline.HBr (3.5 g) was suspended in ether and shaken with 2N NaOH (2-5 equivalents) on an ice bath, until it was completely dissolved. The PAC was then added dropwise very slowly from a funnel with vigorous shaking. Excess NaOH was present to drive the reaction to completion. After the addition of PAC, the mixture was stirred at 0C for an additional 15-30 minutes. The ether layer was washed with water, then with saturated NaHCO3. It was then dried over Na2SO4, filtered and was brought to complete dryness. The solid residue from the ether layer was then crystallized from an ethanol-water mixture (70-80% ethanol). The yield, was approximately 55% without subjecting the residual amide to further separation from the aqueous layer.

Provenance & Evidence