Nitric Acid → HCID 178512464, compound

Participants

Reaction Steps

A freshly prepared solution of cyanamide (0.48 g, 11.43 mmol) in water (1 ml) was added to a solution of 5-aminoindole (1.00 g, 7.56 mmol) in ethanol (5 ml). The mixture was treated with concentrated nitric acid (69%, 0.51 ml, 7.90 mmol) and then refluxed for 18 h. A further quantity of cyanamide (0.24 g, 5.71 mmol) was added and then heating continued for 5 h. The reaction mixture was cooled to room temperature and evaporated in vacuo. The residue was triturated with ethyl acetate and the resulting precipitate collected and washed with ethyl acetate, then diethyl ether to give 5-guanidinoindole nitrate (1.67 g) as a brown solid m.p. 132-134°. δH (d6DMSO) 6.46 (1H, s), 6.92 (1H, dd, J 1.8, 8.5 Hz), 7.07 (4H, s), 7.43 (3H, m), 9.35 (1H, s) and 11.25 (1H, br s).

Provenance & Evidence