Hydrochloric Acid → HCID 20515428, compound

Participants

Reaction Steps

The solution of 61 g (0.19 mole) of potassium 1,4,5-trimethyl-3-[(2-nitrophenyl)amino]-1H-pyrrole-2-carboxylate obtained in Example 3 is adjusted to pH 2 with concentrated hydrochloric acid in a circulatory hydrogenation apparatus, and 0.5 g of palladium-on-charcoal (10%) is added. When the internal temperature reaches 40° C., hydrogenation is started. Sufficient hydrogen is metered to keep the internal temperature at about 100° C. When a sudden drop in the absorption of hydrogen is observed, the solution is allowed to cool; it is filtered under nitrogen, and the residue on the filter is washed 6 times with 5 ml of 1-methyl-2-pyrrolidone each time. The combined filtrates are concentrated to half their volume on a rotary evaporator. The resulting solution is subsequently processed in Example 5 without further purification.

Provenance & Evidence