2,5-Pyridinediamine → HCID 178512279, compound

Participants

Reaction Steps

To a stirred mixture of the crude 2,5-diaminopyridine from Step 1 (0.0719 mol) and 100 ml of ethylene glycol dimethylether, under nitrogen, was added diphenylcyanocarbonimidate (17.1 g, 0.0718 mol) in one portion. This mixture was stirred at room temperature for 5 hours and concentrated in vacuo. The residue was triturated three times with Et2O. The solid residue (17.5 g) was stored under nitrogen until it was chromatographed in two portions: 5.0 g was chromatographed over 1000 ml of silica gel (230-400 mesh) by gravity elution with 5% MeOH/CHCl3 at a rate of 21 ml/minute to give 3.02 g of product; the other 12.5 g was chromatographed over 1000 ml of silica gel in the same manner (a poorer separation resulted at this loading) to give 7.31 g of product. The two lots were combined and crystallized from CH3CN to give 8.32 g (45.8%), m.p. 191°-192.5° C. of the titled product as amber needles. (An additional 0.98 g (5.4%) of dark amber needles was also obtained.)

Provenance & Evidence