Pyridine → Pyrrolo[2,1-f][1,2,4]triazine-2,4(1H,3H)-dione

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Reaction Conditions

Reaction Steps

Ethyl chloroformate (4.9 ml, 51 mmol) was added dropwise to a stirred mixture of 1-amino-1H-pyrrole-2-carboxamide (5.85 gm, 46.7 mmol, Journal of Heterocyclic Chemistry, 1994, 31, 781) and dry pyridine (4.2 mL, 51 mmol) in dry dioxane (48 mL) under N2 at RT. The mixture was heated at reflux for 1 hr and then the solvent was removed. The residue was heated at 155° C. for 17 hr and then allowed to cool to RT. The cooled residue was triturated with MeOH. The solid precipitate was collected by filtration and washed with cold MeOH to give 4.43 g 1A (63% yield). 1H NMR (DMSO-d6): 6.34 (br. s, 1H), 6.75 (br. s, 1H), 7.12 (br.s, 1H); MS: 152 (M+H)+; and RP HPLC ret. t.: 0.36 min (YMC Xterra S 7: 3.0×50 mm column, 2 min gradient, 5 mL/min.

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