Ethyl isocyanate → 7-Bromo-2-(3-ethyl-ureido)-[1,2,4]triazolo[1,5-a]pyridine-5-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

2-Amino-7-bromo-[1,2,4]triazolo[1,5-a]pyridine-5-carboxylic acid ethyl ester (7) (760 mg, 2.66 mmol) was dissolved in THF/toluene (1:1, 40 mL), then ethyl isocyanate (1.89 g, 26.6 mmol) and a catalytic quantity of dibutyltindiacetate (10 drops) were added to the mixture. The reaction was then heated in a sealed tube at 100° C. for 15 h. This mixture was allowed to cool, then the solvents removed under reduced pressure to afford a solid which was purified by flash chromatography on silica 2% MeOH/CH2Cl2 as eluant) to give 7-bromo-2-(3-ethyl-ureido)-[1,2,4]triazolo[1,5-a]pyridine-5-carboxylic acid ethyl ester (8) LCMS (APCI+) 356, 358.

Provenance & Evidence