Ethyl chloroformate → methyl {6-[(1-bromo-2-methylindolizin-3-yl)carbonyl]-2,4-dioxo-1,4-dihydroquinazolin-3(2H)-yl}acetate

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Reaction Steps

Ethyl chloroformate (1.3 mL; 13.5 mmol) is added dropwise to a solution of methyl N-({2-amino-5-[(1-bromo-2-methylindolizin-3-yl)carbonyl]phenyl}carbonyl)glycinate (2 g; 4.5 mmol) in 9 mL of pyridine at 0° C. After 15 min of stirring at ambient temperature, the reaction medium is concentrated to dryness and then diluted with ethyl acetate. The solution is washed with a 0.1 M hydrochloric acid solution and a saturated solution of sodium chloride, dried over sodium sulphate and concentrated to dryness. The yellow solid obtained is dissolved in 20 mL of anhydrous tetrahydrofuran and heated at reflux in the presence of diaza(1,3)bicyclo[5,4,0]undec-7-ene (1.35 mL; 9 mmol) for 1 h. The reaction medium is diluted with ethyl acetate, washed with a 0.1 M hydrochloric acid solution and a saturated solution of sodium chloride, dried over sodium sulphate and concentrated to dryness to give 2 g (95%) of a yellow powder.

Provenance & Evidence