反应详情

To a suspension of tert-butyl 5-(3-benzoylureido)-4-cyano-3-methylthiophene-2-carboxylate (example 64a) (18 g, 60.52 mmol) in EtOH (200 mL) was added NaOH (75 mL, 2N). The suspension became clear, and the mixture was heated to reflux for 30 min. After cooling to rt, the reaction was filtered, and the filtrate was cooled to 0° C. in an ice/water bath. The solution was neutralized with 10% acetic acid. The precipitated solid was collected by filtration, and heated in EtOH at 80° C. under N2 for 20 min. After cooling to rt, the product was collected by filtration and washed with 10% EtOH in H2O to yield tert-Butyl 4-amino-5-methyl-2-oxo-1,2-dihydrothieno[2,3-d]pyrimidine-6-carboxylate (10.73 g, 63%) as a brown solid. 1H NMR (400 MHz, DMSO-d6) δ 1.51 (s, 9H), 2.73 (s, 3H), 3.18 (s, 2H). MS 282.2 (MH+).

1. temperaturethe mixture was heated
2. temperatureto reflux for 30 min
3. filtrationthe reaction was filtered
4. temperaturethe filtrate was cooled to 0° C. in an ice/water bath
5. filtrationThe precipitated solid was collected by filtration
6. temperatureheated in EtOH at 80° C. under N2 for 20 min
7. temperatureAfter cooling to rt
8. filtrationthe product was collected by filtration
9. washwashed with 10% EtOH in H2O