2-Aminothiazole → 7-Methyl-5H-(1,3)thiazolo(3,2-a)pyrimidin-5-one

To a stirred solution of 2-aminothiazole (5.0 g, 49.930 mmol) in acetic acid (40 ml) was added ethyl acetoacetate (9.746 g, 74.90 mmol) at room temperature. The reaction mixture was heated to reflux for 12 h under nitrogen. The reaction mixture was allowed to cool to room temperature. The residue obtained after concentration of the reaction mixture was basified with saturated solution of sodium bicarbonate and diluted with ethyl acetate (500 ml). The organic layer was washed with brine, dried over anhydrous Na2SO4 and concentrated to afford a crude product which was purified by silica gel column chromatography using 1% methanol in chloroform to give 4.20 g of the product as a white solid; 1H NMR (300 MHz, CDCl3) δ 2.38 (s, 3H), 6.15 (s, 1H), 6.95 (d, J=4.8 Hz, 1H), 7.94 (d, J=4.8 Hz, 1H).

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for 12 h under nitrogen
3. customThe residue obtained after concentration of the reaction mixture
4. washThe organic layer was washed with brine
5. dry with materialdried over anhydrous Na2SO4
6. concentrationconcentrated
7. customto afford a crude product which
8. customwas purified by silica gel column chromatography

ORD record

ord-8a880dbfdf5c456fada5bae3f6438721

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08518955B2