反应详情

Compound C3 (9.95 g, 52.0 mmol) and formamidine acetate (previously azeotroped with toluene, 13.5 g, 130 mmol) were combined in 2-butanol (160 mL) and heated at reflux for 3 hours. The reaction mixture was cooled and concentrated in vacuo. The residue was partitioned between ethyl acetate and saturated aqueous sodium bicarbonate solution, and the aqueous layer was extracted twice with ethyl acetate. The combined organic layers were dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was suspended in a mixture of heptane and ethyl acetate; filtration provided the product as a pale brown powder. Yield: 8.20 g, 37.6 mmol, 72%. LCMS m/z 219.3 [M+H]+. 1H NMR (500 MHz, DMSO-d6), presumed to be a mixture of rotamers and/or tautomers; characteristic peaks: δ 7.99-8.07 (m, 1.6H), 7.51 and 7.52 (2 s [1:1 ratio], 0.6H), 7.30 (dd, J=9.8, 9.8 Hz, 0.4H), 7.16-7.21 (m, 3.4H), 2.26 and 2.18 (2 s [1.6:1 ratio], 3H).

1. temperatureheated
2. temperatureat reflux for 3 hours
3. temperatureThe reaction mixture was cooled
4. concentrationconcentrated in vacuo
5. customThe residue was partitioned between ethyl acetate and saturated aqueous sodium bicarbonate solution
6. extractionthe aqueous layer was extracted twice with ethyl acetate
7. dry with materialThe combined organic layers were dried over magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated in vacuo
10. additionThe residue was suspended in a mixture of heptane and ethyl acetate
11. filtrationfiltration